Processing of Speech in Complex Listening Environments by Individuals with Obscure Auditory Dysfunction

Abstract

Obscure auditory dysfunction (OAD) is a disorder characterized by patient report of excessive amounts of difficulty understanding speech in the presence of background noise, despite relatively normal hearing sensitivity. It has been hypothesized that OAD may be the result of mild cochlear dysfunction, central auditory processing deficits, and/or psychological disorders. To evaluate auditory processing aspects of this disorder, speech recognition was measured in complex listening conditions for 10 normal-hearing persons with self-reported problems understanding speech in noisy environments. Ten normal-hearing listeners without reported difficulty hearing speech in noise served as controls. Each participant completed a standard audiometric evaluation, the QuickSIN test (standard clinical test of speech recognition in noise), and experimental speech recognition measures in simulated background environments, which included a range and combination of competitor stimuli presented in monaural and binaural conditions. The results show that the OAD participants had poorer overall speech recognition abilities in noise than did control participants for the experimental speech recognition tasks. The pattern of performance deficits suggests that the speech-understanding problems of these OAD participants are not attributable to abnormally poor binaural hearing or to a reduction in masking release. Further, performance deficits exhibited by listeners with OAD were not identified by a standard clinical speech-in-noise measure.