Effects of Acoustic Overstimulation on AP Threshold at Various Frequency

Abstract

The effects of an intense sound (2kHz, 100 to 130dB, 3 or 30minutes) upon the AP threshold was examined at frequencies ranging from 2 to 16kHz in guinea pigs. The most affected frequency was much higher in our guinea pigs than the values predicted from the phenomenon of the half octave shift. The present study exhibited the dose correlation between the amount of the greatest threshold shift and the frequency at which the greatest threshold shift was observed. These results seem to relate to the vibratory patterns of the traveling wave along the basilar membrane, i. e. the maximum amplitude of the vibration moves toward the base of the cochlear with the increases of stimulus strength.