SPEECH-PERCEPTION AIDS FOR HEARING-IMPAIRED PEOPLE - CURRENT STATUS AND NEEDED RESEARCH

Both the overall aging of the population and its exposure to higher noise levels have increased the tendency to hearing loss and the importance of improved hearing aids for speech perception. This article reviews improvements in conventional electroacoustic hearing aids, as well as recently developed alternative classes of speech-perception aids, including surgically implanted cochlear stimulators, and vibrotactile, electrocutaneous and optical stimulating devices. It is concluded that the most effective aid for the vast majority of hearing-impaired persons is, and will remain for the immediate future, the electroacoustic hearing aid. In those cases for which no benefit is demonstrated for the electroacoustic aid, generally meaning persons with profound hearing loss, either the cochlear implant or a tactile aid may provide some improvement in the understanding of speech. In rare cases, some speech understanding in the absence of lip reading is achieved by patients with cochlear implants, for unexplained reasons. This and other pressing questions about speech processing need to be addressed by the research community if more effective aids are to be developed for the use of the 36.5 million hearing-impaired persons expected in the U.S. by the year 2050.