Experimental and clinical studies of the large amplitude evoked potential of facial muscles on the affected side in intratemporal facial verve palsy

Abstract

An abnormal increment of the amplitude in electroneuronography (ENoG) could be observed on the affected side of intratemporal nerve palsy. In order to study both the significance and mechanism of this phenomenon, the ENoG findings of facial nerve palsy cases were recorded. As a result, 10% of the findings showed a great amplitude potential. In animal experiments, 35% of the guinea pigs also showed a great amplitude potential in the facial muscles on the affected side. An electromicroscopic examination of the facial nerve at the compressed site revealed a separation of the myelin sheath laminae. Due to changes in the resistance of the myelin sheath, the iron dynamic state, which is related to the excitability of the nerve also changed and showed hyperexcitability.