Surgical treatment of drug-resistant nocturnal frontal lobe epilepsy

Abstract

Of the cases with nocturnal frontal lobe epilepsy (NFLE) approximately 30% are refractory to antiepileptic medication, with several patients suffering from the effects of both ongoing seizures and disrupted sleep. From a consecutive series of 522 patients operated on for drug-resistant focal epilepsy, 21 cases (4%), whose frontal lobe seizures occurred almost exclusively (>90%) during sleep, were selected. All patients underwent a comprehensive pre-surgical evaluation, which included history, interictal EEG, scalp video-EEG monitoring, high-resolution MRI and, when indicated, invasive recording by stereo-EEG (SEEG). There were 11 males and 10 females, whose mean age at seizure onset was 6.2 years, mean age at surgery was 24.7 years and seizure frequency ranged from <20/month to >300/month. Nine patients reported excessive daytime sleepiness (EDS). Prevalent ictal clinical signs were represented by asymmetric posturing (6 cases), hyperkinetic automatisms (10 cases), combined tonic posturing and hyperkinetic automatisms (4 cases) and mimetic automatisms (1 case). All patients reported some kind of subjective manifestations. Interictal and ictal EEG provided lateralizing or localizing information in most patients. MRI was unrevealing in 10 cases and it showed a focal anatomical abnormality in one frontal lobe in 11 cases. Eighteen patients underwent a SEEG evaluation to better define the epileptogenic zone (EZ). All patients received a microsurgical resection in one frontal lobe, tailored according to pre-surgical evaluations. Two patients were operated on twice owing to poor results after the first resection. Histology demonstrated a Taylor-type focal cortical dysplasia (FCD) in 16 patients and an architectural FCD in 4. In one case no histological change was found. After a post-operative follow-up of at least 12 months (mean 42.5 months) all the 16 patients with a Taylor's FCD were in Engel's Class Ia and the other 5 patients were in Engel's Classes II or III. After 6 months post-surgery EDS had disappeared in the 9 patients who presented this complaint pre-operatively. It is concluded that patients with drug-resistant, disabling sleep-related seizures of frontal lobe origin should be considered for resective surgery, which may provide excellent results both on seizures and on epilepsy-related sleep disturbances. An accurate pre-surgical evaluation, which often requires invasive EEG recording, is mandatory to define the EZ. Further investigation is needed to explain the possible causal relationships between FCD, particularly Taylor-type, and sleep-related seizures, as observed in this cohort of NFLE patients.

Nocturnal Frontal Lobe Epilepsy

“…ADNFLE and sporadic NFLE show similar clinical and electroencephalographic features [11][12][13]21]. In the high majority of NFLE patients, seizures begin before the age of 20 years, with a peak during childhood [4,[11][12][13]21], although onset during adulthood has been also reported [11,12,21].…”

“…In the high majority of NFLE patients, seizures begin before the age of 20 years, with a peak during childhood [4,[11][12][13]21], although onset during adulthood has been also reported [11,12,21]. Seizure frequency is usually high, and patients generally experience many seizures a night [12,13], although the frequency may diminish during adulthood [11,21].…”

“…It is now recognized that NFLE is not a homogeneous disease as familial, idiopathic, sporadic, cryptogenetic, or symptomatic forms do exist [4,[11][12][13]. In addition, a genetic heterogeneity is also evident within the familial type [14].…”

Avaliação da arquitetura do sono em crianças com epilepsia refratária

“…21 Desde este relato, vários tipos de epilepsias têm sido descritos com origem cortical e etiologias variáveis, as quais se apresentam com crises, exclusiva ou predominantemente, durante o sono. 22,23 Uma série de publicações voltou-se para este ponto sugerindo que alguns tipos de malformações do desenvolvimento cortical, mais especificamente displasia cortical focal tipo II, conforme classificação de Palmini e colaboradores, 12 estão mais associadas a anormalidades epilépticas relacionadas ao sono, não somente em função da refratariedade das crises, como também pela presença dos surtos curtos recorrentes pseudoperiodicamente organizados ocorrendo durante o sono de ondas lentas. 24,25 Esta é uma área ainda incipiente e grupos diferentes relataram resultados diferentes, em consequência à inclusão de casos não homogêneos e provavelmente a questões metodológicas envolvidas.…”

Diffusion Tensor Imaging Assessment of the Epileptogenic Zone in Children with Localization-Related Epilepsy

“…Up to 72% of patients with MR imaging-negative epilepsy who had surgery were found to have FCD, and others have nonspecific findings such as gliosis on histopathology. [9][10][11][12][13] Identification of an anatomic abnormality has important therapeutic and prognostic implications, with considerably better outcomes in patients with an identifiable lesion than in those with MR imaging-negative localization-related epilepsy.…”