Evaluating the role of age on speech-in-noise perception based solely on temporal envelope information

Acoustic amplitude modulation (AM) patterns carry significant auditory information, particularly in speech. AM masking, influenced by frequency selectivity in the modulation domain, is considered a crucial factor for speech intelligibility in noisy environments. Based on recent evidence suggesting an age-related decline in AM frequency selectivity, this study examined whether elevated AM masking in older listeners is associated with challenges in speech intelligibility. Speech reception thresholds (SRTs) were measured using tone-vocoded speech with maskers varying in AM content, and AM masked thresholds were assessed at a target modulation frequency of 4 Hz. Participants included young (n = 14, 19-25 years) and older (n = 14, 57-79 years) listeners with normal hearing. The study hypothesized that SRTs would be greater in the older group in a manner that varied with modulation frequency. Although AM masked thresholds indicated reduced AM selectivity with age, the pattern of SRTs did not confirm the hypothesis. Instead, the results showed no significant effect of the modulation frequency content of the maskers on the SRTs. Furthermore, the main effect of age on SRTs approached, but did not reach, significance. The results underscore the need for further investigation into the relationship between AM selectivity and speech intelligibility.