The surgical neuromonitoring research group at Sunnybrook Research Institute, under Dr. David Houlden, focuses on the neurophysiology of human sensorimotor systems.
In the operating room, we monitor electrical responses from nerve, spinal cord, brain and muscles to detect and prevent inadvertent injury to the nervous system during surgery. It is not known why some patients have temporary deterioration of these electrical responses and wake up with new neurological deficits, while others do not. We are testing the hypothesis that the duration of neurophysiological deterioration plays a role.
Patients undergoing cerebrovascular operations have a small chance of stroke during surgery. We are using new intraoperative modalities (like transcranial Doppler) to determine if these strokes are related to emboli, hemodynamic ischemia (or both) so that interventions may be made during surgery to reduce neurological complications.
Our group is also studying a test called the vestibular evoked myogenic response (VEMP). During the test, a loud click is delivered to one ear causing neck muscles to contract on the same side. The pathways mediating the VEMP are not clearly understood. A balance organ in the inner ear (called the saccule) is thought to be involved. To prove this, we intend to stimulate it directly during surgery and record the resultant neck muscle response. Accordingly, we are working in close association with scientists in otolaryngology and surgeons who perform surgery in the inner ear. Dizziness is one of the most common complaints after head injury so we are studying VEMP in these patients to determine its relationship to dizziness.