[Transcranial magnetic stimulation of the facial nerve in patients with acoustic neuroma]

Abstract

Magnetic stimulation of the human facial nerve was used in 30 patients with small or medium-sized acoustic neurinomas pre-operatively. Needle-EMG revealed symmetrical aspect in the orbicularis oris muscle on the affected and on the contralateral side. The latencies in the extracranial part of the facial nerve after supramaximal electric stimulation in the area of the stylomastoid foramen and the latencies after temporo-occipital, transcranial magnetic stimulation were measured. A comparison of the data showed a significant increase in the temporal conduction time (difference between latencies after transcranial magnetic stimulation and electrical mastoid stimulation) between the healthy and the affected side in most cases. This study revealed tendencies between prolongation of the latencies and the tumour size. No correlations were obtained to audiological or intra-operative findings.