Abstract
Four groups of subjects have been investigated, using a manual phase audiometer. Group I consisted of 20 normal-hearing subjects, Group 2 of 22 subjects with unilateral or asymmetric cochlear hearing loss, Group 3 of 14 subjects with surgically verified CPA tumours, and Group 4 of 15 subjects with unilateral conductive impairment. In this report we suggest an upper borderline value for detecting interaural time differences of 120 μs. If the subject is able to detect only a value exceeding 120 μs, there is likely to be a retrocochlear lesion.