Depth Electrode Cortical Reverberation Monitoring After Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of death and disability and imposes burden on the health-system and society. Beyond the first impact of the injury, secondary brain injury processes, include elevated intracranial pressure (ICP), impaired autoregulation, seizures, and cortical spreading depolarizations (CSDs). These effects drive lesion expansion and worsen outcomes. Observational cohorts show that CSDs are common after severe TBI and that higher CSD burden results in worse recovery.

This is a preliminary, prospective interventional feasibility study to investigate the use of cortical reverberation (CR) monitoring in patients with traumatic brain injury (TBI) requiring a clinically indicated external ventricular drain (EVD) placement. EVDs are required to monitor and manage significant intracranial pressure. During standard-of-care EVD placement at the bedside in the intensive care unit (ICU), a single multi-contact depth electrode will be placed adjacent to the EVD catheter through the same burr hole. The electrode will be connected to a stimulator and recording system. Biphasic, charge-balanced intracortical pulses (1-6 mA, 60-1000 µs) will be delivered between adjacent contacts once every 3 seconds (0.33 Hz) for the duration of monitoring. Continuous electrocorticography (ECoG) will be recorded from the same electrode contacts. Recordings will be reviewed daily by a study neurosurgeon or an epileptologist for evidence of electrographic seizure activity. CR responses will be analyzed offline to assess feasibility, signal quality, and correlation with concurrent physiologic measures obtained from multimodal monitoring. The duration of study monitoring will be determined by the length of time that invasive neuromonitoring is clinically indicated. The depth electrode will be removed at the bedside once EVD monitoring is discontinued or the patient is discharged from the ICU.