Aging effects on auditory and vestibular responses: a longitudinal study.
OBJECTIVE
To identify age-related changes in the auditory and vestibular systems in normal older subjects followed serially over time.


METHODS
Pure tone hearing levels, speech reception threshold, speech discrimination scores, and vestibulo-ocular responses were measured in 57 normal older subjects (mean age, 82) on 5 yearly examinations.


RESULTS
There was a significant (P < .001) increase in pure tone threshold averages (about 1 dB per year) and speech reception threshold averages (about 2 dB per year), and a significant (P < .001) decrease in discrimination scores (about 2% per year) over the 5 years of follow-up. There was a significant (P < .05) amplitude-dependent decrease in gain and increase in phase lead of the vestibulo-ocular reflex and a significant (P < .01) decrease in gain of visual-vestibular responses at low frequency sinusoidal stimulation over the 5 examinations. Years 1 to 5 differences in individual subjects were significantly (P < .01) correlated across auditory and vestibular tests, but not between auditory and vestibular tests (P > .01).


CONCLUSIONS
This is the first longitudinal study to show age-related decreases in auditory and vestibular responses in normal older subjects. Because the age-related changes in the auditory system were not correlated with age-related changes in the vestibular system, the 2 systems may age at different rates in the same individual. These changes likely result from degeneration in both peripheral and central structures, although age-related changes in the central nervous system probably are more important from a functional point of view.
Enrietto
J A
JA
Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095-1769, USA.
Jacobson
K M
KM
Baloh
R W
RW
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001284:Atrophy / Q000473:pathology; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000473:pathology*; D001309:Auditory Threshold / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006311:Hearing Disorders / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D008297:Male; D009410:Nerve Degeneration / Q000150:complications / Q000473:pathology; D011446:Prospective Studies; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D013069:Speech Reception Threshold Test; D014724:Vestibular Function Tests