Nearly 25 million people in the United States have a hearing loss. These hearing losses vary in severity from a mild loss that interferes with a person's ability to communicate by speech, to profound or total deafness. People in the latter group usually communicate by sign language or other visual means of communication. Although hearing aids, TTY's (also known as TDD's, telephone devices for deaf people) and other assistive devices are widely used, the majority of persons with hearing loss do not make use of technological aids. Costs are high, many technological aids are not as effective as they could be, and many potential consumers are unaware of the benefits that technological aids can provide. The Rehabilitation Engineering Research Center (RERC) on Hearing Enhancement and Assistive Devices is designed to address these problems in an efficient and productive way. This is done by developing and evaluating improved cost-effective technological aids for the various groups of people with hearing loss, according to their needs (e.g. people with moderate hearing losses, people with severe or profound hearing losses, young children, older adults and people with both vision and hearing loss). Specific projects include the development and evaluation of improved instrumentation for detecting hearing loss at an early age, development and evaluation of improved hearing aids, providing improved access to modern telecommunications, developing and evaluating specialized technology for community, home and work environments including technology for the various groups noted above, who have special needs. All of this work is supported by an active program of dissemination and training to ensure effective utilization of the research results and assistive devices developed by this research center.