Monitoring auditory functions during cranial nerve microvascular decompression operations by direct recording from the eighth nerve

A method is described for recording sound-evoked responses directly from the eighth nerve during operations in the cerebellopontine angle, particularly during microvascular decompression operations for cranial nerve dysfunction. This method provides important information to the surgeon during the operation that cannot be provided by recording brain-stem auditory evoked potentials (BAEP) using surface electrodes. By recording sound-evoked responses intracranially and recording BAEP with scalp electrodes, the risk of hearing loss in these operations is decreased.