Source and sink nodes in absence seizures.

As opposed to focal epilepsy, absence seizures do not exhibit a clear seizure onset zone or focus since its ictal activity rapidly engages both brain hemispheres. Yet recent graph theoretical analysis applied to absence seizures EEG suggests the cortical focal presence, an unexpected feature for this type of epilepsy. In this study, we explore the characteristics of absence seizure by classifying the nodes as to their source/sink natures via weighted directed graph analysis based on connectivity direction and strength estimation using information partial directed coherence (iPDC). By segmenting the EEG signals into relatively short 5-sec-long time windows we studied the evolution of coupling strengths from both sink and source nodes, and the network dynamics of absence seizures in eight patients.

Temporopolar blurring in temporal lobe epilepsy with hippocampal sclerosis and long-term prognosis after epilepsy surgery.

PURPOSE: We conducted a retrospective study in order to investigate the clinical significance of temporopolar grey/white matter abnormalities (GWMA) in patients with temporal lobe epilepsy (TLE) and unilateral hippocampal sclerosis (HS) with a long post-surgical follow-up. METHODS: The study comprised 122 consecutive patients with medically refractory TLE and unilateral HS who underwent epilepsy surgery and had a minimum postoperative follow-up of 5 years. Patients were divided into two groups, based on findings of pre-surgical MRI: group 1 with GWMA and 2 with normal signal and grey/white matter definition in temporal pole. Demographic and clinical data were reviewed and compared between groups. RESULTS: GWMA were found in 52.5% of patients, always ipsilateral to HS. Compared with group 2, group 1 patients had earlier epilepsy onset (mean, 9.3 vs 14.4 years, P=0.001), a higher occurrence of first seizure ≤2 years of age (25.8% vs 10.5%, P=0.036; OR=2.96 [95% CI=1.07-8.19]), and greater prevalence of left HS (76.6% vs 43.1%, P<0.001; OR=4.31 [95% CI=1.98-9.38]). No differences were found in gender, presence or type of initial precipitating injury, history of secondary generalized seizures, duration of epilepsy, seizure frequency before surgery, neuropsychological evaluation and presence or lateralization of pre-surgical interictal epileptiform discharges. Postoperative follow-up varied from 5 to 11.5 years (mean 7.4) and was similar in both groups (P=0.155). The proportion of patients classified as seizure-free (Engel class I) at last follow-up in groups 1 and 2 were 73.4% and 69%, respectively (P=0.689). Similarly, the percentages of seizure-free patients with no antiepileptic drugs at last evaluation were not different between groups (P=0.817). In logistic regression analysis, left HS (P=0.001; OR=4.166 [95% CI=1.86-9.34]) and age at epilepsy onset ≤2 years (P=0.047; OR=3.885 [95% CI=1.86-17.50]) were independently associated with risk of having GWMA. CONCLUSION: GWMA are frequent findings in patients with TLE and HS, and may help lateralize the epileptogenic zone. Our data support the hypothesis that GWMA are caused by seizure-related insults during the critical period of cerebral myelination. GWMA did not influence the postoperative seizure outcome of patients with TLE and HS, even after an extended duration of post-surgical follow-up.

Auras in temporal lobe epilepsy with hippocampal sclerosis: relation to seizure focus laterality and post surgical outcome.

We examined the relationship between presence and frequency of different types of auras and side of lesion and post surgical outcomes in 205 patients with medically intractable mesial temporal lobe epilepsy (MTLE) with unilateral hippocampal sclerosis (HS). With respect to the number of auras, multiple auras were not associated with side of lesion (p=0.551). The side of HS was not associated with the type of auras reported. One hundred fifty-seven patients were operated. The occurrence of multiple auras was not associated with post-surgical outcome (p=0.740). The presence of extratemporal auras was significantly higher in patients with poor outcome. In conclusion, this study suggests that the presence of extratemporal auras in patients with MTLE-HS possibly reflects extratemporal epileptogenicity in these patients, who otherwise showed features suggestive of TLE. Therefore, TLE-HS patients undergoing pre-surgical evaluation and presenting clinical symptoms suggestive of extratemporal involvement should be more extensively evaluated to avoid incomplete resection of the epileptogenic zone.

Low educational level effects on the performance of healthy adults on a Neuropsychological Protocol suggested by the Commission on Neuropsychology of the Liga Brasileira de Epilepsia.

OBJECTIVE: To assess cognitive measures and impact of education on cognitive performance (CP) of low educational levels healthy adults (LELHA) on a Neuropsychological Protocol (NP) suggested by the Liga Brasileira de Epilepsia. METHOD: 138 subjects from an Education Program for Adults divided into two, age and gender matched groups of 69 subjects, answered the NP: Group 1 (mean of 6.9 ± 2.95 months of formal education) and Group 2, 47.8 ± 10 months. Data were compared as z-scores. RESULTS: The mean IQ was 77.1 ± 5.50 and 79.4 ± 3.30 in Groups 1 and 2, respectively (p=0.001). Both performed below the normal curve and Group 1 worse than 2. CP correlated with schooling, especially executive functions (54.1% vs 36.2%) and language (52.9% vs 25.7%). CONCLUSION: LELHA showed significant cognitive impairment in verbal and visuospatial areas. If these results had been obtained in epilepsy patients they would be interpreted as global cognitive impairment.

Low educational level effects on the performance of healthy adults on a Neuropsychological Protocol suggested by the Commission on Neuropsychology of the Liga Brasileira de Epilepsia / Efeitos de baixo nível de escolaridade no desempenho de adultos saudáveis em um protocolo neuropsicológico sugerido pela Comissão de Neuropsicologia da Liga Brasileira de Epilepsia

OBJECTIVE: To assess cognitive measures and impact of education on cognitive performance (CP) of low educational levels healthy adults (LELHA) on a Neuropsychological Protocol (NP) suggested by the Liga Brasileira de Epilepsia. METHOD: 138 subjects from an Education Program for Adults divided into two, age and gender matched groups of 69 subjects, answered the NP: Group 1 (mean of 6.9±2.95 months of formal education) and Group 2, 47.8±10 months. Data were compared as z-scores. RESULTS: The mean IQ was 77.1±5.50 and 79.4±3.30 in Groups 1 and 2, respectively (p=0.001). Both performed below the normal curve and Group 1 worse than 2. CP correlated with schooling, especially executive functions (54.1 percent vs 36.2 percent) and language (52.9 percent vs 25.7 percent). CONCLUSION: LELHA showed significant cognitive impairment in verbal and visuospatial areas. If these results had been obtained in epilepsy patients they would be interpreted as global cognitive impairment.

OBJETIVO: Avaliar o desempenho cognitivo e o impacto do nível de educação formal em indivíduos adultos saudáveis com baixa escolaridade (IASBE) em um protocolo neuropsicológico (PN) sugerido pela Liga Brasileira de Epilepsia. MÉTODO: 138 indivíduos do programa EJA - Educação para Jovens e Adultos, divididos em 2 grupos de 69 sujeitos pareados por idade e sexo (6,9±2,95 vs 47,8±10 meses de escolaridade) responderam ao PN. Dados foram convertidos em z-scores. RESULTADOS: O QI médio foi 77,1±5,50 e 79,4±3,30 nos Grupos 1 e 2, respectivamente (p=0,001). Ambos tiveram resultados abaixo da curva normal e o Grupo 1 mostrou pior desempenho do que o 2, especialmente nas funções executivas (54,1 por cento vs 36,2 por cento) e linguagem (52,9 por cento vs 25,7 por cento). CONCLUSÃO: IASBE apresentaram comprometimento cognitivo tanto em tarefas verbais como visuoespaciais. Se estes resultados tivessem sido obtidos em pacientes com epilepsia seriam interpretados como indicativos de disfunção cognitiva global.

Atypical presentation in Rasmussen encephalitis: delayed late-onset periodic epileptic spasms.

A five-and-a-half-year-old girl started experiencing progressive left hemiparesis at age two and a half years. At age five years and four months she started presenting clusters of asymmetric periodic epileptic spasms with no hypsarrhythmia. The ictal EEG showed periodic, constant and stereotyped complexes. Serial brain imaging revealed progressive atrophy of the right hemisphere with increased T2 signal on MRI. She underwent a right hemispherotomy, and histological examination showed signs of inflammation and features of focal cortical dysplasia (FCD). She has been seizure-free for 16 months. This case is unique in the following aspects: the presence of typical Rasmussen encephalitis features of progressive unilateral brain involvement without seizures, a delay of almost three years prior to seizure onset; an atypical seizure type presentation with periodic epileptic spasms and the presence of FCD associated with inflammatory changes. [Published with video sequences].

Prognosis of juvenile myoclonic epilepsy is related to endophenotypes.

PURPOSE: To investigate if phenotypic variations have prognostic implications in juvenile myoclonic epilepsy (JME). METHODS: Sixty-five consecutive JME patients had video-EEG recording and were followed for at least three years. Reflex traits were defined as seizures and/or EEG discharges induction by eye-closure, photic stimulation, language, praxis or calculation. Patients had psychiatric evaluation and answered to STAI (State-Trait Anxiety Inventory). Seizure control was classified according to Prasad et al. (2003).(24) Patients were divided into Group 1: good seizure control and Group 2: moderate or poor seizure control. Video-EEG/EEG evaluation was repeated in 21 patients. RESULTS: Forty of 65 (61.5%) patients reached good seizure control, 25 (38.5%) of whom became seizure free. Group 2 patients had longer epilepsy duration (13.9±9.0 vs. 8.7±8.2; p=0.019); higher prevalence of the combination of all three seizure types (72.0% vs. 30.0%; p=0.003); discharges in baseline EEG (56.0% vs. 22.5%; p=0.008); seizure recording (68% vs. 20%; p<0.001) and sensitivity to praxis (63.6% vs. 29.6%; p=0.023). Compared to seizure-free patients, those with persistent seizures presented younger age at epilepsy onset (12.6±3.33 years vs. 15.4±5.47 years; p=0.015); higher prevalence of personality disorders (25% vs. 4%; p=0.029); higher scores in STAI-T (45.9±11.31 vs. 36.6±11.43; p=0.011) and higher incidence of sensitivity to praxis (58.6% vs. 25.0%; p=0.04) and to language (53.8 vs. 16.7%; p=0.026) tasks. Repetition of EEG/video-EEG revealed a parallel evolution of reflex traits disappearance and seizure control. DISCUSSION: Clinical features and reflex traits have prognosis implications in JME.

Prevalence of epilepsy in children from a Brazilian area of high deprivation.

This study assessed the prevalence rate of epilepsy and its causes in children and adolescents in one area of high deprivation in São Paulo, São Paulo, in Southeast Brazil. Between July 2005 and June 2006, 4947 families from a population of 22,013 inhabitants (including 10,405 children and adolescents between the ages of 0 and 16 years) living in the shantytown of Paraisópolis, were interviewed. In the first phase, a validated questionnaire was administered, to identify the occurrence of seizures. In the second phase, clinical history, neurologic examination, electroencephalography, and structural neuroimaging were performed. The diagnosis of epilepsy, including etiology, seizure types, and epileptic syndrome classification, was according to criteria of the International League Against Epilepsy. The screening phase identified 353 presumptive cases. In the second phase, 101 of these cases (33.8%) received the diagnosis of epilepsy. Crude prevalence of epilepsy was 9.7/1000 and prevalence of active epilepsy was 8.7/1000. Partial seizures were the most frequent seizure type (62/101). Symptomatic focal epilepsy was the most common form, and hypoxic-ischemic encephalopathy the most common etiology, reflecting the socioeconomic conditions of this specific population. Adequate public policies regarding perinatal assistance could help reduce the prevalence of epilepsy.

Are personality traits of juvenile myoclonic epilepsy related to frontal lobe dysfunctions? A proton MRS study.

PURPOSE: Personality traits characterized by emotional instability and immaturity, unsteadiness, lack of discipline, hedonism, frequent and rapid mood changes, and indifference toward one's disease have been associated with patients who have juvenile myoclonic epilepsy (JME). Literature data demonstrate worse seizure control and more psychosocial dysfunctions among patients with JME who have those traits. In this controlled study we performed a correlation analysis of psychiatric scores with magnetic resonance spectroscopy (MRS) values across JME patients, aiming to verify the existence of a possible relation between frontal lobe dysfunction and the prevalence of personality disorders (PDs) in JME. METHODS: Sixteen JME patients with cluster B PDs, 41 JME patients without any psychiatric disorder, and 30 healthy controls were submitted to a psychiatric evaluation and to a quantitative multivoxel MRS of thalamus; insula; cingulate gyrus; striatum; and frontal, parietal, and occipital lobes. Groups were homogeneous according to age, gender, and manual dominance. Psychiatric evaluation was performed through the Scheduled Clinical Interview for DSM-IV, Axis I and II (SCID I and II, respectively). RESULTS: A significant reduction of N-acetyl-aspartate over creatinine (NAA/Cr) ratio was observed mainly in the left frontal lobe in the JME and PD group. In addition, a significant increase in the glutamate-glutamine over creatinine GLX/Cr ratio was also observed in this referred region in the same group. DISCUSSION: These data support the hypothesis that PDs in JME could represent neuronal dysfunction and possibly a more severe form of this epileptic syndrome.

Estimulação fótica: padronização do método de acordo com o consenso europeu: [revisão] / Photic stimulation: standardization of the method based on european consensus: [review]

INTRODUÇÃO: Embora a fotostimulação intermitente (FEI) seja rotineiramente utilizada nos laboratórios de eletrencefalografia (EEG), raramente é utilizada de forma padronizada. A FEI é um método de ativação utilizado no EEG de rotina que pode desencadear tanto respostas fisiológicas quanto potencialmente patológicas. Historicamente, o termo fotossensibilidade se refere às respostas anormais à estimulação com luz estroboscópica durante o registro do EEG. OBJETIVO: O objetivo desta publicação é revisar os aspectos diagnósticos do procedimento da FEI, baseados no encontro de consenso realizado em Heemstede na Holanda, em 1996, com o propósito de facilitar e padronizar a detecção de pacientes fotossensíveis.

INTRODUCTION: Although intermittent photic stimulation (IPS) is a widespread and routinely used procedure in EEG laboratories, only relatively recently has a standardization of the IPS method been proposed. IPS is an activation method used during EEG procedure that may trigger either physiological or potentially pathological responses. Historically, the term photosensitivity is referred to abnormal responses to stroboscopic light during EEG. OBJECTIVE: The purpose of this publication was to provide an overview of the diagnostic aspects of IPS procedure, based on data presented at Consensus Meetings held in Heemstede, the Netherlands, in 1996, with the purpose of facilitating the detection of photosensitive patients.

Neuropsychological profile of patients with juvenile myoclonic epilepsy: a controlled study of 50 patients.

The purpose of this study was to verify possible cognitive dysfunction in patients with juvenile myoclonic epilepsy (JME) and its relationship to factors related to epilepsy and schooling. Fifty subjects diagnosed with JME and 50 controls underwent neuropsychological assessment evaluating intellectual functions, attention, memory, executive functions, and language. The patients were further divided into two subgroups on the basis of educational level: < or = 11 and >11 years of formal education. Participants diagnosed with JME scored significantly below age-, education-, and gender-matched controls on neuropsychological measures of attention, immediate verbal memory, mental flexibility, control of inhibition, working memory, processing speed, verbal delayed memory, visual delayed memory, naming, and verbal fluency. A positive correlation was observed between duration of epilepsy and cognitive decline. However, in the group of patients with >11 years of education, this correlation was not significant. In this series of patients with JME, neuropsychological evaluation suggests widespread cognitive dysfunction outside the limits of the frontal lobes. The duration of epilepsy correlated with cognitive decline, and patients with higher education manifested less progression of deficits.

Correlation between temporal pole MRI abnormalities and surface ictal EEG patterns in patients with unilateral mesial temporal lobe epilepsy.

OBJECTIVE: The objective of this retrospective study is to analyze ictal patterns observed during continuous Video-EEG monitoring in patients with temporal lobe epilepsy (TLE) due to unilateral hippocampal sclerosis (HS), and to correlate these EEG patterns to temporal pole abnormalities observed on magnetic resonance imaging exams. METHODS: We analyzed 147 seizures from 35 patients with TLE and unilateral HS. Ictal patterns were classified and correlated to signal abnormalities and volumetric measures of the temporal poles. Volume differences over 10% were considered abnormal. RESULTS: The most frequent type of ictal pattern was rhythmic theta activity (RTA), encountered in 65.5% of the seizures. Rhythmic beta activity (RBA) was observed in 11% of the seizures, localized attenuation in 8%, interruption of epileptiform discharges in 6%, repetitive discharges in 5.5%, and rhythmic delta activity (RDA) in 4%. Sixty-six percent of the patients presented signal abnormalities in the temporal pole that were always ipsilateral to the HS. Sixty percent presented significant asymmetry of the temporal poles consisting of reduced volume that was also always ipsilateral to HS. Although patients with RTA as the predominant ictal pattern tended to present asymmetry of temporal poles (p=0.305), the ictal EEG pattern did not correlate with temporal pole asymmetry or signal abnormalities. CONCLUSIONS: RTA is the most frequent initial ictal pattern in patients with TLE due to unilateral HS. Temporal pole signal changes and volumetric reduction were commonly found in this group of patients, both abnormalities appearing always ipsilateral to the HS. However, neither temporal pole volume reduction nor signal abnormalities correlated with the predominant ictal pattern, suggesting that the temporal poles are not crucially involved in the process of epileptogenesis.