Analysis of Seizure Manifestations of ‘Pure’ Frontal Lobe Origin

Abstract

Summary: With the intention of subclassifying frontal lobe epilepsies based on ictal semiology, we scrutinized the seizure manifestations in 18 patients with “pure” frontal lobe epilepsy who underwent corticectomy restricted to the frontal lobe after undergoing invasive long‐term EEG/video monitoring and achieved excellent seizure outcome. All patients had well‐localized lesions. By combining principal seizure manifestations unequivocally appearing during the ictal events, we were able to subdivide the patients into the following three groups: group 1, supplementary motor seizures with tonic posturing and other relevant symptoms with consciousness retained; group 2, focal motor seizures with elementary clonic and/or tonic symptoms with consciousness also retained; and group 3, psychomotor seizures with various automatisms usually accompanying impairment of consciousness. In addition, localization of the epileptogenic lesions enabled us to conclude that in both the focal motor seizure group and the supplementary motor seizure group the epileptogenic zones were restricted to the posterior third of the frontal lobe generating somatomotor manifestations, whereas in the psychomotor seizure group the epileptogenic zones were largely in the anterior two thirds of the frontal lobe, where there may be no neuronal substratum primarily generating seizure manifestations. The electroclinical progress of psychomotor automatisms in 3 patients is presented in relation to seizure spread.