AGING, AUDITORY SUPPRESSION AND FEQUENCY SELECTIVITY

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Auditory suppression is a mechanism whereby strong excitation at one frequency can suppress activity at adjacent frequencies. In young adults, auditory suppression can significantly enhance the frequency resolving power of the auditory system (the ability to resolve individual components of complex signals). The purpose of the proposed pilot study is to examine auditory suppression in older adults to determine if age-related changes in suppressive mechanisms impair frequency resolution in this population. Age differences in auditory suppression will be investigated by comparing auditory filters (one index of frequency resolution) obtained with simultaneous and forward masking procedures in young and old adults. Comparisons of auditory filters measured with imultaneous and forward masking paradigms can provide an indication of the integrity of suppressive mechanisms because suppression is revealed in forward, but not in simultaneous, masking paradigms. Thus, as deficits in auditory suppression increase, auditory filters measured with simultaneous and forward masking procedures become more similar. The hypothesis under investigation in the proposed pilot study is that older adults will exhibit less of a difference between frequency selectivity measured with forward and simultaneous basking paradigms because age-related deficits in auditory suppression will reduce the benefits of suppressive mechanisms that have been observed in young adults. Evidence of age-related declines in auditory suppression could have important clinical implications because deficits in speech perception and other auditory functions resulting from impaired suppressive mechanisms would be uniikely to benefit from traditional clinical interventions such as amplification (hearing aids). The results of the proposed study will also provide important ilot data for a more extensive research proposal concerning age-related changes in psychoacoustic abilities, such s auditory suppression, that are independent of the well-established hearing loss in older adults and that can have profound effects on the perception of speech and other auditory stimuli.