Investigation of binaural interference in normal-hearing and hearing-impaired adults.

When speech recognition testing is performed under diotic conditions, some elderly persons with asymmetric hearing loss exhibit a phenomenon in which the performance of the poorer ear interferes with that of the better ear. This binaural interference phenomenon has been estimated to occur in 8 to 10 percent of elderly hearing aid users. The purpose of the present study was to investigate the prevalence of this phenomenon in groups (n = 12) of young and elderly listeners with normal hearing, plus groups of elderly listeners with hearing loss who were aided or unaided. Of 48 subjects tested, only 2 exhibited significant evidence of binaural interference, a result that is close to that expected by chance. Although both of these subjects were elderly, one had normal hearing and the other was aided binaurally. A third elderly unaided subject exhibited a significant binaural advantage. Further studies are needed to determine the prevalence of binaural interference in normal-hearing or hearing-impaired listeners in any decade of life.