Extratemporal Group Research Articles

Voxel-based morphometric magnetic resonance imaging postprocessing in non-lesional pediatric epilepsy patients using pediatric normal databases.

Pre-surgical evaluation of pediatric patients with drug-resistant focal epilepsy and negative (non-lesional) magnetic resonance imaging (MRI) is particularly challenging. Focal cortical dysplasia (FCD), a frequent pathological substrate in such setting, may be subtle on MRI and evade detection. The aim of this study was to use voxel-based MRI postprocessing to improve the detection of subtle FCD in pediatric surgical candidates. A consecutive cohort of pediatric patients undergoing pre-surgical evaluation with a negative MRI by visual analysis was included. MRI postprocessing was performed using a voxel-based morphometric analysis program (MAP) on T1-weighted volumetric MRI, with comparison to an age-specific normal pediatric database. The pertinence of MAP-positive areas was confirmed by surgical outcome and pathology. A total of 78 patients were included. Forty-four patients (56%) had positive MAP regions. Complete resection of the MAP-positive regions was positively associated with seizure-free outcome compared with the no/partial resection group (P < 0.001). Patients with no/partial resection of the MAP-positive regions had worse seizure outcomes than the MAP-negative group (P = 0.002). The MAP-positive rate was 100%, 77%, 63% and 40% in the 3-5, 5-10, 10-15 and 15-21 year age groups, respectively. MAP-positive rates were 45% in patients with temporal resection and 63% in patients with extratemporal resection. Complete resection of the MAP-positive regions was positively associated with seizure-free outcome in the extratemporal group (P = 0.001) but not in the temporal group (P = 0.070). Our data suggest the importance of using MRI postprocessing in the pre-surgical evaluation process of pediatric epilepsy patients with apparently normal MRI.

3 Tesla MRI-negative focal epilepsies: Presurgical evaluation, postoperative outcome and predictive factors

ObjectiveTo investigate presurgical diagnostic modalities, clinical and seizure outcome as well as predictive factors after resective epilepsy surgery in 3 Tesla MRI-negative focal epilepsies. Patients and methodsThis retrospective study comprises 26 patients (11 males/15 females, mean age 34±12years, range 13–50 years) with 3 Tesla MRI-negative focal epilepsies who underwent resective epilepsy surgery. Non-invasive and invasive presurgical diagnostic modalities, type and localization of resection, clinical and epileptological outcome with a minimum follow-up of 1year (range 1–11 years, mean 2.5±2.3years) after surgery as well as outcome predictors were evaluated. ResultsAll patients underwent invasive video-EEG monitoring after implantation of intracerebral depth and/or subdural electrodes. Ten patients received temporal and 16 extratemporal or multilobar (n=4) resections. There was no perioperative death or permanent morbidity. Overall, 12 of 26 patients (46%) were completely seizure-free (Engel IA) and 65% had a favorable outcome (Engel I–II). In particular, seizure-free ratio was 40% in the temporal and 50% in the extratemporal group. In the temporal group, long duration of epilepsy correlated with poor seizure outcome, whereas congruent unilateral FDG-PET hypometabolism correlated with a favorable outcome. ConclusionsIn almost two thirds of temporal and extratemporal epilepsies defined as “non-lesional” by 3 Tesla MRI criteria, a favorable postoperative seizure outcome (Engel I–II) can be achieved with accurate multimodal presurgical evaluation including intracranial EEG recordings. In the temporal group, most favorable results were obtained when FDG-PET displayed congruent unilateral hypometabolism.

Evaluation of Ictal Consciousness in Temporal and Extra Temporal Epilepsy: Observations from a Tertiary Care Hospital in India.

Background and PurposeDifferences in consciousness during seizures depend on the location of the seizure onset.MethodsThe present study evaluates ictal consciousness using the ictal consciousness inventory (ICI) in drug refractory mesial temporal (MTLE), neocortical temporal (NTLE) and extra temporal epilepsy (ETLE). This was a cross sectional cohort study with 45 patients with mesial temporal epilepsy, 47 with extra temporal and 11 patients with neocortical temporal epilepsy. The ICI a 20 item questionnaire was used to calculate the scores for level (L, question 1–10) and content (C, question 11–20) of consciousness.ResultsThe patients in mesial temporal group had higher ICI-L scores, p = 0.0129 as compared to the extra temporal group, but no difference was observed in the content of consciousness. The ICI-L and C scores were not different in the mesial temporal and the neocortical temporal group (p = 0.53 and 0.65) respectively.ConclusionsPatients with mesial temporal epilepsy had a higher level of consciousness than the extra temporal group but there was no difference in the content. Also there was no difference in the level and content of consciousness between mesial and the neocortical temporal group.

Clinical features of late-onset partial cryptogenic epilepsy: Toward an idiopathic temporal epilepsy?

Adult-onset epilepsy is commonly thought to be secondary to a brain lesion. However, the etiology of adult-onset epilepsy remains unknown in approximately 25% of patients, despite progress in medical and diagnostic tools. In the present study, we investigated whether late-onset partial cryptogenic epilepsies could be subgrouped based on seizure semiology and clinical characteristics. A total of 41 patients with late-onset cryptogenic epilepsy were included, and the corresponding clinical and electrophysiological data were analyzed. The following three clinical subgroups were identified: 1) a group that fulfilled the diagnostic criteria of transient epileptic amnesia (TEA); 2) a group with late-onset cryptogenic epilepsies with a temporal seizure semiology; and 3) a cryptogenic extratemporal group, which was consistent with the categorization of cryptogenic epilepsies, i.e., epilepsies involving unknown lesions. The temporal group showed homogeneous clinical characteristics, especially a rapid evolution and a greater tendency toward generalization and pharmacoresistance compared with the other two groups. Transient epileptic amnesia was associated with a higher frequency of sleep disorders than either of the other groups. Our findings argue for the clinical identification of a subgroup of late-onset temporal epilepsy that might constitute an idiopathic form. The association between TEA and sleep disorders would suggest a possible pathophysiological role of sleep apnea syndromes in TEA.

Qualitative and Quantitative Hippocampal MRI Assessments in Intractable Epilepsy

Aims. To acquire normative data of hippocampal volumes and T2 relaxation times, to evaluate and compare qualitative and quantitative assessments in evaluating hippocampi in patients with different durations of intractable epilepsy, and to propose an imaging protocol based on performance of these techniques. Methods. MRI analysis was done in 50 nonepileptic controls and 30 patients with intractable epilepsy on 1.5T scanner. Visual assessment and hippocampal volumetry were done on oblique coronal IR/T2W and T1W MP-RAGE images, respectively. T2 relaxation times were measured using 16-echo Carr-Purcell-Meiboom-Gill sequence. Volumetric data was normalized for variation in head size between individuals. Patients were divided into temporal (n = 20) and extratemporal (n = 10) groups based on clinical and EEG localization. Results. In controls, right hippocampal volume was slightly more than the left with no effect of age or gender. In TLE patients, hippocampal volumetry provided maximum concordance with EEG. Visual assessment of unilateral pathology concurred well with measured quantitative values but poorly in cases with bilateral pathologies. There were no significant differences of mean values between extratemporal group and controls group. Quantitative techniques detected mild abnormalities, undetected on visual assessment. Conclusions. Quantitative techniques are more sensitive to diagnose bilateral and mild unilateral hippocampal abnormalities.

Clinicopathological features and surgical outcomes of intractable epilepsy due to focal cortical dysplasia

Objective To study the correlation with subtypes of focal cortical dysplasia(FCD) and surgical outcomes in patients with intractable epilepsy due to FCD.Method According to Palmini's FCD classification,the clinical,radioiogical and pathological features of 42 intractable epilepsy patients of FCD received surgical treatment were reviewed retrospectively.Results Among 42 epilepsy patients,the FCD lesions were located in 24 temporal lobes,14 frontal lobes,6 parietal lobes,3 occipital lobes,5 multilple lesions.The positive rate of preoperative MRI examination was 62%.The subtypes of FCD were identified as following:FCD type Ⅰ A in 9,FCD type Ⅰ B in 21,FCD type Ⅱ A in 5 and FCD type Ⅱ B in 7,respectively.FCD type Ⅰ B was the predominant pathological subtype and almost located in temporal lobe associated hippocampal sclerosis.The curative rate of FCD surgery in temporal lobe epilepsy group was 67% and that in extratemporal group was 43% (Engle Ⅰ a)during follow -up period (at leastⅠ year).Conclusions FCD is a common cause of intractable epilepsy.The different intrinsic neuropathological characteristics,particularly the potential epileptogenic feature,have significant correlations with clinical findings.Further study should be made between each category with its surgical outcome. Key words: Focal cortical dysplasia; Intractable epilepsy; Pathology; Surgical procedures,operative

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INTRODUÇÃO: Artigo de revisão baseado em analise crítica da literatura atual sobre o tratamento cirúrgico da epilepsia na infância. OBJETIVOS: Realizar revisão bibliográfica e atualização sobre a cirurgia de epilepsia na infância. RESULTADOS: A cirurgia da epilepsia tem como objetivo o controle das crises e a melhora da qualidade de vida do paciente sem determinar seqüelas inaceitáveis. Uma vez constatada a refratariedade das crises ao tratamento medicamentoso, o paciente deverá ser investigado para a correta localização da área responsável pelas crises, utilizando-se o vídeo-EEG para registro das crises, a avaliação neuropsicológica e os exames funcionais e anatômicos de neuro-imagem. Em relação ao momento da cirurgia, sabemos que: (1) os pacientes mais jovens apresentam melhores resultados quanto aos aspectos psicossociais; (2) a maior incidência de tumores ocultos nas epilepsias parciais refratárias na criança favorecem uma intervenção precoce; (3) a longa espera entre o início da epilepsia e a cirurgia pode predispor a um controle mais pobre das crises; e (4) a neuroplasticidade é um importante aliado nas crianças podendo reduzir o risco de déficit pós-operatório. O maior objetivo da cirurgia da epilepsia é o controle absoluto das crises. É importante também considerar o seguimento global do paciente, incluindo a satisfação dos pais, a melhora no desenvolvimento neuropsicomotor e social, as atividades da vida diária, as modificações comportamentais e no rendimento escolar. Nas séries pediátricas, 60-100% dos pacientes tem uma boa evolução pós-operatória. Os pacientes com epilepsia temporal têm uma maior taxa de ausência de crises quando comparados com o grupo extratemporal. CONCLUSÕES: A cirurgia da epilepsia em crianças tornou-se uma opção realística para casos selecionados e tende a se expandir num futuro próximo. Devemos reconhecer as formas de epilepsia que tem um curso catastrófico, evitando tentativas demoradas de controle com fármacos antiepilépticos que não mudarão a evolução da doença e que retardando o tratamento cirúrgico podem piorar o prognóstico. A terapêutica cirúrgica só deve ser indicada se houver uma boa oportunidade de melhorar a qualidade de vida do paciente.

The localizing and lateralizing value of ictal/postictal coughing in patients with focal epilepsies

Postictal coughing has so far been reported to indicate a temporal origin of focal epilepsy. A trend towards non-dominant hemisphere lateralization and mesial temporal localization has been suggested. However, postictal coughing has also been reported in a few patients with extratemporal epilepsies. We have retrospectively evaluated the localizing and lateralizing value of ictal/postictal coughing in 197 patients with temporal and extratemporal epilepsy who received presurgical video-EEG long-term recordings from 1999 to 2001. There was no statistical significant difference in percentage of coughing patients in both groups. However, only patients belonging to the temporal group presented with coughing as a regular element of seizure semiology (simple partial and complex partial seizures) whereas in the extratemporal group coughing occurred more sporadically. Within the temporal group a statistically significant tendency to left-sided seizure onset and a statistically not significant preponderance of mesial seizure onset was observed. Additional vegetative signs were observed only in about half of the patients. These results suggest that coughing occurs in both temporal and extratemporal lobe epilepsy and may only be indicative of temporal lobe seizure onset if representing a regular semiologic element. Coughing may be due to two different mechanisms, one dependent and the other independent from additional vegetative symptoms.

Pediatric epilepsy surgery at the University of Alberta: 1988-2000

Epilepsy surgery is considered a treatment option for patients with intractable seizures. Relatively few studies of efficacy, safety, and long-term outcome are available for the pediatric age group. This study describes a 12-year experience with pediatric epilepsy surgery at the University of Alberta. Records of pediatric epilepsy surgery patients admitted to the Comprehensive Epilepsy Program at the University of Alberta between 1988 and 2000 were reviewed. All patients received preoperative and postoperative clinical evaluation, seizure charts, testing of drug levels, electroencephalogram, computed tomography/magnetic resonance imaging, neuropsychologic testing, and long-term video electroencephalogram monitoring. The patients were reassessed after surgery at 6 weeks, 6 months, and 1 year and then yearly. The duration of follow-up was 1 year to 12 years. Forty-two patients underwent temporal lobectomies; 35, extratemporal resection. The age at surgery ranged from 6 months to 16 years. Thirty-two (76%) of temporal lobe patients became seizure-free (Engel Class I) vs 24 (68%) for the extratemporal group (Engel Class I). One patient (2%) in the temporal group had an Engel Class II outcome and one patient (3%) in the extratemporal group had the same Engel Class II outcome. Three patients (4%) manifested postoperative complications, and there were no deaths. Patients reported improvement in cognitive abilities, behavior, and quality of life after the surgery. Epilepsy surgery in children is effective and safe. Many children are seizure-free after the operation and remain so, although the results of temporal lobectomy are better than for extratemporal resections. There are few complications, and children often have an improved quality of life.

Verbal Memory and IQ in Children who Undergo Focal Resection for Intractable Epilepsy:A Clinical Review

AbstractPrevious studies have indicated an increased likelihood of intellectual and memory impairments in children with epilepsy. It has been argued that early surgical intervention in children with intractable seizures might be advantageous to their development. We conducted a retrospective review of pre- and postoperative IQ and verbal memory scores in 16 paediatric patients who underwent temporal (N= 10) or extra-temporal (N= 6) focal surgery for epilepsy. Patients with an extratemporal seizure focus performed significantly worse than patients with a temporal lobe seizure focus on Full Scale IQ and Verbal IQ before surgery. Postoperatively a statistically significant decline in verbal memory, but not in any of the IQ indices was noticed in the extratemporal group. Individual outcome analyses revealed a significant decline in verbal memory in 22% of temporal lobectomy and 60% of extratemporal cases. Our review suggests that verbal memory but not IQ is vulnerable to postoperative decline in children who undergo focal extratemporal surgery for intractable epilepsy. The findings raise the possibility that extratemporal regions play a role in anterograde memory in children. Given the small number of subjects in this study, further investigations into the cognitive effects of paediatric surgical intervention are recommended.

Predictors of seizure outcome following cortical resection in pediatric and adolescent patients with medically refractory epilepsy.

Several preoperative clinical variables have been reported to have value as predictors of seizure outcome following the surgical resection of epileptogenic focus in adults who have had medically refractory epilepsy. The present paper reports the results of a retrospective review of the ability of these variables to predict seizure outcome in a group of pediatric patients who had medically refractory epilepsy and underwent surgical resection of an epileptogenic focus at the Children's Hospital of Eastern Ontario. Variables in this review included age at first seizure, age at time of surgery, duration of seizures, seizure type, sex, family history, etiology, level of intelligence, EEG data, results of imaging studies, findings on examination of the central nervous system, and location and site of surgical resection. We found 64 patients who met the entry criteria for this review. Normal intelligence and tumor as etiology were associated with a good postoperative seizure outcome in patients who had a temporal resection; no variables had positive correlation with outcome in the extratemporal group. Caution must be used in the extrapolation of data and inclusion of studies of predictors of seizure outcome for adults to pediatric age groups.

Significance of interictal temporal lobe delta activity for localization of the primary epileptogenic region.

Because interictal temporal lobe delta activity (TLDA) has been described in 30 to 90% of patients with temporal lobe epilepsy (TLE) but has not been investigated in patients with extratemporal epilepsy, we sought to determine the localizing significance of TLDA. We compared the presurgical interictal scalp EEG results of 47 consecutive patients who received extratemporal resection (40 frontal and 7 parietal-occipital) for intractable epilepsy with 43 consecutive patients who received anterior temporal lobectomy. We defined lateralized TLDA as runs of lower than 4-Hz waveforms that were easily distinguished from the background rhythms and were maximal at electrodes T4, F8, and T6 or T3, F7, and T5. The lateralized TLDA was subcategorized as temporal intermittent rhythmic delta activity (TIRDA) or temporal intermittent polymorphic delta activity (TIPDA). A chi-square test was used to determine the association of the lobe of the epileptogenic zone with TIRDA and TIPDA. We found TIRDA in 12 (28%) and TIPDA in 8 (19%) patients in the temporal lobe group, and TIRDA in 2 (4%) and TIPDA in 9 (19%) patients in the extratemporal group. TIRDA was strongly associated with TLE (p < 0.003), whereas TIPDA occurred at an equal rate in both groups. Similar to anterior temporal epilepsy, lateralized TIPDA is present in up to 20% of patients with extratemporal epilepsy. The presence of TIRDA strongly suggests TLE but may infrequently occur in extratemporal epilepsy. Caution should be used when using lateralized TLDA as a presurgical localizing finding.