Patterns of Injury Produced by Overstimulation of the Ear

Abstract

Measurements of the cochlear potentials as recorded from the round window were carried out on a series of guinea pig ears to ascertain the effects of injury by overstimulation with various tones. The results showed general impairments of the responses after such injury. With rare exceptions, the maximum responses to any tone are much less impaired than the sensitivity, and the maximums are more seriously affected for the low tones. In general, these changes are independent of the frequency of the tone producing the injury. These observations confirm those of earlier studies on the patterns of action of tones in the cochlea, and indicate that all tones when raised to extreme levels cause widespread damage to the hair cells. It is suggested that certain hair cells, which are normally involved in the peak actions of all tones, are particularly susceptible to damage by overstimulation.