Comparison of two cortical measures of binaural hearing acuity

Abstract

Objective Multiple studies have demonstrated binaural hearing deficits in the aging and those with hearing loss. Consequently, there is great interest in developing efficient clinical tests of binaural hearing acuity to improve diagnostic assessments and to assist clinicians when fitting binaural hearing aids and/or cochlear implants. Design Two cortical measures of interaural phase difference sensitivity, the acoustic change complex (ACC) and interaural phase modulation following response (IPM-FR), were compared on three metrics using five different stimulus interaural phase differences (IPDs; 0°, ±22.5°, ±45°, ±67.5° and ±90°). These metrics were scalp topography, time-to-detect, and input–output characteristics. Study sample Ten young, normal-hearing listeners. Results Scalp topography qualitatively differed between ACC and IPM-FR. The IPM-FR demonstrated better time-to-detect performance on smaller (±22.5° and ±45°) but not larger (67.5°, and ±90°) IPDs. Input–output characteristics of each response were similar. Conclusions The IPM-FR may be a faster and more efficient tool for assessing neural sensitivity to subtle IPD changes. However, the ACC may be useful for research or clinical questions concerned with the topographic representation of binaural cues.