Basic and applied research on tactile aids for deaf people: Progress and prospects

A brief introduction describes the alternative methods for replacement of the sense of hearing, including the educational procedures of sign language and lipreading, the medical procedure of cochlear implants, and the sensory substitution procedures of visual or tactual displays. For the tactual displays, which are most commonly electronically activated, a listing of desirable objectives is discussed in some detail. Among these are a better understanding of the processing capabilities of the skin, the form an efficient transducer may take, and what features of the speech stream may most profitably be extracted for processing and display to the sense of touch. Because the technology for device design and production in this area is seriously retarded, a great amount of space is devoted to the precise specification of a transducer for the tactile display; included is a discussion of direct electrocutaneous stimulation as a realistic alternative. A number of multichannel displays exist, and several of these may be workable systems if their transducer elements can be kept small and use little energy. What is of current, even urgent, importance is the early and widespread deployment of a single‐channel tactile aid to permit the general assessment of the effectiveness of a simple sensory adjuvant for a deaf person who has lipreading skills.