Magnetic brainstem stimulation of the facial nerve.

Electrophysiological evaluation of cranial nerves provides information on its functional aspects and may be a valuable adjunct to imaging. In 10 normal subjects, we used transcranial magnetic stimulation with a double cone coil at the posterior head region to obtain orbicularis oris motor evoked potentials. Our findings suggest activation of descending facial fibers proximal to brainstem motoneurons. This method is advocated as an adjunct in the electrodiagnostic workup of facial nerve dysfunction.