title: Temporary hearing loss from exposure to moderately intense tones in rhesus monkeys.
abstract: The amount and duration of temporary threshold shift produced by exposure to moderately loud sounds were quantitatively examined in rhesus monkeys using a simple, behavioral reaction-time procedure. Subjects were exposed to pure tones (100 dB SPL) either at the threshold test frequency or half an octave below (-1/2 OCT) the test frequency, usually for a duration of 3-minutes. Many features of the results were comparable to those observed in human subjects following exposure to similar sounds: (1) both the magnitude and the time course of recovery from the hearing loss were a function of the frequency and duration of the exposure stimulus with higher-frequency and longer-lasting stimuli producing greater threshold shifts and longer recovery time courses; (2) recovery time courses were monotonic and approximately exponential; (3) at low- and mid-frequency regions of hearing, intense stimulation at the test frequency and at -1/2 OCT produced similar threshold shifts and durations of recovery, while for high-frequency hearing -1/2 OCT stimuli always yielded greater losses and longer recovery periods; (4) although the peak hearing loss was either at , or a half octave above, the exposure frequency, the overall threshold-shift pattern was always assymmetrically distributed toward higher frequencies; (5) alterations in functions relating response latency to stimulus intensity were demonstrable. These psychophysical experiments form a framework that will permit further investigations into the physiologic basis of temporary threshold shift in an animal model highly similar to man.
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000818:Animals; D001522:Behavior, Animal; D004195:Disease Models, Animal; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology*; D008253:Macaca mulatta; D012075:Remission, Spontaneous