ASPECT MEDICAL SYSTEMS, INC. KEY EMPLOYEE CHANGE IN CONTROL SEVERANCE BENEFITS PLAN

ASPECT MEDICAL SYSTEMS, INC.

KEY EMPLOYEE CHANGE IN CONTROL SEVERANCE BENEFITS PLAN

SECTION 1. INTRODUCTION

     This Key Employee Change in Control Severance Benefits Plan (the “Severance Benefits Plan”) sets forth the terms and conditions for the provision of severance pay and certain other benefits to Eligible Employees (as defined below) of Aspect Medical Systems, Inc. or any successor entity or assignee (“the “Company”) whose employment is involuntarily terminated without cause or voluntarily terminated for good reason following a change in control of the Company as set forth in this Severance Benefits Plan.

SECTION 2. DEFINITIONS

     For purposes of this Severance Benefits Plan, the following terms shall have the meanings set forth below:

     (a) “BASE SALARY” means the annual base salary for an Eligible Employee (as defined in this Section 2(f)) as in effect on the Change in Control Date.

     (b) “BOARD” means the Board of Directors of the Company.

     (c) “CAUSE” shall have such meaning provided for in the Company’s 2001 Stock Incentive Plan, as amended, and as may be further amended from time to time (the “Plan”).

     (d) “CHANGE IN CONTROL EVENT” shall have such meaning provided for in the Plan.

     (e) “CHANGE IN CONTROL DATE” means the first date on which a Change of Control Event occurs.

     (f) “ELIGIBLE EMPLOYEE” shall mean those employees of the Company holding any of the positions listed in Exhibit A to this Severance Benefits Plan as of the Change of Control Event.

     (g) “GOOD REASON” shall mean the occurrence, without the Eligible Employee’s written consent, of either (i) a reduction in the Eligible Employee’s annual base salary as in effect on the Change in Control Date or as the same was or may be increased thereafter from time to time or (ii) a change by the Company in the location at which the Eligible Employee performs his or her principal duties for the Company to a new location that is both (i) outside a radius of 50 miles from the Eligible Employee’s principal residence immediately prior to the Change in Control Date and (ii) more than 20 miles from the location at which the Eligible Employee performed his or her principal duties for the Company immediately prior to the Change in Control Date; or a requirement by the Company that the Eligible Employee travel on Company business to a substantially greater extent than required immediately prior to the Change in Control Date.

     (h) “INVOLUNTARY TERMINATION WITHOUT CAUSE” means an Eligible Employee’s dismissal from or discharge by the Company for a reason other than Cause. The termination of an Eligible Employee’s employment will not be deemed to be an “Involuntary Termination Without Cause” if such termination occurs as a result of the Eligible Employee’s voluntary resignation without Good Reason or by reason of the Eligible Employee’s death or disability.

     (i) “QUALIFYING TERMINATION” means that an Eligible Employee’s employment with the Company is terminated by the Eligible Employee for Good Reason or is terminated by the Company without Cause, as applicable, within twelve (12) months following a Change in Control Event.

SECTION 3. ELIGIBILITY AND PARTICIPATION

     Individuals shall be deemed “Eligible Employees” to participate in the Severance Benefits Plan if they have previously been duly appointed to at least one of the offices of the Company listed in the attached Exhibit A and have held such office(s) for a period of at least one (1) month prior to the Change in Control Date. For the avoidance of any doubt, should any Eligible Employee hold more than one office with the Company that would entitle the Eligible Employee to benefits pursuant to this Severance Benefits Plan, such Eligible Employee shall not be entitled to multiple severance benefits pursuant to Section 4 below but shall only receive benefits in accordance with such of the Eligible Employee’s office as would entitle the employee to the greatest benefits hereunder.

SECTION 4. SEVERANCE BENEFITS AND OTHER PAYMENTS

     Eligible Employees are eligible to receive the following benefits on the following conditions:

     (a) SEVERANCE PAYMENTS. If an Eligible Employee is subject to a Qualifying Termination, the Eligible Employee will be entitled to a lump sum payment from the Company in an amount equal to the product of (i) the “Severance Multiple” (as defined below), multiplied by (ii) the sum of (A) the Eligible Employee’s Base Salary at the time of the termination of the Eligible Employee’s employment, plus (B) the average of the Eligible Employee’s last three annual bonuses paid (annualized for partial years) by the Company. Such lump sum payment will be payable in accordance with the terms set forth in the Eligible Employee’s severance agreement to be executed in connection with the employee’s termination, but in no event later than two and one-half months following the end of the fiscal year in which the Eligible Employee’s Qualifying Termination occurs (the “Short-Term Deferral Period”).

     For purposes of this Section 4(a), “Severance Multiple” shall mean the following:

     In addition, the Eligible Employee will be paid a one lump sum cash payment representing the Eligible Employee’s target bonus for the year in which the Qualifying Termination occurs on the date of termination, multiplied by a fraction, the numerator of which shall equal the number of days the Eligible Employee was employed by the Company during the fiscal year in which the Qualifying Termination occurs and the denominator of which shall be 365. Such cash payment shall be made to the Eligible Employee no later than by the expiration of the Short-Term Deferral Period. Notwithstanding anything in this Severance Benefits Plan to the contrary, in no event will any payments be made pursuant to this Section 4(a) or any other provision of this Severance Benefits Plan unless and until a release of claims is executed in accordance with Section 4(f) below and such release becomes enforceable.

     (b) HEALTH BENEFITS. If the Eligible Employee timely elects continued health insurance coverage under the federal “COBRA” law, 29 U.S.C. § 1161 et seq. , following a Qualifying Termination, the Company shall continue to pay that portion of the premium costs for the type of group health insurance coverage, including coverage for his or her eligible dependents, that the Company paid on behalf of the Eligible Employee immediately prior to the Eligible Employee’s termination of

employment, for a period starting on the Qualifying Termination date and continuing for the following applicable periods:

provided , however, that the Company will pay such premiums for the Eligible Employee and his/her eligible dependents (if applicable) only for coverage for which such individual and dependents (if applicable) were enrolled as of the date of the Qualifying Termination. The Eligible Employee shall continue to pay any remaining premium costs for such continuation coverage (including coverage for his/her eligible dependents) that he/she had been required to pay as an active employee immediately prior to the Qualifying Termination during the period set forth above, and shall pay all premium costs thereafter for as long as, and to the extent that, the Eligible Employee remains eligible for COBRA continuation.

     (c) EQUITY ACCELERATION. Nothing in this Severance Benefits Plan shall be deemed to modify or alter, in any manner, any outstanding equity awards issued to an Eligible Employee pursuant to any stock-based plan operated by the Company.

     (d) PARACHUTE PAYMENTS. Notwithstanding any other provision of this Severance Benefits Plan, in the event that an Eligible Employee becomes entitled to payments and/or benefits or any other amounts in the “nature of compensation” as a result of a Change in Control Event or Qualifying Termination, (all such payments and benefits, including the payments and benefits provided under this Severance Benefits Plan, being hereinafter called “Total Payments”) that would be subject (in whole or part) to the excise tax (the “Excise Tax”) imposed under section 4999 of the Internal Revenue Code of 1986, as amended, and the regulations promulgated thereunder (the “Code”), the Total Award shall be reduced, to the extent necessary so that no portion of the Total Payments is subject to the Excise Tax. In the event that the Total Award is reduced in accordance with the preceding sentence, such reduction shall first be applied to cash payments to which the Eligible Employee is entitled to receive under this Severance Benefits Plan and, to the extent such cash payments are not sufficient to satisfy the Excise Tax, then such reduction shall apply to Company equity awards then held by the Eligible Employee. This reduction shall only occur if (i) the net present value of such Total Payments, as so reduced (and after subtracting the net amount of federal, state and local income taxes on such reduced Total Payments) is greater than or equal to (ii) the net present value of such Total Payments without such reduction (but after subtracting the net amount of federal, state and local income taxes on such Total Payments and the amount of Excise Tax to which an Eligible Employee would be subject in respect of such unreduced Total Payments). All determinations required to be made under this section shall be made by the Compensation Committee of the Board after consultation with any advisors it shall deem appropriate. All fees and expenses of such calculations shall be borne solely by the Company. If any portion of the Total

Payments becomes subject to the Excise Tax, the Eligible Employee acknowledges and agrees that the payment of such tax, together with any interest and penalties, shall be the Eligible Employee’s sole responsibility.

     (e) EARNED BUT UNPAID BENEFITS. An Eligible Employee will also be entitled to receive any earned but unpaid benefits as of the Qualifying Termination date, including salary earned but unpaid, the Eligible Employee’s annual bonus for the most recently completed financial year, if any, and any unused accrued vacation time.

     (f) RELEASE. The receipt of any severance benefits under this Severance Benefits Plan is expressly conditioned upon any Eligible Employee executing a release of claims in favor of the Company, substantially in the form attached to this Severance Benefits Plan as Exhibit B , and such release of claims must become effective in accordance wi