Aspect Medical Systems Announces Progress of BRITE Major Depression Study.

-National Multicenter Trial Underway to Assess Accuracy of Aspect's Brain Assessment Technology in Predicting the Effectiveness of Antidepressant Medications-

NORWOOD, Mass. -- Aspect Medical Systems, Inc. (NASDAQ: ASPM) today is providing a scheduled update on the status of the BRITE (Biomarkers for Rapid Identification of Treatment Effectiveness) major depression trial. Patient enrollment for the study is running on schedule and is expected to be completed by the end of the first quarter of 2007. Results from a planned interim analysis of data from the first 156 enrolled subjects have been presented to the data safety monitoring board and have shown that Aspect's EEG biomarker technology is a significant predictor of patient response. Two abstracts describing interim study results have been submitted for presentation at the annual meeting of the American Psychiatric Association taking place in May. If accepted, updated study results will be released publicly at that time. Additional abstracts are being prepared for submission to other 2007 psychiatric conferences.

"We are pleased with the results of the BRITE trial interim analysis," said Nassib Chamoun, president and CEO of Aspect Medical Systems. "The results further our understanding of the role of Aspect's brain assessment technology and bring us one step closer to our goal of developing products that help clinicians improve the care of patients suffering from depression."

Aspect is conducting the BRITE trial in collaboration with leading depression researchers at ten prestigious facilities across the United States. The goal of the study is to determine the accuracy of using Aspect's brain assessment technology to predict the effectiveness of antidepressant medications. In addition, the study seeks to determine the most effective alternative treatment for subjects who show a poor response to a selective serotonin reuptake inhibitor (SSRI) and to expand the company's database to allow further optimization of Aspect's technology. Future trials are expected to focus on assessing the potential impact of Aspect's technology in helping clinicians to improve patient outcomes.

"Antidepressant medications are highly effective, but the current approach to medication selection for an individual patient is based on trial and error. It usually takes many months before an effective antidepressant is identified and a patient feels better," said Andrew Leuchter, M.D., Professor of Psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, principal investigator for the trial, and chair of Aspect's Neuroscience Advisory Board. "Patients and clinicians involved with the BRITE trial have been very positive about the potential of using this brain assessment technology to optimize care and are enthusiastic about the ease-of-use of the technology in practice."

More information about the BRITE trial is available at www.brite-md.com.

About Aspect Medical Systems, Inc.

Aspect Medical Systems, Inc. (NASDAQ: ASPM) is a global market leader in brain monitoring technology. To date, the Company's Bispectral Index (BIS) technology has been used to assess more than 17.4 million patients and has been the subject of approximately 2,570 published articles and abstracts. BIS technology is installed in approximately 70 percent of hospitals listed in the July 2006 U.S News and World Report ranking of America's Best Hospitals and in approximately 51 percent of all domestic operating rooms. In the last twelve months BIS technology was used in approximately 16 percent of all U.S. surgical procedures requiring general anesthesia or deep sedation. BIS technology is available in more than 160 countries. Aspect Medical Systems has OEM agreements with eight leading manufacturers of patient monitoring systems. The company is also investigating how other methods of analyzing brain waves may aid in the diagnosis and management of neurological diseases, including depression and Alzheimer's disease. For more information, visit Aspect's Web site at http://www.aspectmedical.com.

Safe Harbor Statement

Certain statements in this release are forward-looking and may involve risks and uncertainties, including statements with respect to the expected ability of the Company's brain assessment technology to predict the effectiveness of antidepressant medications, the anticipated outcomes and benefits of the BRITE trial, the Company's expectation that the enrollment of patients for the BRITE trial will be completed in the first quarter of 2007 and the Company's anticipated timing with respect to the release of data from the trial, the Company's plans for future studies, the Company's ability to successfully develop tools for the diagnosis and treatment of neurological diseases, such as depression and Alzheimer's disease and the benefits of such tools, if developed, for the general population of patients with such diseases. There are a number of factors that could cause actual results to differ materially from those indicated by these forward-looking statements. For example, the completion of the Company's BRITE trial could be delayed and/or the trial could be unsuccessful as a result of various factors including delays in patient enrollment, lower than anticipated retention rates for patients in the trial, negative trial outcomes and the failure of the trial to establish the predictive accuracy of the Company's brain assessment technology in predicting the effectiveness of antidepressant medications. In addition, even if the trial achieves its outcome objectives, the Company may not be able to successfully develop products for the diagnosis and treatment of neurological diseases, such as depression and Alzheimer's disease, achieve widespread market acceptance of any such products that it may develop or to compete with new products or alternative techniques that may be developed by others. There are additional factors that could cause the Company's actual results to vary from its forward-looking statements, including without limitation those set forth under the heading "Risk Factors" in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2005 and the Company's Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2006, each as filed with the Securities and Exchange Commission. In addition, any forward-looking statements represent the Company's views only as of the date of this press release and should not be relied upon as representing the Company's views as of any subsequent date. While the Company may elect to update forward-looking statements in the future, it specifically disclaims any obligation to do so, even if its expectations change. Therefore, you should not rely on these forward-looking statements as representing the Company's views as of any date subsequent to the date of this press release.

Aspect, Bispectral Index and BIS are registered trademarks of Aspect Medical Systems, Inc. All other trademarks, service marks and company names are the property of their respective owners.