EEG and Epilepsy

Despite tremendous progress in structural and functional neuroimaging techniques with improved spatial resolution, the electroencephalogram (EEG) provides the best temporal resolution of cortical function and remains an essential tool in the diagnosis and treatment of epilepsy. This chapter reviews the basis for the EEG and related techniques (magnetoencephalography and electrical source imaging), discusses the use of these techniques in the evaluation and treatment of epilepsy, and provides a framework for how the EEG can be used to provide appropriate treatment choices. Presurgical evaluation of interictal and ictal scalp EEG, along with the clinical and neuroimaging, data is fundamental for localizing the epileptogenic zone (EZ). However, ictal EEG recordings are a more important aspect of the presurgical evaluation than interictal EEG abnormalities in localizing the EZ. The ultimate goal of localization of abnormal activity, such as interictal epileptiform discharges, from EEG is to find the intracranial sources generating a given distribution of scalp potentials.