Further Studies of the Effects of Continuous White Noise of Moderate Intensity (70-80 Db Spl) On the Cochlea in Young Guinea Pigs:Time Course and Distribution of Hair Cell Degeneration

Abstract

Guinea pigs aged one week were exposed to white noise at a maximum of 76 dB SPL for 7 days and were then killed 3, 8 and 16 weeks later for histological examination of the cochlea by the surface preparation method. Appreciable increases in outer hair cell losses were observed in the apical turn 3/3½, chiefly in the outer two rows, between the 3rd and 8th week, but not between the 8th and 16th week. No significant losses were seen in control groups corresponding to the 3- and 8-week periods, although in the control group for 16 weeks' survival, small deficits, attributable to natural ageing, were seen in the apical half-turn, 3/3½.