A pseudo free-field measure of auditory disability

Conventional measures of auditory disability via speech identification scores are usually monaural, or occasionally, diotic. Circumstances of everyday listening usually contain stereophonic (dichotic) cues, whilst such listening situations can be tested in a free field environment they are difficult to standardize and calibrate. A procedure has been developed by recording the signals from two Zwislocki couplers in a KEMAR mannikin to produce a headphone-presented set of speech material containing the important dichotic cues present in free field listening. This enables readily calibrated and experimentally controllable conditions to be set up to measure aspects of auditory disability and, for example, its alleviation via amplification. Two examples of the use of the test are provided: (i) the assessment of the benefits of the presence of stereophonic cues on speech identification in both the real free field and simulated conditions, and (ii) the benefits of monaural and binaural provision of amplification of hearing impaired people in directional listening situations.