The excessive, indiscriminate use of masking during measurements of pure-tone bone-conduction thresholds can reduce or eliminate air-bone gaps. This may result in an abnormal, audiometrically induced bone-conduction threshold shift and suggest to the otologist the need for auditory brainstem response testing and/or magnetic resonance imaging. A case is presented in which the inappropriate use of the masking plateau method resulted in a reduction of the air-bone gap in an ear with a mild conductive hearing loss. The audiometric Weber test should be used in these cases, and nonmasked bone thresholds should be used to determine the actual level of the cochlear reserve.
Source URL: http://www.entjournal.com/article/how-eliminate-air-bone-gaps-audiometrically-use-too-much-masking#comment-0