Electrical and transcranial magnetic stimulation in the diagnosis of facial palsy

Electrical and transcranial magnetic stimulation in the diagnosis of facial palsy Lindke T1,2, Lindke A3, Scherf-Geschke C1, Ebke M2, Bunten S1, Happe S1 1Department of Clinical Neurophysiology, 2 Department of Neurology,3 Department of Internal Medicine, Klinikum-Bremen Ost/University of Göttingen, Germany Objective: Unilateral facial weakness is a common symptom and in 60–75% due to idiopathic peripheral facial nerve palsy, also known as Bell's palsy. Other causes can be acute viral infections, borreliosis, diabetes, pregnancy, trauma, tumors of the parotic gland, and other systemic diseases. Therapeutic decisions vary depending on the etiology, therefore early diagnosis is needed. A conduction block of the facial nerve within the canalicular portion is considered typical for Bell's palsy when investigated within three days after onset of symptoms. Transcranial magnetic stimulation (TMS) and electrical stimulation of the facial nerve is presumed to be of high relevance. Methods: In our retrospective study we investigated the clinical and electrophysiological data of 256 patients with the diagnosis of peripheral facial palsy (ICD 10: G 51.0) who were admitted at the Department of Neurology, Klinikum Bremen-Ost, between January 2000 and December 2005 within the first three days after onset of symptoms. Clinical evaluation was based on the Brack and Houseman scale for facial palsy. Routine blood tests and an analysis of the cerebrospinal fluid were performed. The electrophysiological investigations included the R1 and R2 response of the blink reflex, pre-auricular electrical stimulation and the response after TMS at the labyrinthine part of the canalicular proportion of the facial nerve regarding latencies and amplitudes. Results: Of the 256 patients who were tested within the first three days after onset of symptoms (122 female, mean age 58 years), 161 were diagnosed with Bell's palsy after eliminating other causes and based on typical clinical and electrophysiological findings. Test results of the remaining patients led to the diagnosis of HSV infection, VZV infection, borreliosis, diabetes, and pregnancy. Discussion: Our retrospective data show that a conduction block in TMS supports the diagnosis of Bell's palsy and leads to the question whether these electrophysiological findings are specific for Bell's palsy and might spare other costly and time consuming tests. Further analysis and a prospective study are ongoing to determine the significance of TMS within three days after onset of symptoms to diagnose the idiopathic peripheral facial nerve palsy.