 SDs which consist of massive waves that depolarize neurons and astrocytes and disrupt local cortical function for minutes to hours, were first demonstrated to occur in severe TBI patients via ECoG recordings obtained from single subdural electrode strips. In these studies, severe TBI patients who underwent neurosurgical intervention for decompression andor hematoma evacuation had a single linear subdural electrode strips six electrodes with 10 mm spacing between electrodes placed near the injury epicenter which allowed continuous ECoG recordings to be obtained for up to 7 days after the initial injury. The above studies, and several subsequent investigations, were important steps to demonstrate that 1 the SD phenomena, which was first described in animal studies, occurs in patients after TBI and 2 SDs are associated with worse outcome after TBI. 