Frequency selectivity in noise-exposed chinchillas.
Davis-RI; Hamernik-RP; Turrentine-GA; Ahroon-WA
J Acoust Soc Am 1990 Nov; 88(S1):S19
A report on frequency selectivity in noised exposed chinchillas was presented. Auditory evoked potential tuning curves were collected on more than 300 noise exposed chinchillas for which both sensory cell loss data and threshold shift data were available. Additionally, tuning curve variables were related to the amount of noise induced permanent threshold shift and sensory cell loss along the cochlea; this analysis was performed in discrete octave bands along the entire length of the cochlea. A systemic relation between the degree of permanent threshold shift, abnormal outer hair cell populations, and changes in tuning were observed. Tuning was not significantly altered in noise exposed cochleas with less than 5 decibels of permanent threshold shift and less than 5% sensory cell damage. The tuning curve was not a sensitive measure of cochlea condition in the presence of considerable sensory cell damage and small permanent threshold shift. Tuning was reduced in both normal and damaged regions of the cochlea when cell loss was restricted to the apical and middle portion of the cochlea. For high frequency lesions, changes in tuning were limited to the region of outer hair cell loss. The low frequency slope appeared to be a more sensitive indicator of noise induced cochlear lesion than the high frequency slope.
NIOSH-Grant; Noise-induced-hearing-loss; Laboratory-animals; Noise-exposure; Noise-frequencies; Auditory-system; Ear-disorders; Hearing-impairment; Sensory-disorders
Communicative Disorders & Scis Research Foundation of Suny P O Box 9 Albany, N Y 12201
Journal of the Acoustical Society of America
State University of New York at Buffalo, Buffalo, New York