Why Do Hearing-Impaired Listeners Fail to Benefit from Masker Fluctuations?

Abstract

Hearing-impaired (HI) listeners do not receive as much benefit to speech intelligibility from fluctuating maskers, relative to stationary noise, as normal-hearing (NH) listeners. Investigators have focused on reduced audibility, deficits in spectral or temporal resolution, or limited cues for target-source separation as possible underlying causes of the reduced FMB. An alternative possibility is that the FMB differences may arise as a consequence of differences in the signal-to-noise ratio (SNR) at which HI and NH listeners are tested. The Extended Speech Intelligibility Index (ESII) was fit to NH data, and then used to make FMB predictions for a variety of results in the literature. Using this approach, reduced FMB for HI listeners and NH listeners presented with distorted speech was accounted for by SNR differences in many cases. HI listeners may retain more of an ability to listen in the gaps of a fluctuating masker than previously thought.