Antidromically evoked facial nerve response

Facial nerve electrodiagnostic tests that are currently available indirectly assess the severity of injury to the intratemporal facial nerve. Antidromic conduction testing is an alternate approach that, if feasible, could provide direct and immediate assessment of proximal facial nerve function. This possibility was tested in a guinea pig model, in which near-field (intracranial) and far-field (extradural) recording techniques were used to assess antidromically evoked facial nerve activity. Response characteristics, topographical distribution, and lesion effects suggest that the recorded potentials represent antidromic activation of the facial nerve. If response amplitude and/or latency can be correlated with the functional state of the nerve, antidromic testing may provide a useful means of assessing proximal facial nerve function in pathologic states.