A signal processing module includes an input module electronically coupled to a sensing probe of a nerve integrity monitoring system. The probe senses electrical signals from a patient during operation of an electrosurgical unit. The input module receives an input signal from the probe. An EMG detection module is coupled to the input module and is adapted to detect conditions in the input signal. The conditions are classified as a function of a level of electromyographic activity. An output module, coupled to the EMG detection module, provides an indication of electromyographic activity in the input signal based on the detected conditions.