Electrocorticography

Electrocorticography (ECoG) is the method of recording electroencephalographic signals directly from surgically exposed cerebral cortex. It detects intraoperatively the cortical regions with substantial epileptiform interictal discharges. Direct cortical stimulation during ECoG provides a method of identifying language, motor, and sensory regions during a craniotomy. Both techniques—the identification of cortex with epileptic activity and cortex with important eloquent functional activity—help determine limits for surgical cortical resection. These are used most commonly during epilepsy and tumor surgery. Anesthetic agents can adversely affect the recording, and ECoG restricts the types of anesthesia that can be used. The amount of spiking from diffuse or remote cortical regions on ECoG can predict the success of postoperative seizure control.