Origin of Delayed Cochlear Microphonics

Abstract

The cochlear microphonic (CM) is an AC receptor potential that is derived from the cochlea. Recently a new component of CM that emerges at the threshold level and has longer latency than the conventional CM has been reported. It is tentatively called as a “delayed CM”. To investigate the origin of the delayed CM, a mathematical model of the cochlea was constructed and simulation of the phenomenon was done using a computer. The result of the simulation suggested that the delayed CM had most probably the same origin as evoked otoacoustic emissions (EOAEs). Consequently the delayed CM seemed to be clinically useful phenomenon related to the most delicate function of the cochlea at the threshold level in the same way as EOAEs.