BIS Monitoring Receives New 510K Related to Reducing the Risk of Awareness with Recall During Surgery.

Business Editors

NEWTON, Mass.--(BUSINESS WIRE)--Oct. 13, 2003

Aspect Medical Systems (NASDAQ: ASPM) today announced that the Food and Drug Administration (FDA) cleared a new indication for use for BIS(TM) monitoring related to reducing the risk of intraoperative awareness with recall in adult patients undergoing general anesthesia and sedation. Awareness occurs when patients do not receive enough anesthesia to remain unconscious. As a result, they may regain consciousness during surgery, become aware of what is happening, and retain memory of this experience after the surgery is over.

"BIS monitoring is the first and only technology to receive marketing clearance for helping clinicians reduce the risk of patients unintentionally waking up while under anesthesia or sedation," stated Nassib Chamoun, president and CEO of Aspect. "We believe that the extensive amount of clinical data supporting this milestone clearly differentiates BIS from any other product on the market and further validates the safety benefits of BIS technology for patients and clinicians."

The new indication for use clearance is based on three clinical studies that demonstrate that the incidence of intraoperative awareness with recall is reduced significantly when the BIS monitor is used to help guide administration of general anesthesia or sedation.

"The studies supporting this marketing clearance were based on the evaluation of more than 30,000 patients. This represents one of the largest prospective research efforts ever undertaken to address an important safety issue in anesthesia," said Paul Manberg, Ph.D., vice president of clinical, regulatory and quality assurance for Aspect. "We now have conclusive data which describes the baseline incidence of awareness, the impact that it has on patients, and the extent that BIS monitoring can be used to help avoid this significant adverse event."

An estimated 20 million patients in the U.S. have surgery under general anesthesia each year. New research has shown that 1 to 2 patients out of every thousand receiving general anesthesia will experience awareness with recall. This translates to approximately 100 awareness cases every operating day nationwide.

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, clinicians can make informed decisions for optimal anesthesia or sedation.

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 and has been used to assess more than 7 million patients. BIS is currently in use in the operating rooms and intensive care units of more than 55 percent of the best-ranked hospitals in the U.S. (based on a U.S. News & World Report ranking) and has been the subject of approximately 1,350 published articles and abstracts. BIS is available in more than 160 countries with a worldwide installed base of monitors and BIS modules of approximately 17,800. Aspect has secured OEM agreements with seven leading manufacturers of patient monitoring systems. Based in Newton, Mass., Aspect employs approximately 200 people worldwide. 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. There are a number of factors that could cause actual results to differ materially from those indicated by these forward-looking statements. For example, Aspect may not be able to achieve widespread market acceptance of its BIS monitoring technology or to compete with new products or alternative techniques that may be developed by others including third-party anesthesia monitoring products approved by the FDA. Aspect also faces competitive and regulatory risks relating to its ability to successfully develop and introduce enhancements and new products. In addition, the Company has limited sales and marketing experience both in the U.S. and internationally and if it is unable to develop and implement a successful sales and marketing strategy, including with respect to its own sales force, domestic and international distributors, original equipment manufacturers and other direct and indirect sales channels, it will not be able to generate meaningful product revenue. Aspect's ability to become and remain profitable will depend upon its ability to promote frequent use of the BIS system so that sales of its BIS sensors increase. Aspect will not be profitable if hospitals and anesthesia providers do not buy and use its BIS systems in sufficient quantities. Cases of surgical awareness during monitoring with the BIS system and significant product liability claims are among the factors that could limit market acceptance. There are other factors that could cause Aspect's actual results to vary from its forward-looking statements, including without limitation those set forth under the heading "Factors Affecting Future Operating Results" in Aspect's Quarterly Report on Form 10-Q for the quarter ended June 28, 2003, as filed with the Securities and Exchange Commission. In addition, any forward-looking statements represent Aspect's views only as of the date of this press release and should not be relied upon as representing Aspect's views as of any subsequent date. While Aspect 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 Aspect's views as of any date subsequent to the date of this press release.

Bispectral Index and BIS are registered trademarks of Aspect Medical Systems, Inc. A-2000 is a trademark of Aspect Medical Systems, Inc. All other trademarks, service marks and company names are the property of their respective owners.