ABSTRACT
Two aspects of age-related declines in auditory temporal processing may contribute
to the difficulties that older adults have perceiving speech in everyday listening
situations: ability to code the temporal properties of the envelope; and the temporal
fine structure of speech. Gap detection and duration discrimination play a role in
coding temporal properties of the envelope, including cues to phoneme contrasts. Significant
age-related declines are found in these psychoacoustic measures but only when sounds
are short; corresponding age-related declines are found in discriminating specific
phonemic contrasts based on gaps. Significant correlations between gap detection thresholds
and word recognition are found, at least in some studies, in conditions of noise,
reverberation, or speeded speech. It is suggested that coding of the temporal fine
structure of speech is compromised by age-related loss of neural synchrony. Loss of
synchrony in older adults could account for poorer frequency discrimination at low
frequencies and problems using harmonic structure to segregate voices from competing
signals. These declines in temporal processing are observed in older adults with good
audiograms and are not correlated with audiometric threshold. More informed audiological
management and rehabilitation requires the consideration of specific age-related temporal
processing declines.
KEYWORD
Temporal processing - auditory aging - speech perception - gap detection - neural
synchrony