Cortical auditory temporal processing abilities in elderly listeners

This study investigated whether objective temporal processing paradigms including voice-onset-time, speech-in-noise, and amplitude modulated-broad-band noise (AM-BBN) are sensitive to disrupted temporal processing in elderly listeners with normal hearing (age-related-temporal processing deficit). We evaluated 15 adults aged 64–80 years using behavioural measures of temporal processing temporal modulation transfer function (TMTF) and speech perception. Cortical auditory evoked potentials (CAEPs) were elicited by three temporal paradigms presented in the sound field at 65 dBSPL: (1) naturally produced stop consonant-vowel (CV) syllables /da/-/ta/ and /ba/-/pa/; (2) speech-in-noise stimuli using the speech sound /da/with varying signal-to-noise ratios (SNRs); and (3) 16 Hz amplitude-modulated (AM) BBN presented in two conditions: (i) alone (representing a temporally modulated stimulus) and (ii) following an unmodulated BBN (representing a temporal change in the stimulus) using four modulation depths. Findings demonstrated a statistically significant mean difference in n1 latency (p<0.05) between normally hearing elderly and young adult listeners in all paradigms. Compared with young adult participants, n1 latency of the CAEP was always prolonged for elderly participants. The three developed temporal processing paradigms are sensitive to disrupted temporal processing in elderly participants, and n1 latency may serve as a reliable objective measure of the efficiency of auditory temporal processing. The aging process affects temporal representations of the acoustic stimulus and reduces the ability to detect temporal cues, evidenced by abnormal n1 latency.