Temporal resolution in young and elderly subjects as measured by mismatch negativity and a psychoacoustic gap detection task.
OBJECTIVE
The speech understanding difficulties of elderly persons with age-related hearing loss may be related in part to reduced auditory temporal resolution. To investigate the effects of aging on temporal resolution, the electrophysiological and psychoacoustic detection thresholds for a very short silent gap within a pure tone were determined, and the relation between the two test results was examined.


METHODS
Behavioral gap detection thresholds were determined in 10 young and 10 elderly normally hearing subjects using an adaptive test procedure. To elicit mismatch negativity (MMN), deviant stimuli with gap durations varying from 6 to 24 ms in 3 ms steps were presented in separate test blocks.


RESULTS
There were no significant differences in the psychoacoustic gap detection thresholds between young and elderly subjects. In contrast, longer gaps were needed to elicit MMN in elderly subjects. They also had significantly reduced MMN peak amplitudes, increased MMN peak latencies, a significantly smaller P2 amplitude and longer P2 latency in their responses to the standard stimulus when compared to the same measures in young subjects.


CONCLUSIONS
Processing of basic temporal stimulus features in elderly subjects is considerably more reduced at the preattentive level (as indicated by MMN), than when attention is directed to the task (as indicated by the psychoacoustic results).
Bertoli
Sibylle
S
HNO-Universitätsklinik, Kantonsspital, Petersgraben 4, CH-4031, Basel, Switzerland. sbertoli@uhbs.ch
Smurzynski
Jacek
J
Probst
Rudolf
R
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D001309:Auditory Threshold; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006320:Hearing Tests / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011304:Presbycusis / Q000503:physiopathology; D011571:Psychoacoustics; D011930:Reaction Time / Q000502:physiology; D013065:Speech Intelligibility / Q000502:physiology; D013997:Time Factors; D013998:Time Perception / Q000502:physiology