Pure-Tone Octave Masking in Listeners with Sensorineural Hearing Loss

Abstract

Phase-locked pure-tone masking was investigated in 16 listeners with sensorineural hearing loss to examine the hypothesis that the sensorineurai ear introduces abnormal distortion. Thresholds for a pure tone at f2, masked by a pure tone at f1 (where f2=2f1), were obtained as a function of the level of the f1 masker for three different f1 frequencies (250, 500, and 1000 Hz) and two different phase relations between f1 and f2 (90° and 270°). Estimates of the level of the aural harmonic were obtained from those masking functions. Analysis of the data in terms of the absolute level of f2 at masked threshold versus the absolute level of f1 results in a conclusion that these pathological ears do not perform differently from normal ears, except along the dimension of hearing loss. That is, their hearing loss does not add significant distortion to the acoustic signal. Even though the present analysis suggests that evaluation of the data for pure-tone octave masking in terms of SL leads to the specious conclusion that the sensorineural ear introduces abnormal distortion, an attempt was made to relate hearing loss to the aural harmonic in less simplistic terms [Research supported by grants from the NINDS of USPHS.]