Recent updates in intraoperative neurophysiological monitoring modalities

Intraoperative neurophysiological monitoring (IONM) is an essential component of modern neurosurgical and spinal surgery, enabling real-time assessment of neural pathway function and early detection of neurological injury. Established modalities—including somatosensory evoked potentials, motor evoked potentials (MEP), D-wave, electromyography, and brainstem auditory evoked potentials—have been extensively validated in clinical practice and contribute to reducing the incidence of postoperative neurological deficits. Recent advances have introduced novel monitoring technologies such as quantitative frequency-domain near-infrared spectroscopy, laser speckle contrast imaging, and corticobulbar MEP that complement conventional electrophysiological methods. The integration of artificial intelligence and machine learning algorithms is driving innovation in automated signal interpretation, artifact rejection, and outcome prediction. Emerging domains including wireless high-density electroencephalography, cortical spreading depolarization monitoring, and intraoperative autonomic nervous system monitoring are expanding the scope of IONM. This review comprehensively summarized recent advances in the technical principles and clinical applications of both established and emerging IONM modalities, current advances by surgical subspecialty, and future directions.