Frequency selectivity in noise-damaged cochleas.
Davis-RI; Hamernik-RP; Ahroon-WA
Audiology 1993 Mar; 32(2):110-131
The changes in tuning characteristics were investigated in chinchillas with specific patterns of noise induced cochlear sensory cell loss. A population of 363 noise exposed chinchillas was used to measure auditory threshold and masked threshold at six audiometric test frequencies. Surgically monaural chinchillas had been exposed to noise varying from very short duration, acute exposure at high intensities to lower level exposure for 5 days as part of other studies. From this group, 70 were chosen and separated into five groups based on the amount of permanent threshold shift and sensory cell losses the animals had incurred. A comparison was made of the tuning curve (TC) metrics to the mean preexposure TC metrics for each group and to the reference preexposure TC metrics obtained from the sample of 363 animals. The noise exposed chinchillas with no measurable permanent threshold shift (PTS) and not more than 3% cell loss in any given octave band demonstrated normal TC properties. For relatively low levels of PTS, TC slopes start to show statistically significant deviations from the norms. Results indicated that in populations with substantial PTS there are concomitant changes in TC metrics. Within regions of the noise damaged cochlea having normal populations of sensory cells, either normal or abnormal TC properties are noted.
Noise-induced-hearing-loss; Laboratory-animals; Noise-exposure; Hearing-loss; Hearing-threshold; Sensory-thresholds; Cell-damage; Noise-frequencies; Audiometry; Auditory-feedback; Auditory-system; Animals; Animal-studies; Sampling; Sampling-methods
Communicative Disorders & Scis Research Foundation of Suny P O Box 9 Albany, NY 12201
State University of New York at Buffalo, Buffalo, New York