Simulated Hearing Loss via Masking: Research and Heuristic Applications

Abstract

The traditional view of masking is the effective exclusion of the nontest ear in conventional behavioral audiometry. Various other applications, however, are possible, including evaluations of auditory evoked potentials. General concepts of masking in psychoacoustic and electrophysiologic testing are reviewed, leading to a detailed summary of new techniques developed to improve the diagnostic power of the auditory-brain-stem response (ABR) test in the detection of eighth-nerve testing-the “stacked ABR.” Another application is the use of filter-shaped noise to simulate hearing loss of particular degree and configuration in normal listeners to assess the accuracy of estimates of hearing loss using electric response audiometry (ERA) and test-retest reliability of a given method of ERA. This article reports on the preliminary results of a study on a recently developed method of ERA based on measurement of the auditory steady-state responses (ASSR). These results demonstrate similar estimates of hearing loss among the measures examined-pure-tone audiometry, ERA using the slow vertex potential, and ERA using the ASSR-although ERA estimates tend to exaggerate the loss by several decibels, even in a highly controlled study. Finally, simulated hearing loss is suggested as a tool for the training of audiologists in methods of both behavioral and electric response audiometry, wherein the instructor can provide a variety of degrees and configurations of hearing loss in a highly predictable manner.