Evoked responses from peripheral stimulation of the facial nerve

Evoked responses to electrical stimulation of the facial nerve were recorded in dogs with vertex electrodes placed both inside and outside the skull. Three waveforms were recorded. The first two waveforms appeared to be related to electrical activity carried by antidromic propagation within fibers of the facial nerve. The third waveform appeared to be caused by the muscular response that occurred as a result of orthograde conduction in the nerve. The effects of changing the stimulation site, voltage, duration, and frequency were recorded. It appears that, by means of far-field techniques, it is possible to reliably record evoked responses that reflect antigrade conduction via fibers of the facial nerve.