Basilar Membrane Vibration Data and Their Relation to Theories of Frequency Analysis

Prolongation of the cochlear microphonic in man. Cochlear microphonic ringing

During routine extra-tympanic electrocochleographic (ECochG) recording we have observed that in many cases more cycles are seen in the cochlear microphonic (CM) recording than are present in the acoustic stimulus. We have termed this phenomenon CM 'ringing'. Ringing is present in 69% of our normal subjects and in 43% of patients with deafness of different aetiologies. In the cochlear and Ménière subgroups those cases showing ringing have a significantly larger CM amplitude (p less than 0.001 and p less than 0.01 respectively). The possible origin of this phenomenon is discussed.

Study of neural excitation in the guinea pig cochlea using low-frequency acoustic modulation

A low-frequency tone has been shown to modulate the amplitudes of cochlear microphonic (CM) and whole nerve (N1) response to a high-frequency tone pip. Whereas the N1 responses was always reduced and had two maxima per cycle of the low-frequency signal, the CM response changed from a single- to a double-maxima pattern as the modulator intensity was increased.