Document:

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                                                 Drager/Aspect Product Agreement
                                                         Drager-Aspect Vers1.doc
                                                                        20.04.99

                                                                    Exhibit 10.6

                          Aspect Medical Systems, Inc.
has requested that the marked portions of this agreement be granted confidential
  treatment pursuant to Rule 406 under the Securities Act of 1933, as amended.

                         Drager/Aspect Product Agreement

                                     between

                          Aspect Medical Systems, Inc.
                                 2 Vision Drive
                                     Natick
                                  MA 01760-2059
                                       USA

                         - hereinafter called "Aspect" -

                                       and

                           Drager Medizintechnik GmbH
                            Moislinger Allee 53 - 55
                                  23558 Lubeck
                                     Germany
                         - hereinafter called "Drager" -

         - Aspect and Drager together hereinafter called "the Parties" -

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                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                      - 2 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

Whereas Aspect has a long-standing tradition of designing, manufacturing and
distributing neuromonitors including the BIS (Bispectral Index) and Sensors for
neuromonitors.

Whereas Drager has a long-standing tradition of designing, manufacturing and
distributing medical equipment.

Whereas Drager is in the process of designing a new anesthesia workplace.

Whereas Drager wishes to integrate Aspect's BIS technology and to offer a
Drager-BIS-Module as an option into this and other workplace solutions for the
[**] and [**]

Whereas Aspect desires to sell and Drager desires to purchase, on the terms and
conditions set forth below in this Agreement, certain quantities of Aspect BIS
Module Kits and the required Sensors manufactured by Aspect.

Now, therefore,

in consideration of the mutual covenants, terms and conditions hereinafter
expressed, the Parties agree as follows:

1.       DEFINITIONS

1.1      The term "Aspect BIS Module Kits" shall mean Aspect's BIS Module Kits
         as further defined in the specifications in Exhibit A.

         The Parties hereto may change Exhibit A, to the extent it may then be
         necessary to reflect a subsequent modification made pursuant to Clause
         7 of this Agreement.

1.2      The term "Drager-BIS-Module" shall mean an Aspect BIS Module Kit that
         is integrated by Drager into a Drager Workplace.

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                                                 Drager/Aspect Product Agreement
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     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

1.3      The term "Aspect BIS Sensor" shall mean a single use disposable sensor
         for the use with the Aspect BIS Module Kits or the Aspect stand-alone
         BIS monitor.

1.4      The term [**] shall mean a [**] that has been [**] in accordance with
         [**] to [**] with the [**] Drager shall own all right, title, and
         interest in any modifications (the "[**]" made to the [**] to [**] the
         [**] for use in the [**]. The [**] will [**] Aspect BIS Module Kits
         sold by Aspect [**]. The [**] may [**] in [**] depending upon
         negotiations between the Parties (See Exhibit A, Section 1.5).

1.5      The term "Products" shall mean the Aspect BIS Module Kits, the
         Drager-BIS-Modules, the Aspect's BIS Sensors,[**].

1.6      The term "Drager Workplace" shall mean a combination of devices for
         [**] and [**] with a [**] and [**] to all [**]. The definition Drager
         Workplace includes a [**] and a [**] for [**].

2.       DRAGER'S RIGHTS TO PURCHASE AND SELL AND ASPECT'S RESPONSIBILITIES

2.1      Drager shall have the non-exclusive right during the term of this
         Agreement to purchase the Aspect BIS Module Kit for the sole purpose of
         integrating the Aspect BIS Module Kit into a Drager Workplace and
         reselling the finished Drager-BIS-Module worldwide.

         Subject to Clause 2.2 Drager shall have the exclusive right during the
         term of this Agreement to purchase the [**] for the [**] of [**] the
         [**] except in the USA. Aspect shall not have the right to manufacture
         or distribute the [**] to [**].

         Drager shall have the non-exclusive right during the term of this
         Agreement to purchase the Aspect BIS Sensor for the non-exclusive
         resale worldwide except in the USA.

2.2      Drager will sell the Drager-BIS-Module, the [**] and the Aspect BIS
         Sensor through its designated distribution network, and Aspect shall
         not with respect to the Drager-BIS-Module and the [**] make any sales
         promotion, shall not establish any branch, shall not have any supply
         depot or supply the Drager-BIS-Module or [**] to any party other than
         Drager.

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                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                      - 4 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

         It is understood, however, that in the event that Drager distributes
         [**] and [**] customers using [**] of the number of [**] used by [**].
         Drager shall then grant Aspect a non-exclusive royalty-free right and
         license under its rights to the [**] to [**] Aspect BIS Sensors that
         have been [**] for use with [**] to [**].

2.3      Aspect agrees to provide all reasonable help for Drager with respect to
         the design and/or integration of the Aspect BIS Module Kit into a new
         Drager Workplace.

2.4      Drager agrees [**] the [**] for an [**] equipment.

2.5      Aspect shall obtain any official approvals, permits, licenses and other
         consent required to sell Aspect's BIS Module Kit and Aspect's BIS
         Sensor worldwide, at such time and in such manner as determined by
         Aspect or required by Drager to serve reasonable commercial purposes of
         both companies. Drager shall receive copies of any such documents.

         Drager shall obtain any official approvals, permits, licenses and other
         consent required to sell Drager products worldwide, in such time and in
         such manner as determined by Drager. If necessary, Aspect shall receive
         copies of any such documents belonging to the Drager-BIS-Module and the
         [**]. Aspect will provide any reasonable support required by Drager to
         obtain the necessary approvals for the Drager-BIS-Module and the [**].

2.6      The parties intend to agree on a co-marketing concept for the Products.

3.       PRICES

3.1      The prices for Aspect BIS Module Kits and BIS Sensors shall be as set
         forth in Exhibit B hereto. The price per product is FOB, Boston as per
         Incoterms 1990. All prices for Aspect BIS Module Kits and BIS Sensors
         are exclusive of all taxes, levies and assessments imposed on such
         products purchased hereunder, excluding taxes based on Aspect's
         possession thereof prior to the originally scheduled delivery and taxes
         on Aspect's net income from the transaction. Drager intends to
         introduce the new Drager anesthesia workplace to the market [**].

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                                                 Drager/Aspect Product Agreement
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                                      - 5 -

  Confidential Materials omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

3.2      Prices, billing and all payments due hereunder shall be in US$.

3.3      September of each year with effect on 1st January of the following
         year, the prices for Aspect's BIS Module Kit set forth in Exhibit B may
         be adjusted by mutual Agreement. The first adjustment of prices may be
         made prior to October 1, 2002 with effect on January 1, 2003.

         The prices for Aspect's BIS Sensor will be based on the Sensor Price
         Schedule set forth in Exhibit B applied to the prevailing List Price of
         the BIS Sensor in the U.S.

         Any adjustments to BIS Sensor prices may only be made prior to October
         1 of each year for effect on January 1 of the following year. Assuming
         [**] are requested [**] by [**] will be based on the Sensor Price
         Schedule set forth in Exhibit B for the [**] to which will be [**]
         required to [**] the [**] (See also Exhibit A, Section 1.5).

4.       PURCHASE

4.1      All Products shall be ordered in writing, specifying the product type,
         number of units, desired delivery date and means of shipment. Purchase
         orders may be sent by facsimile machine. Such orders shall be
         considered to have been accepted by Aspect only upon Aspect's issuance
         of written acknowledgment confirming its acceptance of the purchase
         order. Aspect's acknowledgment may be sent by facsimile machine and
         shall state delivery date.

4.2      Ownership of, title to, and risk of loss with respect to any product
         sold to Drager hereunder shall pass to Drager upon delivery to carrier
         in Boston packed and ready for shipment to Drager. Aspect shall ship
         products in a manner consistent with Aspect's usual shipping practices.
         Transportation and shipping charges from Boston, including costs
         incurred by Aspect relating to packing, storage, documentation and
         similar items which result from special shipping instructions of
         Drager, and the cost of any insurance which Drager may request in
         connection with the products, shall be added to the price stated on
         invoices and shall be paid by Drager at the time that payment of the
         purchase price for such products is due and payable.

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                                                 Drager/Aspect Product Agreement
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                                      - 6 -

  Confidential Materials omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

4.3      Drager shall have the right to handle the purchase of Products via
         another company belonging to the Drager Group. Drager will inform
         Aspect in writing with respect to such decision. Drager will further
         ensure that this company will adhere to the provisions of this
         Agreement.

5.       FORECAST, DELIVERY TIME

5.1      Drager shall provide a non-binding quarterly rolling forecast for a
         minimum of the successive two quarters.

5.2      Aspect shall ship the Products in lots of [**] units.

5.3      Aspect shall ship Aspect BIS Module Kits within (eight) 8 weeks of its
         receipt of purchase orders therefore, assuming the quantity ordered is
         reasonably consistent with the forecast.

5.4      Aspect shall ship [**] within (four) 4 weeks of its receipt of purchase
         orders therefore, assuming the quantity ordered is reasonably
         consistent with the forecast.

5.5      In the event of cancellation of any purchase order, Drager will be
         liable to Aspect for the payment of reasonable cancellation charges.

6.       PAYMENT; INSPECTIONS; RETURNS

6.1      All purchases hereunder shall be paid within thirty (30) days from date
         of invoice to Drager.

6.2      All Products received by Drager shall conform in all material respects
         to the specifications set forth in Exhibit A.

         Receiving inspection by Drager may be performed on a sampling basis
         which shall be in accordance with the Testing Specifications as
         established in Exhibit C. Exhibit C will be negotiated later.

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                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                      - 7 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

         Acceptance by Drager on a sampling basis shall not prejudice or
         restrict the right of Drager to accumulate and return at Aspect's
         expense for full credit or replacement (freight and insurance prepaid
         to Drager) non-conforming Products discovered during Drager's
         inspection process, which in no event shall extend beyond the warranty
         period provided in Clause 8. Any such return must be made within 30
         days of discovery of any such Products' nonconformance by Drager.

         Aspect must be given the opportunity to inspect and/or correct Products
         for which Drager shall request credit or replacement to enable Aspect
         to determine for itself that said Products do not meet specifications,
         and such credit or replacement shall be made by Aspect only if and when
         it determines that Products do not meet specifications. No Product may
         be returned without Aspect's approval, which, subject to the last
         sentence of the preceding Paragraph under this Clause 6.2, shall not be
         unreasonably withheld.

7.       MODIFICATION OF PRODUCTS

7.1.     Aspect shall inform Drager

         (a)      about planned modifications of Aspect's BIS Module Kit,
                  Aspect's BIS Sensors, [**] and modifications relating to BIS
                  of Aspect's stand alone Monitor,

         (b)      of any modification which will affect the approval of the
                  Products or the Drager Workplace and /or the proper function
                  within the Drager Workplace.

         In case (b), Aspect shall not be allowed to modify Aspect's BIS Module
         Kit, Aspect's BIS Sensor or [**] sold to Drager without Drager's prior
         written consent. Additionally Drager shall have the right to decide if
         Drager wishes to take over the modification. If Drager refuses to take
         over the modification, Aspect shall be obliged to deliver the
         unmodified Aspect BIS Module Kit, Aspect's BIS Sensors and [**] for a
         period of eighteen (18) months beginning with the date Drager announces
         its decision. After this eighteen-months period Aspect can cease to
         deliver the unmodified Aspect BIS Module Kit, Aspect's BIS Sensors or
         [**]. In the event that Aspect believes that a modification or
         improvement relates to patient safety, Drager will accept these
         modifications under the condition that Aspect will agree to repair or
         replace Aspect's BIS Module Kits, Aspect's BIS Sensors or [**]
         previously provided to Drager or Drager customers at no charge.

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                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                      - 8 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

7.2.     Drager shall promptly inform Aspect of any proposed modification which
         will affect Aspect product approval.

7.3      Aspect agrees in principle to [**] of the [**] and [**] the [**] is
         [**]. Aspect and Drager must agree on a mutually-acceptable time
         schedule and on a mutually-acceptable price for the [**] Aspect shall
         own all right title and interest in any [**] to the Aspect BIS Module
         Kit pursuant to this Section 7.3.

8.       WARRANTY

8.1      Subject to Exhibit E, Aspect hereby warrants to Drager that for a
         period of twelve (12) months after each Product is sold by Drager, or
         an authorized Drager Distributor and delivered to an end user, or
         eighteen (18) months after such Products are received from Aspect by
         Drager, whichever period shall be shorter, that such Products will
         conform in all material respects to the specifications set forth in
         Exhibit A and be free from any defects in workmanship and materials. In
         the event of a breach of the warranty under this Section, Aspect's
         responsibility and Drager's remedy shall first be repair or replacement
         of the Product, at Aspect's option. In the event that, after Aspect has
         attempted to repair or replace the product, the Product does not
         conform to the warranty provided in this Section 8.1, Aspect will
         refund the purchase price for such Product. This paragraph summarizes
         Aspect's responsibility and Drager's sole remedy with respect to the
         warranty set forth in this Section 8.1.

8.2      Notwithstanding the foregoing, Aspect's warranty as set forth above
         does not cover:

         (i)      defects emanating from improper or unauthorized use or
                  maintenance of such products by Drager or any subsequent
                  purchaser thereof;

         (ii)     normal deterioration or normal wear and tear;

         (iii)    disposable items such as the [**] Aspect BIS Sensor after the
                  expiration date marked on the Sensor packaging

         (iv)     catastrophe, fault or negligence of Drager or anyone claiming
                  through or on behalf of Drager; or

         (v)      subject to Exhibit A, causes external to the Products
                  including without limitation power or air conditioning
                  failure.

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                                                 Drager/Aspect Product Agreement
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                                      - 9 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

8.3      THE PROVISIONS OF THE FOREGOING WARRANTIES ARE IN LIEU OF ANY OTHER
         WARRANTY, WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL (INCLUDING ANY
         WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE).

9.       QUALITY ASSURANCE

         Aspect shall adhere to a quality assurance system in accordance with
         the Quality Assurance Agreement as established in Exhibit D.

10.      SERVICE

10.1     Drager assumes full responsibility to render service with respect to
         the maintenance, repair, or replacement of Products, accessory items,
         or parts therefor sold by Drager.

10.2     Aspect agrees to supply Drager, at Drager's expense, with any and all
         special tools and equipment reasonably required for Drager to service,
         maintain or test the Products sold hereunder. Drager agrees to make
         payment for such items to Aspect within thirty (30) days from the date
         of invoice.

10.3     Aspect shall adhere to the Service Agreement as per Exhibit E. Exhibit
         E will be negotiated later.

11.      TRAINING AND DOCUMENTS

         Aspect personnel shall be made available free of charge for a
         reasonable number of training sessions reasonably required by Drager
         with respect to the sales and application know-how, the maintenance,
         repair or replacement of the Products, or parts therefore.

         Aspect will supply Drager free of charge with a reasonable quantity of
         technical, sales and application materials for internal purposes in
         English and German (if available) such as manuals and other technical
         materials relating to the Aspect BIS Module Kits and Aspect's BIS
         Sensors. Aspect will supply Drager at cost price with a reasonable
         quantity of catalogues and literature relating to the Aspect BIS Module
         Kits and Aspect's BIS Sensors.

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                                                 Drager/Aspect Product Agreement
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                                     - 10 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

         Drager agrees to provide, at its own expense, and subject to Aspect's
         prior written approval, translation and printing of technical, sales,
         operation and service materials in the language(s) commonly used in the
         areas where Drager will sell the Products.

         Drager Lubeck will coordinate training and flow of information for all
         Drager participants. Training will be held in English language.

12.      REPLACEMENT PARTS

         Subject to Exhibit E, Aspect agrees to supply Drager with replacement
         parts for the Aspect BIS Module Kits sold hereunder for a period of ten
         (10) years after the date of the last sale of Aspect BIS Module Kits by
         Aspect to Drager hereunder. Prices for the replacement parts will be
         set by Aspect in accordance with Clause 3. Drager shall make payment of
         the replacement parts supplied hereunder within thirty (30) days from
         the date of invoice.

13.      PATENT INDEMNITY

13.1     (a) Except as provided below, Aspect shall defend and indemnify Drager
         from and against any damages, liabilities, costs and expenses
         (including reasonable attorneys' fees) arising out of any claim that
         the Aspect BIS Module, the Aspect BIS Sensor or the [**] infringe a
         valid patent or copyright or misappropriates a trade secret of a third
         party, provided that (i) Drager shall have promptly provided Aspect
         written notice thereof and reasonable cooperation, information, and
         assistance in connection therewith, and (ii) Aspect shall have sole
         control and authority with respect to the defense, settlement, or
         compromise thereof. Should any Product become or, in Aspect's opinion,
         be likely to become the subject of an injunction preventing its use as
         contemplated herein, Aspect may, at its option, (1) procure for Drager
         the right to continue using such product, (2) replace or modify such
         product so that it becomes non-infringing, or, if (1) and (2) are not
         reasonably available to Aspect after consultation in good faith with
         Drager, then (3) terminate Drager's rights to the allegedly infringing
         product and refund to Drager the amount which Drager has paid to Aspect
         for such products which are in the possession of Drager or its
         subdistributors. Drager will immediately inform Aspect as soon as
         Drager becomes aware of any threatened or actual liability claim by a
         third party relating to the Aspect BIS Module, the [**] and the Aspect
         BIS Sensor.

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                                                 Drager/Aspect Product Agreement
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                                     - 11 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

         (b) Aspect shall have no liability or obligation to Drager hereunder
         with respect to any patent, copyright or trade secret infringement or
         claim thereof based upon (i) use of the Products by Drager in
         combination with devices or products other than the Drager Workplace,
         (ii) use of the Products in an application or environment for which
         such Products were not designed or contemplated, (iii) modifications,
         alterations or enhancements of the Products not created by or for
         Aspect, or (iv) any claims of infringement of a patent, copyright or
         trade secret in which Drager or any affiliate of Drager has an
         interest. Drager shall indemnify and hold Aspect harmless from all
         costs, damages and expenses (including reasonable attorneys' fees)
         arising from any claim enumerated in clauses (i) through (iv) above,
         provided that (i) Aspect shall have promptly provided Drager written
         notice thereof and reasonable cooperation, information, and assistance
         in connection therewith, and (ii) Drager shall have sole-control and
         authority with respect to the defense, settlement or compromise
         thereof. Aspect will immediately inform Drager as soon as Aspect
         becomes aware of any threatened or actual liability claim by a third
         party relating to Clause (iv) above.

         (c) the foregoing states the entire liability of the Parties with
         respect to infringement of patents, copyrights and trade secrets by the
         Products or any part thereof or by their operation.

13.2     The obligation of the Parties hereto as set forth in this Clause 13
         shall continue notwithstanding the termination of this Agreement.

14.      TRADEMARK

         Any Drager-BIS-Module or [**] sold by Drager under this Agreement shall
         bear the trademark of Drager.

         Drager is required to mark the Drager-BIS-Module and [**] additionally
         to the Drager trademark with the Aspect BIS(TM) trademark as approved
         by Aspect and in accordance with the following provisions:

(a)      Ownership. Drager acknowledges and agrees that Aspect is the sole and
         exclusive owner of all right, title and interest in and to the
         following trademarks (the "Aspect Trademarks"): "Aspect", "BIS", "BIS
         Sensor".

         Drager recognizes the value of the Aspect Trademarks and the good will
         associated with the Aspect Trademarks. Drager agrees that its use of
         the

<PAGE>   12
                                                 Drager/Aspect Product Agreement
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                                     - 12 -

         Aspect Trademarks and any good will arising therefrom shall inure to
         the benefit of Aspect. Nothing contained herein shall create, nor shall
         be construed as an assignment of, any right, title or interest in or to
         the Aspect Trademarks to Drager, other than the grant of a license in
         Section 14(c) below; it being acknowledged and agreed that all other
         right, title and interest in and to the Aspect Trademarks is expressly
         reserved by Aspect. Drager shall keep the Aspect Trademarks free from
         all liens, mortgages or other encumbrances. Drager agrees that it will
         not attack or otherwise challenge the title, validity or any other
         rights of Aspect in or to the Aspect Trademarks.

(b)      Notice. All Products that use the Aspect Trademarks shall be
         accompanied, where reasonable and appropriate, by a proprietary notice
         with respect to Aspect consisting of the following elements:

         1. The statement "[insert trademark(s)] is a proprietary trademark(s)
         of Aspect."

         2. Drager will include the "(TM)" or "(R)" symbol, as instructed by
         Aspect, a reasonable time before the first prominent use of the Aspect
         Trademark in the Products.

         3. Drager shall reproduce copyright and trademark notices of Aspect in
         the relating documents.

(c)      License. Aspect hereby grants to Drager a nonexclusive, worldwide,
         royalty-free license (without the right to sublicense) to use the
         Aspect Trademarks to designate and promote Products. Drager shall have
         no other right to use, display or utilize the Aspect Trademarks for any
         other purpose or in any other manner.

(d)      Quality Standards. Upon reasonable notice and request, Aspect may
         inspect copies of the Products, advertising and promotional materials
         on which the Aspect Trademarks are used so that Aspect may monitor
         compliance with this Agreement. Quality standards are further described
         in Exhibit D to this Agreement.

(e)      Protection and Infringement. Drager agrees to cooperate with and assist
         Aspect in obtaining, maintaining, protecting, enforcing and defending
         Aspect proprietary rights in and to the Aspect Trademarks. In the event
         that Drager learns of any infringement, threatened infringement or
         passing-off of the Aspect Trademarks, or that any third party claims or
         alleges that the Aspect Trademarks infringe the rights of the third
         party or are otherwise liable to

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                                                 Drager/Aspect Product Agreement
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                                     - 13 -

         cause deception or confusion to the public, Drager shall be required to
         notify Aspect giving the particulars thereof, and Drager shall provide
         necessary information and assistance to Aspect in the event that Aspect
         decides that proceedings should be commenced.

(f)      Termination. In addition to the termination rights set forth in Section
         21 hereof, in the event that Drager is in material breach of any
         provision of this Section 14, Aspect may, upon 30 days written notice,
         terminate the license granted in Section 14(c) if Drager does not cure
         such breach or default within such 30-day period. The parties recognize
         that curing such breach or default may require development of a new
         version of the Product. If this is the case, then Drager will be deemed
         to have cured such breach or default if, within the 30-day cure period,
         Drager presents to Aspect a plan for revision of the Product that will
         cure such breach or default, such plan is reasonably acceptable to
         Aspect, and such revision is released and distributed within three
         months following written notice of such breach or default.

         In addition to the provisions of Section 21 hereof, upon termination of
         the license granted in Section 14(c), or upon termination of this
         Agreement, for whatever cause except Sections 21.5, 21.6 and 21.7:

         1.       Drager shall immediately cease and desist from any further use
                  of the Aspect Trademarks and any trademarks confusingly
                  similar thereto, either directly or indirectly;

         2.       All rights in the Aspect Trademarks granted to Drager
                  hereunder shall immediately revert to Aspect;

         3.       In the event that this Agreement is terminated for any reason
                  other than a material breach or material default by Drager,
                  Drager shall have a period of 30 days thereafter to dispose of
                  all of the unsold Products bearing the Aspect Trademarks and
                  advertising and promotional materials relating thereto which
                  had been completed by it prior to such termination, provided
                  such Products and materials were in the process of manufacture
                  more than 30 days before such termination.

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                                                 Drager/Aspect Product Agreement
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     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

15.      PRODUCT RECALL PROGRAM

         In the event of any recall of the Product by Aspect or required by
         Drager for safety or efficacy reasons resulting from Aspect's failure
         to supply any BIS Module Kits, Aspect BIS Sensors, or [**] that (1)
         conform in all material respects to the specifications set forth in
         Exhibit A or (2) are free from defects in workmanship and materials,
         Aspect agrees to repair or replace all recalled Products previously
         supplied to Drager at no expense to Drager. Aspect also agrees to
         consult with Drager to establish a reasonable process for managing the
         recall. Drager will maintain all necessary sales records to facilitate
         the recall.

16.      PRODUCT LIABILITY

16.1     Aspect will indemnify, protect, and save Drager harmless from all
         claims, demands, suit, or actions for damages to property or person
         which may be sustained by any third party, and which are caused by any
         defect or deficiency in the design or manufacture of any of the
         Products sold to Drager under this Agreement.

         The foregoing indemnity shall survive the expiration or termination of
         this Agreement, but Aspect shall not be responsible for any loss or
         damage caused by acts or omissions of Drager. Aspect shall have no
         liability or responsibility of any kind to Drager under this Clause 16
         for any claims, demands, suits, or actions unless Aspect shall have
         been notified within 30 days time following notification to Drager of
         any such claims, demands, suits, or actions and shall have an adequate
         opportunity to defend. Aspect shall have the sole control and authority
         with respect to the defense, settlement or compromise thereof.

         Should Drager desire to have its own counsel participate in any such
         action or suit, the cost of such counsel shall be borne exclusively by
         Drager. The obligation of the Parties set forth in this Clause 16 shall
         continue notwithstanding the termination of this Agreement.

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                                                 Drager/Aspect Product Agreement
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     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

16.2     Drager will indemnify, protect, and save Aspect harmless from all
         claims, demands, suit, or actions for damages to property or person
         which may be sustained by any third party and which are caused by any
         defect or deficiency in the design or manufacture of the Drager
         Workplace or of that portion of the Drager-BIS-Module developed or
         manufactured by Drager, or which relate to the failure of Drager to
         incorporate the Aspect BIS Module Kit within the Drager-BIS-Module in
         accordance with the technical information provided by Aspect, or
         Drager's activities in connection with use or sale of the Products.

         The foregoing indemnity shall survive the expiration or termination of
         this Agreement, but Drager shall not be responsible for any loss or
         damage caused by acts or omissions of Aspect. Drager shall have no
         liability or responsibility of any kind to Aspect under this Clause 16
         for any claims, demands, suits, or actions unless Drager shall have
         been notified within [**] time following notification to Aspect of any
         such claims, demands, suits, or actions and shall have an adequate
         opportunity to defend. Drager shall have sole control and authority
         with respect to the defense, settlement or compromise thereof.

         Should Aspect desire to have its own counsel participate in any such
         action or suit, the cost of such counsel shall be borne exclusively by
         Aspect. The obligation of the Parties set forth in this Clause 16 shall
         continue notwithstanding the termination of this Agreement.

17.      [**] PROJECT

17.1     It is Drager's intention that the Product will become the [**] for
         monitoring the level of hypnosis in Drager anesthesia Workplaces and it
         is [**] of the [**]. However, Drager shall be free to provide
         alternative technology in the event that

         (i)      necessary regulatory approvals for the Products are withdrawn
                  and will not be granted during a [**] period after withdrawn,

         (ii)     approvals have not been granted within a period of [**]
                  following the completion of the Drager-BIS-Module and
                  submission of the necessary requests for approvals to the
                  appropriate regulatory agencies

         (iii)    Aspect is unable to supply Aspect BIS Module Kits in
                  accordance with the specifications and is unable to
                  reinstitute supply within [**] days of written notification

<PAGE>   16
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 16 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

         (iv)     Aspect's market share worldwide for monitoring the effect of
                  anesthesia on the brain with BIS [**].

         (v)      Aspect stops or reduces marketing and product improvement
                  activities materially below the level currently performed.

17.2     Drager may offer in Drager anesthesia workplaces and in other Drager
         products complementary parameters [**] to Aspect's Bispectral Index.
         Any parameter claimed to be a measure of the hypnotic effect of
         anesthetics based on processing of the continuous EEG, is considered to
         be [**] will only be [**] to the BIS.

         Notwithstanding the foregoing, Drager is free to offer EEG parameters
         based on the continuous EEG such as median frequency, spectral edge
         frequency, compressed spectral array (CSA) and/or density spectral
         array (DSA), and may also offer evoked potentials, in addition to the
         BIS.

17.3     In the event that the Aspect's BIS Module Kit sold to Drager contains
         applications unique to Drager Aspect shall for the term of this
         Agreement and for [**] after its termination refrain from selling
         similar products to any third party.

18.      FORCE MAJEURE

         Neither Aspect nor Drager shall be liable for any delay in, or failure
         of, performance hereunder due to any contingency reasonably beyond its
         control, rendering performance commercially unreasonable including, but
         not limited to, an act of God, war (declared or undeclared),
         mobilization, riot, strike, labor dispute, fire, flood, shortages, or
         failure or delays of energy, materials, supplies or equipment,
         unavailability of transportation, goods or services, transportation
         embargoes or delays, or breakdowns in machinery or equipment,
         governmental restrictions or actions but shall not include any royalty
         or other payment imposed or agreed to by Aspect or Drager resulting
         from a third party claim of intellectual property right infringement or
         violation as further described in Clause 13; provided, however, that
         the Party affected shall exert its reasonable best efforts to eliminate
         or cure or overcome any of such causes and to resume performance of its
         covenants.

<PAGE>   17
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 17 -

19.      SECRECY

19.1     If marked as "Confidential Information", Drager and Aspect are each
         obliged to preserve in strict confidence any trade secrets,
         confidential information and technical information of the other Party
         and to refrain from disclosing, during the period of this Agreement and
         any time after expiration of this Agreement, any such information to
         third parties. Notwithstanding the foregoing, information which is
         orally or visually disclosed to the recipient by the disclosing party,
         or is disclosed in writing without an appropriate letter, proprietary
         stamp or legend, shall constitute Confidential Information if the
         disclosing party, within thirty (30) days after such disclosure,
         delivers to the recipient a written document or documents describing
         such Confidential Information and referencing the place and date of
         such oral, visual or written disclosure and the names of the employees
         or officers of the recipient to whom such disclosure was made.

         Both Parties represent and warrant that they have exercised, and will
         continue to exercise the same standard of due care in hiring,
         supervising and selecting those employees to whom they disclose such
         confidential information, so that the confidentiality of all such
         information is protected. No such confidential information disclosed by
         either party to the other in connection with this Agreement shall be
         disclosed to any person or entity other than the recipient's employees
         and contractors directly involved with the recipient's use of such
         information who are bound by written agreement to protect the
         confidentiality of such information, and such information shall be
         otherwise protected by the recipient from disclosure to others with the
         same degree of care accorded to its own proprietary information.

19.2     The Parties' obligation of non-disclosure shall not apply with respect
         to such information, which

         (1)      is already known to the receiving Party before disclosure by
                  the divulging Party, providing that the receiving Party has
                  written records to substantiate its knowledge; or

         (2)      is in the public domain at the time of disclosure to the
                  receiving Party or, after such disclosure, enters into the
                  public domain through no fault of the receiving Party;

         (3)      is independently developed by the receiving Party without
                  reference to or reliance on the Confidential Information; or

<PAGE>   18
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 18 -

         (4)      is lawfully disclosed to the receiving Party by a third party
                  under circumstances permitting its unrestricted disclosure by
                  the receiving party.

         Upon termination of this Agreement, each party shall promptly deliver
         to the other all confidential information of the other party in the
         possession or control of such party and all copies thereof. The
         obligations under this Section 19 shall continue for both parties for a
         period of 3 years after delivery by Aspect to Drager of the last
         Product under this Agreement.

20.      RELATIONSHIP BETWEEN THE PARTIES

         During the term hereof, the relationship of the Parties is that of
         seller (Aspect) and buyer (Drager).

         Nothing herein contained shall be deemed to authorize or empower either
         Party, its affiliates, its agents or employees, to act as agent for the
         other Party or conduct business in the name, or for the account of the
         other Party or any of its affiliates or otherwise bind it or them in
         any manner.

21.      TERM AND TERMINATION

21.1     This Agreement shall come into force when it has been duly signed by
         both Parties and shall remain in force until December 31, 2005, unless
         earlier terminated in accordance with the provisions hereof.

         It shall be automatically renewed thereafter for additional periods of
         one (1) calendar year each unless one Party gives at least twelve (12)
         calendar months prior to the end of the original term hereof and each
         one (1) year period thereafter a written notice to the other Party of
         its intention to terminate. First notice of termination may not be
         given until [**].

<PAGE>   19
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 19 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

21.2     Aspect shall have the right to terminate this Agreement, effective upon
         the delivery of written notice to Drager, in the event Drager fails to
         make any payment when due to Aspect pursuant to this Agreement or any
         invoice for Products. Aspect will [**] to Drager after Drager's receipt
         of Aspect's written demand for payment, provided Aspect has submitted
         proof of delivery in order to rectify any payment problem or
         discrepancy and has stated that the Agreement will be terminated if
         Drager fails to make the due payment within the [**].

21.3     Furthermore, either Party may terminate this Agreement if the other
         Party commits any material breach of its obligations hereunder (other
         than payment defaults addressed in Clauses 21.2 hereof) and such breach
         is not resolved within [**] after written notice thereof is given to
         the Party in breach of this Agreement.

21.4     Should Drager or Aspect at any time during the period of this Agreement
         be adjudged bankrupt or insolvent, or have a Receiver appointed in
         respect of its assets or shall make any arrangement or composition with
         its creditors or shall be wound up, whether voluntarily or
         compulsorily, or make a general assignment for the benefit of
         creditors, then in such event the other Party may, at its option,
         terminate this Agreement effective upon giving notice thereof in
         writing to the other. In the event either Drager or Aspect exercises
         this option, said Party shall incur no liability or obligation with
         respect to said termination.

21.5     In the event of the merger, consolidation or sale of substantially all
         assets of Aspect to a competitor of Drager, Drager may, at its option,
         terminate Section 17 of this Agreement effective upon giving notice
         thereof in writing to Aspect. In the event Drager wishes to exercise
         this option, Drager shall do so within 30 days following written notice
         from Aspect of the merger, consolidation or sale of substantially all
         assets of Aspect, and neither Aspect (or its successors) or Drager
         shall incur liability or obligation with respect to said termination.

         In the event of the merger, consolidation or sale of substantially all
         assets of Drager to a company outside of the Drager-Group, Aspect may,
         at its option, terminate this Agreement effective upon giving notice
         thereof in writing to Drager. In the event Aspect exercises this
         option, Aspect shall do so within 30 days following written notice from
         Drager of the merger, consolidation or sale of substantially all assets
         of Drager, and neither Drager (or its successors) or Aspect shall incur
         liability or obligation with respect to said termination.

<PAGE>   20
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 20 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

21.6     Subject to the second paragraph of this Section 21.6, in the event of
         termination the Parties agree that Drager shall have the right to
         purchase the Aspect BIS Module Kit and the [**] for [**] following
         termination of the Agreement or Aspect BIS Sensors for [**] following
         termination of the Agreement.

         In the event of termination of the Agreement as a result of a material
         breach of the Agreement by Drager in accordance with Sections 21.2 or
         Section 21.3, Drager shall not be permitted to continue to purchase
         [**] Aspect BIS Sensors beyond [**] termination of the Agreement. If
         Aspect intends to [**] of the [**] the Parties shall [**] in good
         faith.

21.7     In the event of termination, the Parties further agree to finalize
         current sales projects. A complete list of these sales projects has to
         be exchanged by the Parties no later than fourteen (14) days after the
         termination.

21.8     Due to the fact that some Exhibits of this Agreement will be negotiated
         later each Party shall have the right to terminate this Agreement if
         the parties cannot reasonably agree on the content of one of these
         Exhibits.

22.      MISCELLANEOUS

22.1     This Agreement shall not be assignable either in whole or in part
         without the prior written consent of the other Party except, subject to
         Section 21.5, to a party that acquires all or substantially all of
         either Parties' business by merger, sale of assets, or otherwise.

22.2     Subject to Clause 21.1 hereof, this Agreement shall inure to the
         benefit of and be binding upon the Parties hereto.

22.3     The headings used herein are for ease of reference only and are not to
         be used in interpretation or construction of this Agreement.

22.4     The provisions of this Agreement and its Exhibits shall not be
         extended, varied, changed, modified or supplemented other than by
         agreement in writing signed by the Parties hereto.

22.5     In the event of any inconsistency or conflict between the provisions of
         this Agreement and any Purchase Order or other document, the provisions
         of this Agreement shall prevail.

<PAGE>   21
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 21 -

22.6     All notices or other communications which shall or may be given
         pursuant to this Agreement shall be in writing in the English language
         and shall be delivered by personal delivery, certified mail, or telefax
         at the address set forth below, or at such other address as such party
         may hereafter designate in writing as the appropriate address for the
         receipt of such notice.

           To Aspect at:

              Aspect Medical Systems, Inc.
              2 Vision Drive
              Natick
              MA 01760-2059
              USA
              Tel.: 508-647-2072
              Fax:   508-647-2059
              Attention: J.Breckenridge Eagle

           To Drager at:

              Drager Medizintechnik GmbH
              Moislinger Allee 53 - 55
              D-23558 Lubeck
              Federal Republic of Germany
              Tel.:  451-882-2295
              Fax:   451-882-2793
              Attention: Business Unit Anaesthesia, Swen Grunitz-Post

         All notices shall be deemed served on the day on which personally
         served, or of by certified mail, or telefax on the date of actual
         receipt.

21.7     The waiver by either Party hereto of any default hereunder or of any
         breach of any covenant, agreement or condition contained herein shall
         not be construed to constitute a waiver of any other default or breach
         hereof whether similar or otherwise.

22.8     If any provision of this Agreement should be held unenforceable, or
         illegal with respect to any jurisdiction, it (i) shall be deemed
         severable from the other provisions which shall remain valid and
         enforceable; and (ii) shall remain in effect in other jurisdiction
         where such provision is otherwise enforceable and legal.

<PAGE>   22
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 22 -

         This Agreement may be executed simultaneously in multiple counterparts,
         each of which shall be deemed an original and all of which together
         shall constitute one and the same agreement.

22.10    Neither party shall have the right to sublicense any of the rights or
         licenses granted under this agreement outside the company group without
         the other's prior written consent.

21.11    Compliance with Laws. Drager shall comply with all laws, legislation,
         rules, regulations, governmental requirements and industry standards
         with respect to the Products, and the performance by Drager of its
         obligations hereunder, existing in any jurisdiction into which Drager
         directly or indirectly distributes the Products. Aspect shall inform
         Drager if export of Aspect's BIS Module Kit or Aspect's Sensors are
         restricted to any country or require certain permission in any country.

21.12    IN THE EVENT THAT U.S. LAW IS APPLIED TO THIS AGREEMENT, ASPECT OR
         DRAGER SHALL NOT BE LIABLE FOR ANY LOSS OF DATA, LOSS OF PROFITS OR
         LOSS OF USE OF THE PRODUCTS OR FOR ANY INDIRECT DAMAGES OF ANY KIND
         (WHETHER SPECIAL, INCIDENTAL, CONSEQUENTIAL OR OTHER INDIRECT DAMAGES)
         IN CONNECTION WITH THE USE OR PERFORMANCE OF THE PRODUCTS.

23.      APPLICABLE LAW

         This Agreement shall be governed, construed and interpreted in
         accordance with the laws of Switzerland, without regard to its conflict
         of laws principles.

         The United Nations Convention on contracts for the International Sale
         of Goods shall not apply.

24.      DISPUTE SETTLEMENT, PLACE OF JURISDICTION

24.1     The Parties shall try to settle any dispute arising in connection with
         this present Agreement amicably. In case of a local sales conflict a
         task force of Drager and Aspect consisting of the persons named under
         Clause 22.6 will take care of such dispute settlement.

24.2     In the event disputes cannot be settled amicably according to Clause
         24.1, in connection with this present Agreement shall be exclusively
         and finally settled by the courts of Zurich.

Natick, ......April 29, 1999.....       Lubeck, .......May 5, 1999..............

J. Breckenridge Eagle                   [Illegible]
 .................................       ........................................
Aspect Medical Systems, Inc.            Drager Medizintechnik GmbH

<PAGE>   23
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 23 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

EXHIBIT A

of the               Drager/Aspect Product Agreement
between              Aspect Medical Systems, Inc.
and                  Drager Medizintechnik GmbH

Products

1.1      The Drager-BIS-Module will incorporate Aspect's BIS Module Kit.

         Aspect's BIS 'Module Kit' is designed specifically for OEM applications
         and allows the integration of Aspect's BIS monitoring technology into
         OEM equipment. The BIS Engine will interface to the patient via the
         Aspect BIS sensor and to the OEM equipment utilizing a serial (RS-232)
         3-wire interface and the necessary power connections.

         The BIS Module Kit consists of a Digital Signal Converter (DSC-2) that
         is placed in proximity to the patient and a small circuit board that
         resides in the OEM equipment. The DSC-2 is a small (palm sized)
         front-end to the BIS Engine circuit board that provides the patient
         interface and performs the high performance analog to digital
         conversion of the EEG signals. The EEG signals are transmitted in
         digital format from the DSC-2 to the BIS engine circuit board via a 12
         foot cable that is hard wired connected at the DSC-2.

         The BIS Engine circuit board measures 3 x 4 inches. This board performs
         digital signal processing on the digitized EEG signal and outputs the
         Bispectral Index to the OEM system via the RS-232 serial connection.
         The board is constructed using double sided surface mount techniques.
         The connections to the BIS Engine circuit board are a serial interface
         (RS-232), power, and DSC connections.

<PAGE>   24

                                                 Drager/Aspect Product Agreement
                                                                        20.04.99

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

                                     - 24 -

       Detailed Technical Specifications:

       Digital Output:             [**]

       Main Parameters:            [**]

       Electrical Safety:          [**]

       Power:                      [**]

       Artifact Rejection:         [**]

       Bispectral Index:           [**]

       Digital Signal Converter (DSC-2)

       Description:                [**] to the [**]

       Weight:                     [**]

       Dimensions:                 [**]

       Cable Length:               [**]

       BIS Engine PCB

       Physical:                   [**]

       Processing Power:           [**]

       Software Upgrades
       [**] software is stored in [**]. Software upgrades can be accomplished
       [**] via the [**].

       Serial Identifier
       Each [**] serial identifier. This allows for [**].

<PAGE>   25
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 25 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

                  [Graphic of Aspect BIS Module Kit and Sensor]

1.2      In addition to the main parameters indicated in Exhibit A, Section 1.1,
         the Aspect BIS Module Kit shall also provide the [**].

         When the Drager-BIS-Module is in use in a Drager Workplace System,
         there will be a possibility to display each of the following [**] as
         well as the [**] in the [**] when used for [**] and in [**].

1.3      Aspect shall ensure that all BIS enhancements that Aspect develops for
         Aspect's stand alone BIS monitor will be available in the BIS Module
         Kit sold to Drager as appropriate and as soon as reasonably possible.

         Drager will agree to distribute a modified BIS Sensor in the event
         Aspect determines that an enhancement to the BIS Module Kit requires
         the use of a modified Sensor. All conditions, prices and so on won't be
         changed for the new sensors. If this occurs, and if [**] in accordance
         with Section 1.5 of Exhibit A, [**] to provide a [**] of the [**] for
         the [**] use of [**]. Possible additional costs will be incorporated in
         the transfer price for the [**] and reasonable volumes will be
         required.

         In the event that Aspect develops a different product involving a
         different type of index, patient sensor, or application, Aspect and
         Drager will develop a mutually-satisfactory new, or amended, agreement.

1.4      For integration into a Drager Workplace, Drager will design an Drager
         Workplace specific Drager-BIS-Module. Aspect will grant all reasonable
         help to Drager designing the Drager-BIS-Module.

1.5      On the [**]. The possibility to use [**] the original Aspect BIS
         monitor will be negotiated later. Possible additional costs [**] will
         be incorporated in the transfer price and [**] will be required.

1.6      Both Parties agree to work out a common technical requirement
         specification for the Products. The latest version of this technical
         requirement specification signed by both Parties will be the
         specification of the Product to be manufactured by Aspect for Drager.

Natick, .....4/29/99.............       Lubeck, .........May 5, 1999 ...........

J. Breckenridge Eagle                   [illegible]
 .................................       ........................................
Aspect Medical Systems, Inc.            Drager Medizintechnik GmbH

<PAGE>   26
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 26 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

         EXHIBIT B

         of the                    Drager/Aspect Product Agreement
         between                   Aspect Medical Systems, Inc.
         and                       Drager Medizintechnik GmbH

         PRICES AND DISCOUNTS

         The price for one Aspect BIS Module Kit is US$[**].

         The components consists of a [**] and [**] and a [**] and [**].

         Drager shall have the right to manufacture on a royalty free basis the
         circuit board based on design specifications provided by Aspect. In
         this case the price for the remaining components is US$[**] for one
         Aspect BIS Module Kit. The Parties will agree in the future on the
         terms of a manufacturing license.

         The price of the Aspect BIS Module Kit always includes 5 Sensors.
         Drager agrees to supply these Sensors together with each
         Drager-BIS-Module to its customers.

         The Parties agree that Aspect will grant to Drager an additional
         discount on the price of the Aspect BIS Module Kit depending on a
         certain yearly quantity : Aspect will grant an additional discount of
         [**] for a yearly quantity of more than [**] Aspect BIS Module Kits.

         Aspect [**] the [**] subsequent to the date of this agreement, for
         products sold by Aspect [**] to other customers of Aspect [**]. Aspect
         will provide Drager with a [**] to [**] that [**] by other Aspect
         customers.

         The price to Drager for the Aspect-BIS-Sensor will be as follows:

         The transfer price to Drager for the Aspect BIS Sensor will vary
         between[**] of the List Price of the Aspect BIS Sensor in the United
         States. This is equivalent to a discount off of Aspect's List price in
         the United States for the BIS Sensor between [**].

<PAGE>   27
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 27 -

     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

         As of January 1, 1999, the List Price for Aspect's BIS Sensor is
         US$15.00 The actual amount of the discount off the U.S. List Price will
         depend upon the volume of Aspect BIS Sensors shipped by Drager for use
         with Drager-BIS-Modules. Prior to the shipment by Drager of the first
         [**]Drager-BIS-Modules, the discount available to Drager for purchase
         of the Aspect BIS Sensors will be set at [**] of Aspect's List Price
         for the BIS Sensor in the United States. Following the shipment of the
         first [**] Drager-BIS-Modules, the discount available to Drager will
         depend upon the volume of Aspect BIS Sensors shipped each quarter
         divided by the number of documented Drager-BIS-Modules installed minus
         the first [**] Drager-BIS-Modules installed. Using this formula, the
         Aspect BIS Sensor price schedule is as follows:

Sensor Shipments per module per quarter-Note 1        Discount off US List price
----------------------------------------------        --------------------------

  up [**]                                             [**]
   [**]                                               [**]
   [**]                                               [**]
   [**]                                               [**]
   [**]                                               [**]
   [**]                                               [**]
or more [**]                                          [**]

Note 1: Sensor consumption rate calculated based on total Aspect BIS Sensors
shipped during the quarter divided by the average Drager-BIS Module installed
base during the quarter minus [**].

In the event that Drager requests that Aspect develop the Drager-BIS-Sensor,
Aspect will sell Drager-BIS-Sensors to Drager in accordance with the same
discount schedule as above, with possible additional costs as noted in Section
1.5 of Exhibit A.

According to Clause 2.1 of the Agreement Drager shall not distribute Sensors in
the USA. Therefore, Aspect will pay a commission to Drager of [**] of the
amounts paid by the customer for each Sensor shipped for use with a
Drager-BIS-Module in the USA.

 Natick, .......4/29/99 ............           Lubeck, ......May 5, 1999  ......

 J. Breckenridge Eagle                         [illegible]
 ...................................           .................................
 Aspect Medical Systems, Inc.                  Drager Medizintechnik GmbH

<PAGE>   28
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 28 -

EXHIBIT C

of the                    Drager/Aspect Product Agreement
between                   Aspect Medical Systems, Inc.
and                       Drager Medizintechnik GmbH

TESTING SPECIFICATIONS FOR THE PRODUCTS

(to be negotiated later)

Natick, .......4/29/99 ................   Lubeck, ......May 5, 1999  .......

J. Breckenridge Eagle                     [illegible]
 .......................................   ..................................
Aspect Medical Systems, Inc.              Drager Medizintechnik GmbH

<PAGE>   29
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 29 -

EXHIBIT D

of the                    Drager/Aspect Product Agreement
between                   Aspect Medical Systems, Inc.
and                       Drager Medizintechnik GmbH

QUALITY ASSURANCE AGREEMENT

(to be negotiated later)

Natick, .......4/29/99 .................         Lubeck, ......May 5, 1999  ....

J. Breckenridge Eagle                            [illegible]
 ........................................         ...............................
Aspect Medical Systems, Inc.                     Drager Medizintechnik GmbH

<PAGE>   30
                                                 Drager/Aspect Product Agreement
                                                                        20.04.99
                                     - 30 -

EXHIBIT E

of the        Drager/Aspect Product Agreement
between       Aspect Medical Systems, Inc.
and           Drager Medizintechnik GmbH

SERVICE AGREEMENT

(to be negotiated later)

Natick, .......4/29/99 .................         Lubeck, ......May 5, 1999  ....

J. Breckenridge Eagle                            [illegible]
 ........................................         ...............................
Aspect Medical Systems, Inc.                     Drager Medizintechnik GmbH<PAGE>   1
                          Aspect Medical Systems, Inc.
has requested that the marked portions of this agreement be granted confidential
  treatment pursuant to Rule 406 under the Securities Act of 1933, as amended.

                                                                    Exhibit 10.7

                          ASPECT MEDICAL SYSTEMS, INC.

                     OEM DEVELOPMENT AND PURCHASE AGREEMENT

         Agreement dated this Sixth day of August, 1999 , by and between Aspect
Medical Systems, Inc, a Delaware corporation with its principal offices located
at Two Vision Drive, Natick, Massachusetts ("Aspect") and Hewlett-Packard GmbH
("HP"), a German corporation with its principal offices located in Germany at
71034 Boblingen, Herrenberger Str. 110-140, for the purchase and/or license by
HP of products under the terms and conditions contained in this Agreement.

1.   BACKGROUND.

          (a)  Aspect is a developer, manufacturer and distributor of medical
               devices, equipment, accessories and related hardware, software
               and related products and accessories.

          (b)  HP is a manufacturer of medical equipment, in particular of
               multiparameter patient monitors.

          (c)  Aspect and HP intend to make available to HP customers a solution
               to integrate Aspect's BIS technology with HP's patient monitors.
               In a first phase of the cooperation Aspect and HP will develop
               appropriate components in a joint project (the "BIS Project").
               In the second phase of the cooperation, HP intends to purchase
               and/or license specified products for integration with its own
               systems and products. Aspect agrees to sell and/or license to HP
               the products described below, subject to the terms and conditions
               contained in this Agreement.

          (d)  It is the intention of both Parties to negotiate a separate,
               independent distribution agreement (the "Distribution Agreement")
               under which HP will also sell the Aspect 2000 BIS Monitor and
               Aspect BIS Sensors in certain geographies.

2.   DEFINITIONS.

          "Aspect's Bispectral Index" or "BIS" is Aspect's proprietary processed
          EEG parameter that measures the hypnotic effects of anesthetic and
          sedative agents on the brain during surgery.

          "HP Patient Monitors" means a family of multi-parameter modular
          patient monitoring systems manufactured by or for HP. When the HP BIS
          System is complete, HP Patient Monitors will display BIS data
          (waveforms, numerics, status info), and provide setup and operation
          information (user interface), alarming, and network connectivity.

          "HP BIS System" is the sum of all components involved in integrating
          the BIS with HP Patient Monitors.

                                        1

<PAGE>   2
          "HP BIS Module" is a standard size parameter module for HP Patient
          Monitors to convert the data as delivered by the HP BIS Engine from
          the BIS Protocol to the HP Patient Monitor's internal format.

          "Module Cable" is a cable used to connect the HP BIS Engine to the HP
          BIS Module.

          "DSC Cable" is a cable used to connect the Digital Signal Converter to
          the HP BIS Engine.

          "HP BIS Engine" is the processing unit for deriving the BIS data from
          the raw EEG signal and consists of Aspect's "BIS Engine" board
          modified for HP and built into a housing with appropriate connectors
          to connect to the DSC Cable and the Module Cable.

          "Digital Signal Converter" (or "DSC") is used to amplify the analog
          EEG signals as acquired by the BIS sensors and convert it from analog
          to digital signals.

          "Aspect BIS Module Kit" means the bundle of all components of the HP
          BIS System that are developed and manufactured by Aspect and
          licensed/sold to HP under this Agreement: DSC, DSC Cable, HP BIS
          Engine, and Module Cable.

          "Aspect BIS Sensor" means a single use disposable sensor manufactured
          by Aspect for use with the Aspect A2000 BIS monitor or with the Aspect
          BIS Module Kit and that is required to generate Aspect's Bispectral
          Index.

          "Sensor Startup Kit" is a set of Aspect BIS Sensors that may be part
          of each HP BIS System sale by HP in selected geographies outside North
          America.

          "A2000" means Aspect's stand-alone BIS monitor for use with the Aspect
          BIS Sensor and that generates Aspect's Bispectral Index.

          "Aspect Products" means Aspect BIS Module Kits and any other product
          that can be ordered by HP as listed in Exhibit A (Aspect Products and
          Purchase Prices).

          "Software" means Aspect software programs in binary code form which
          are designed for use with the Aspect BIS Module Kit.

          "BIS Protocol" is Aspect's proprietary communication protocol provided
          for purposes of communication between the HP BIS Engine, the HP BIS
          Module and HP Patient Monitors

          "Documentation" means the BIS Engine Serial Interface Specification.

          "Territory" shall mean all countries in which HP is permitted under
          this Agreement to distribute Aspect Products.

          "Party" or "Parties" shall mean Aspect and HP each individually or
          jointly.

                                        2

<PAGE>   3

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

3.   BIS MODULE DEVELOPMENT PROJECT.

     3.1. PROJECT SCOPE

          (a)  Aspect and HP will be performing activities to develop a HP BIS
               System. Aspect will modify Aspect's standard BIS Engine product
               described in Exhibit B to create a HP BIS Engine. HP will develop
               a HP BIS Module to interface with Aspect's modified BIS Engine.

          (b)  The following specifications/documents will be created and agreed
               upon by both parties prior to completion of Phase 1 of the Module
               Development Project:

               -    Functional Technical Specification (FTS): This is a
                    specification that defines the interface between the HP BIS
                    Engine and the HP BIS Module. This document is an HP
                    specification that is derived principally from
                    specifications and materials from Aspect.

               -    System Hazard Analysis: To be performed in Phase 1 of the
                    project.

               -    External Specification: Specification describing the HP BIS
                    Module and the Aspect BIS Module Kit as a system from the
                    customer's viewpoint.

               -    Project Plan: The project plan will include a detailed
                    project schedule, detailed project description, and other
                    information not included in the FTS.

     3.2. PROJECT TIMING

The overall project duration is expected to be approximately [**]. The product
introduction is planned for [**]. The expected major project milestones are
described below:

August, 99        Start Project - Phase 1 - Definition
Dec, 99           Start Phase 2A - Specification

     3.3. PROJECT PHASE DESCRIPTIONS

The following phases of the project closely correlate with the standard internal
project phases of the HP development process.

                                        3

<PAGE>   4

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

PHASE 1: PROJECT DEFINITION

Phase 1 defines the project at a high level.

The principal technical issues to resolve are the [**] requirements and the [**]
requirements for the [**].

At the end of Phase 1 the following documents are created: External
Specification (preliminary), Functional Technical Specification (preliminary),
an initial Hazard Analysis, and a detailed Project Schedule., In addition, HP
shall create internal Functional Plans, including a development plan,
verification and validation plan, manufacturing plan, marketing plan,and
regulatory plan.

PHASE 2A: SPECIFICATION

In Phase 2A the detailed design specifications are created: External
Specification (Final), Technical Specification (Final), Hazard Analysis (Final)
and definition of Aspect's Qualification Test Procedure (verification and
validation plan for all items identified under the Functional Technical
Specification).

PHASE 2B: DESIGN (IMPLEMENTATION)

The actual electrical, circuit schematics, and mechanical design and
implementation is performed in Phase 2B. The output of Phase 2B is a functional
prototype. This functional prototype is intended to be a faithful representation
of the product, including actual molded materials, electronics and software.
During this phase, the Outgoing Inspection Procedure from Aspect is also
defined.

PHASE 3: VERIFICATION

Design verification testing of software, electronics and mechanical components
is performed in Phase 3. Additionally EMI testing of the system is performed in
this phase of the project. Aspect will perform an [**] of the [**] as a [**]
with the BIS Module.

Clinical field trials are started in Phase 3. It is anticipated that field
trials of the BIS Module System will be conducted in [**] hospitals in Europe
and [**] hospitals in the US. The completion of field trials occurs by the end
of Phase 4.

During this phase, results of the Qualification Tests and Outgoing Inspection
will also be reviewed for all prototypes.

PHASE 4: VALIDATION

The following tasks are accomplished during Phase 4: Software Validation: Formal
validation testing of the BIS Module System.

                                        4

<PAGE>   5

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

Manufacturing Pilot Build: It is expected that [**] systems will be built, of
which [**] units will be required at the beginning of Phase 3 for clinical field
trials. The systems will be used for clinical trials, engineering test, and for
sales demos. Final Test Procedure: Used to 100% test the Aspect BIS Module Kit
and HP BIS Module as a final test in manufacturing.

     3.4 PROJECT MANAGEMENT.

          (a)  Each party shall appoint a "Project Manager" who oversees and
               manages the joint project on a day-to-day basis.

          (b)  The Project Managers shall meet regularly based on the project
               needs to assess the project status and discuss and resolve any
               issues or problems. These meetings may be held face-to-face or as
               telephone or video conferences.

          (c)  Both Parties' project teams shall conduct project meetings from
               time to time as deemed useful.

          (d)  Each Party shall bear its own communication and travel costs.

          (e)  All communication in conjunction with this Agreement shall be
               directed to the appropriate person and address as listed in
               Exhibit C (Contact Persons/Addresses).

     3.5. JOINT RESPONSIBILITIES.

          (a)  Both Parties will actively work together in performing a joint
               Hazard Analysis for the HP BIS System at the beginning of the BIS
               Project.

          (b)  Both Parties will generate a joint External Specification of the
               HP BIS System.

          (c)  The parties will jointly develop and agree on a Verification and
               Validation Plan for testing the performance and safety of the
               entire BIS System prior to its release to shipment.

          (d)  The verification and validation of the HP BIS System will be
               performed under HP's overall responsibility at HP's Boeblingen
               premises. Aspect agrees to support this effort as defined in the
               Verification and Validation Plan and as may be required in case
               of problems. Verification and validation of Aspect's BIS Module
               Kit will be performed by Aspect in Aspect's Natick facility.
               After successful validation by HP of the HP BIS System, Aspect
               will also validate the HP BIS System output and confirm in a
               written certificate that the BIS value as displayed on the HP
               Patient Monitor is equivalent to Aspect's BIS implementation.

          (e)  Both parties will inform each other of any planned change in its
               products that may affect compatibility of the HP BIS System
               components or the available regulatory approvals. The Change
               Notification Agreement Form (attached as Exhibit D) will be used
               for this purpose.

                                        5

<PAGE>   6

          (f)  Both parties will provide each other reasonable engineering
               consultation free of charge.

          (g)  Aspect and HP will provide each other free of charge with certain
               number of prototypes and product samples for development,
               verification and validation, and getting regulatory approvals.

     3.6. HP RESPONSIBILITIES.

          (a)  HP shall develop the HP BIS Module according to the mutually
               agreed Functional Technical Specification and External
               Specification at HP's own cost.

          (b)  HP will take responsibility for the development, design and
               performance of the HP BIS Module and for the combination of the
               Aspect components (BIS Module Kit) with the HP components (HP BIS
               Module, HP Patient Monitor) of the HP BIS System.

     3.7. ASPECT RESPONSIBILITIES.

          (a)  Aspect shall develop the HP BIS Engine, the DSC Cable and the
               Module Cable according to the mutually agreed specifications at
               Aspect's own cost.

          (b)  Aspect will take responsibility for the development, design and
               performance of the Aspect BIS Module Kit.

          (c)  Aspect shall make available the BIS Protocol specification to HP
               for implementation into the HP BIS Module or otherwise into HP
               Patient Monitors.

          (d)  Aspect will undertake reasonable efforts to maintain backward
               compatibility for future versions of the BIS Protocol, however no
               guarantee is given.

          (e)  Aspect will inform HP of future changes to the BIS Protocol as
               early as possible and make available such changed BIS Protocol
               specification to HP. The Change Notification Agreement Form
               (attached as Exhibit D) will be used for this purpose.
               Notwithstanding anything to the contrary in the Change
               Notification Agreement Form, HP shall not withhold its approval
               of any future changes to the BIS Protocol as provided in Section
               3.7 (d).

4. PURCHASE AND SALE OBLIGATIONS; LICENSES.

          (a)  General. Subject to the terms and conditions of this Agreement,
               Aspect agrees to sell to HP the Aspect Products listed on Exhibit
               A (Aspect Products and Purchase Prices). For these products,
               Aspect grants to HP or HP's subdistributors a non-exclusive,
               worldwide distribution right for the term of this Agreement. HP
               represents and warrants that the components of the Aspect BIS
               Module Kits purchased from Aspect under this Agreement shall be
               used as components in, incorporated into, or integrated with,
               systems and products which HP sells or leases to third-party
               users in the regular course of business. HP further certifies
               that the components of the Aspect BIS Module Kits will only be
               resold, leased, rented, licensed or otherwise transferred to
               third parties for use as a part of an HP BIS System or as
               replacement parts used in HP BIS Systems.

                                        6

<PAGE>   7

          (b)  BIS Sensors. Apart from section 4.a., Aspect hereby grants HP the
               right to distribute Aspect BIS Sensors solely to HP's customers
               outside North America and solely for use with HP BIS Systems.

          (c)  Sensor Startup Kit. Aspect hereby grants HP the right to sell the
               Sensor Startup Kit for use with the HP BIS System in geographies
               outside North America.

          (d)  Software License. Aspect hereby grants to HP a non-exclusive and
               non-transferable worldwide license, without the right to
               sublicense (except to purchasers of HP BIS Systems and to HP's
               subdistributors), during the term of the Agreement to use the
               Software and related Documentation provided by Aspect solely in
               connection with operation of the components of Aspect BIS Module
               Kit in the HP BIS System. Thereafter, Aspect grants to HP a right
               to use the Software and related Documentation used in conjunction
               with the HP BIS Systems being sold by HP on the date of
               termination with respect to service and support of installed HP
               BIS Systems for a period of 10 years, after termination of the
               Agreement. All rights granted to HP customers to use the HP BIS
               System shall be irrevocable as long as such customers are in
               compliance with the terms of use for such HP BIS Systems and does
               not cure such non-compliant use within 90 days of being notified.
               HP shall not disclose, furnish, transfer, distribute or otherwise
               make available the Software, the Documentation or any portion
               thereof in any form to any third party (other than to purchasers
               of HP BIS Systems and to HP's subdistributors) and shall not
               duplicate the Software, the Documentation or any part thereof
               (other than for HP's internal use). Title to and ownership of and
               all proprietary rights in or related to the Software, the
               Documentation and all partial or complete copies thereof shall at
               all times remain with Aspect or its licensor(s). This Agreement
               shall not be construed as a sale of any rights in the Software,
               the Documentation, any copies thereof or any part thereof. All
               references in this Agreement to sale, resale or purchase of the
               BIS Module Kits or the components thereof, or references or like
               effect, shall, with respect to the Software and the Documentation
               mean licenses or sublicenses of the Software and the
               Documentation pursuant to this Section 4. HP shall not
               disassemble, decompile or otherwise reverse engineer the Software
               or any part thereof, except if Aspect is required under
               applicable law to permit HP to reverse engineer any Software. In
               such event, HP may reverse engineer the Software but only to the
               extent Aspect is required to permit such reverse engineering. HP
               shall retain and shall not alter or obscure any notices, markings
               or other insignia which are affixed to the Software, the
               Documentation or any part thereof at the time it receives such
               Software or such Documentation.

          (e)  BIS Protocol License. Aspect hereby grants to HP a non-exclusive,
               worldwide, irrevocable, royalty-free license to implement
               Aspect's proprietary BIS Protocol and sell it to HP's end
               customers as part of its products for use solely with the Aspect
               BIS Module Kit.

                                        7

<PAGE>   8

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

5. ROYALTIES.

          (a)  For each BIS Module Kit that HP is purchasing from Aspect HP
               shall pay a purchase price for the BIS Module Kit and a royalty
               fee as specified in Exhibit A (Aspect Products and Purchase
               Prices).

          (b)  Within 30 days after the Effective Date, HP shall pay Aspect an
               amount of [**] US$ as prepaid royalties, which will be credited
               against the actual royalty component of the purchase price that
               is due for the sale of the first [**] Aspect BIS Module Kits. It
               is understood that [**] of this amount to [**] in connection with
               the [**].

          (c)  In the event that the Agreement is terminated by HP because
               Aspect is unable to deliver a HP BIS Engine before October
               31st,[**](in accordance with Section 23.2, paragraph b), or in
               the event Aspect fails to deliver the first [**] Aspect BIS
               Module Kits for whatever reason, excluding breach by HP or
               failure to order then Aspect shall refund HP according to the
               following rules:

               (i)  Aspect shall refund to HP that part of the prepayment that
                    is not yet consumed by unit royalties, however not more than
                    [**] US$.

               (ii) Aspect shall [**] of the [**] that is [**] for the [**]. For
                    purposes of [**] it is [**].

          (d)  Aspect agrees to [**] a [**] in accordance with the terms
               outlined in [**] in accordance with Section 5 (c) in the event
               that [**] as determined on a [**] and [**] following the [**] of
               [**]. HP agrees to [**] for [**] in connection with [**]. At such
               time as Aspect completes an initial public offering of its common
               stock, the requirement to [**] will terminate.

6. SCOPE OF DELIVERY

          (a)  Purchase Orders. Purchase orders (via Fax, e-mail, other
               electronic transmission or paper) for Aspect Products to be
               purchased under this Agreement (the "Orders") must be received by
               Aspect during the term of this Agreement and must specify a
               delivery date in accordance with the lead-time schedule outlined
               below under Section 6, paragraph e) All HP Purchase Orders will
               make reference to the appropriate engineering drawing or
               manufacturing reference numbers.

          (b)  Order Acknowledgements. HP purchase orders will be acknowledged
               by Aspect within 5 days after receipt of the order, provided that
               the order is technically correct and that the requested delivery
               time is within the agreed lead time and that the latest forecast
               provided by HP is not exceeded by more than [**] and the quantity
               ordered does not exceed by more than [**] the quantity ordered in
               the preceding month. If the requested delivery time is lower than
               the agreed lead time, or if HP's latest forecast is exceeded by
               more than [**], Aspect shall use reasonable efforts to complete
               the order requirements and to acknowledge the order within 10
               days of its receipt. Order acknowledgements shall not be
               unreasonably withheld.

          (c)  Forecasts. HP shall furnish to Aspect a non-binding monthly
               forecast during the term of this Agreement with the number and
               type of Aspect Products for which HP expects to submit orders for
               the following twelve months. Existing open purchase orders are
               not usually reflected in these forecast numbers.

                                        8

<PAGE>   9

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

          (d)  Cancellation Charges. In the event of the cancellation of any
               Order by HP, HP shall be liable for the payment of cancellation
               charges based on the number of days prior to scheduled delivery
               that written notice of cancellation is received by Aspect, as
               outlined below:
<TABLE>
<CAPTION>
<S>                                                          <C>
    > 10 weeks prior to acknowledged delivery                [**]
    6 - 10 weeks prior to acknowledged delivery              [**] of order value
    4 - 6 weeks prior to acknowledged delivery               [**] of order value
    2 - 4 weeks prior to acknowledged delivery               [**] of order value
    < 2 weeks prior to acknowledged delivery                 [**] of order value
</TABLE>

          (e)  Lead Times. Lead times for the Aspect BIS Module Kit are expected
               to be 12 weeks.

7. PRICES.

          (a)  Purchase Prices. The prices of Aspect Products purchased by HP
               hereunder (the "Purchase Prices") which are ordered during the
               term of the Agreement shall be as set forth in Exhibit A (Aspect
               Products and Purchase Prices).

          (b)  Purchase Price Changes. In consideration of the market situation
               and after consultation with HP, the Purchase Prices set forth in
               Exhibit A (Aspect Products and Purchase Prices) will be reviewed
               12 months after first delivery of production units and annually
               thereafter. Any price increase will become effective only after
               mutual agreement between both Parties, subject to the following:

               (i)  In the event the materials cost for the Aspect BIS Module
                    Kit increases by more than [**]. Aspect shall have the right
                    no more than once per year during the term of this Agreement
                    to increase the Purchase Price of the Aspect BIS Module Kit
                    by an equivalent amount by giving HP written notice of such
                    increase not less than [**] days prior to the date upon
                    which the increased Purchase Price is to become effective.
                    No Purchase Price increase shall apply to Orders for Aspect
                    Products accepted by Aspect prior to or during such [**] -
                    day period which are to be delivered within [**] days of the
                    date of such notice.

          (c)  Aspect may reduce the Purchase Price of any Aspect Product at any
               time. Such reduction shall be applicable to all Aspect Products
               not shipped at the time of the reduction.

          (d)  [**] the Purchases Prices [**] the [**] for [**] and based on
               similar terms and conditions [**] that has entered into a [**]
               the date of this agreement.

          (e)  Taxes. All prices for Aspect Products are exclusive of all
               federal, state and local taxes, levies and assessments, and HP
               shall be responsible for the payment of all such taxes, levies
               and/or assessments imposed on Aspect Products purchased and/or
               licensed by HP hereunder, excluding taxes based on Aspect's net
               income

                                        9

<PAGE>   10

              from the transaction. HP shall be responsible for providing in a
              timely manner all documentation, in the nature of exemption
              certificates or otherwise, necessary to allow Aspect to refrain
              from collections, such as sales tax, which it would otherwise be
              obligated to make

8. TERMS OF PAYMENT.

          (a)  Invoices. HP shall pay to Aspect the Purchase Price of all Aspect
               Products shipped hereunder within 30 days after the receipt of
               Aspect's invoice. Nothing herein shall affect Aspect's right to
               withhold shipment or otherwise exercise its rights under Section
               24 (Termination) hereof in the event of HP's failure to make
               payment when due for Aspect Products delivered to HP. Aspect's
               invoices to HP for Aspect Products purchased under this Agreement
               shall be addressed to:

                  Hewlett-Packard GmbH
                  Department ASC-AP
                  Postfach 1430
                  D-71004 Boeblingen
                  Germany

                  Late Payment Charge. Subject to applicable law, service and/or
                  interest charges not exceeding the lesser of 1-1/2% per month
                  or the highest amount permitted by law may, at the election of
                  Aspect, be assessed on amounts past due more than 30 days.

9. SHIPMENT AND DELIVERY.

          (a)  Delivery Location. Each shipment must indicate the exact address
               of the recipient on the outside of the packaging as follows:

               Hewlett-Packard GmbH
               HSG-E Healthcare Solution Group Europe
               c/o Js. Mueller Spedition GmbH
               Eugen Zeyer Str. 1
               D-75382 Althengstett
               Germany

          (b)  All shipments hereunder shall be freight collect, F.C.A. point of
               origin (Incoterms 1990). All Aspect Products shall be deemed
               delivered and subject to HP's dominion and control when placed in
               the possession of the carrier, packed and ready for shipment to
               HP.. Aspect shall cooperate with HP in the documentation and
               proof of loss claims promptly presented by HP to the appropriate
               carrier and/or insurer.

          (c)  Delivery and Packaging Instructions Delivery and Packaging
               requirements will need to conform to the standards outlined in
               the HP Delivery and Packaging Standard (attached as Exhibit E)

                                       10

<PAGE>   11

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

          (d)  Delivery Date and Date of Dispatch. The requested delivery date
               will be specified on the HP Purchase Order. Aspect will utilize
               reasonable efforts to ensure that the order is delivered in
               accordance with Aspect's order acknowledgement and that the the
               date of dispatch is 10 days prior to the delivery date.

10. ACCEPTANCE.

Any Aspect Product shipped hereunder may be subjected to inspection and
performance testing by HP, in accordance with applicable product specifications
in effect at the time of delivery of such Aspect Products to HP. HP shall
provide written notice to Aspect of the rejection of any such Aspect Product
within [**] days of the date of receipt of any Aspect Product; if more than
[**]% of Aspect Products received in any single shipment do not pass HP's
inspection or performance testing HP may reject the entire shipment lot. Aspect
shall have [**] days from receipt of a notice from HP rejecting an Aspect
Product either, at its option, to make any necessary repairs to the defective
Aspect Product or to replace it. If Aspect replaces an Aspect Product, HP shall
dispose of the replaced Aspect Product in accordance with Aspect's instructions
and at Aspect's expense. HP's sole remedy for rejected Aspect Products shall be
limited to repair or replacement of such Aspect Products.

11. WARRANTY.

          (a)  General. Aspect warrants solely to HP that Aspect Products
               (including Software) delivered hereunder shall perform
               substantially in accordance with the specifications in Exhibit B
               (Aspect's Standard Module Kit) or other applicable product
               specifications as published by Aspect in effect at the time of
               delivery of such Aspect Product (including Software), and shall
               be free from defects in materials and workmanship, when given
               normal, proper and intended usage, for twelve months from the
               date of installation of the HP BIS System at HP's end customer
               site, or eighteen months from the date of shipment by Aspect to
               HP, whichever is less . Aspect agrees, during the applicable
               warranty period, to repair or replace (at Aspect's option) all
               defective Aspect Products within 30 days after date of return to
               Aspect and without cost to HP. This warranty shall not apply to
               expendable components and supply items, such as, but not limited
               to, cables (except for failures occurring within 180 days of
               receipt of shipment), fuses and bulbs (or disposable items such
               as an Aspect BIS Sensor after the expiration date marked on the
               Sensor packaging); nor shall Aspect have any obligation under
               this Agreement to make repairs or replacements which are required
               by normal wear and tear, or which result, in whole or in part,
               from catastrophe, fault or negligence of HP, or anyone claiming
               through or on behalf of HP, or from improper or unauthorized use
               of Aspect Products, or use of Aspect Products in a manner for
               which they were not designed, or by causes external to Aspect
               Products such as, but not limited to, power or air conditioning
               failure.

                                       11

<PAGE>   12

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

          (b)  Warranty Procedures. HP shall notify Aspect of any Aspect
               Products which it believes to be defective during the applicable
               warranty period and which are covered by the warranties set forth
               in paragraph (a). At Aspect's option, such Aspect Products shall
               be returned by HP to Aspect's designated facility for examination
               and testing, or may be repaired on site by Aspect. Aspect shall
               either repair or replace, within 30 days of receipt by Aspect,
               any such Aspect Product found to be so defective and promptly
               return such Aspect Products to HP. Transportation and insurance
               costs, and/or risk of loss or damage during shipments, shall be
               borne by Aspect. Should Aspect's examination and testing not
               disclose any defect covered by the foregoing warranty, Aspect
               shall so advise HP and dispose of or return the Aspect Product in
               accordance with HP's instructions and at HP's sole expense.

          (c)  Repair Warranty. Aspect warrants its repair work and/or
               replacement parts for the duration of the original warranty
               period as set forth in paragraph (a) or at least 6 months
               whichever is longer.

          (d)  LIMITATION. THE PROVISIONS OF THE FOREGOING WARRANTIES ARE IN
               LIEU OF ANY OTHER WARRANTY, WHETHER EXPRESS OR IMPLIED, WRITTEN
               OR ORAL (INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR
               A PARTICULAR PURPOSE). THE FOREGOING WARRANTIES EXTEND TO HP ONLY
               AND SHALL NOT BE APPLICABLE TO ANY OTHER PERSON OR ENTITY
               INCLUDING, WITHOUT LIMITATION, CUSTOMERS OF HP.

12. SERVICE AND SUPPORT.

          (a)  Service and Support. HP shall be responsible for providing
               installation, customer training, service and support (including
               repair) to its end customers for the Aspect Products sold
               hereunder and HP shall bear all related costs incurred for labor,
               parts, or travel to perform such service.

          (b)  Central Repair Service. For the term of this Agreement, Aspect
               agrees to provide central repair service to HP for Aspect
               Products sold hereunder at a charge and as further detailed in
               Exhibit F (Service/Repair).

          (c)  Excessive Failure Rate. If the Annual Failure Rate of Aspect's
               BIS Module Kit excluding out-of-box failures and cables exceeds
               the value as specified in Exhibit B (Aspect's Standard Module
               Kit) by more than [**] then Aspect shall reimburse HP for any
               additional cost (including material and labor, ) incurred by HP
               for repairing the units in excess of the above limit.

          (d)  Service Period. For a period of [**] following the last delivery
               to HP of the applicable Aspect Product ordered by HP hereunder,
               Aspect shall make available repair service (or at Aspect's sole
               discretion, exchange units for the Aspect Products) for purchase
               by HP and third party users of the Aspect products at

                                       12

<PAGE>   13

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.
               Aspect's then-current prices for such repair services and
               exchange units. After expiry of this [**] period, Aspect may, in
               its sole discretion, continue to supply repair services (and/or
               exchange units for the Aspect Products) subject to the mutual
               written agreement of the Parties.

          (e)  Service Reporting. Aspect shall maintain a complete record of all
               repair activities performed on any Aspect products received for
               repair, and will provide HP with a monthly report on all service
               actions including failure and repair statistics at a sub-
               assembly levelas laid down in Exhibit F (Service/Repair). Service
               Reports for each product shall be sent electronically by email to
               responsible procurement and technical marketing engineer (Contact
               Persons shown in Exhibit C, Contact Persons / Addresses).
               Rootcause analysis is to be performed and reported by Aspect in
               case of abnormal failures, incidents and malfunctions.

13. QUALITY ASSURANCE.

          (a)  Both parties agree to maintain ISO900x, EN460x, European
               directive 93/42/EEC Annex II ("MDD AX-II") certification status
               and compliance with the U.S. Food and Drug Administration's
               ("FDA") Quality System Regulation ("QSR"), the European Medical
               Device Directive ("MDD"), and other appropriate regulations
               pertinent to the development, manufacturing and marketing of this
               kind of medical product.

          (b)  All Products developed under this Agreement shall fully comply
               with the above quality requirements and guidelines (MDD AX-II,
               FDA QSR, etc.)

          (c)  If the actual Annual Failure Rate ("AFR") of the BIS Module Kit
               or subcomponents thereof exceeds the expected value specified in
               Exhibit B (Aspect's Standard Module Kit) by more than [**] then
               Aspect agrees to investigate the root cause of the problem and
               take the appropriate corrective actions to bring the AFR back
               into the specified range.

14. REGULATORY MATTERS.

          (a)  Aspect shall assume full regulatory responsibility for the Aspect
               Products, including obtaining and maintaining all applicable
               governmental authorizations and regulatory approvals required to
               distribute the BIS Module Kit. Both Parties will work together to
               develop a regulatory plan during phase 1 of the Project which
               defines precisely what these regulatory and localization
               requirements are for all countries where the HP BIS System is
               intended to be sold. In particular, Aspect shall be responsible
               for generating its own Device Master Record for the BIS Module
               Kit and obtaining the CE-mark. It is understood that the BIS
               Module Kit will be a component of the HP BIS System for which HP
               assumes full regulatory responsibility as provided in Section 14
               (c).

                                       13

<PAGE>   14

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

          (b)  HP shall assume full regulatory responsibility for the HP
               Products, including obtaining and maintaining all applicable
               governmental authorizations and regulatory approvals required to
               distribute the HP Patient Monitors and the HP BIS Module in all
               countries in the Territory.

          (c)  HP shall assume the regulatory responsibility for the combination
               of the Aspect and HP components in the HP BIS System. Aspect
               shall fully support HP as required in the process of obtaining
               regulatory approvals by making available to HP any required
               information, data, certificates, or technical files in the
               requested formats.

          (d)  For bringing the Aspect Products into the market in countries
               affected by the European Medical Device Directive ("MDD"), Aspect
               is the legally responsible manufacturer under the MDD as named in
               detail in Exhibit C (Contact Persons/Addresses). The Aspect
               Products shall be marked accordingly.

          (e)  HP and Aspect shall inform each other in writing immediately
               about any event that may require incident reporting in any
               country of the Territory.

          (f)  In the event of any recall of an Aspect Product required by a
               governmental agency for safety or efficacy reasons, or requested
               by Aspect at its sole discretion, which is the result of Aspect's
               failure to supply Aspect Products that (1) conform in all
               material respects to the applicable published specifications
               (including the specifications set forth in Exhibit B (Aspect's
               Standard Module Kit)) or (2) are free from defects in material
               and workmanship (when given normal, proper and intended usage),
               Aspect agrees to repair or replace at its own costs all Aspect
               Products subject to the recall and previously delivered to HP.
               Aspect also agrees to consult with HP to establish a reasonable
               process for managing the recall and Aspect shall be [**]
               (including, but not limited to [**] that are consistent with the
               recall process agreed to by the Parties. In the event the recall
               is not required by a governmental agency for safety or efficacy
               reasons, but is instead requested by Aspect at its sole
               discretion, Aspect will be responsible for determining the scope
               of the recall, including the number of units, timeframe for the
               recall, and criteria for completion. HP agrees to maintain all
               necessary sales records to facilitate the recall.

          (g)  HP may at its sole discretion delegate some of the obligations
               under this Section 14 to its subdistributors.

          (h)  For the purpose of facilitating product traceability, all
               Products purchased from Aspect by HP will require identification
               of an internal order number and tracking code.

15. PRODUCT CHANGES; DISCONTINUED PRODUCTS; FUTURE PRODUCTS; CONTINUED SUPPLY.

          (a)  Product Changes. Aspect shall have the right, at any time and
               from time to time, to make substitutions and modifications to
               Aspect Products, provided that such substitutions or
               modifications will not materially affect form, fit or function of
               Aspect

                                       14

<PAGE>   15

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

          Products. In the event that any proposed substitution or modification
          affects, in Aspect's reasonable judgment, the form, fit or function of
          a Aspect Product, Aspect shall give HP written notice of such proposed
          substitution or modification at least [**] days prior to its taking
          effect and HP shall have the right, during such [**] -day period and
          for [**] days thereafter, to order Aspect Products without such
          substitution or modification for delivery within [**] days after such
          substitution or modification takes effect. Aspect shall give written
          notice of any proposed change to the Aspect Products using the
          Supplier Change Notification Agreement Form (attached as Exhibit D)
          and provide the appropriate verification and validation information
          evaluating the affect on the HP BIS System. Notwithstanding anything
          to the contrary in the Change Notification Agreement Form, HP shall
          not unreasonably withhold its approval of any such changes.

     (b)  Discontinued Products. Aspect agrees to notify HP in writing not less
          than [**] in advance of the discontinuance of any Aspect Product. HP
          shall be able to place orders for at least [**] after receipt of the
          written notice in any case. In addition, HP shall be entitled to
          determine its lifetime-buy quantities and place a corresponding last
          purchase order.

     (c)  Future Products. The Aspect Products are designed for use in measuring
          the effects of anesthetic and sedative agents on the brain during
          surgery. In the event that Aspect develops a product involving a
          different type of index, patient sensor, or application, Aspect and HP
          agree to discuss a new agreement for the purchase of such new product
          or products by HP.

     (d)  Continued Supply. In the event that (a) Aspect makes an assignment for
          the benefit of creditors, or a receiver, trustee in bankruptcy or
          similar officer is appointed to take charge of any or all of Aspect's
          property, or Aspect files a voluntary petition under federal
          bankruptcy laws or similar state statutes or such a petition is filed
          against Aspect and is not dismissed within sixty (60) days, and (b)
          Aspect fails to deliver Aspect Products ordered by HP under this
          Agreement within [**] of the delivery date specified on a purchase
          order complying with Section 4 and accepted by Aspect in accordance
          with Section 4, upon request of HP, Aspect shall grant to HP, a
          nonexclusive license to use the Manufacturing Materials to make and
          have made the Aspect Products for use in the HP BIS System, until [**]
          after Aspect is ready and able to deliver Aspect Products to HP under
          the terms of this Agreement and has notified HP thereof. This includes
          a non-exclusive license to use any tools, design documentation, or any
          other manufacturing materials which may be necessary. The
          manufacturing materials supplied by Aspect shall include a list of the
          Aspect suppliers of parts for Aspect Products. Upon exercise by HP of
          the manufacturing license set forth above, HP shall pay Aspect a
          "Manufacturing License Fee" equal to the royalty specified on Exhibit
          A (Aspect's Products and Purchase Prices).

                                       15

<PAGE>   16

16. OWNERSHIP AND PROTECTION OF RESULTS.

     (a)  It is expressly agreed that neither Aspect nor HP will transfer to any
          Party any patent rights, copyrights or intellectual property of any
          kind that either Party owns at the effective date of this agreement.

     (b)  Aspect shall retain the title to and possession of any models,
          patterns, dies, molds, jigs, fixtures, and other tools made for or
          obtained in connection with this Agreement and solely related to the
          Aspect Products, even if made for, obtained by or paid for by HP.

     (c)  If there are developments (including patentable inventions) conceived,
          created or reduced to practice as part of the joint development
          project then the rights to such developments shall be retained (a) by
          Aspect if conceived, created or reduced to practice solely by Aspect,
          or (b) by HP, if solely conceived, created or reduced to practice by
          HP, or (c) jointly by HP and Aspect (without any duty to account to
          the other) if jointly developed by HP and Aspect provided that:

          HP shall assign to Aspect all rights to any development relating to
          Aspect's BIS Module Kit

          and Aspect shall assign to HP all rights to any development relating
          to the HP Patient Monitor or HP BIS Module subject to Aspect's
          retained rights to the BIS Protocol.

17. DOCUMENTATION AND TRAINING.

         Aspect agrees to provide HP with such product literature, operations
and maintenance manuals, other information and training (including training to
avoid possible misrepresentation of Aspect's Bispectral Index) as is mutually
agreed, to enable HP properly to sell and maintain Aspect Products, provided
that in no event shall the source code or source listings of Aspect Software be
required to be disclosed or provided by Aspect to HP pursuant to this Section 17
or otherwise. Such training needs to begin at least three months prior to
introduction of the HP BIS System and will be defined as part of the Project's
marketing plan.

18. CONFIDENTIALITY.

         No confidential information disclosed by either party to the other in
connection with this Agreement shall be disclosed to any person or entity other
than the recipient party's employees and contractors directly involved with the
recipient party's use of such information who are bound by written agreement to
protect the confidentiality of such information, and such information shall
otherwise be protected by the recipient party from disclosure to others with the
same degree of care accorded to its own confidential information of like
importance. In addition, each party and its representatives shall use the
confidential information only for the purposes specified under this Agreement
and such information shall not be used for any other purpose without the prior
written consent of the disclosing party. To be subject to this provision,
information must be delivered in writing and designated as proprietary or, if
initially delivered orally, must be confirmed

                                       16

<PAGE>   17

in writing as confidential within 30 days after the oral disclosure. Information
will not be subject to this provision if it is or becomes a matter of public
knowledge without the fault of the recipient party, if it was a matter of
written record in the recipient party's files prior to disclosure to it by the
other party, or if it was or is received by the recipient party from a third
person under circumstances permitting its unrestricted disclosure by the
recipient party. Upon termination of this Agreement, each party shall promptly
deliver to the other all confidential information of the other party in the
possession or control of such party and all copies thereof, provided that each
party may retain a copy thereof for archival purposes. The obligations under
this Section 18 shall continue for both parties for a period of 10 years after
delivery by Aspect to HP of the last Aspect Product under this Agreement. HP is
entitled to transmit confidential information of Aspect to Hewlett-Packard
Company and to its subsidiaries and affiliated companies. In this case these
companies may only use such information to the same extent as HP is entitled to
under this Agreement. HP will be responsible that these companies comply with
the confidentiality provisions of this Agreement.

19. INDEMNITIES.

     19.1. INDEMNITIES BY ASPECT.

          (a)  Except as provided below, Aspect shall defend and indemnify HP
               from and against any damages, liabilities, costs and expenses
               (including reasonable attorneys' fees and court costs) arising
               out of any claim that Aspect Products purchased and/or licensed
               hereunder infringe any patent or copyright or misappropriate a
               trade secret of a third party, provided that (i) HP shall have
               promptly provided Aspect written notice thereof and reasonable
               cooperation, information, and assistance in connection therewith,
               and (ii) Aspect shall have sole control and authority with
               respect to the defense, settlement, or compromise thereof. Should
               any Aspect Products delivered hereunder become or, in Aspect's
               opinion, be likely to become the subject of such a claim, Aspect
               may, at its option, either (x) procure for HP the right to
               continue purchasing and using such Aspect Products, or (y)
               replace or modify such Aspect Products so that they become
               non-infringing or if (x) and (y) are not reasonably available to
               Aspect, then (z) terminate HP's rights under this Agreement to
               purchase the allegedly infringing Product and refund to HP the
               amount which HP has paid to Aspect for such Products which are in
               the possession of HP, upon return of such Products in their
               unopened packages to Aspect at its principal facility in the
               United States (freight and insurance at Aspect's expense). In
               such event, Aspect may withhold further shipments of infringing
               or potentially infringing Aspect Products.

               Aspect shall have no liability or obligation to HP hereunder with
               respect to any patent, copyright infringement or trade secret
               misappropriation or claim thereof based upon

               (i)  compliance with designs, plans or specifications of HP,

               (ii) use of Aspect Products by HP in combination with devices or
                    products not purchased and/or licensed hereunder where the
                    Aspect Products would not themselves be infringing,

                                       17

<PAGE>   18

               (iii)use of the Aspect Products by HP in an application or
                    environment for which such Aspect Products were not designed
                    or contemplated, or

               (iv) modifications of the Aspect Products by HP

          (b)  Aspect's liability hereunder shall not exceed the purchase and/or
               license price paid by HP for the Aspect Products found to be
               infringing. The foregoing states the entire liability of Aspect
               with respect to infringement or misappropriation of patents,
               copyrights and trade secrets by the Products or any part thereof
               or by their operation.

          (c)  In the event that any claim is brought against HP as a result of
               personal injuries and/or property damages resulting from that
               portion of the HP BIS System developed and manufactured by
               Aspect, and provided further that such claims do not arise as a
               result of the misuse of the HP BIS System , or the use of the HP
               BIS System in an application for which it was not designed by
               Aspect, where such claim would not have occurred but for such
               misuse or use, Aspect agrees that it shall indemnify and hold HP
               harmless from and against any damages, liabilities, costs and
               expenses arising out of such claim, provided that HP shall
               promptly provide Aspect written notice thereof and reasonable
               cooperation, information and assistance in connection therewith
               and Aspect shall have sole control and authority with respect to
               the defense, settlement or compromise.

         19.2.    INDEMNITIES BY HP.

              (a) Except as provided below, HP shall defend and indemnify Aspect
              from and against any damages, liabilities, costs and expenses
              (including reasonable attorneys' fees and court costs) incurred by
              Aspect as a result of or arising from HP's activities under this
              Agreement, including, without limitation, product liability,
              customer warranty and service claims, provided that

               (i)  Aspect shall have promptly provided HP written notice
                    thereof and reasonable cooperation, information and
                    assistance in connection therewith, and

               (ii) HP shall have sole control and authority with respect to the
                    defense, settlement or compromise thereof, and provided
                    further that

              (iii) HP shall not be liable to Aspect under this Section 19.2 to
                    the extent that such damages, liabilities, costs and
                    expenses arise from Aspect's negligence or a breach of any
                    representation or warranty by Aspect hereunder.

20. TRADEMARKS.

     20.1. ASPECT TRADEMARKS.

          (a)  Ownership. HP acknowledges and agrees that Aspect is the sole and
               exclusive owner of all right, title and interest in and to the
               trademarks (the "Aspect Trademarks") identified on Exhibit H
               (Aspect Trademarks). HP recognizes the value of the Aspect
               Trademarks and the good will associated with the Aspect
               Trademarks. HP agrees that its use of the Aspect Trademarks and
               any good will

                                       18

<PAGE>   19

          arising therefrom shall inure to the benefit of Aspect. Nothing
          contained herein shall create, nor shall be construed as an assignment
          of, any right, title or interest in or to the Aspect Trademarks to HP,
          other than the grant of a license in Section 20.1 (c) below; it being
          acknowledged and agreed that all other right, title and interest in
          and to the Aspect Trademarks is expressly reserved by Aspect. HP shall
          keep the Aspect Trademarks free from all liens, mortgages or other
          encumbrances. HP agrees that it will not attack or otherwise challenge
          the title, validity or any other rights of Aspect in or to the Aspect
          Trademarks.

          (b)  Notice. All HP BIS Systems that use the Aspect Trademarks shall
               be accompanied, where reasonable and appropriate, by a
               proprietary notice consisting of the following elements:

               (i)  The statement "[insert trademark(s)] is a trademark(s) of
                    Aspect Medical Systems, Inc."

               (ii) HP will include the "(TM)" or "(R)" symbol, as instructed by
                    Aspect, after the first prominent use of the Aspect
                    Trademark in the HP Patient Monitor and related materials.
                    HP shall have a period of 30 days in which to begin to use
                    the "(R)" symbol in replacement of the "(TM)" symbol upon
                    receiving instruction to do so by Aspect. HP may continue to
                    deliver stocked literature before the change becomes
                    effective.

              (iii) HP shall reproduce copyright and trademark notices of Aspect
                    on the "splash screen" or in the same location where HP
                    reproduces its own copyright notices .

          (c)  License. Aspect hereby grants to HP a nonexclusive, worldwide,
               royalty-free license (without the right to sublicense) to use the
               Aspect Trademarks to designate and promote Aspect Products in HP
               BIS Systems. HP shall have no other right to use, display or
               utilize the Aspect Trademarks for any other purpose or in any
               other manner.

          (d)  Quality Standards.

               (i)  Upon reasonable notice and request, and at a mutually
                    acceptable date and location, Aspect may inspect the
                    advertising and promotional materials on which the Aspect
                    Trademarks are used so that Aspect may monitor compliance
                    with this Agreement.

               (ii) Compliance. Aspect acknowledges the high standards of
                    quality and excellence established by HP with respect to
                    products bearing HP's trademarks. HP acknowledges the high
                    standards of quality and excellence established by Aspect
                    with respect to products bearing the Aspect Trademarks. HP
                    agrees that HP Patient Monitors with which the Aspect
                    Trademarks are used shall be of such quality so as to
                    maintain such high standards and to reflect well upon
                    Aspect. HP agrees to adhere to HP's own or the following
                    quality standards (whichever may be more rigorous) for use
                    of the Aspect Trademarks by HP:

                    -    In order to ensure that Aspect Products and HP Patient
                         Monitors distributed under the Aspect Trademarks comply
                         with the consistent quality standards of Aspect, all
                         Aspect Products and HP Patient Monitors distributed by
                         or for HP

                                       19

<PAGE>   20

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

                         which bear an Aspect Trademark shall conform to those
                         standards which Aspect provides to HP in writing. HP
                         shall cause each major new release of such HP Patient
                         Monitors to comply with such standards or remove the
                         Aspect Trademark(s) from any such new release, which
                         does not comply with such standards. HP shall have a
                         period of 30 days in which to bring newly shipped HP
                         Patient Monitors into compliance with any standard
                         provided to it by Aspect following the date of this
                         Agreement.

                    -    HP acknowledges that if Aspect Products or HP Patient
                         Monitor products bearing the Aspect Trademarks fail to
                         satisfy the quality standards set forth above, the
                         substantial good will which Aspect have built and now
                         possess in the Aspect Products and in the Aspect
                         Trademarks will be impaired.

          (e)  Protection and Infringement. HP agrees to cooperate with and
               assist Aspect in obtaining, maintaining, protecting, enforcing
               and defending Aspect' proprietary rights in and to the Aspect
               Trademarks. In the event that HP learns of any infringement,
               threatened infringement or passing-off of the Aspect Trademarks,
               or that any third party claims or alleges that the Aspect
               Trademarks infringe the rights of the third party or are
               otherwise liable to cause deception or confusion to the public,
               HP shall notify Aspect giving the particulars thereof, and HP
               shall provide necessary information and assistance to Aspect in
               the event that Aspect decides that proceedings should be
               commenced.

          (f)  Termination. In addition to the termination rights set forth in
               Section 23 hereof, in the event that HP is in material breach of
               any provision of this Section 20, Aspect may, upon [**] written
               notice, terminate the license granted in Section 20.1 (c) if HP
               does not cure such breach or default within such [**] period. The
               parties recognize that curing such breach or default may require
               development of a new version of HP BIS System. If this is the
               case, then HP will be deemed to have cured such breach or default
               if, within the [**] cure period, HP presents to Aspect a plan for
               revision of HP Product that will cure such breach or default,
               such plan is reasonably acceptable to Aspect, and such revision
               is released and distributed within three months following written
               notice of such breach or default.

               In addition to the provisions of Section 23 hereof, upon
               termination of the license granted in Section 20.1 (c), or upon
               termination of this Agreement, for whatever cause:

               (i)  HP shall immediately cease and desist from any further use
                    of the Aspect Trademarks and any trademarks confusingly
                    similar thereto, either directly or indirectly;

               (ii) All rights in the Aspect Trademarks granted to HP hereunder
                    shall immediately revert to Aspect;

              (iii) In the event that this Agreement is terminated for any
                    reason other than a material breach or material default by
                    HP, HP shall have a period of 30 days thereafter to dispose
                    of all of the unsold HP BIS Systems bearing the

                                       20

<PAGE>   21

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

                    Trademarks and advertising and promotional materials
                    relating thereto which had been completed by it prior to
                    such termination, provided such HP BIS Systems and materials
                    were in the process of manufacture more than [**] before
                    such termination.

          (g)  Promotional Claims. The general form of any promotional claims by
               HP regarding Aspect's Bispectral Index technology and/or the
               integration of this technology in HP Patient Monitors, and the
               specific form of the use of Aspect's trade names and trademarks,
               and of intended use claims regarding Aspect's Bispectral Index
               technology, in promotional material, advertisement, and/or in
               written technical literature shall be subject to review and
               approval by Aspect prior to its publication or display.

     20.2. HP TRADEMARKS.

          (a)  The general form of any potential claim by Aspect that HP uses
               Aspect's Bispectral Index technology as part of the HP Patient
               Monitors, and the specific form of the use of HP's trade names
               and trademarks in promotional material, advertisement, and/or in
               written technical literature shall be subject to review and
               approval by HP prior to its publication or display.

          (b)  Upon termination of this Agreement any reference to HP and it's
               trademarks must be immediately removed from any literature or
               other display and must no longer be distributed.

21. EXPORT.

     HP shall not export, directly or indirectly, HP BIS Systems or other
     products, information or materials provided by Aspect hereunder, to any
     country for which the United States requires any export license or other
     governmental approval at the time of export without first obtaining such
     license or approval. It shall be HP's responsibility to comply with the
     latest United States export regulations, and HP shall defend and indemnify
     Aspect from and against any damages, fines, penalties, assessments,
     liabilities, costs and expenses (including reasonable attorneys' fees and
     court costs) arising out of any claim that HP BIS Systems or other
     products, information or materials provided by Aspect hereunder were
     exported or otherwise shipped or transported in violation of applicable
     laws and regulations.

22. CO-MARKETING PROGRAM.

     (a)  HP and Aspect may agree to undertake co-marketing programs in certain
          geographies.

     (b)  HP and Aspect have agreed on a co-marketing program in North America
          as described in Exhibit G (Co-Marketing Program) to this Agreement.

                                       21

<PAGE>   22

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

23. TERM; DEFAULT AND TERMINATION.

    23.1. TERM AND RENEWAL.

          The initial term of this Agreement shall commence on the date first
          specified above (the "Effective Date") and shall continue for a period
          of 6 years. The term of this Agreement shall be automatically renewed
          for successive 12 month periods unless either party provides written
          notice of termination to the other party at least 60 days prior to
          expiration of the Agreement.

    23.2. TERMINATION FOR GOOD CAUSE.

          (a)  The Agreement may be terminated by Aspect giving 30 days written
               notice to HP in the event HP has not commercially introduced an
               HP BIS System by October 31st 2001.

          (b)  The Agreement may be terminated by HP giving 30 days written
               notice to Aspect if Aspect has failed to provide a BIS Module Kit
               with the necessary regulatory approvals to HP by [**].

          (c)  Events of Default. The following shall constitute events of
               default under this Agreement:

               (i)  if either Party assigns this Agreement or any of its rights
                    or obligations hereunder except in connection with the sale
                    of such Party's business to which this Agreement relates
                    (the word "assign" to include, without limiting the
                    generality thereof, a transfer of a majority interest in the
                    Party) without the prior written consent of the respective
                    other Party. Notwithstanding the foregoing, it is understood
                    that this Agreement shall be assigned to Agilent
                    Technologies GmbH, at Herrenberger Strasse 110 - 130,
                    D-71034 Boeblingen, Germany and that Aspect consents to such
                    assignment.; or

               (ii) if either Party shall neglect or fail to perform or observe
                    any of its obligations to the other Party hereunder,
                    including, without limiting the generality thereof, the
                    timely payment of any sums dueor Aspect's inability to
                    deliver Aspect Products, and such failure is not cured
                    within [**] in the event of a default in the payment of
                    amounts owed the other Party) after written notice thereof
                    from the other Party; or

              (iii) if there is (w) a dissolution, termination of existence,
                    liquidation, insolvency or business failure of either Party,
                    or the appointment of a custodian or receiver of any part of
                    either Party's property, if such appointment is not
                    terminated or dismissed within thirty (30) days; (x) a
                    composition or an assignment or trust mortgage for the
                    benefit of creditors by either Party; (y) the commencement
                    by either Party of any bankruptcy proceeding under

                                       22

<PAGE>   23

                           Confidential Materials omitted and filed separately
                         with the Securities and Exchange Commission. Asterisks
                         denote omissions.

                    the United States Bankruptcy Code or any other federal or
                    state bankruptcy, reorganization, receivership, insolvency
                    or other similar law affecting the rights of creditors
                    generally; or (z) the commencement against either Party of
                    any proceeding under the United States Bankruptcy Code or
                    any other federal or state bankruptcy, reorganization,
                    receivership, insolvency or other similar law affecting the
                    rights of creditors generally, which proceeding is not
                    dismissed within thirty (30) days.

          (d)  Remedies. Upon any event of default, and in addition to any other
               remedies either Party may have at law or in equity, the
               non-defaulting Party may cancel any outstanding Order, refuse to
               make or take further Orders or deliveries, cancel any discount
               given, and declare all obligations immediately due and payable.
               The non-defaulting Party shall have all the remedies of a secured
               party under the Uniform Commercial Code and any other applicable
               law. The defaulting Party shall be liable for the other Party's
               expense of retaking, holding, preparing for sale, selling and the
               like, including reasonable attorneys' fees and legal expenses in
               the event of default. Cancellation fees shall not be due and
               payable.

    23.3. INSURANCE.

          Upon request, Aspect shall provide evidence of product liability,
          general liability and property damage insurance against an insurable
          claim or claims which might or could arise regarding Aspect products
          purchased from Aspect. Such insurance will contain a minimum limit of
          liability for bodily injury and property damage of not less than
          2,000,000 (two million) US$.

24. GENERAL PROVISIONS.

     (a)  Force Majeure. In the event that either Party is prevented from
          performing, or is unable to perform, any of its obligations under this
          Agreement due to any act of God, fire, casualty, flood, war, strike,
          lock out, failure of public utilities, injunction or any act,
          exercise, assertion or requirement of governmental authority,
          epidemic, destruction of production facilities, insurrection,
          inability to procure materials, labor, equipment, transportation or
          energy sufficient to meet manufacturing needs, or any other cause
          beyond the reasonable control of the Party invoking this provision,
          and if such Party shall have used its best efforts to avoid such
          occurrence and minimize its duration and has given prompt written
          notice to the other Party, then the affected Party's performance shall
          be excused and the time for performance shall be extended for the
          period of delay or inability to perform due to such occurrence.

     (b)  Publicity. Neither Party shall originate any publicity, news release
          or other public announcement relating to this Agreement or the
          existence of an arrangement between the Parties without the prior
          written approval of the other Party, except as otherwise required by
          law.

                                       23

<PAGE>   24

     (c)  Waiver. The waiver by either Party of a breach or a default of any
          provision of this Agreement by the other Party shall not be construed
          as a waiver of any succeeding breach of the same or any other
          provision, nor shall any delay or omission on the part of either Party
          to exercise or avail itself of any right, power or privilege that it
          has, or may have hereunder, operate as a waiver of any right, power or
          privilege by such Party.

     (d)  No Agency. Nothing contained in this Agreement shall be deemed to
          constitute either Party as the agent or representative of the other
          Party, or both Parties as joint ventures or partners for any purpose.
          Neither Party shall be responsible for the acts or omissions of the
          other Party, and neither Party will have authority to speak for,
          represent or obligate the other Party in any way without prior written
          authority from the other Party.

     (e)  Survival of Obligations. All obligations of either Party which, by
          their nature, require performance after the expiration or termination
          of this Agreement, namely the sections on Royalties (5.(c)), Warranty
          (11), Service and Support (12), Regulatory Matters (14), Ownership and
          Protection of Results (16), Confidentiality (18), Indemnities (19),
          Trademarks (20) shall survive the expiration or termination of this
          Agreement and continue to be enforceable.

     (f)  LIMITATION ON LIABILITY. EXCEPT AS PROVIDED IN SECTION 19.1, ASPECT'S
          LIABILITY ARISING OUT OF THE MANUFACTURE, SALE OR SUPPLYING OF ASPECT
          PRODUCTS OR THEIR USE OR DISPOSITION, WHETHER BASED UPON WARRANTY,
          CONTRACT, TORT OR OTHERWISE, SHALL NOT EXCEED THE AMOUNT OF
          2,000,000.00 (TWO MILLION) US$. IN NO EVENT SHALL ASPECT BE LIABLE TO
          HP OR ANY OTHER PERSON OR ENTITY FOR SPECIAL, INCIDENTAL,
          CONSEQUENTIAL, OR OTHER INDIRECT DAMAGES (INCLUDING, BUT NOT LIMITED
          TO, LOSS OF PROFITS, LOSS OF DATA OR LOSS OF USE DAMAGES) ARISING OUT
          OF THE MANUFACTURE, SALE OR SUPPLYING OF ASPECT PRODUCTS.

     (g)  Severability. In the event that any provision of this Agreement is
          held by a court of competent jurisdiction to be unenforceable because
          it is invalid or in conflict with any law of any relevant
          jurisdiction, the validity of the remaining provisions shall not be
          affected and the rights and obligations of the Parties shall be
          construed and enforced as if the Agreement did not contain the
          particular provisions held to be unenforceable.

     (h)  Governing Law. This Agreement shall be governed by and construed in
          accordance with the laws of the Commonwealth of Massachusetts.

     (i)  Notices. Any notice or communication with regard to the termination of
          or changes to this Agreement from one Party to the other shall be in
          writing and either personally delivered or sent via certified mail,
          postage prepaid and return receipt requested addressed, to such other
          Party at the address of such Party specified in this Agreement or such
          other address as either Party may from time to

                                       24

<PAGE>   25

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

          time designate by notice hereunder.

     (j)  Entire Agreement. This Agreement constitutes the entire agreement
          between the Parties. No waiver, consent, modification or change of
          terms of this Agreement shall bind either Party unless in writing
          signed by both Parties, and then such waiver, consent, modification or
          change shall be effective only in the specific instance and for the
          specific purpose given. There are no understandings, agreements,
          representations or warranties, expressed or implied, not specified
          herein regarding this Agreement or the Aspect Products purchased
          and/or licensed hereunder. Only the terms and conditions contained in
          this Agreement shall govern the transactions contemplated hereunder,
          notwithstanding any additional, different or conflicting terms which
          may be contained in any Order or other document provided by one Party
          to the other. Failure of Aspect to object to provisions contained in
          any Order or other document provided by HP shall not be construed as a
          waiver of the terms and conditions of this Agreement nor an acceptance
          of any such provision. Retention by HP of Aspect Products delivered
          hereunder shall be conclusively deemed to be a confirmation of the
          terms and conditions hereof.

     (k)  Headings. Captions and headings contained in this Agreement have been
          included for ease of reference and convenience and shall not be
          considered in interpreting or construing this Agreement.

     (l)  Exhibits: The following Exhibits shall be part of this Agreement:

                    Exhibit A:         Aspect Products and Purchase Prices

                    Exhibit B:         Aspect's Standard Module Kit

                    Exhibit C:         Contact Persons/Addresses Prices

                    Exhibit D:         Change Notification Agreement

                    Exhibit E:         Delivery and Packaging Standard

                    Exhibit F:         Service/Repair

                    Exhibit G:         Co-Marketing Program

                    Exhibit H:         Aspect Trademarks

                    Exhibit I:         [**]

         IN WITNESS WHEREOF, this Agreement has been duly executed as a sealed
instrument as of the date specified above.

Aspect Medical Systems, Inc.                       Hewlett-Packard GmbH

By: /s/ J. Breckenridge Eagle                By: /s/ Anthony [illegible]
   --------------------------                   ------------------------------
Title:  Chairman                             Title:    General Manager
      -----------------------                      ---------------------------
                                                   Patient Monitoring Division

                                       25

<PAGE>   26

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

                EXHIBIT (A):ASPECT'S PRODUCTS AND PURCHASE PRICES
<TABLE>
<CAPTION>

ORDERABLE                                  ASPECT             HP         UNITS (EA)       Aspect               HP          ROYALTIES
PARTS / PRODUCTS                          PART NO.         ID Number     CASES (PK)     List Price         Base Price        (US$)
                                                                                           (US$)        (US$) - Note A
----------------------------------        --------         ---------     ----------     ----------      ---------------    ---------
<S>                                      <S>               <C>           <C>            <C>             <C>                <C>
BIS MODULE KIT (new unit, includes          tbd               tbd           1 ea           [**]               [**]            [**]
DSC, DSC Cable, HP BIS Engine,
Module Cable, User Manual)

Sensor Startup Kit                                                          5 ea                              [**]            [**]

DSC (replacement)                                                                                             [**]            [**]

DSC Cable (replacement)                                                                                       [**]            [**]

HP BIS Engine (replacement)                                                                                   [**]            [**]

Module Cable (replacement)                                                                                    [**]            [**]

User Manual                                                                                                   [**]            [**]
Service Manual                                                                                                [**]            [**]

BIS Application Note (english)                                                                                [**]            [**]

BIS Application Note (french)                                                                                 [**]            [**]

 ...                                                                                                                           [**]
BIS Brochure                                                                                                  [**]            [**]
                                                                                                                              [**]

</TABLE>

Note A:

The HP Purchase Price is the sum of the [**] (based on [**] and the [**] (based
on [**]. In addition to the [**] specified above, HP shall pay to Aspect for
each BIS Module Kit purchased an additional sum to allow Aspect to recover the
incremental costs for Aspect to provide the [**] (including the [**] in lieu of
[**]. It is currently estimated that these incremental costs will be [**] per
module kit.

                                       26

<PAGE>   27

          Confidential Materials omitted and filed separately with the
          Securities and Exchange Commission. Asterisks denote omissions.

EXHIBIT (B):              ASPECT'S STANDARD MODULE KIT

ASPECT'S STANDARD BIS MODULE KIT.

Aspect's BIS 'Module Kit' is designed specifically for [**] and allows the [**]
and to the [**] and the necessary power connections.

The BIS Module Kit consists of a [**] that is placed in [**] that provides the
[**] the high performance analog to [**] of the [**] from the [**] that is [**]
at the [**].

The BIS Engine [**] on the [**] to the [**] via the [**] is constructed [**] to
the [**] are a [**]

       Detailed Technical Specifications:
       ----------------------------------

       Digital Output:              [**]
                                    [**]

       Main Parameters:             [**]
                                    [**]

       Electrical Safety:           [**]

       Power:                       [**]
                                    [**]
                                    [**]

       Artifact Rejection:          [**]

       Bispectral Index:            [**]

       Digital Signal Converter (DSC-2)
       --------------------------------
       Description:                 [**]

                                       27

<PAGE>   28

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

       Weight:                      [**]

       Dimensions:                  [**]
                                    [**]

       Cable Length:                [**]

BIS Engine PCB

       Physical:                    [**]

       Processing Power:            [**]

Software Upgrades

       [**] software is stored in [**]. Software upgrades can be [**] via the
       [**].

Serial Identifier

       [**] is given a [**]. This allows for [**] of every [**].

Annual Failure Rate

       The current [**] rate for the [**] and the [**] of the Project, this
       information will need to be [**]

                                       28

<PAGE>   29

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

                     Exhibit (C): Contact Persons/Addresses

                   Contact Persons and responsibilities at HP:
                   ------------------------------------------

 -------------- ------------- ---------------------- --------------------
  Person         Title         Responsibility         E-mail
                                                      Phone Number/
                                                      Fax Number
 -------------- ------------- ---------------------- --------------------
 [**]            [**]          [**]                   [**]
 -------------- ------------- ---------------------- --------------------

MAILING ADDRESS:    Hewlett-Packard GmbH
                    [**]

PHONE:              [**]

INVOICE ADDRESS:    Hewlett-Packard GmbH

                                       29
<PAGE>   30

               Confidential Materials omitted and filed separately with the
               Securities and Exchange Commission. Asterisks denote omissions.

                     Exhibit (C): Contact Persons/Addresses

                Contact Persons and responsibilities at Aspect:
                -----------------------------------------------

 -------------- ------------- ---------------------- --------------------
  Person         Title         Responsibility         E-mail
                                                      Phone Number/
                                                      Fax Number
 -------------- ------------- ---------------------- --------------------
 [**]            [**]          [**]                   [**]
 -------------- ------------- ---------------------- --------------------

MAILING ADDRESS:    Aspect Medical Systems, Inc.
                    2 Vision Drive
                    Natick, MA 01760-2059
                    USA

                                       30
<PAGE>   31

EXHIBIT (D):  CHANGE NOTIFICATION AGREEMENT FORM

                                       31

<PAGE>   32

--------------------------------------------------------------------------------
                     Hewlett-Packard Medical Products Group
--------------------------------------------------------------------------------

MPG SUPPLIER CHANGE NOTIFICATION AGREEMENT FORM

             -------------------------------------------------------------------

NOTICE         UNCONTROLLED IN PRINTED FORM UNLESS STAMPED IN RED

             -------------------------------------------------------------------

DOCUMENT     The document owner is listed below:
OWNERSHIP

             --------------------------------- ---------------------------------
                         FUNCTION                            TITLE
             --------------------------------- ---------------------------------
              MPG Quality Department            Quality System Engineer
             --------------------------------- ---------------------------------

                         ---------- ------------------ -------------------------
REVISION HISTORY
                         ---------- ------------------ -------------------------
                           REV. #     CHANGE ORDER #        CHANGE SUMMARY
                         ---------- ------------------ -------------------------
                             A      2920-1998-01-00009
                         ---------- ------------------ -------------------------
                             B      2920-1998-01-00019  Revise footer to read
                                                        "HP Proprietary".
                                                        Separate "Contact for
                                                        Questions" and Return
                                                        To".
                         ---------- ------------------ -------------------------

                                       32

Rev. B  Document Number: A-Q2920-00142    GRS#MF502                  Page 1 of 2
Title: MPG Supplier Change Notification Agreement Form  For HP Internal Use Only

<PAGE>   33

--------------------------------------------------------------------------------
                     Hewlett-Packard Medical Products Group
--------------------------------------------------------------------------------

MPG SUPPLIER CHANGE NOTIFICATION AGREEMENT FORM, continued

--------------------------------------------------------------------------------
 TO:                                     FROM:
--------------------------------------  ----------------------------------------
 SUPPLIER NAME:                          DATE:
--------------------------------------  ----------------------------------------
 SUPPLIER FAX # OR ADDRESS:
                          ----------------------------------------------------

                          ----------------------------------------------------

                          ----------------------------------------------------

--------------------------------------------------------------------------------
DEAR SUPPLIER, CONTRACTOR, OR CONSULTANT:
Hewlett Packards's Medical Products Group (MPG) manufactures in a regulated
environment, and is required to maintain procedures to ensure that all purchased
products and services conform to specified requirements. MPG has determined that
the product or service you supply to MPG impacts, directly or indirectly, the
quality of our finished devices. We ask that you agree to notify MPG of any
changes in the product or service, so that we can determine whether the change
may affect the quality of our finished devices. Although HP's standard purchase
order terms and conditions include this provision, the intent of this document
is to ensure direct supplier recognition and acceptance of this requirement.
TO ENSURE THAT MPG HAS YOUR AGREEMENT ON THIS REQUIREMENT, WE ASK THAT YOU
REVIEW AND SIGN THE AGREEMENT BELOW. IT IS REQUESTED THAT THE SIGNATORY BE THE
QUALITY MANAGER AND THE GENERAL MANAGER (OR DESIGNEE) DIRECTLY INVOLVED WITH THE
MANUFACTURER OF OUR PRODUCT.

--------------------------------------------------------------------------------
                          CHANGE NOTIFICATION AGREEMENT
                          -----------------------------

Changes to product, components or services supplied to Hewlett Packard Medical
Products Group (MPG) will not be made without prior written notification to, and
written approval from, MPG. This includes, but is not limited to, the following
types of changes:
*  Product or service design changes
* Production process changes that affect design and/or production specifications
* Change of manufacturing or service facility location
* Changes that have a significant impact upon your quality system
* Other
       -----------------------------------------------------------------------
Notification must be made to each MPG purchasing location affected by this
change.
--------------------------------------------------------------------------------
SUPPLIER COMMENTS:
                  ------------------------------------------------------------

                  ------------------------------------------------------------

--------------------------------------------------------------------------------
QUALITY MGR:                            GENERAL MGR (OR DESIGNEE):
--------------------------------------  ----------------------------------------
SIGNATURE:                                                   SIGNATURE:
DATE:                                                        DATE:
                                                             TITLE:
--------------------------------------  ----------------------------------------
CONTACT FOR QUESTIONS:                                       TELE:
--------------------------------------  ----------------------------------------
RETURN TO:
--------------------------------------------------------------------------------
STREET:                                                      CITY/STATE/ZIP:
TELE:                                                        FAX:
--------------------------------------------------------------------------------

                                       33
<PAGE>   34

EXHIBIT (E):  DELIVERY AND PACKAGING STANDARD

                                       34
<PAGE>   35

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

 ORIGINATOR:  HP/CPDE-ENGINEERING, G-BOBLINGEN

 TABLE OF CONTENTS                                        PAGE
 -----------------                                        ----

1.       GENERAL
1.1.     Applicability                                     2
1.2.     Place of delivery                                 2

2.       DEFINITIONS                                       2

3.       IDENTIFICATION REQUIREMENTS                       3
3.1.     Delivery Note                                     3
3.2.     Load Unit Label                                   4
3.3.     Product Identification Label                      5
3.4.     Customs Declaration                               5
3.5.     Transport Declaration (Dangerous Goods)           5

4.       PACKAGING REQUIREMENTS                            6
4.1.     Delivery Mode                                     6
4.2.     Packages (Boxes)                                  6
4.3.     Load Carriers (Pallets)                           6
4.4.     Dimensions                                        7
4.5.     Load Unit Protection                              7
4.6.     Environmental Requirements                        7
4.7.     Transport Regulations (Dangerous Goods)           7
4.8.     Treatment of Inconsistencies                      8

5.       REVISION CONTROL                                  8

                                       35
<PAGE>   36

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

1.       GENERAL
----------------

1.1.     APPLICABILITY
         This specification is applicable to all goods delivered to the premises
         of Hewlett-Packard Businesses in Boblingen and Waldbronn with according
         production plants and distribution centers in Europe.

         Practices other than those stipulated herein must be ratified on a
         case-by-case basis by the purchasing department concerned.
         Hewlett-Packard reserves the right to reject deliveries that do not
         comply with this specification.

1.2.     PLACE OF DELIVERY
         Since HP has several receiving locations in Europe it is essential that
         goods be delivered to the address specified on the purchase order or in
         the purchasing agreement.

2.       DEFINITIONS
--------------------

         [Graphic depiction of track, load units, product labels, load
         carrier/pallet, package/box and mother/box]

                                       36
<PAGE>   37

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

3.       IDENTIFICATION REQUIREMENTS
------------------------------------

3.1.     DELIVERY NOTE:
         no deliveries without a delivery note
         delivery note has to be fixed on the outside of the load or handed out
         by the freight forwarder

--------------------------------------------------------------------------------
                          DELIVERY NOTE / LIEFERSCHEIN

Supplier:
Fa Meler u Sohne
Kaakonbachatr 34
8000 Monehen
Tel:  (089) 2804-1999

--------------------------------------------------------------------------------
SUPPLIER CODE  0055885
--------------------------------------------------------------------------------

--------------------------------------  ----------------------------------------
DELIVERY NOTE NO.:  349812              DATE:  16.01.1999
--------------------------------------  ----------------------------------------
SHIP TO:
Hewlett-Packard GmbH
c/o Logistic Group International
Waldbronn Gebaude 5
Herronbarger Str. 124
71034 Boblingen
--------------------------------------------------------------------------------
RECEIVING ENTITY/NAME:  CPOE / Hohenstein
--------------------------------------------------------------------------------
DESTINATION CODE                    BB14-4500
--------------------------------------------------------------------------------
LOAD UNIT:                          12 boxes on 3 pallets
--------------------------------------------------------------------------------
BOX NO'S:                           6016-XX001 - 6016-XXX12
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
POS. HP ORDER NO.  SECTION      ITEM     HP PART NO.    QUALITY    UNIT MEASURED
      (9 digits)  (3 digits) (4 digits)                 (shipped)    (shipped)
---- ------------ ---------- ---------- ------------- ----------- --------------
     [Graphic depiction of bar codes]
---- ---------------------------------------------------------------------------
 01   N81853921    010.       0100        8120-6809     1000        EA
---- ------------ ---------- ---------- ------------- ----------- --------------
 DESCRIPTION:  Powercord:  UK version
--------------------------------------------------------------------------------
     [Graphic depiction of bar codes]
---- ---------------------------------------------------------------------------
 02   N81853821    0100       010         5964-6108     1200        EA
---- ------------ ---------- ---------- ------------- ----------- --------------
DESCRIPTION:  Software & Accessories Broschore
--------------------------------------------------------------------------------
COUNTRY OF ORIGIN  Germany    [Graphic depiction of bar codes]
--------------------------------------------------------------------------------

                           OPTIONAL DATA PER BUSINESS
        -----------
Legend:  MUST DATA
        -----------

                                       37
<PAGE>   38

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

32.      LOAD UNIT LABELS
         (unique products only)
An adhesive label shall be affixed to each load unit. If a delivery is
consisting of multiple, separate load units, the individual load unit shall be
numbered consecutively (e.g., 1 of 7, 2 of 7, etc.)
--------------------------------------------------------------------------------
                    LOAD UNIT LABEL/LADEENIHEITENAUSZEICHUNG
                (UNIQUE PRODUCTS ONLY       NUR SORTENREINE WARE)

Supplier:
Fa Meler u Sohne
Kaakonbachatr 34
8000 Monehen
Tel:  (089) 2804-1999
--------------------------------------------------------------------------------
SUPPLIER CODE  0055865
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
DELIVERY NOTE NO.:  349912              DATE:  15.01.1999
--------------------------------------  ----------------------------------------
SHIP TO:
Hewlett-Packard GmbH
c/o Logistic Group International
Waldbronn Gebaude 5
Herronbarger Str. 124
71034 Boblingen
--------------------------------------------------------------------------------
RECEIVING ENTITY/NAME:  CPOE / Josef Hohenstein
--------------------------------------------------------------------------------
DESTINATION CODE                    B614-4500
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
(p) HP PRODUCT                                                TOTAL WEIGHT (kg)
NO.
-----------------    -----------------    -----------------   ------------------
[Graphic depiction of bar codes]
--------------------------------------------------------------------------------
C2530-84430                                                   283
-----------------    -----------------    -----------------   ------------------

-----------------    -----------------    -----------------   ------------------
(q) QUANTITY:        LOAD UNIT NO:                            SUPPLIER LOT NO.
--------------------------------------------------------------------------------
[Graphic depiction of bar codes
--------------------------------------------------------------------------------
Q6000                T12345878                                987654
-----------------    -----------------    -----------------   ------------------

-----------------    -----------------    -----------------   ------------------
  HP ORDER NO:            SECTION:              ITEM:         COUNTRY OF ORIGIN:
   (9-digits)            (3-digits)          (4-digits)
--------------------------------------------------------------------------------
[Graphic depiction of bar codes]
--------------------------------------------------------------------------------
N820-86975           010                  0100                USA
-----------------    -----------------    -----------------   ------------------
Box 1 of 3
--------------------------------------------------------------------------------
                           OPTIONAL DATA PER BUSINESS

        -----------
Legend:  MUST DATA
        -----------

                                       38
<PAGE>   39

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

3.3.     PRODUCT IDENTIFICATION LABELS
         Each smallest package unit (picking unit) of an article must be labeled
         on the outside and shall contain only parts having the same part number
         belonging to the same order.

--------------------------------------------------------------------------------
 (p) HP PART NO:
---------------------------------- ------------------ --------------------------
 [Graphic depiction of bar codes]
--------------------------------------------------------------------------------
 P9Z80-1250
---------------------------------- ------------------ --------------------------
 DESCRIPTION:  Monitor EX300 VGA
---------------------------------- ------------------ --------------------------
 (q) QUANTITY:                      UNIT MEASURE:      VOLUME (cdm)
---------------------------------- ------------------ --------------------------
 [Graphic depiction of bar codes]
--------------------------------------------------------------------------------
 Q1                                 EACH               180
---------------------------------- ------------------ --------------------------
 COUNTRY OF ORIGIN:                 SUPPLIER LOT NO:   (s) SERIAL NO:  (Range)
---------------------------------- ------------------ --------------------------
 [Graphic depiction of bar codes]
---------------------------------- ------------------ --------------------------
 GERMANY                            T12345678          2323444
--------------------------------------------------------------------------------

                           OPTIONAL DATA PER BUSINESS
        -----------
Legend:  MUST DATA
        -----------

3.4.     CUSTOMS DECLARATION
         For deliveries from Non-EU countries and customs relevant deliveries
         from EU countries an Invoice must be attached with all infos for
         customs declaration (Part number, Oder number, Quantity, Box quantity
         and Box weight, Box number, Currency, Item-value and invoice-value,
         Terms of Delivery, CoO, Terms of payment etc.).
         Customs relevant deliveries must be notified on Boxes and Documents.

3.5.     TRANSPORT DECLARATIONS (DANGEROUS GOODS)
         Dangerous Goods must be notified on Boxes and Documents

                                       39
<PAGE>   40

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

4.       PACKAGING REQUIREMENTS
-------------------------------

4.1.     DELIVERY MODE
         Goods shall be delivered on pallets, if

         --       the volume exceeds 1 m(3)(35 cubic feet)
         --       the weight exceeds 25 kg (66 lbs)
         --       or the consignment consists of more than 5 package units

                  maximum weight per consignment unit:  1000 kg
                  (2200 lbs) incl. load carrier

4.2.     PACKAGES (BOXES)
         Individual packages shall not have a handling weight exceeding 15 kg
         (33 lbs)

4.3.     LOAD CARRIERS (PALLETS)
         All goods shall be delivered on reusable four-way-entry flat pallets
         made of untreated solid wood. Openings for the handling with pallet
         jacks have to be kept open on the small sides (base runners lengthwise
         only).

         Pallets have to be accessible from four sides by regular material
         handling devices. Dimensions must be (unless otherwise specified):
         --       1200 x 100 mm (industry pallets);
         --       1200 x 800 mm Euro pallet
         In exceptional cases 40 x 48 inches.

[Graphic depiction of a load carrier (pallet)]

                                       40
<PAGE>   41

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

4.4      DIMENSIONS
         The goods shall be stacked on the pallet without overhang. A load unit
         shall not exceed an overall height of 1930 mm (76 inches) - including
         pallet. Additional restrictions on height may apply depending on the
         destination, and the purchasing department in question must be
         consulted regarding these restrictions.

4.5.     LOAD UNIT PROTECTION
         Shipment units shall be secured in such a way the good cannot slip or
         the unit loose its integrity. This shall be ensured by the use of
         shrink or stretch wrapping, banding, additional layer sheets,
         interlocked stacking, etc., but shall not hinder the accessibility with
         material handling devices (fork lifts or pallet jack). The products
         shall not be damaged by the LoaD Unit Protection.

4.6.     ENVIRONMENTAL REQUIREMENTS FOR PACKAGING
         GENERAL POINTS
         Packaging should be kept to the minimum amount required to preserve the
         security and hygiene of the packaged products.
         Additionally, any applicable legal norms (see appendix) as well as HP
         specific regulations concerning environment, workplace safety and
         workplace security are to be adhered to. (Refer also to HP's GENERAL
         SPECIFICATION FOR ENVIRONMENT A-5951-1745-1).

         REQUIREMENTS
         --       Low material variety per packaging
         --       Easy separability of the various materials
         --       Avoidance of composite materials
         --       Use of standard and reusable packaging
         --       Material labeling (especially with plastics)
         --       Handling labeling

         --       Recommended packaging materials:
                  Paper, cardboard, corrugated cardboard, untreated wood, iron,
                  aluminum, glass, PE, PP, PS, PET, drying agents: silica gel,
                  active clay

         --       Packaging materials and packaging aids to be avoided:
                  PVC (vinyl), wood chips, compressed fiberboard, wood shavings,
                  straw, loose fill materials, "bio" packaging materials based
                  on plant starch, "popcorn"

         APPENDIX: EXCERPTS OF THE RELEVANT LEGAL NORMS FOR PACKAGING AND
         PACKAGING WASTE
         --       European Waste Guidelines (Europaische Abfallrahmenrichtlinie)
                  75/442/EWG
         --       European Packaging Guidelines (Europaische
                  Verpackungsrichtlnie) 94/62/EG
         --       European Decision 97/129/EG regarding the labeling of
                  packaging material
         --       Industrial Recycling law (Kreislaufwirtschaftsgesetz) and
                  accompanying Waste Law
         --       Transport of Hazardous Waste Law (Gefahrgutbeforderungsgesetz)
                  and accompanying Hazardous Waste Law (Gefahrgutrecht/e.g GGVS)
         --       Packaging Act
         --       Chemical Law (Chemikaliengesetz) and Hazardous Materials Act
                  (Gefahrstoffverordnung) "BGB"
         --       CFC-Halon Prohibition Act (FCKW-Halon-Verbots-Verordnung)

4.7.     TRANSPORT REGULATIONS (DANGEROUS GOODS)

                                       41
<PAGE>   42

--------------------------------------  ----------------------------------------

 HEWLETT-PACKARD GMBH                    DELIVERY-AND PACKAGING STANDARD
 HEWLETT-PACKARD EUROPE BV

--------------------------------------  ----------------------------------------

4.8.     TREATMENT OF INCONSISTENCIES
         In many instances, the packaging is covered by the stipulations of the
         HP product specification. In the event of inconsistencies arising with
         the packaging regulations in the product specification or in existing
         agreements, the supplier shall consult the purchasing department
         concerned.

5.       REVISION CONTROL
-------------------------

--------------------------------------------------------------------------------
   Revision     Changes                            Approved           Date
-------------- ---------------------------------- ------------------ -----------
       D        Completely revised;                Peter Klement      28.04.1999
                English Edition A-5961-3658-1
                German Edition A-5961-3658-2
-------------- ---------------------------------- ------------------ -----------

--------------------------------------------------------------------------------

                                       42
<PAGE>   43
     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

                          EXHIBIT (F): SERVICE/REPAIR

1. REPAIR STRATEGY:

FULL UNIT REPAIR:

-    Defective units will be shipped from HP GSL (Global Support Logistics) to
     Aspect for repair.
-    Aspect repairs and ships the units within [**] to HP GSL after receipt.
     Each repair unit will be labeled with an internal HP order number and
     tracking number by Aspect. Tracking number and maybe other data must be
     labeled as barcode on the shipment carton by Aspect.

2. Repair Price

Repair consists of [**]

To define for each product:
[**]

Goal for full unit exchange: [**]
Right for Aspect to [**]

To define: [**]

A table detailing the [**] will be defined preliminarily during [**].

3. Handling of Repair Costs:

[**] will pay the then current [**] for any defective unit that is returned to
Aspect. On a regular basis HP will determine the number of units under warranty
that have been replaced/repaired and [**].
Repaired units with "No trouble found" classification Aspect [**] for the
difference between [**] and the following amounts only [**].

                                       43
<PAGE>   44
     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

                       EXHIBIT (G): CO-MARKETING PROGRAM

ASPECT/HP JOINT MARKETING PROGRAM - NORTH AMERICA

Both Parties have agreed on the following outline for a joint marketing program,
designed to encourage customers in North America to [**] to implementation of an
integrated BIS measurement module on HP Viridia patient monitors.

PROGRAM DETAILS:

Aspect's and HP's sales force in North America will offer the [**] and will
agree to [**] for the [**] of the [**] of the [**] at a price of [**] the
current list price for the [**], unless the Parties agree that [**] that the
[**] under this program should be [**]. The current list price for the [**], as
outlined below.

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
                         Qty 1     Qty 2-5    Qty 6-12    Qty 13-19    Qty >20
--------------------------------------------------------------------------------
<S>                      <C>        <C>         <C>          <C>        <C>
List Price $             [**]       [**]        [**]         [**]       [**]
--------------------------------------------------------------------------------
[**]       $             [**]       [**]        [**]         [**]       [**]
--------------------------------------------------------------------------------
</TABLE>

1.   [**] to [**] to fulfill [**] by this program will be purchased at a [**]
     of [**].

2.   Customers taking advantage of this program will be [**] an [**] of [**] for
     the [**] (to be defined) [**] of the [**] for [**] in North America [**],
     although customer expectations need to be set [**]. There  will be [**] to
     the customer for this [**], although the customer may need to [**] to [**]
     some of his [**] (see below).

3.   Aspect and HP will jointly [**] for this [**] and [**] will provide
     information on the expected cost to the customer of having to [**] in order
     to be [**] with the [**].

4.   [**] the [**] this program and who also purchase [**] under the program,
     these new [**] will be [**] to the appropriate [**] (if necessary) at [**].

5.   Both parties will [**] a [**] this program for customers who have recently
     purchased the [**] was [**].

6.   Aspect will for customers who [**] after the  [**] and invoice the
     customer.

                                       44
<PAGE>   45
     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

7.   Aspect will [**] on a [**] for [**] of [**] as a result of this program
     (account details to be defined).

8.   Aspect will provide [**] of [**] this program on a [**].

9.   HP will [**] of [**] of [**] from customers taking advantage of this
     program. The methodology for the calculation and payment of these [**] will
     be defined in the Distribution Agreement between the Parties.

10.  [**] the [**] is [**] will be responsible for [**] at those sites under the
     program. Aspect will be [**] for [**] of the [**].

11.  The timing for implementation of this program will be determined by [**] of
     [**] and [**] of [**], based on their [**] the [**] schedule. The current
     expectation is that this could be done once the project has [**] of the
     [**], at which point [**] has been defined and all risks are understood.

12.  In the event that the [**] is [**], for whatever reason, [**] for [**]
     under this program [**] the customer for any [**] for the [**] the list
     prices defined above.

13.  If development of the [**] is [**] such that [**] North American [**], both
     Parties [**] with a [**] of [**]. [**] of [**] by both Parties in good
     faith, [**] determined by reasons for the [**].

14.  In the event that the customer [**] the [**] for [**] and [**] the customer
     for any [**] made for the [**] the [**] the list prices defined above.

                                       45
<PAGE>   46

                         EXHIBIT (H): ASPECT TRADEMARKS

                                       46
<PAGE>   47

                         EXHIBIT (H): ASPECT TRADEMARKS

TRADEMARK                  REFERENCE
---------                  ---------

Aspect(R)                  None *
A-2000(TM)                 A-2000 is a trademark of Aspect Medical Systems, Inc.
Bispectral Index(R)        Bispectral is a registered trademark of Aspect
                           Medical Systems, Inc.
BIS(R)                     BIS is a registered trademark of Aspect Medical
                           Systems, Inc. BIS logo is a registered trademark of
                           Aspect Medical Systems, Inc.

[graphic depiction of Aspect's BIS logo]

*   This trademark is registered as a trademark to another company, and is used
    under license by Aspect Medical Systems.

                                       47
<PAGE>   48
     Confidential Materials omitted and filed separately with the Securities
              and Exchange Commission. Asterisks denote omissions.

                               EXHIBIT (I): [**]

[**]

WHEREAS

We, [**], herewith confirm that we have knowledge that Hewlett-Packard GmbH,
Herrenberger Str. 110-140, 71034 Boblingen, Germany ("HP") has granted Aspect
Medical Systems, Inc., 2 Vision Drive, Natick, MA 01760-2059, USA ("Aspect")
[**] under an "OEM Development and Purchase Agreement" (hereinafter referred to
as the "Agreement"), dated August 6th, 1999 and Aspect has certain contingent
obligations to refund portions of such prepayment in accordance with Section 5
(c) of this Agreement.

THEREFORE

We undertake, [**] under the Agreement. We undertake with [**] in accordance
with the Agreement, we shall [**].

[**] of the Agreement [**]. It is understood that the [**] of the Agreement.

                                       48

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