The Effects of Parameter Variations in Bekesy Audiometry in a Patient with Acoustic Neurinoma

Abstract

Fixed frequency Bekesy thresholds were compared between a normal hearing subject and a patient with acoustic neurinoma. Thresholds were obtained with two major stimulus groups: (a) interrupted stimuli with a variety of on and off durations and (b) frequency modulated stimuli with various modulating frequencies and frequency deviations. Systematic threshold changes with parameter variation were demonstrated for both types of subject and with both types of stimuli. These changes were relatively minor for the normal hearing subject and for the good ear of the pathological subject, but for the bad ear of the latter, certain parameter combinations yielded the classic decaying type III trace, while with other combinations stable traces could be obtained. The intensity level at which the threshold tracing stabilized was a direct function of the stimulus parameters.