Facial nerve electromyography and other cranial nerve monitoring

Cranial nerves can be damaged during a variety of surgical procedures. The function of the cranial nerves can be monitored during surgery with electromyography (EMG), compound nerve and muscle action potentials (MAP), and auditory evoked potentials (AEP). We report important technical considerations that allow reliable recordings of these modalities during surgery, the criteria for determining a significant change in these electrophysiologic measures of function, the application of these techniques to specific surgical procedures, and the data that support the utility of cranial nerve monitoring.