Aspect Medical to Report Third Quarter 2004 Results October 20, 2004; Conference Call Scheduled for Same Day

Business Wire, Sept 21, 2004

NEWTON, Mass. -- Aspect Medical Systems, Inc. (Nasdaq: ASPM) will report earnings results for the 2004 third quarter on Wednesday, October 20, 2004. Following the earnings announcement on Wednesday morning, the Company will host a conference call and live webcast at 10:00 a.m. Eastern Daylight Time for all interested parties, including financial analysts, portfolio managers, individual investors and members of the press. To participate in the, call please dial 1-888-896-0863 (domestic), 1-973-935-8507 (international), or access the webcast at http://www.aspectmedical.com on the Investor page, at or http://ccbn.com. Telephone replays will be available by dialing 1-877-519-4471 (domestic), or 1-973-341-3080 (international), access code 5210078. The webcast replay will be available from October 20, 2004 until October 28, 2004.

About Aspect Medical Systems, Inc.

Aspect Medical Systems, Inc. (NASDAQ: ASPM) is a global market leader in brain monitoring technology. Aspect's BIS(TM) technology directly measures the effects of anesthetics and sedatives on the brain. The technology has been used to assess more than 9 million patients and has been the subject of approximately 1,500 published articles and abstracts. BIS technology is installed in approximately 33 percent of all domestic operating rooms and is available in more than 160 countries. Aspect Medical Systems has OEM agreements with seven leading manufacturers of patient monitoring systems. Aspect is also investigating how other methods of analyzing EEG may aid in the diagnosis and management of neurological diseases, including depression and Alzheimer's. Based in Newton, Mass., Aspect employs more than 200 people worldwide. For more information, visit Aspect's Web site at www.aspectmedical.com

For further information regarding Aspect Medical Systems, Inc., visit the Aspect Medical Systems, Inc. website at http://www.aspectmedical.com