Search

Objective Frontal lobe epilepsy (FLE) is the second most common epilepsy among drug-resistant focal epilepsies. Semiologic and electrophysiologic features of FLE present some difficulties because frontal lobe seizures are brief, accompanied by complex motor activities and emotional signs. The rich connectivity of the frontal lobe with other areas leads to the rapid and widespread propagation of seizure activity, which contribute to the difficulty of evaluating the semiologic and EEG patterns of the seizure. In this study, we investigated semiologic, interictal, ictal, and postictal EEG characteristics; the imaging data of patients with FLE and the possible contribution of these data to localization and lateralization of seizures. Materials and methods The medical records of patients who were diagnosed as having FLE between 2010 and 2019 in our clinic were evaluated retrospectively. The diagnosis of FLE was considered either when patients had a structural lesion in the frontal region or seizure semiology and EEG characteristics were compatible with FLE. Clinical, electrophysiologic, and imaging features were investigated in these patients. Results We have evaluated 146 seizures in 36 patients (17 lesional and 19 non-lesional according to MRI). There were 110 focal motor or nonmotor seizures, 18 bilateral tonic-clonic seizures, and 18 subclinical seizures. There were 16 patients with aura. The most common semiologic feature was hyperkinetic movements. Among the interictal EEGs, 30.5 % included focal anomalies. Among the ictal EEGs, 69.1 % were non-localizing or lateralizing. The most common ictal pattern was rhythmic theta activity (21.2 %). In four patients, who had non-localizing or lateralizing EEG, the postictal EEG was informative. Our study showed a low percentage of localized FDG-PET, which, however, involved visual analysis. Conclusion Our results support the previously known difficulties in the determination of the epileptogenic zone of FLE. Semiologic and electrophysiologic correlation studies, longer postictal records, and quantitative analysis of FDG-PET may contribute to a better characterization of the disease.

Patient 1: A 6-year-old girl was admitted with a 1 year history of atonic seizures (head drops). Her motor and mental development had been normal until age 5 years, but her family had noted behavioral changes about 2 months after the onset of seizures. Her past medical history was remarkable for febrile seizures. Physical and neurological examinations were unremarkable. Electroencephalography (EEG) demonstrated multifocal spike and wave paroxysms generalizing during sleep and bilateral widespread pseudo-periodic slowwave paroxysms with high amplitude (Fig 1). Atonic-myoclonic seizures were recorded. Brain magnetic resonance imaging (MRI) revealed no abnormalities but was performed under suboptimal conditions. Subacute sclerosing panencephalitis was first considered, but no cells or antimeasles antibodies were detected in cerebrospinal fluid. Further testing for metabolic disorders was unremarkable. Her repeat MRI revealed diffuse band heterotopia (Fig 2). Patient 2: A 7-year-old girl was admitted with atonicmyoclonic seizures manifested by dropping of the head, falling, jerking, and dropping objects. Motor and mental development had been normal until the seizure onset at the age of 4 years, but subsequently her family noted behavioral changes. Her EEG findings included spike and wave paroxsyms propagating from both occipital regions, bilateral pseudo-periodic slowwave and sharp wave discharges, and atonic seizures. Subtle MRI changes suggested band heterotopia, and bilateral band heterotopia was confirmed on her second MRI.