Distribution Pattern of Cochlear Combination Tones

This study is designed to determine whether or not traveling waves accompany combination tone components generated in the cochlea, and also to describe the amplitude distribution of these nonlinear products. Cochlear microphonics were monitored with the differential electrode technique from the first and third turns of guinea pig cochleas. Cancellation of the distortion components was attempted by introducing bone conducted pure tones at the frequency of the combination tone and of controllable amplitude and phase. It was demonstrated that combination tone components can never be canceled simultaneously throughout the cochlea. It was shown that the reason for this inability to cancel is that combination tones are not distributed as their own frequency would indicate, but instead, they seem to have a distribution peculiar to these nonlinear components.