Variability in the depression of cochlear microphonic responses after noise exposure

20 guinea pigs were exposed to a broad band noise (120-140 dB SPL) for short durations. The conditions of stimulation were strictly identical for all animals. Cochlear microphonic responses (CM) were recorded with conventional differential electrodes after each exposure, from the first turn of the cochlea. Variations were observed in the degree of CM depression and also in the alteration of the CM transfer function. The origin of this variability is discussed.