Intractable seizures of frontal lobe origin: Clinical characteristics, localizing signs, and results of surgery

Purpose: We analyzed the clinical characteristics of seizures of frontal lo be (FL) origin with particular emphasis on establishing different categorie s and determining if these categories had any localizing or lateralizing va lue. In addition, results of surgery are reported. Methods: Seizure characteristics were established by historical review and electroencephalographic/videotape analysis of 449 seizures in 26 adult pati ents with refractory seizures of FL origin. Results: No outstanding risk factor was identified for seizures of FL origi n. Seizures were frequent (7.1 per week), brief (mean duration, 48.3 second s), and had a nocturnal preponderance in 58% of the patients. Status epilep ticus was reported in 54%, and generalized convulsions as a prominent seizu re type were reported in 26% of patients. The most common reported aura was a nonspecific sensation, often localized to the head (35%). Early forced h ead and eye deviation was not a consistent lateralizing sign, whereas late head and eye deviation always occurred contralateral to the site of seizure origin. Early asymmetric tonic posturing occurred consistently contralater al to the side of seizure origin. Clinical seizure patterns did not consist ently localize to specific regions of the frontal lobe, although there were some noticeable trends: focal clonic seizures were associated with seizure origin in the frontal convexity; tonic seizures were most often associated with origin in the supplementary motor area but also occurred with origin in other parts of the frontal lobe; seizures resembling typical temporal lo be seizures with oroalimentary automatisms were observed with seizure origi n in the orbitofrontal region; and seizures with hyperactive, frenetic auto matisms were not associated with any specific region within the frontal lob es. Eighty percent of patients had favorable seizure outcome after surgery (class I/II). Conclusion: Although certain clinical features are characteristic for seizu res of frontal lobe origin and some have lateralizing value, they do not lo calize to specific areas within the FL. After careful presurgical evaluatio n, both lesional and nonlesional patients benefit from epilepsy surgery.