Cochlear Microphonics Generated By Microwave Pulses*

Oscillations at 50 kHz have been recorded from the round window of guinea pigs during irradiation by 918-MHz pulsed microwaves. The oscillations promptly follow the stimulas, outlast it by about 200 musec and measure to 50 muV in amplitude. They precede the auditory nerve's response and disappear with death. They are interpreted to be a cochlear microphonic and hence to demonstrate that the microwave auditory effect, in the guinea pig at least, is accompanied by a mechanical disturbance of the hari cells of the cochlea.