Abstracts

Rationale: Frontal lobe epilepsy is the most common extratemporal epilepsy type in large surgical serises.Clinical and EEG features of temporal lobe epilepsies are better defined compared to extratemporal lobe epilepsies especially frontal lobe seziures. The usefulness of ictal EEG recordings in frontal lobe seizures is limited owing to muscle artefacts in motor seizures and the large surface area of frontal cortex. The aim of this study was to evaluate both semiological findings and ictal EEG features of seizures in children with frontal lobe epilepsy and analyse if they differed from adult patients with frontal lobe seizures. Methods: We reviewed pediatric patients with frontal lob epilepsy admitted to Hacettepe University Children's Hospital Video-EEG Monitoring Unit between January 2007- December 2009. We analysed 549 archived seizures from 79 patients, aged between 1-17 years (mean 9.9 3.8 years).Ictal events were classified with respect to Semiological Seizure Classification. Results: 29% of the patients had no obvious risk factors for epilepsy and had normal MRI. MRI was abnormal in 49 patients; cortical dysplasia was the leading etiology (22.8%), perinatal insult was the second most common cause. 35 of 79 patients had more than one type of seizure onset; 238 seizures(43%) showed semiological evolution. Seizures were brief (25.7 26.9 seconds), nocturnal and sleep- related. The mean duration of postictal confusion was 27 seconds. Most common seizure components were simple motor manifestations, mostly focal tonic seizures and versive seizures, 50% and 26,8% respectively. Hypermotor seizures constituted 19.6% of all seizures. Myoclonic seizures and otomotor seiuzures were not seen. Secondarily generalized tonic-clonic seizures were recorded in 35 seizures (6.3%) of 16 patients. Most common lateralizing semiology was focal tonic seizure. Ictal EEG recordings were not informative in identifying the epileptogenic foci in 351 (64%) at seizure onset. 263 seizures (48%) had lateralizing EEG features. Postictal EEG showed unilateral slowing or supression in 35.4% of seizures without lateralizing or localizing ictal onset. Lateralizing ictal EEG and semiological features were predominately seen in seizures with right frontal onset. Conclusions: Frontal lobe seizures in childhood occur most commonly during nocturnal sleep. Motor features, especially tonic and versive seizures are prominent in children with frontal lobe epilepsy similar to adults. However, hypermotor seizures and secondarily generalized tonic-clonic seizures are relatively rare in children compared to adults with frontal lobe epilepsy. Malformations of cortical development are the first cause in our symptomatic cases. Of note, in our series the second most common cause is brain injury due to perinatal insult where as in current literature tumors are the second cause in pediatric series.