Aspect Medical Systems Features New Research at American Society of Anesthesiologists Meeting.

-BIS Technology Featured in Nearly 100 Scientific Posters and Sessions-

NEWTON, Mass. -- Researchers from around the world are presenting nearly 100 scientific posters and sessions referencing BIS[TM] technology at the American Society of Anesthesiologists (ASA) Annual Meeting in Chicago this week. BIS monitoring, developed by Aspect Medical Systems, Inc. (NASDAQ: ASPM), is the world's leading level-of-consciousness monitoring technology for measuring the effects of anesthetics and sedatives on the brain. BIS-related research presented at the meeting of more than 5,000 anesthesiologists covers a broad spectrum of topics including short and long term outcome benefits of BIS monitoring, intraoperative awareness and the role of fluctuations in BIS values in assessing pain both during and after surgery.

"The volume and diversity of BIS-related research presented at the ASA meeting reflect the growing global interest in use of BIS to help clinicians improve the safety and quality of care," said Nassib Chamoun, president and CEO of Aspect. "We are pleased that brain monitoring and prevention of awareness remain prominent topics at the ASA meeting and we believe that this extensive scientific evidence supports use of brain function monitoring for many diverse patient populations. New research being presented at the meeting also furthers our understanding of the impact of anesthetic management on near and longer-term patient outcomes."

Anesthetic management and patient outcomes

Research being presented at ASA that is supported by Aspect include two studies that evaluated how rapid changes in BIS values and EMG (electromyogram, or electrical activity generated by muscle) may be useful in assessing patient response to pain during surgery. The first study demonstrated that BIS values and EMG show greater and more frequent fluctuations before a patient responded (e.g. moved) in reaction to painful surgical events. The second study demonstrated that highly variable BIS and EMG measurements during surgery were associated with patients reporting greater pain during recovery. "These studies suggest that BIS and EMG variability may be clinically useful in improving pain management and comfort for patients during and after their surgery," said Scott Greenwald, Ph.D., vice president of Research at Aspect and lead author of the first study.

A third study explored the relationship between depth of consciousness (as measured by BIS) and changes in inflammatory biomarkers after surgery. This prospective, randomized study compared BIS-guided anesthetic with standard clinical practice to determine the effects of minimizing exposure to anesthetics on inflammatory response. Patients in the BIS monitored group received 33 percent less anesthetic and showed a less severe inflammatory response compared to controls. "The findings from this pilot study potentially reinforce the clinical benefit of using BIS as a measure to avoid excessively deep anesthesia and suggest that anesthetic titration may also help modify the inflammatory response to the trauma of surgery," said Peter Sebel, MBBS, a professor of anesthesiology at Emory University School of Medicine and lead investigator in the study.

Commenting on the new research, Chamoun stated, "We believe that these new studies further support the use of brain monitoring and underscore Aspect's continuing commitment to improve patient care through sound clinical research and development of new products. Aspect is actively working with leading investigators to better understand the linkage between optimized anesthetic management and improved patient outcomes," said Chamoun.

About BIS Monitoring

Using a sensor placed on the patient's forehead, BIS monitoring translates information from the electroencephalogram (EEG) into a single number that represents each patient's level of consciousness. This number - the BIS value - ranges from 100 (indicating an awake patient) to zero (indicating the absence of brain activity). Using the BIS value to guide administration of anesthetic medication, in conjunction with other vital signs, allows clinicians to make better-informed decisions to achieve optimal anesthesia.

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 16.3 million patients and has been the subject of approximately 2,570 published articles and abstracts. BIS technology is installed in approximately 68 percent of hospitals listed in the July 2006 U.S. News and World Report ranking of America's Best Hospitals and in approximately 49 percent of all domestic operating rooms. In the last twelve months BIS technology was used in approximately 15 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 seven 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 regarding the role of brain function monitoring and its effect on the safety and quality of patient care and the Company's belief that global interest in BIS is increasing. There are a number of important factors that could cause actual results to differ materially from those indicated by these forward-looking statements. For example, the use of BIS may not prove in further clinical studies to be clinically useful to improving patient care. Moreover, the Company may not achieve widespread market acceptance of its BIS monitoring technology among anesthesiologists. The Company also faces other barriers to market penetration and acceptance. The Company may not be able to compete with new products or alternative techniques that may be developed by others, including third-party anesthesia monitoring products approved by the FDA, and also faces competitive and regulatory risks relating to its ability to successfully develop and introduce enhancements and new products, including products to aid in the treatment of neurological disorder. Cases of awareness with recall during monitoring with the BIS system and significant product liability claims are among the factors that could limit market acceptance. 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 July 1, 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.

BIS, the BIS logo and Bispectral Index are trademarks of Aspect Medical Systems, Inc. and are registered in the USA, EU and other countries. BISx and BIS VISTA are trademarks of Aspect Medical Systems, Inc. All other trademarks, service marks and company names are the property of their respective owners.