First seizure: EEG and neuroimaging following an epileptic seizure.

An early EEG (within 48 h) and high-resolution magnetic resonance imaging (hr_MRI) are the methods of choice for an accurate diagnosis after a first seizure presentation. Together with a careful history and examination, they will allow definition of the epilepsy syndrome in two-thirds of patients and help assess the individual risk for seizure recurrence, which is determined by the specific syndrome and is highest with focal epileptiform activity on EEG. Despite the heterogeneity of first seizure studies, EEG and etiology are consistently found to be the best predictors for seizure recurrence and prognosis. The additional yield of sleep-deprived EEG and sleep EEG is uncertain; yet MRI is essential for detecting brain tumors and other structural bases for new epilepsy. The rate occurrence of remote symptomatic seizures increases significantly with age and the most common etiology in the elderly with a first seizure is stroke; however, its exact relevance to epileptogenicity is yet to be defined. There is a striking lack of systematic studies using early EEG and hr_MRI in order to better characterize epileptogenic areas and elucidate the mechanisms of seizure provocation.