Exhibit A

                                     Option
                                   (Attached)



<PAGE>




                                 AMENDMENT NO. 1
                                    TO OPTION

     This  Amendment  No. 1 is made as of October 16, 2008 between  Zynex,  Inc.
(formerly known as Zynex Medical Holdings, Inc.)
(the "Company") and Stalwart Investments, LLC ("Stalwart").

                                    RECITALS

         On  September  27,  2004,  the Company  granted to Stalwart  the Option
attached as Exhibit A (the  "Option").  Stalwart  has  exercised  the Option for
100,000 shares at the exercise price of $0.40 per share.  There remains  subject
to the Option,  prior to this Amendment,  a total of 1,800,000  shares of common
stock of the  Company  at an  exercise  price  from $1.75 per share to $4.00 per
share. The parties wish to amend the Option as stated in this Amendment.

                                    AGREEMENT

         In consideration  of the amendments  stated below, the parties agree as
follows.

1.       Cashless Exercise.

     (a)  The holder of the (Option may exercise in whole or part,  from time to
          time prior to the  expiration  date,  by  delivery to the Company of a
          duly executed  Notice of Exercise,  the following  parts of the Option
          (a) for cash or (b) by conversion in a cashless  exercise as explained
          below:

                                    400,000 at $1.75 each
                                    200,000 at $2.00 each
                                    200,000 at $2.25 each
                                    200,000 at $2.50 each

     (b)  In any such a cashless  exercise,  the holder may  convert  any of the
          above  listed  parts of the  Option  into a number  of  shares  of the
          Company  commons tock  determined by dividing (a) the  aggregate  fair
          market  value of the shares of common  stock of the  Company for which
          the Option is being  exercised  and are  otherwise  issuable  upon the
          exercise  of the  Option  minus the  aggregate  exercise  price of the
          shares for which the Option is being  exercised by (b) the fair market
          value  of  one  share  of  common  stock  of the  Company.  (c) If the
          Company's  common stock is traded in a public market,  the fair market
          value of each share of common  stock shall be the  closing  price of a
          share  reported  for the business  day  immediately  before the holder
          delivers  its Notice of  Exercise  to the  Company.  If the  Company's
          common stock is traded in a public market but there is no such closing
          price,  then the fair market value shall be the average of the closing
          bid and asked prices reported for the business day immediately  before
          the delivery of such Notice of Exercise. If the Company's stock is not
          traded in a public market, the Board of Directors of the company shall
          determine the fair market value in its reasonable  good faith judgment
          as of the  business  day  immediately  before the holder  delivers its
          Notice of Exercise to the Company. (d) The Notice of Exercise shall be
          in the form of notice attached as Exhibit B.

2.       Cancellation of Part of the Option

          (a)  The  Company  and  Stalwart  agree  that,  as of the date of this
               Amendment, the following parts of the Option are hereby cancelled
               and may not be exercised in any manner:

                           200,000 at $2.75 each
                           200,000 at $3.00 each
                           200,000 at $3.50 each

          (b)  The following part of the Option shall remain  exercisable by the
               holder for cash only:

                           200,000 at $4.00 each

         3.  Confirmation.  The Company  and  Stalwart  confirm  that the Option
attached  hereto as Exhibit A as amended by  Sections 1 and 2 above  constitutes
the  entire  Option  and that no  consideration  other  than as  stated  in this
Amendment has been provided by the Company or Stalwart for the changes stated in
this Amendment.

         The parties  have  executed  this  Amendment  effective  as of the date
stated above.

                             ZYNEX, INC.

                         By: __________________________
                             Name: Thomas Sandgaard
                             Title: President and Chief Executive Officer

                            STALWART INVESTMENT, LLC

                         By: ___________________________
                             Name: Aaron Lamkin
                             Title: Managing Member
October 20, 2008