Abstract
PURPOSE: The aim of this study was to evaluate (a) the effect of aging on spectral and temporal resolution, as measured both behaviorally and electrophysiologically, and (b) the contributions of spectral and temporal resolution and cognition to speech perception in younger and older adults. METHOD: Eighteen younger and 18 older listeners with normal hearing or no more than mild-moderate hearing loss participated in this cross-sectional study. Speech recognition was assessed with the QuickSIN test and six-band noise-vocoded sentences. Frequency discrimination, temporal interval discrimination, and gap detection thresholds were obtained using a three-alternative forced-choice task. Cortical auditory evoked potentials were recorded in response to tonal frequency changes and to gaps in noise. Cognitive testing included nonverbal reasoning, vocabulary, working memory, and processing speed. RESULTS: There were age-related declines on many outcome measures, including speech perception in noise, cognition (nonverbal reasoning, processing speed), behavioral gap detection thresholds, and neural correlates of spectral and temporal processing (smaller P1 amplitudes and prolonged P2 latencies in response to frequency change; smaller N1-P2 amplitudes and longer P1, N1, P2 latencies to temporal gaps). Hearing thresholds and neural processing of spectral and temporal information were the main predictors of degraded speech recognition performance, in addition to cognition and perceptual learning. These factors accounted for 58% of the variability on the QuickSIN test and 41% of variability on the noise-vocoded speech. CONCLUSIONS: The results confirm and extend previous work demonstrating age-related declines in gap detection, cognition, and neural processing of spectral and temporal features of sounds. Neural measures of spectral and temporal processing were better predictors of speech perception than behavioral ones. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.28883711.