<PAGE>

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

                                                                    Exhibit 10.1

                          ASPECT MEDICAL SYSTEMS, INC.

                     OEM DEVELOPMENT AND PURCHASE AGREEMENT

Agreement dated this February 13, 2003, by and between Aspect Medical Systems,
Inc., a Delaware corporation with its principal offices located at 141 Needham
Street, Newton, Massachusetts ("Aspect") and Dixtal ("Dixtal"), a Brazilian
corporation with its principal offices located at Av. Rodrigo Otavio, 1111
Japiim, Manaus - AM, Brazil 69077-000 for the purchase and/or license by Dixtal
of products under the terms and conditions contained in this Agreement.

1.       BACKGROUND

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

         1.2      Dixtal is a developer, manufacturer and distributor of medical
                  devices, equipment, related hardware, software and related
                  products and accessories, including multiparameter patient
                  monitors.

         1.3      Dixtal desires to integrate Aspect's BIS technology into
                  Dixtal's multiparameter patient monitors.

         1.4      Aspect agrees to sell and/or license to Dixtal the products
                  described below, subject to the terms and conditions contained
                  in this Agreement.

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.

         "Dixtal Patient Monitor" means any multi-parameter patient monitoring
         system manufactured by or for Dixtal. When the BIS Module Development
         Project is complete, the Dixtal BIS module will allow the Dixtal
         Patient Monitor to display BIS and provide setup and operation
         information (user interface), alarming, and network connectivity.

         "Dixtal BIS Module" is the sum of all components involved in
         integrating the BIS with Dixtal Patient Monitors.

         "DSC Cable" is a cable used to connect the DSC-XP to the Dixtal BIS
         Engine.

         "Dixtal 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 Dixtal.

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<PAGE>

         "Digital Signal Converter - XP" (or "DSC-XP") is used to amplify the
         analog EEG signals as acquired by the BIS sensors and convert it from
         analog to digital signals. The DSC-XP components are provided to Dixtal
         by Aspect for final assembly by Dixtal. The DSC-XP is used by Dixtal
         BIS Module customers to obtain the BIS.

         "Aspect BIS Module Kit" are the Aspect components of the Dixtal BIS
         Module that are developed by Aspect and licensed/sold to Dixtal under
         this Agreement: DSC-XP components, DSC Cable, Dixtal BIS Engine, and
         Module Cable. The DSC Cable, Dixtal BIS Engine and Module cable are
         manufactured by Aspect. The DSC-XP components are provided to Dixtal
         for assembly.

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

         "A2000 XP" 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 Kit and any other product
         that can be ordered by Dixtal as listed in Exhibit A (Aspect Products
         and Purchase Prices).

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

         "Documentation" means the BIS Engine Serial Interface Specification.

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

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

                                       2

<PAGE>

3.       BIS MODULE DEVELOPMENT PROJECT.

         3.1      Project Management.

                  (a) Each Party shall appoint a "Project Manager" who shall
                      oversee and manage 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) Each Party shall bear its own communication and travel
                      costs.

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

         3.2      Dixtal Responsibilities.

                  (a) Dixtal shall develop the Dixtal BIS Module according to
                      mutually agreed specifications at Dixtals own cost.

                  (b) Dixtal shall develop, design and test the modular
                      integration of the components of the Aspect BIS Module Kit
                      with the Dixtal Patient Monitors.

                  (c) Dixtal shall assemble and test the DSC-XP using
                      specifications and procedures provided by Aspect. Dixtal
                      shall label the DSC-XP as a Dixtal product and shall
                      establish assembly protocols and labeling conventions to
                      identify on the Dixtal label the board set through the
                      Dixtal label on the DSC-XP housing. In addition to Dixtal
                      product specific information, the label will display the
                      BIS logo and appropriate Aspect trademark references as
                      required in Section 19.1.

         3.3      Aspect Responsibilities.

         Aspect shall design, develop, and test the Aspect BIS Module Kit
         according to the mutually agreed specifications.

4.       PURCHASE AND SALE OBLIGATIONS: LICENSES

         4.1      General. Subject to the terms and conditions of this
                  Agreement, Aspect agrees to sell to Dixtal the Aspect Products
                  listed on Exhibit A (Aspect Products and Purchase Prices). The
                  components of the Aspect BIS Module Kits purchased from Aspect
                  under this Agreement shall only be used as components in,
                  incorporated into, integrated with, the Dixtal BIS Module
                  which Dixtal sells or leases to third-party users in the
                  regular course of business. The components of the Aspect BIS
                  Module Kits shall only be resold, leased, rented, licensed or
                  otherwise transferred to third parties for use as a part of a
                  Dixtal BIS Module or as replacement parts used in Dixtal BIS
                  Modules and Dixtal shall only sell Aspect approved accessories
                  including cables

                                       3

<PAGE>

                  and sensor products in connection with any Dixtal BIS Module.
                  During the term of this Agreement, Dixtal agrees that it may
                  offer complementary but not directly competitive products to
                  the Dixtal BIS Module. Dixtal products other than the Dixtal
                  BIS Module that display a parameter claiming to be a measure
                  of the hypnotic effect of anesthesia, are considered to be
                  directly competitive products for purposes of this Section
                  4.1.

         4.2      Distribution of Aspect BIS Sensors. Aspect hereby grants to
                  Dixtal a non-exclusive right to distribute Aspect BIS Sensors
                  solely to Dixtal customers within Brazil who have purchased
                  Dixtal BIS Modules. Prices for Aspect BIS Sensors purchased by
                  Dixtal hereunder shall be as set forth in Exhibit A (Aspect
                  Products and Purchase Prices).

         4.3      Aspect Software License. Aspect hereby grants to Dixtal a
                  non-exclusive and non-transferable license, without the right
                  to sublicense (except to purchasers of Dixtal BIS Modules),
                  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 Dixtal BIS Module. Thereafter, Aspect grants to Dixtal a
                  right to use the Software and related Documentation used in
                  conjunction with the Dixtal BIS Modules being sold by Dixtal
                  on the date of termination with respect to service and support
                  of installed Dixtal BIS Modules for a period of 10 years after
                  termination of the Agreement. All rights granted to Dixtal
                  customers to use the Dixtal BIS Modules shall survive any
                  termination of this Agreement as long as such customers remain
                  in compliance with the terms of use for such Dixtal BIS
                  Modules. Dixtal 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 Dixtal BIS Modules
                  (including Dixtal's subdistributors) and shall not duplicate
                  the Software, the Documentation or any part thereof (other
                  than for Dixtal's internal use as provided above). Title to
                  and ownership of any and all proprietary rights in or related
                  to the Software and the Documentation therefore shall at all
                  times remain with Aspect or its licensor(s). Nothing in this
                  Agreement shall be construed as a sale of any rights in the
                  Software or the Documentation. All references in this
                  Agreement to sale, resale or purchase of the Aspect BIS Module
                  Kits or the components thereof, or references of 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. Dixtal shall not disassemble,
                  decompile or otherwise reverse engineer the Software or any
                  part thereof. Dixtal shall retain and shall not alter or
                  obscure any notices, markings or other insignia affixed to the
                  Software, the Documentation or any part thereof at the time it
                  receives such Software or such Documentation.

         4.4      Exclusivity. Nothing in this Agreement shall be construed to
                  grant Aspect any license to sell, distribute or license to any
                  third party any components of Dixtal incorporated in the
                  Dixtal BIS Module or the Dixtal BIS Engine. It is understood
                  that Aspect sells, distributes, and licenses to other third
                  parties both generic and customized Aspect BIS Engines and
                  Aspect BIS Module Kits to meet the needs of other OEM
                  customers, and

                                       4

<PAGE>

                  nothing in this Agreement shall prohibit Aspect from
                  continuing to sell, distribute, or license these products or
                  components thereof to customers other than Dixtal.

         4.5      Standard of Care: Priority. In connection with Aspect's
                  performance of its obligations hereunder, Aspect shall use
                  commercially reasonable efforts in the performance of its
                  obligations hereunder and will do so with the same degree of
                  care, skill and prudence customarily exercised when engaged in
                  similar activities for its other OEM customers.

5.       SCOPE OF DELIVERY

         5.1      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 5.6. All Dixtal Purchase Orders
                  shall make reference to the appropriate engineering drawing or
                  manufacturing reference numbers. There is a minimum volume
                  commitment of [**] for the first order. Volume commitments for
                  subsequent years in this Agreement are detailed in Appendix A.

         5.2      Order Acknowledgements. Dixtal purchase orders shall 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 Dixtal is not exceeded by
                  more than [**]% and the quantity ordered does not exceed by
                  more than [**] percent ([**]%) of the quantity ordered in the
                  preceding month. If the requested delivery time is less than
                  the agreed lead time, or if Dixtal's latest forecast is
                  exceeded by more than [**]%, or if the quantity ordered
                  exceeds by more than [**] percent ([**]%) the quantity ordered
                  in the preceding month, Aspect shall use reasonable efforts to
                  complete the requirements of such nonconforming orders within
                  [**] days from the date it receives such nonconforming order
                  and to acknowledge such orders within 10 days of its receipt.
                  Order acknowledgements shall not be unreasonably withheld

         5.3      Forecasts. Dixtal shall furnish to Aspect a non-binding
                  quarterly forecast during the term of this Agreement with the
                  number and type of Aspect Products for which Dixtal expects to
                  submit orders for the following twelve months.

         5.4      Installed Base Reporting. On a quarterly basis, Dixtal will
                  report units installed and overall installed base of Dixtal
                  BIS modules. This report will include number of units
                  installed, date installed and the location.

         5.5      Cancellation Charges. In the event of the cancellation of any
                  Order by Dixtal, Dixtal shall be liable for the payment of
                  cancellation charges based on the number of days prior to
                  scheduled delivery date that written notice of cancellation is
                  received by Aspect, as outlined below:

                                       5

<PAGE>

<TABLE>
<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>

         5.6      Lead Times. Lead times for the Aspect BIS Module Kit are
                  expected to be [**] ([**]) days. Late deliveries are subject
                  to late fees of 1% per month (pro-rated daily). In the event
                  of late deliveries by Aspect, Aspect will also promptly
                  reimburse Dixtal for expedited shipment charges that Dixtal
                  incurs as a direct result of late shipments of the Aspect BIS
                  Module Kit from Aspect.

6.       PRICES.

         6.1      Purchase Prices. The prices of Aspect Products purchased by
                  Dixtal 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).

         6.2      Purchase Price Changes. In consideration of the market
                  situation and after consultation with Dixtal, the Purchase
                  Prices set forth in Exhibit A (Aspect Products and Purchase
                  Prices) shall be reviewed 12 months after first delivery of
                  production units and annually thereafter. Any price adjustment
                  shall become effective only after mutual agreement between
                  both Parties. In the event materials costs for the Aspect
                  Products increase by more than [**] percent ([**]%), 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 Products without the consent of Dixtal by an equivalent
                  amount by delivering reasonable documentation supporting such
                  increase and by giving Dixtal written notice of the increase
                  not less than ninety (90) 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 ninety
                  (90) day period, which are to be delivered within ninety (90)
                  days of the date of such notice. Notwithstanding anything to
                  the contrary in this Section 6.2, no Purchase Price increase
                  shall apply unless Aspect has used its reasonable efforts to
                  find alternate suppliers of the materials that have increased
                  in cost and, despite exercising such reasonable efforts, was
                  not able to locate such alternate suppliers.

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

                                       6

<PAGE>

                  be obligated to make.

7.       TERMS OF PAYMENT.

         7.1      Invoices. Dixtal shall pay to Aspect the Purchase Price for
                  all Aspect Products shipped hereunder within sixty (60) 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 21 (Termination) hereof in
                  the event of Dixtal's failure to make payment when due for
                  Aspect Products delivered to Dixtal. Dixtal shall have the
                  right to provide Aspect with a specific address to which
                  Aspect will send invoices for Aspect Products purchased under
                  this Agreement.

Late Payment Charge. Subject to applicable law, service and/or interest charges
not exceeding the lesser of 1% per month or the highest amount permitted by law
may, at the election of Aspect, be assessed on amounts past due more than thirty
(30) days (that is, more than thirty (30) days after the payment due date as
specified in Section 7.1).

8.       SHIPMENT AND DELIVERY.

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

                         DIXTAL BIOMEDICA IND E COM LTDA
                         AV. RODRIGO OTAVIO, 1111 JAPIIM
                                   MANAUS - AM
                                BRAZIL 69077-000

         8.2      Delivery Terms. All shipments hereunder shall be FOB Aspect's
                  Massachusetts point of origin (Incoterms 1990). All Aspect
                  Products shall be deemed delivered and subject to Dixtal's
                  dominion and control only when placed in the possession of a
                  carrier designated by Dixtal, properly packed and ready for
                  shipment to Dixtal. Aspect shall cooperate with Dixtal in the
                  documentation and proof of loss claims promptly presented by
                  Dixtal to the appropriate carrier and/or insurer.

         8.3      Delivery Date and Date of Dispatch. The requested delivery
                  date shall be specified on the Dixtal Purchase Order provided
                  that such delivery date must be at least [**] days after the
                  date Aspect receives the Order; provided, however, that Aspect
                  shall use its reasonable efforts to deliver the Order as early
                  as reasonably possible (taking other customer demands on
                  Aspect into account). Aspect shall utilize reasonable efforts
                  to ensure that the order is delivered in accordance with
                  Aspect's order acknowledgement and that the date of dispatch
                  is ten (10) days prior to the delivery date. Late delivery
                  penalties to Aspect will apply as specified in Section 5.6 of
                  this Agreement.

                                       7

<PAGE>

9.       ACCEPTANCE.

         Any Aspect Product shipped hereunder may be subjected to inspection and
         performance testing by Dixtal, to confirm that it functions in
         accordance with Aspect's applicable product specifications in effect at
         the time of delivery of such Aspect Products to Dixtal. Dixtal 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.
         Aspect shall have [**] days from receipt of a notice from Dixtal
         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, Dixtal shall dispose of the replaced
         Aspect Product in accordance with Aspect's instructions and at Aspect's
         expense. Dixtal's sole remedy for rejected Aspect Products shall be
         limited to prompt repair or replacement of such Aspect Products.

10.      WARRANTY.

         10.1     General. Aspect warrants solely to Dixtal that Aspect Products
                  (excluding the DSC-XP components) 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 [**] months
                  from the date of shipment of the Dixtal BIS Module to Dixtal's
                  end customer site or [**] months from the date of shipment by
                  Aspect to Dixtal, whichever is less. This warranty shall not
                  apply to expendable components and supply items, such as, but
                  not limited to, cables, 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 Dixtal, or
                  anyone claiming through or on behalf of Dixtal, 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.

         10.2     DSC-XP. Aspect warrants solely to Dixtal that the components
                  for the DSC-XP shall be free from defects in materials and
                  workmanship, when given normal, proper and intended usage, for
                  [**] months from the date of shipment by Aspect to Dixtal.
                  Aspect shall have no 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 Dixtal, or anyone claiming through or
                  on behalf of Dixtal, or from improper or unauthorized use of
                  the DSC-XP components, or use of the DSC-XP components in a
                  manner for which they were not designed.

         10.3     Warranty Procedures. Dixtal shall notify Aspect of any Aspect
                  Products which it believes to be defective during the
                  applicable warranty period and which are covered

                                       8

<PAGE>

                  by the warranties set forth in Section 10.1. At Aspect's
                  option, such Aspect Products shall be returned by Dixtal to
                  Aspect's designated facility for examination and testing, or
                  may be repaired on site by Aspect. Aspect shall either repair
                  or replace, within [**] days of receipt by Aspect, any such
                  Aspect Product found to be so defective and promptly return
                  such Aspect Products to Dixtal. Transportation and insurance
                  costs shall be borne by Aspect. Should Aspect's examination
                  and testing not disclose any defect covered by the foregoing
                  warranty, Aspect shall so advise Dixtal and dispose of or
                  return the Aspect Product in accordance with Dixtal's
                  instructions and at Dixtal's sole expense, and Dixtal shall
                  reimburse Aspect for such transportation and insurance costs.

         10.4     Repair Warranty. Aspect warrants its repair work and/or
                  replacement parts for the duration of the original warranty
                  period as set forth in Section 10.1 or at least [**],
                  whichever is longer.

         10.5     DISCLAIMER OF WARRANTIES. 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, FITNESS FOR A PARTICULAR PURPOSE OR
                  NONINFRINGEMENT.

11.      SERVICE AND SUPPORT.

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

         11.2     Service Training. Aspect agrees to provide initial service
                  training to a mutually agreed upon number of Dixtal service
                  representatives prior to the market release of the BIS module,
                  as well as periodic (annually at a minimum) ongoing training
                  for existing and new Dixtal service personnel.

         11.3     Service Period. For a period of [**] years following the last
                  delivery to Dixtal of the applicable Aspect Product ordered by
                  Dixtal hereunder, Aspect shall use its reasonable efforts to
                  make available repair service (or at Aspect's sole discretion,
                  exchange units for the Aspect Products) for purchase by Dixtal
                  and third party users of the Aspect products at Aspect's
                  then-current prices for such repair services and exchange
                  units. After expiry of this [**] year 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.

12.      Quality Assurance.

         12.1     Certification Status. Both parties agree to maintain, as
                  applicable, compliance with the U.S. Food and Drug
                  Administrations ("FDA") Quality System Regulation

                                       9

<PAGE>

                  ("QSR"), the European Medical Device Directive ("MDD"), and
                  other appropriate regulations pertinent to the development,
                  manufacturing and marketing of medical products similar to the
                  Aspect Products.

         12.2     Aspect Product Compliance. All Aspect Products sold by Aspect
                  under this Agreement shall fully comply with the above quality
                  requirements and guidelines (MDD, FDA QSR, etc.).

         12.3     QA and Regulatory Audits. Aspect shall permit Dixtal's Quality
                  Assurance department to conduct a reasonable audit of its
                  facilities at a mutually agreed upon date after the date of
                  this Agreement for the purpose of approving its status as an
                  OEM supplier, and reasonable periodic audits thereafter for
                  the purpose of confirming continuing compliance with
                  applicable quality and regulatory requirements and guidelines.
                  Such audits shall be scheduled with at least thirty (30) days
                  advance notice during normal business hours and shall not take
                  place more than once per calendar year.

13.      REGULATORY MATTERS.

         13.1     Aspect Products. 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 Aspect BIS
                  Module Kit. Both Parties shall work together to develop a
                  regulatory plan which defines precisely what the regulatory
                  and localization requirements are for Brazil.

         13.2     Device Master Record. Aspect shall be responsible for
                  generating its own Device Master Record for the Aspect
                  Product, except the DSC-XP. Aspect shall maintain traceability
                  at the board level on the DSC-XP. Dixtal shall be responsible
                  for generating the Device Master Record for the assembled
                  DSC-XP. It is understood that the Aspect BIS Module Kit shall
                  be a component of the Dixtal BIS Module. Dixtal shall be
                  responsible for obtaining and maintaining all applicable
                  governmental authorizations and regulatory approvals required
                  to distribute the combination of Aspect and Dixtal products in
                  the Dixtal BIS Module as provided in Section 13.3.

         13.3     Dixtal Patient Monitors. Dixtal shall assume full regulatory
                  responsibility for the Dixtal Patient Monitors, including
                  obtaining and maintaining all applicable governmental
                  authorizations and regulatory approvals required to distribute
                  the Dixtal Patient Monitors in all countries in the Territory.

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

                                       10

<PAGE>

         13.5     Product Complaints and Incident Reporting. Dixtal and Aspect
                  shall inform each other in writing immediately about any event
                  that may require incident reporting in any country. Dixtal and
                  Aspect shall inform each other in writing within two (2)
                  business days of a customer complaint regarding the Dixtal BIS
                  Module, the Aspect Products, or (within the Territory) Aspect
                  BIS Sensors. Both parties will cooperate and use commercially
                  reasonable efforts to resolve such customer complaints.
                  Closure of any customer complaint relating to the Dixtal BIS
                  Module will occur when Dixtal notifies Aspect that the problem
                  is resolved. Closure of any customer complaint relating solely
                  to Aspect Products or Aspect Sensors will occur when Aspect
                  notifies Dixtal that the problem is resolved.

         13.6     Recalls. In the event of any recall of an Aspect Product
                  required by either a governmental agency, by Aspect, or by
                  Dixtal for safety or efficacy reasons 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 [**]
                  all Aspect Products subject to the recall and previously
                  delivered to Dixtal. Aspect also agrees to consult with Dixtal
                  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 that Aspect at its sole discretion
                  requests a recall that is not required by a governmental
                  agency for safety or efficacy reasons, Aspect shall be
                  responsible for determining the scope of the recall, including
                  the number of units, timeframe for the recall, and criteria
                  for completion. Dixtal agrees to maintain all necessary sales
                  records to facilitate the recall.

         13.7     Delegation. Dixtal may at its sole discretion delegate some of
                  the obligations under this Section 13 to its sub-distributors.

         Traceability. For the purpose of facilitating product traceability, all
         Products purchased from Aspect by Dixtal shall require identification
         of an internal order number and tracking code.

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

         14.1     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 shall not materially affect form, fit, function,
                  reliability, serviceability, performance, functional
                  interchangeability or interface capability of Aspect Products.
                  In the event that any proposed substitution or modification
                  affects, in Aspect's reasonable judgment, the form, fit,
                  function, reliability, serviceability, performance, functional
                  interchangeability or interface capability of an Aspect
                  Product, Aspect shall give Dixtal written notice of such
                  proposed substitution or modification at least [**] days prior
                  to its taking effect and Dixtal shall have the right, during
                  such [**] day period and for [**] days thereafter, to

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<PAGE>

                  order Aspect Products without such substitution or
                  modification for delivery up to [**] days after such
                  substitution or modification takes effect. Aspect shall
                  provide the appropriate verification and validation
                  information for evaluating the effect of the change on the
                  Dixtal BIS Module.

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

         14.3     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 this or a different type of index, patient
                  sensor, or application, Aspect and Dixtal agree to discuss in
                  good faith a new agreement for the purchase of such new
                  product or products by Dixtal.

15.      OWNERSHIP AND PROTECTION OF RESULTS.

         15.1     No Transfer of Ownership. It is expressly agreed that neither
                  Aspect nor Dixtal shall transfer to the other Party any patent
                  rights, copyrights or other intellectual property of any kind
                  that either Party owns as of the Effective Date of this
                  Agreement.

         15.2     Models, Patterns, Dies, etc. 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 related to the Aspect Products, even
                  if made for, obtained by or paid for by Dixtal.

         15.3     Developments. If there are developments (including patentable
                  inventions) conceived, created or reduced to practice under
                  this Agreement then the rights to such developments shall be
                  retained (a) by Aspect if conceived, created and reduced to
                  practice solely by Aspect, or (b) by Dixtal, if solely
                  conceived, created and reduced to practice by Dixtal, or (c)
                  jointly by Dixtal and Aspect (without any duty to account to
                  the other) if jointly developed by Dixtal and Aspect, provided
                  that:

                      (i)      Dixtal shall assign to Aspect all rights to any
                               developments conceived, created or reduced to
                               practice by Dixtal solely relating to the Aspect
                               BIS Module Kit; and

                      (ii)     Aspect shall assign to Dixtal all rights to any
                               development solely relating to the Dixtal Patient
                               Monitor.

16.      DOCUMENTATION AND TRAINING.

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<PAGE>

         Aspect agrees to provide Dixtal with such product literature,
         operations and maintenance manuals, and other information and training
         (including training to avoid possible misrepresentation of Aspect's
         Bispectral Index) as is mutually agreed, to enable Dixtal to properly
         sell and maintain Aspect Products. Aspect will use its best reasonable
         efforts to provide adequate training to Dixtal in Brazil at a mutually
         agreed training session on an annual basis. Dixtal and Aspect agree to
         share the costs of this training session.

17.      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 confidential, or if initially delivered
         orally, must be identified at the time of disclosure, and confirmed in
         writing as confidential within ten (10) days after such oral
         disclosure. Information shall 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, if it was
         or is received by the recipient Party from a third person under
         circumstances permitting its unrestricted disclosure by the recipient
         Party, or if it was independently developed by the recipient Party
         without reference to the confidential information. Upon termination of
         this Agreement, each Party shall promptly destroy 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 one
         copy thereof for archival purposes. The obligations under this Section
         17 shall continue for both parties for a period of five (5) years after
         delivery by Aspect to Dixtal of the last Aspect Product under this
         Agreement. Dixtal is entitled to transmit confidential information of
         Aspect to Dixtal subsidiaries and affiliated companies. In such, case
         these subsidiaries and affiliated companies may only use such
         information to the same extent as Dixtal is entitled to use such
         information under this Agreement. Dixtal shall be responsible if any of
         these subsidiaries and affiliated companies fails to comply with the
         confidentiality provisions of this Agreement.

18.      WARRANTIES AND INDEMNITIES.

         18.1     Warranties by Aspect.

              (a) Aspect represents and warrants that it either has all rights,
                  title and interest in, or valid licenses to, the Aspect
                  Products and any related intellectual property rights

                                       13

<PAGE>

                  thereto. Aspect represents and warrants that it has not
                  granted in the Territory any exclusive licenses or exclusive
                  sublicenses in the Aspect Products that would prevent it from
                  granting Dixtal the licenses set forth in Section 4.3 (Aspect
                  Software License). Aspect also represents and warrants that it
                  has the right and authority to engage in the joint development
                  of the Dixtal BIS module as contemplated hereunder and that to
                  its knowledge such activity will not infringe upon or
                  misappropriate any third party's intellectual property rights.

              (b) Aspect warrants that it will deliver all Aspect Products free
                  from the rightful claims of any third party for infringement
                  of any Patents, Trademarks or Copyrights or misappropriation
                  of Trade Secrets. Aspect also warrants that as of the date of
                  this Agreement, Aspect has received no notice of a claim of
                  infringement or misappropriation from any third party
                  regarding Aspect Products. Dixtal's exclusive remedy with
                  respect to breach of any warranty provided in this Section
                  18.1 shall be that Aspect will defend at its own expense, and
                  will pay the costs and damages (including attorneys fees,
                  other professional fees and other costs of litigation or
                  settlement) made in settlement or awarded as a result of, any
                  action brought against Dixtal or any of Dixtal's customers
                  based on an allegation of such infringement or
                  misappropriation with respect to any Aspect Product, provided
                  that the Indemnification Procedures set forth in Section 18.3
                  are followed. If an injunction is obtained against Dixtal's or
                  its customers' use of an Aspect Product by reason of an
                  infringement or misappropriation described above, or if in
                  Aspect's opinion an Aspect Product or any part thereof is
                  likely to become the subject of a claim of such infringement
                  or misappropriation, Aspect will, at its option and its own
                  expense procure the right for Dixtal and its customers to
                  continue using such Aspect Product, or replace or modify such
                  Aspect Product or any part thereof so that it becomes
                  non-infringing. If neither of the foregoing options are
                  reasonably available to Aspect, Aspect shall have the right to
                  discontinue supplying such Aspect Products to Dixtal. Aspect
                  shall not have any obligation to Dixtal or its customers under
                  any provision of this Section if the infringement or
                  misappropriation claim is based upon the modification of any
                  Aspect Product not made by Aspect, the use of Aspect Products
                  in combination with any program or equipment, or any part
                  thereof, not furnished or recommended in writing by Aspect, or
                  the use of such Aspect Products in a manner or environment, or
                  for any purpose, for which Aspect did not design or license
                  them.

              (c) In the event that any claim is brought against Dixtal as a
                  result of personal injuries and/or property damages resulting
                  from that portion of the Dixtal BIS Module developed and
                  manufactured by Aspect, and provided further that such claims
                  do not arise as a result of the misuse of the Aspect Products,
                  or the use of the Aspect Products 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 Dixtal and its directors, officers,
                  employees, representatives and agents harmless from and
                  against any damages, liabilities,

                                       14

<PAGE>

                  costs and expenses (including attorneys' and other
                  professional fees and other costs of litigation) arising out
                  of such claim, provided that the procedures set forth in
                  Section 18.3 are followed.

         18.2     Warranties by Dixtal.

              (a) Dixtal represents and warrants that it either has all rights,
                  title and interest in, or valid license to, the Dixtal Patient
                  Monitor and any related intellectual property rights thereto.
                  Dixtal also represents and warrants that it has the right and
                  authority to engage in the development of the Dixtal BIS
                  Module as contemplated hereunder and that to its knowledge
                  such activity will not infringe upon or misappropriate any
                  third party's intellectual property rights or violate the
                  terms of any agreement Dixtal has entered into with a third
                  party.

              (b) Dixtal warrants that as of the date of this Agreement, Dixtal
                  has received no notice of a claim of infringement or
                  misappropriation from any third party regarding the Dixtal
                  Patient Monitor or any other Dixtal-supplied component of the
                  Dixtal BIS Module. Aspect's exclusive remedy with respect to
                  breach of any warranty provided in this Section 18.2 shall be
                  that Dixtal will defend at its own expense, and will pay the
                  costs and damages (including attorneys fees, other
                  professional fees and other costs of litigation or settlement)
                  made in settlement or awarded as a result of, any action
                  brought against Aspect or any of Aspect's customers based on
                  an allegation of such infringement or misappropriation with
                  respect to any Dixtal Patient Monitor or any other
                  Dixtal-supplied component of the Dixtal BIS Module, provided
                  that the Indemnification Procedures set forth in Section 18.3
                  are followed. If an injunction is obtained against Aspect's or
                  its customers' use of a Dixtal Patient Monitor or any other
                  Dixtal-supplied component of the Dixtal BIS Module by reason
                  of an infringement or misappropriation described above, or if
                  in Dixtal's opinion a Dixtal Patient Monitor or any other
                  Dixtal-supplied component of the Dixtal BIS Module or any part
                  thereof is likely to become the subject of a claim of such
                  infringement or misappropriation, Dixtal will, at its option
                  and its own expense procure the right for Aspect and its
                  customers to continue using such Dixtal Patient Monitor or any
                  other Dixtal-supplied component of the Dixtal BIS Module, or
                  replace or modify such Dixtal Patient Monitor or any other
                  Dixtal-supplied component of the Dixtal BIS Module or any part
                  thereof so that it becomes non-infringing. Dixtal shall not
                  have any obligation to Aspect or its customers under any
                  provision of this Section 18.2 if the infringement or
                  misappropriation claim is based upon the use of Dixtal Patient
                  Monitors or any other Dixtal-supplied component of the Dixtal
                  BIS Modules in combination with any program or equipment, or
                  any part thereof, not furnished or recommended in writing by
                  Dixtal, or the use of such Dixtal Patient Monitors or any
                  other Dixtal-supplied component of the Dixtal BIS Modules in a
                  manner or environment, or for any purpose, for which Dixtal
                  did not design or

                                       15

<PAGE>

                  license them.

              (c) In the event that any claim is brought against Aspect as a
                  result of personal injuries and/or property damages resulting
                  from the Dixtal BIS Module or the DSC-XP assembled by Dixtal,
                  and provided further that such claims do not arise as a result
                  of the defective design or operation of that portion of the
                  Dixtal BIS Module developed or manufactured by Aspect, Dixtal
                  agrees that it shall indemnify and hold Aspect and its
                  directors, officers, employees, representatives and agents
                  harmless from and against any damages, liabilities, costs and
                  expenses (including attorneys' and other professional fees and
                  other costs of litigation) arising out of such claim, provided
                  that the procedures set forth in Section 18.3 are followed.

         18.3     Indemnification Procedures.

              (a) In the event that any person intends to claim indemnification
                  pursuant to this Agreement, (an "Indemnitee"), it shall
                  promptly notify the indemnifying Party (the "Indemnitor") in
                  writing of such alleged liability, provided that the failure
                  to promptly notify the Indemnitor shall not relieve the
                  Indemnitor of any obligation under this Agreement except to
                  the extent such failure to provide prompt notice adversely
                  impairs the Indemnitor's ability to defend against the claim,
                  suit or proceeding.

              (b) The Indemnitor shall have the sole right to control the
                  defense and settlement thereof, provided, that (i) the
                  Indemnitor may not consent to imposition of any obligation or
                  restriction on the Indemnitee in any settlement unless
                  mutually agreed among Aspect and Dixtal (ii) Indemnitor shall
                  keep Indemnitee fully informed and permit the Indemnitee to
                  participate (at Indemnitee's expense) as the Indemnitee may
                  reasonably request and (iii) Indemnitee may, without affecting
                  its right to indemnity hereunder, defend and settle any such
                  claim, suit or proceeding if Indemnitor declines to defend
                  against such claim, suit or proceeding or Files for
                  Bankruptcy. The Indemnitee shall cooperate with the Indemnitor
                  and its legal representatives in the investigation of any
                  action, claim or liability covered by this Agreement.

              (c) The Indemnitee shall not, except at its own cost, voluntarily
                  make any payment or incur any expense with respect to any
                  claim or suit without the prior written consent of Indemnitor,
                  which Indemnitor shall not be required to give, provided that
                  the Indemnitee may, without affecting its right to indemnity
                  hereunder, defend and settle any such claim, suit or
                  proceeding if the Indemnitor declines to take responsibility
                  or Files for Bankruptcy.

19.      TRADEMARKS.

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<PAGE>

         19.1     Trademarks.

              (a) Ownership. Dixtal acknowledges and agrees that Aspect is the
                  sole and exclusive owner of all right, title and interest in,
                  or has valid licenses to the trademarks (the "Aspect
                  Trademarks") identified on Exhibit D (Aspect Trademarks).
                  Aspect acknowledges and agrees that Dixtal is the sole and
                  exclusive owner of all right, title and interest in and to the
                  trademarks (the "Dixtal Trademarks") identified on Exhibit D
                  (collectively the "Aspect and Dixtal" Trademarks). Each Party
                  recognizes the value of the other Party's Trademarks and the
                  good will associated with the other Party's Trademarks. Dixtal
                  agrees that its use of the Aspect Trademarks and any good will
                  arising there from shall inure to the benefit of Aspect.
                  Aspect agrees that its use of the Dixtal Trademarks and any
                  good will arising therefrom shall inure to the benefit of
                  Dixtal. 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 Dixtal, or the Dixtal
                  Trademarks to Aspect, other than the grant of the licenses in
                  Section 19.1 (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 and its licensors,
                  and all other right, title and interest in and to the Dixtal
                  Trademarks is expressly reserved by Dixtal. Each Party shall
                  keep the other Party's Trademarks free from all liens,
                  mortgages or other encumbrances. Each Party agrees that it
                  shall not attack or otherwise challenge the title, validity or
                  any other rights of the other Party in or to its Trademarks.

              (b) Notice. All Dixtal BIS Modules 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
                       [or licensed to] Aspect Medical Systems, Inc."

                  (ii) Dixtal shall include the "(TM)" or "(R)" symbol, as
                       instructed by Aspect, after the first prominent use of
                       the Aspect Trademark in the Dixtal Patient Monitor and
                       related materials. Dixtal shall have a period of 60
                       days in which to begin to use the "(R)" symbol in
                       replacement of the "(TM)" symbol upon receiving
                       instructions to do so by Aspect for all new stock of such
                       materials. Dixtal may continue to deliver stocked
                       literature before the change becomes effective. Dixtal
                       shall reproduce copyright and trademark notices of Aspect
                       on the "splash screen" or in the same location where
                       Dixtal reproduces its own copyright and trademark
                       notices.

              (c) License. Each Party hereby grants to the other a nonexclusive,
                  worldwide, royalty-free license (without the right to
                  sublicense) to use the other Party's Trademarks to designate
                  and promote Aspect Products in conjunction with Dixtal

                                       17

<PAGE>

                  BIS Modules. Neither Party shall have any other right to use,
                  display or utilize the other Party's Trademarks for any other
                  purpose or in any other manner.

              (d) Quality Standards.

                  (i)  Inspection. Upon reasonable notice and request, each
                       Party will furnish to the other samples of its applicable
                       advertising and promotional materials as necessary to
                       allow the requesting Party to monitor compliance with
                       this Agreement.

                  (ii) Compliance. Aspect acknowledges the high standards of
                       quality and excellence established by Dixtal with respect
                       to products bearing Dixtal's trademarks. Dixtal
                       acknowledges the high standards of quality and excellence
                       established by Aspect with respect to products bearing
                       the Aspect Trademarks. Each Party agrees that Dixtal BIS
                       Modules with which both parties' Trademarks are used
                       shall be of such quality so as to maintain such high
                       standards and to reflect well upon both Parties. Each
                       Party agrees to adhere to its own or the following
                       quality standards (whichever may be more rigorous) for
                       use of the other Party's Trademarks in connection with
                       the Dixtal BIS Module:

                           -        In order to ensure that the Dixtal BIS
                        Module distributed under both parties' Trademarks
                        complies with the consistent quality standards of each
                        Party, all Dixtal BIS Modules distributed by or for
                        Dixtal which bear an Aspect Trademark shall conform to
                        those commercially reasonable standards which Aspect
                        provides to Dixtal in writing. Dixtal shall cause each
                        major new release of such Dixtal BIS Modules to comply
                        with such standards or remove the Aspect Trademark(s)
                        from any such new release, which does not comply with
                        such standards. Dixtal shall have a period of [**] days
                        in which to bring newly manufactured Dixtal BIS Modules
                        into compliance with any commercially reasonable
                        standard provided to it in writing by Aspect following
                        the date of receipt of such standard.

                           Each Party acknowledges that if Dixtal BIS Modules
                        bearing both Parties' Trademarks fail to satisfy the
                        quality standards set forth above, the substantial good
                        will which each Party has built and now possess in its
                        own products and Trademarks shall be impaired.

              (e) Protection and Infringement. Each Party agrees to cooperate
                  with and assist the other Party in obtaining, maintaining,
                  protecting, enforcing and defending the other Party's
                  proprietary rights in and to its Trademarks. In the event that
                  either Party learns of any infringement, threatened
                  infringement or passing-off of the other Party's Trademarks,
                  or that any third party claims or alleges that the other
                  Party's Trademarks infringe the rights of the third party or
                  are otherwise liable to cause deception or confusion to the
                  public, the Party obtaining such information shall notify the
                  other Party giving the particulars thereof, and if such claims
                  or

                                       18

<PAGE>

                  allegations relate to this Agreement, the Dixtal BIS Module,
                  the Aspect BIS Kit or Aspect Products sold hereunder, shall
                  provide necessary information and assistance reasonably
                  requested by such other Party in the event that such other
                  Party decides that proceedings should be commenced.

              (f) Termination. In addition to the termination rights set forth
                  in Section 21 hereof, in the event that either Party is in
                  material breach of any provision of this Section 19, the
                  non-breaching Party may, upon [**] days written notice,
                  terminate the license granted in Section 19.1 (c) if the
                  breaching Party does not cure such breach or default within
                  such [**] day period. In addition to the provisions of Section
                  21 hereof, upon termination of the license granted in Section
                  19.1 (c), or upon termination of this Agreement, for whatever
                  cause:

                  (i)  Each Party shall immediately cease and desist from any
                       further use of the other Party's Trademarks and any
                       trademarks confusingly similar thereto, either directly
                       or indirectly;

                  (ii) All rights in the Aspect Trademarks granted to Dixtal
                       hereunder shall immediately revert to Aspect, and all
                       rights in the Dixtal Trademarks granted to Aspect
                       hereunder shall immediately revert to Dixtal;

                  (iii) In the event that this Agreement is terminated for any
                       reason other than a material breach or material default
                       by Dixtal, Dixtal shall thereafter to dispose of all of
                       the unsold Dixtal Patient Monitors bearing the Trademarks
                       and advertising and promotional materials relating
                       thereto which had been completed by it prior to such
                       termination, provided such Dixtal Patient Monitors and
                       materials were in the process of manufacture before such
                       termination.

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

                                       19

<PAGE>

20.      EXPORT.

         Dixtal shall not export, directly or indirectly, Aspect Products
         (including when integrated into a Dixtal Patient Monitor) 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 Dixtal's responsibility
         to comply with the latest United States export regulations, and Dixtal
         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 Dixtal Patient Monitors or other products, information or
         materials provided by Aspect hereunder were exported or otherwise
         shipped or transported in violation of applicable laws and regulations.

21.      TERM; DEFAULT AND TERMINATION.

         21.1     Term and Renewal. The initial term of this Agreement shall
                  commence on the Effective Date and shall continue for a period
                  of three (3) years following introduction of the Dixtal BIS
                  Module. The term of this Agreement shall be renewed
                  automatically for successive twelve (12) month periods, unless
                  either Party provides written notice of termination to the
                  other Party at least sixty (60) days prior to expiration of
                  the Agreement.

         21.2     TERMINATION FOR GOOD CAUSE.

                  (a)  Termination by Aspect. The Agreement may be terminated by
                       Aspect giving thirty (30) days prior written notice to
                       Dixtal in the event Dixtal has not commercially
                       introduced a Dixtal BIS Module by [**].

                  (b)  Termination by Dixtal. The Agreement may be terminated by
                       Dixtal giving 30 days prior written notice to Aspect if
                       Aspect has failed to provide an Aspect BIS Module Kit
                       consistent with the specifications outlined in Exhibit B
                       to Dixtal by [**].

         21.3     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 without the
                             prior written consent of the respective other
                             Party, except: (a) as specifically permitted under
                             this Agreement; or (b) in connection with the sale
                             or other transfer 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) or

                                       20

<PAGE>

                       (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
                             due, and such failure is not cured within [**] days
                             ([**] days 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 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 ("File for
                             Bankruptcy").

         21.4     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 terminate the Agreement, 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. Any such termination
                  or other action taken by the non-defaulting Party pursuant to
                  this Section 21.4 shall not relieve the defaulting Party of
                  its obligations hereunder and the non-defaulting Party shall
                  retain all legal and equitable remedies after such
                  termination.

22.      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 shall contain a minimum limit of
         liability for bodily injury and property damage of not less than [**]
         US$.

23.      DISPUTE RESOLUTION

         23.1     General. Any dispute, controversy or claim arising out of or
                  relating to this Agreement or any related agreement or the
                  validity, interpretation, breach or termination thereof (a
                  "Dispute"), including claims seeking redress or asserting
                  rights under applicable law, shall be resolved in accordance
                  with the procedures set forth

                                       21

<PAGE>

                  herein. Until completion of such procedures, no Party may take
                  any action not contemplated herein to force a resolution of
                  the Dispute by any judicial or similar process, except to the
                  limited extent necessary to; (i) avoid expiration of a claim
                  that might eventually be permitted hereby; or (ii) obtain
                  interim relief, including injunctive relief, to preserve the
                  status quo or prevent irreparable harm.

         23.2     Waiver. In connection with any Dispute, the parties expressly
                  waive and forego any right to (i) punitive, exemplary,
                  statutorily, enhanced or similar damages in excess of
                  compensatory damages and (ii) trial by jury.

         23.3     Good Faith Negotiations. Any Dispute relating to this
                  Agreement (a "Dispute") will be resolved first through good
                  faith negotiations between appropriate management-level
                  representatives of each Party having responsibility for the
                  sale or use of products involved.

         23.4     Mediation. If within sixty (60) days the parties are unable to
                  resolve the dispute through good faith negotiation, either
                  Party may submit a Dispute for resolution by mediation
                  pursuant to the Center for Public Resources Model Procedure
                  for Mediation of Business Disputes as then in effect. The
                  mediation shall be conducted in Boston, Massachusetts.
                  Mediation will continue for at least thirty (30) days unless
                  the mediator chooses to withdraw sooner. At the request of
                  either Party, the mediator will be asked to provide an
                  evaluation of the Dispute and the parties' relative positions.
                  Each Party shall bear its own costs of mediation effort.

         23.5     Arbitration. After completion of any mediation effort, a Party
                  may submit the Dispute for resolution by arbitration pursuant
                  to the Non-Administered Arbitration Rules of the Center for
                  Public Resources as in effect on the date hereof, unless the
                  parties agree to adopt such rules as in effect at the time of
                  the arbitration. The arbitral tribunal shall be composed of
                  one arbitrator; and the arbitration shall be conducted in
                  Boston, Massachusetts. If the resolution of the Dispute is not
                  found within the terms of this Agreement, the arbitrator shall
                  determine the Dispute in accordance with the governing law of
                  the Agreement, without giving effect to any conflict of law
                  rules or other rules that might render such law inapplicable
                  or unavailable. The prevailing Party in any arbitration
                  conducted under this Section shall be entitled to recover from
                  the other Party (as part of the arbitral award or order) its
                  reasonable attorneys' fees and other costs of arbitration.

         23.6     Applicable Law. The law applicable to the validity of this
                  arbitration provision, the conduct of the arbitration, the
                  challenge to or enforcement of any arbitral award or order or
                  any other question of arbitration law or procedure shall be
                  governed exclusively by the Federal Arbitration Act, 9 U.S.C.
                  sections 1-16; however, the award can be modified or vacated
                  on grounds cited in the Federal Arbitration Act or, if the
                  arbitrator's findings of facts are not supported by
                  substantial evidence or the conclusions of law are erroneous,
                  under the laws of the Commonwealth of Massachusetts. The place
                  of arbitration shall be in Boston, Massachusetts. The parties
                  agree that the federal and state courts located in the
                  Commonwealth of

                                       22

<PAGE>

                  Massachusetts shall have exclusive jurisdiction over any
                  action brought to enforce this arbitration provision, and each
                  Party irrevocably submits to the jurisdiction of said courts.
                  Notwithstanding the foregoing sentence, either Party may apply
                  to any court of competent jurisdiction, wherever situated, for
                  enforcement of any judgment on an arbitral award.

         23.7     Time Limit. Except as time barred under any applicable statute
                  of limitation of lesser duration, any claim by either Party
                  shall be time-barred unless the asserting Party commences an
                  arbitration proceeding with respect to such claim within two
                  years after the cause of action has accrued.

         23.8     Provisional or Interim Judicial Measures. Notwithstanding any
                  other provision of this Agreement, the parties expressly agree
                  that prior to the first meeting of the arbitrator either shall
                  have the right to apply to any state or federal court in the
                  Commonwealth of Massachusetts or any other court that would
                  otherwise have jurisdiction, for provisional or interim
                  measures.

         23.9     Consolidated Proceedings. Each Party hereby consents to a
                  single, consolidated arbitration proceeding of multiple
                  claims, or claims involving more than two parties. The
                  prevailing Party or parties in any arbitration conducted under
                  this paragraph shall be entitled to recover from the other
                  Party or parties (as part of the arbitral award or order) its
                  or their reasonable attorneys' fees and other reasonable costs
                  of arbitration.

24.      GENERAL PROVISIONS.

         24.1     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.

         24.2     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.

         24.3     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

                                       23

<PAGE>

                  may have hereunder, operate as a waiver of any right, power or
                  privilege by such Party.

         24.4     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 venturers or
                  partners for any purpose. Neither Party shall be responsible
                  for the acts or omissions of the other Party, and neither
                  Party shall have authority to speak for, represent or obligate
                  the other Party in any way without prior written authority
                  from the other Party.

         24.5     Survival of Obligations. All obligations of either Party under
                  Sections 4.3 (but only insofar as it relates to the rights of
                  Dixtal customers to continue using Dixtal BIS Modules), 10
                  (Warranty), 11 (Service and Support), 13 (Regulatory Matters),
                  15 (Ownership and Protection of Results), 17
                  (Confidentiality), 18 (Indemnities), 19 (Trademarks), 23
                  (Dispute Resolution), and 24.6 (Limitation on Liability) shall
                  survive the expiration or termination of this Agreement and
                  continue to be enforceable.

         24.6     LIMITATION ON LIABILITY. EXCEPT AS PROVIDED IN SECTION 18,
                  EACH PARTY'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 (ALL AMOUNTS PAID AND PAYABLE BY DIXTAL TO
                  ASPECT FOR SERVICE AND SUPPORT PURSUANT TO SECTION 11 OF THIS
                  AGREEMENT. IN NO EVENT SHALL EITHER PARTY BE LIABLE TO THE
                  OTHER PARTY 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.

         24.7     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.

         24.8     Governing Law. This Agreement shall be governed by and
                  construed in accordance with the laws of the Commonwealth of
                  Massachusetts, without reference to conflict of laws
                  principles, and shall not be governed by the U.N. Convention
                  on Contracts for the International Sale of Goods.

         24.9     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

                                       24

<PAGE>

                  or such other address as either Party may from time to time
                  designate by notice hereunder.

         24.10       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 Dixtal
                  shall not be construed as a waiver of the terms and conditions
                  of this Agreement nor an acceptance of any such provision.

         24.11       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.

         24.12       Exhibits: The following Exhibits shall be part of this
                  Agreement:

                     Exhibit A: Aspect Products and Purchase Prices

                     Exhibit B: Aspect's Standard BIS Module Kit

                     Exhibit C: Contact Persons/Addresses Prices

                     Exhibit D: Aspect and Dixtal Trademarks

         24.13       Beneficiaries. Except for the provisions of Section 18
                  hereof, which are also for the benefit of the other Persons
                  indemnified, this Agreement is solely for the benefit of the
                  parties hereto and their respective affiliates, successors in
                  interest and permitted assigns and shall not confer upon any
                  other person any remedy, claim, liability, reimbursement or
                  other right in excess of those existing without reference to
                  this Agreement.

         24.14       Assignment. Neither Party may assign or delegate this
                  Agreement or any rights or obligations under this Agreement
                  without the prior written consent of the other, which shall
                  not be unreasonably withheld; provided, however, that Dixtal
                  may, without the prior written consent of Aspect, assign and
                  delegate this Agreement and any or all of its rights and
                  obligations hereunder to any of its affiliates, and provided
                  that either party shall have the right to assign this
                  Agreement in connection with a sale of the

                                       25

<PAGE>

                  business of such party to which this Agreement relates.

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

Dixtal Medical Systems, Inc. Dixtal Medical Systems, Inc.

By:   /s/ illegible             By:    /s/ illegible
  ----------------------------    --------------------------
Title: Director                 Title: Commerical Director

Aspect Medical Systems, Inc.

By:   /s/ J. Neal Armstrong
  ----------------------------

Title: CFO

                                       26

<PAGE>

                                    EXHIBIT A
                       ASPECT PRODUCTS AND PURCHASE PRICES

A) ASPECT BIS MODULE KIT COMPONENT PRICES:

<TABLE>
<S>               <C>                                         <C>
186-0138-DX       BIS ENGINE, DIXTAL                          $ [**]
140-0037          DSC-XP PREAMP BOARD, TESTED                 $ [**]
140-0038          DSC-XP COMM BOARD, TESTED                   $ [**]
150-0027          SHLD, RFI, DSC                              $ [**]
150-0036          HOUSING, DSC                                $ [**]
175-0021          DSC-MON CBL W.LEMO OVMLD                    $ [**]
175-0045          PIGTAIL, DSC3/XP                            $ [**]
175-0046          PIC, SNSR+                                  $ [**]
194-0113          DSC-XP LOGO                                 $ [**]
605-0022          SCRWMACH 4-40X250                           $ [**]
605-0024          SCRWMACH 4-40X750                           $ [**]
675-0004          CABTIE, 3.9"                                $ [**]
800-0007          CLIPS, BADGE, VINYL, LONG                   $ [**]
150-0026          GSKT, HSNG, DSC                             $ [**]
</TABLE>

Yearly Module Kit Volume Expectations:

<TABLE>
<S>      <C>
2003     [**]
2004     [**]
2005     [**]
</TABLE>

B) ASPECT BIS SENSOR:

Transfer price to Dixtal for distribution solely to Dixtal customers in Brazil
and solely for use with Dixtal BIS Modules:

<TABLE>
<S>               <C>                                 <C>
186-0106          QUATRO SENSOR                       $ [**]
</TABLE>

                                       27

<PAGE>

                                    EXHIBIT B
                SPECIFICATIONS: ASPECT'S STANDARD 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 /
         TTL) 3-wire interface and the necessary power connections.

         The BIS Module Kit consists of a Digital Signal Converter (DSC-XP) that
         is placed in proximity to the patient and a small circuit board that
         resides in the OEM equipment. The DSC-XP 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-XP to the BIS engine circuit board via a 12
         foot cable that is hard wired at the DSC-XP.

         The small BIS Engine circuit board performs digital signal processing
         on the digitized EEG signal and outputs the Bispectral Index to the OEM
         system via the RS-232 / TTL 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 / TTL), power, and
         DSC connections.

         Detailed Technical Specifications:

         Digital Output:              [**]
                                      [**]
         Main Parameters:             [**]
         Electrical Safety:           [**]
         Power:                       [**]
                                      [**]
                                      [**]
         Artifact Rejection:          [**]
         Bispectral Index:            [**]

         Digital Signal Converter (DSC-XP)

         Description:                 [**]
         Weight:                      [**]
         Dimensions:                  [**]
                                      [**]
         Cable Length:                [**]

         BIS Engine PCB

                      Physical:               [**]

              Software Upgrades

                                       28

<PAGE>

                                    The BIS engine software is stored in
                                    reprogrammable FLASH memory. Software
                                    upgrades can be accomplished on-site or
                                    remotely via the serial interface.

              Serial Identifier

                           Each BIS engine is given a unique serial identifier.
                           This allows for electronic identification/tracking of
                           every BIS Engine.

                                       29

<PAGE>

                                    EXHIBIT C
                            CONTACT PERSONS/ADDRESSES

CONTACT PERSONS AND RESPONSIBILITIES AT ASPECT:
<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------
                                                                              EMAIL
                                                                              PHONE NUMBER
PERSON                 TITLE                          RESPONSIBILITY          FAX NUMBER
======================================================================================================
<S>                    <C>                            <C>                     <C>
                       Director of Marketing                                  jrubin@aspectms.com
                       Operating Room,                                        617-559-7257
Joan Rubin             OEM and Procedural Sedation    Contract                617-559-7960
------------------------------------------------------------------------------------------------------
                       Manager of OEM                                         smesrobian@aspectms.com
                       Engineering                                            617-559-7576
 Steve Mesrobian                                      Project Manager         617-559-7576
------------------------------------------------------------------------------------------------------
                       VP, Regulatory                                         pmanberg@aspectms.com
                                                                              617-559-7076
 Paul Manberg                                         Regulatory matters      617-559-7076
------------------------------------------------------------------------------------------------------
                       Business                                               eknudsen@aspectms.com
                       Development                    Latin America           617-559 7735
 Eric Knudsen          Manager                        Distribution            707-248-1631
------------------------------------------------------------------------------------------------------
</TABLE>

 MAILING ADDRESS: Aspect Medical Systems, Inc.
                  141 Needham St.
                  Newton, MA 02464
                  USA

CONTACT PERSONS AND RESPONSIBILITIES AT DIXTAL:

[To be provided by Dixtal with thirty (30) days of the date of this Agreement]

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------
                                                                              EMAIL
                                                                              PHONE NUMBER
 PERSON                TITLE                          RESPONSIBILITY          FAX NUMBER
======================================================================================================
<S>                    <C>                            <C>                     <C>
                                                                              Ivan@dixtal.com.br
                                                                              55-11-5548-4155
Ivan Consoli Ireno     Commercial Director            Contract                55-11-5548-4883
------------------------------------------------------------------------------------------------------
                                                                              Rafael@dixtal.com.br
                       Manager of                                             55-11-5548-4155
Rafael Holzhacker      Engineering                    Project Manager         55-11-5548-4883
------------------------------------------------------------------------------------------------------
</TABLE>

                                       30

<PAGE>

<TABLE>
<S>                    <C>                            <C>                     <C>
                                                                              Fabbrini@dixtal.com.br
                                                                              55-11-5548-4155
Marcelo Fabbrini       Industrial Manager             Regulatory matters      55-11-5548-4883
------------------------------------------------------------------------------------------------------
                                                                              Vivi@dixtal.com.br
                                                                              55-11-5548-4155
Viviane Haro          Purchasing Agent                Ordering                55-11-5548-4883
------------------------------------------------------------------------------------------------------
</TABLE>

MAILING ADDRESS:
                       DIXTAL BIOMEDICA IND E COM LTDA
                       Av. Rodrigo Otavio, 1111  Japiim
                       Manaus - AM
                       Brazil 69077-000

                                       31

<PAGE>

                                    EXHIBIT D
                          ASPECT AND DIXTAL TRADEMARKS

TRADEMARK                     REFERENCE

Aspect(R)                     Aspect is a trademark of Aspect Medical
                              Systems, Inc

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(R) LOGO]                 BIS logo is a registered trademark of Aspect
                              Medical Systems, Inc.

                                       32