The role of high-frequency hearing in age-related speech understanding deficits.
An experiment was conducted to further explore the effect of ageing on speech understanding under degraded listening conditions. Two groups of subjects, aged 20-39 years and 50-75 years were tested. Measurements were made of hearing thresholds in each ear from 0.25-10kHz, consonant discrimination in quiet and continuous speech spectrum noise (S/N= -10 dB) and monophonic and stereophonic frequency selectivity. Neither group would have been diagnosed as hearing-impaired. Nonetheless, the older group had significantly higher hearing thresholds, which increased systematically with frequency. Poorer consonant discrimination in noise was observed for the older group. This outcome was correlated with high-frequency thresholds, not with age. There was no between-group difference in stereophonic frequency selectivity, minimizing the possibility of age-related changes in central auditory processing. Monophonic frequency selectivity, an index of cochlear processing, was correlated with speech understanding. The results support the conclusion that observed age-related effects are secondary to cochlear dysfunction.
Abel
S M
SM
The Samuel Lunenfeld Research, Institute of Mount Sinai Hospital, Toronto, Canada.
Sass-Kortsak
A
A
Naugler
J J
JJ
D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology; D001309:Auditory Threshold / Q000502:physiology; D005260:Female; D006316:Hearing Loss, High-Frequency / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D011571:Psychoacoustics; D012720:Severity of Illness Index; D013067:Speech Perception / Q000502:physiology*