Comparison between the Frequency Specificities of Auditory Brainstem Response Thresholds to Clicks with and without High-Pass Masking Noise

Abstract

In this study, the frequency specificity of the auditory brain stem response (ABR) threshold to a click masked with 1590-Hz high-pass masking noise is compared with the frequency specificity of the unmasked click-evoked ABR threshold. The ABR threshold to the high-pass-noise-masked click stimulus is low frequency specific and corresponds with the 1000-Hz pure-tone threshold. Although the ABR threshold to the unmasked click stimulus corresponds with the ‘3 000’-Hz pure-tone threshold, the frequency specificity seems much less pronounced than that of the low-frequency-specific stimulus. This study shows, however, that this apparent lack of frequency specificity can be attributed to the selection of pure-tone hearing losses. The ABR threshold evoked by an unmasked click stimulus is, therefore, preeminently useful as a high-frequency point of a two-point audiogram. The possible reasons why the ABR threshold evoked by a broad-band stimulus as the unmasked click corresponds with the higher frequencies of the pure-tone audiogram are discussed.

Key Words:

• Auditory brainstem response
• Frequency specificity