Audiogram construction using frequency-specific auditory brainstem response (ABR) thresholds.

Brainstem evoked response audiometry (ABR) permits auditory pathway assessment without the need for voluntary response. Brainstem responses are unaffected by attention, drugs, and most other confounding conditions. Consequently, if ABR could be used to determine hearing threshold in the speech frequencies, it would have great value for patients who are unable or unwilling to respond accurately during behavioral audiometric testing. Utilizing broad band clicks, one can only estimate hearing sensitivity in the frequency range of 2,000 to 4,000 Hz. This is inadequate for medical or legal purposes in which hearing in the speech frequencies must be assessed. Consequently, we have developed a modified ABR technique that permits a more accurate determination of hearing threshold at 500, 1,000, 2,000 and 3,000 Hz, as illustrated in tests on 27 normal ears. This technique has great potential value for neonatal and mentally handicapped populations, as well as for individuals involved in hearing loss litigation.