Effects of age and hearing loss on perceptual and physiological measures of temporal envelope processing and spatial release from speech-on-speech masking

Abstract

AbstractOlder adults often experience difficulties understanding speech in adverse listening conditions. These difficulties are partially attributed to auditory temporal-processing deficits associated with aging even in the absence of hearing loss. The aim of this study was to assess effects of age and hearing loss on temporal envelope processing and speech-on-speech masking. Listeners with normal and near-normal hearing across a wide age range (20 to 66 years) were tested using a series of psychophysical (amplitude-modulation detection, gap detection, and interaural-envelope-phase discrimination), physiological (electroencephalographic envelope-following responses), speech perception (spatial release from masking), and cognitive (processing speed) measures. Results showed that: (i) psychophysical measures of monaural and binaural envelope processing and neural measures of envelope processing are not affected by aging after accounting for audiometric hearing loss, (ii) behavioral gap-detection thresholds decline with age, (iii) aging results in a reduction of spatial release from masking, even as speech intensity is amplified in the region of hearing loss, (iv) aging is associated with poorer measures of cognitive function. Although age significantly contributed to a decline in spatial release from speech-on-speech masking, individual differences in envelope processing and in scores from nonauditory cognitive tests used in this study were not significant predictors of speech performance.HighlightsAge per se does not affect psychophysical and physiological measures of monaural amplitude-modulation processing.Age does not affect the ability to detect interaural disparities in envelope timing between the ears.Gap detection thresholds degrades with age even after hearing thresholds are statistically accounted for.Age, independent of hearing thresholds, can substantially reduce spatial release from masking.Cognitive ability declines with age. However, such declines do not necessarily cause deficits in spatial release from masking.