Auras and subclinical seizures: characteristics and prognostic significance.

The characteristics and prognostic significance of subclinical seizures and independent auras were studied in 40 patients with partial epilepsy who had long-term electroencephalographic (EEG) monitoring with intracranial electrodes. Focal, restricted subclinical seizures were noted in 23 patients, and 11 patients experienced auras that were accompanied by ictal EEG discharges. Auras and subclinical seizures usually were identical in EEG appearance, but were distributed differently among patients. The subclinical seizures and auras usually had the same origin as complex partial seizures, but did not always reliably indicate complex partial seizure origin. Subclinical seizures and auras were of favorable prognostic significance for patients undergoing temporal lobectomy. A majority (greater than 80%) of individuals with subclinical seizures and auras were free of complex partial seizures after surgery, whereas a minority (29%) of patients without subclinical seizures and auras became free of complex partial seizures.