PROGNOSTICATION OF BELLS-PALSY USING TRANSCRANIAL MAGNETIC STIMULATION

Transcranial magnetic stimulation (TMS) provides a method to noninvasi ve excitation of the facial nerve in its intracranial segment close to the internal acoustic meatus. Thus, the site of facial nerve activati on with TMS is proximal to or within the site of the lesion in Bell's palsy. To evaluate the prognostic capability of TMS in unilateral Bell 's palsy we examined 137 patients with this method, and compared the r esults with electroneuronography (ENoG). Within 0-4 days from the onse t of palsy, the patients with elicitable TMS responses recovered bette r than those in whom TMS responses were not elicitable. If TMS was per formed 5-9 days or 10-28 days after the onset of palsy, it did not pro vide any prognostic information. Based on amplitude side-to-side diffe rences, ENoG did not contribute prognostic information during the firs t 9 days from the onset of palsy. Later on, 10-28 days after the onset of palsy, ENoG showed an increased capability to discriminate the pat ients with poor prognosis. Thus, elicitable facial motor response with TMS predicts good prognosis of Bell's palsy at an early stage whereas poor response with ENoG predicts less favorable prognosis at a later stage.