Usefulness of Transcranial Magnetic Stimulation in Diagnosis of Acute Bell's Palsy

ABSTRACT

OBJECTIVE: To investigate the diagnostic significance of transcranial magnetic stimulation (TMS) compared with electroneurography (ENoG) in very early period of Bell's palsy. METHOD: Thirty-six Bell's palsy patients within four days of disease onset were recruited and disease severity was assessed using the House-Brackmann grading system on the first visit, on the second visit (14 days later) and one year later. TMS at the labyrinthine segment was performed only on the first visit, while ENoG was done on the first and second visit. RESULTS: The amplitude ratio of magnetically evoked muscle responses between the affected side and the healthy side was correlated significantly with the clinical course and the final outcome which were documented using the House-Brackmann grade, whereas ENoG was not on the first visit. On the other hand, ENoG on the second visit was correlated significantly with the final outcome. CONCLUSION: In the early period of Bell's palsy, magnetically evoked muscle responses by TMS reflect neural insult more accurately than ENoG. TMS could be a useful measuring tool for the diagnosis and prognosis of Bell's palsy in the acute stage.