What can we learn about hearing aids from cochlear implants?

Cochlear implants have changed the rehabilitation of profoundly hearing-impaired patients. A wide range of performance is reported for postlingually deaf adult patients using multichannel (Nucleus and Inerad) cochlear implants. For the 63 patients described here, performance ranges from 0 to 62% correct word recognition, from 0 to 98% lipreading enhancement measured as a percentage of the possible enhancement, and from 0 to 98% on understanding words in sentences. Prelingually deaf children also show benefit from their cochlear implants, but they require more time to obtain benefit than postlingually deaf children and adults. Experience with cochlear implants has suggested a few observations that could be useful to hearing aid development, including: (1) field trials are essential; (2) signal processing should preserve and enhance frequency resolution; (3) the fitting process for a sophisticated hearing aid may require several days to adjust properly; (4) fitting algorithms should focus on individuals rather than averages; (5) patients will wear a larger device if their handicap is great enough and if the improvement is sufficient; and (6) patients should and will accept expensive hearing aids.