Sequential auditory scene analysis is preserved in normal aging adults.
Normal aging is accompanied by speech perception difficulties, especially in adverse listening situations such as a cocktail party. To assess whether such difficulties might be related to impairments in sequential auditory scene analysis, event-related brain potentials were recorded from normal-hearing young, middle-aged, and older adults during presentation of low (A) tones, high (B) tones, and silences (--) in repeating 3 tone triplets (ABA--). The likelihood of reporting hearing 2 streams increased as a function of the frequency difference between A and B tones (Delta f) to the same extent for all 3 age groups and was paralleled by enhanced sensory-evoked responses over the frontocentral scalp regions. In all 3 age groups, there was also a progressive buildup in brain activity from the beginning to the end of the sequence of triplets, which was characterized by an enhanced positivity that peaked at about 200 ms after the onset of each ABA--triplet. Similar Delta f- and buildup-related activity also occurred over the right temporal cortex, but only for young adults. We conclude that age-related difficulties in separating competing speakers are unlikely to arise from deficits in streaming and might instead reflect less efficient concurrent sound segregation.
The Rotman Research Institute, Baycrest Centre for Geriatric Care, Toronto, Ontario, Canada. joel_snyder@hms.harvard.edu
Joel S
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Snyder
Claude
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Alain
D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged