Selective dysacusis--a preliminary report.

The symptom of poor speech discrimination in the presence of background noise is a well-recognized feature of elevated hearing thresholds due to cochlear damage. Similar symptoms occasionally occur in patients with no detectable audiological abnormality. In a study to evaluate the frequency selectivity of such patients consistent abnormalities were found using an electrophysiological technique based on extratympanic electrocochleography. These findings indicated that frequency specific responsiveness of the cochlea may be affected before conventional behavioural tests reveal abnormalities. This syndrome has been described as selective dysacusis.