Since the primary damage from traumatic brain injury (TBI) is irreversible, the focus of medical management of TBI is preventing secondary injury that can be life-threatening and worsen patient outcome. Insight into the pathologic mechanisms of secondary injury, which are largely unknown, is required for developing better treatments.

In preliminary studies, the investigators have found that a pathologic brain activity, known as spreading depression, recurs in a large number of TBI patients in the first week after injury. Spreading depressions are short-circuits of brain function that arise spontaneously from an injury and spread repeatedly as waves into neighboring brain tissue. Animal research has shown that spreading depressions can cause secondary injury to the brain.

The primary objective of this observational study is to determine whether the occurrence or severity of spreading depression is related to worse neurologic recovery from TBI. Results from the study will determine whether monitoring of spreading depression should be used as a guide or target for improved medical management of the TBI patient.

Inclusion Criteria:

• 18-80 years old
• diagnosis of TBI
• craniotomy performed as per required treatment of TBI
• craniotomy surgery < 7 days after TBI
• GCS<13 at time of decision for surgery
• expected neuromonitoring for >72 hr

Exclusion Criteria:

• any failure to meet above criteria
• pregnancy
• GCS 3 with fixed, dilated pupils

Patients admitted to study hospitals who require neurosurgery for acute traumatic brain injury.