Effect of degree of hearing loss on diagnostic audiometric tests.

Results of five diagnostic audiometric tests--(1) auditory, brain-stem response (ABR) audiometry, (2) the acoustic reflex (AR) test, (3) speech audiometry, (4) threshold Bekesy audiometry, and (5) supra-threshold adaptation test (STAT)--were examined in sixty cases of confirmed eighth nerve disorder. Test results were classified as either (1) positive for eighth nerve site, (2) negative for eighth nerve site, or (3) ambiguous for site of disorder owing to severity of hearing loss. Findings suggest that degree of hearing loss is an important factor in test interpretation. In general, ability to interpret test results unambiguously decreases as degree of hearing loss increases, especially for sensitive test procedures like ABR and speech audiometry.