[Clinical value of interaural time discrimination].

The interaural time discrimination (ITD) is one of the azimuthal sound location cues. In multiple sclerosis subjects, deficits in binaural timing discrimination are closely related to abnormalities in brainstem auditory evoked potentials (BAEPs). To determine if psychophysical performances could be related to the BAEPs in other otoneurological deficits, thresholds of ITD were measured in 168 patients and the results correlated to the electrophysiological responses to clicks. Both tests were normal in 29.8% and abnormal in 42.2% of cases. A discrepancy existed in 28.0%: ITD abnormal--BAEPs normal in 23.2%, ITD normal--BAEPs abnormal in 4.8%. In conclusion, in cases with normal ITD thresholds, the probability of a retrocochlear lesion is low. The test of ITD is helpful when the interpretation of the BAEPs is difficult because of desynchronized waves.