title: Age-related changes in sensitivity of the postpubertal ear to acoustic trauma.
abstract: Although the age of the postpubertal mammal is typically ignored in evaluating the damaging effects of noise on the ear, it was shown to account for over 65% of the variability in the mouse. 44 inbred CBA/J mice, ranging in age from 60 (early postpuberty) to 360 days (late middle age), were tested for cochlear AP thresholds at frequencies from 2 to 64 kHz. They were then subjected to 5 min of a 124 dB octave band (12-24 kHz) noise. Although all the mice had similar pre-exposure thresholds, the extent of noise-induced AP threshold elevation and the frequencies most severely affected depended upon the ages of the mice. The youngest subjects had the greatest threshold elevations, being most pronounced at, and 1 octave above, the center frequency of the noise exposure. With increasing age there was a progressively less severe effect. The oldest subjects had cochlear AP threshold elevations which were restricted to a frequency 2 octaves above the exposure frequency.
mesh_terms: D000200:Action Potentials; D000367:Age Factors; D000818:Animals; D001309:Auditory Threshold; D003051:Cochlea / Q000503:physiopathology*; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology*; D051379:Mice; D008808:Mice, Inbred CBA