Diplacusis in Unilateral High-Frequency Hearing Losses

Abstract

Pitch-matching performances of five subjects with unilateral high-frequency hearing losses and of five subjects with normal hearing were compared on seven conditions at 4000 cps. The method of adjustment was used in two intra-aural, one binaural, and two interaural conditions all at 40 dB and two interaural conditions at 80 dB. Three major findings emerged: (1) there was a marked decrease in acuity, larger DLF values, under all conditions involving the ears with hearing losses; (2) positive time-order errors seemed to be inherent in the procedures used, but they were markedly increased in conditions involving the ears with hearing losses; (3) diplacusis was found in one subject with normal hearing and in all subjects with hearing losses. In each instance, the ear with the impaired hearing was pitched higher than the ear with normal hearing.