Abstract

Meeting abstract. No PDF available. ABSTRACT Sensitivity to the temporal fine structure (TFS) of sounds is considered important for understanding speech, especially in the presence of background noise, but few studies have employed objective measures to assess the relationship between sensitivity to TFS and listening to speech. Here, we used EEG (electroencephalography) to obtain an objective measure of sensitivity to the TFS of low-frequency sounds (520-Hz amplitude-modulated tones) in listeners who also undertook a speech-discrimination task (discrimination of vowel-consonant-vowel, VCV, sounds in background noise). Two different sound levels (60 and 80 dB SPL) and three different signal-to-noise ratios (SNRs; -6, 0 and + 6 dB) were used. Three symmetric interaural phase modulations (IPMs), were measured: -60°/60°, -90°/90°, and -120°/120°. A fourth condition used an IPM switching between 0° and 180° degrees. IPM-FRs were higher for the 0/180° degrees than all other conditions. Employing the ratio of the 3 symmetric to the asymmetric (0/180°) IPM-FR as a measure of the neural dynamic range of TFS processing, we found that VCV scores increased with age at 60 dB SPL, but not 80 dB SPL, and indeed were better at 60 compared to 80 dB SPL in older listeners, and correlated with a higher ratio of IPM-FRs.