Effects of age and hearing loss on spatial release from speech-on-speech masking, performance in envelope-based psychophysical tasks, and EEG envelope-following responses

Abstract

Behavioral measures of amplitude modulation (AM) detection and envelope interaural-phase-difference (eIPD) detection reflect listeners’ ability to process temporal information. Robust encoding of temporal envelopes is necessary for understanding speech in a complex acoustic environment and for spatial segregation of a target speech from interfering background. It has been suggested that a large variability in performance in psychophysical tasks involving temporal envelope processing and in spatial release from masking for speech intelligibility may arise from cochlear synaptopathy. However, many studies have not found significant correlations between these measures and the amount of self-reported noise exposure in young listeners with audiometrically normal hearing. Similarly, electroencephalographic envelope-following responses did not significantly correlate with noise exposure or with behavioral performance reliant on envelope processing young normal-hearing population. In this study, behavioral measures in psychophysical tasks (AM and eIPD detection) and speech intelligibility in two-talker babble were measured for listeners with normal and near-normal hearing across a wide age range (20 to 69 years). Correlational analyses were performed using behavioral measures and envelope-following responses collected from the same listeners. Results will be discussed in terms of sensitivity of these measures to effects of aging and high-frequency hearing loss. [Work supported by NIH Grant R01 DC015987.]