Addendum 1 To The Oem Agreement

Exhibit 10.35


ADDENDUM 1
OEM Development and Purchase Agreement


Addendum 1 to the agreement dated the 6th day of August, 1999 (the "Agreement"), by and between Aspect Medical Systems, Inc. ("Aspect") and Philips Medizinsysteme Boeblingen GmbH ("Philips") (formerly Agilent Technologies, Inc.).


Per section 7 of the Agreement, Prices, Aspect is [**] the list price on the Aspect BIS Module Kit (exclusive of royalty) from $[**] for the US/CAN version and $[**] for the ROW version, to a uniform $[**], regardless of geography. The attached Exhibit A, dated January 29, 2003, replaces Exhibit A in the Agreement.


For the purpose of calculating the volume discount for the calendar year 2003, all BIS Module Kits shipped from January 1, 2003 through December 31, 2003 will be included in the total volume discount calculation. List price will be charged and any volume discount earned will be issued at the time it is earned either as a credit or cash at the preference of Philips.


Please indicate your acceptance of this Addendum by signing below.


Aspect Medical Systems, Inc. Philips Medizinsysteme Boeblingen GmbH


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