Scalp EEG in the epilepsy surgery evaluation

Electroencephalography (EEG) with scalp electrodes can provide unique evidence of epileptogenicity and, as such, it has a pivotal role in the evaluation of patients with medically intractable epilepsy for epilepsy surgery. The putative epileptogenic zone is identified by evaluation of the interictal and ictal scalp EEG in concert with a variety of other structural and functional diagnostic modalities that often include high-resolution structural MRI, task-based functional MRI, interictal fluorodeoxyglucose (FDG)-PET, ictal SPECT and neuropsychological testing. The role of the scalp EEG in individual potential surgical patients varies depending on the presence of structural MRI abnormalities. Many patients can proceed to resective surgery without the need for intracranial EEG monitoring if scalp EEG is concordant with structural abnormalities. When intracranial monitoring is necessary, scalp EEG plays an integral role in determining the intracranial electrode locations.