The effect of surgery in encephalopathy with electrical status epilepticus during sleep.

PURPOSE: We analyzed clinical and electroencephalography (EEG) outcomes of 13 patients with pharmacoresistant encephalopathy with electrical status epilepticus during sleep (ESES) following epilepsy surgery. METHODS: All patients had symptomatic etiology of ESES and preoperative neuropsychological deterioration. Ten patients had daily atypical absences. Clinical outcome was assessed at 6 months and at 2 years after surgery. Clinical and EEG data were reviewed retrospectively. The spike propagation pattern and area and source strength in source montage were analyzed from preoperative and postoperative EEG studies. KEY FINDINGS: Preoperative sleep EEG showed electrical status epilepticus during sleep (SES) with one-way interhemispheric propagation in nine patients and with two-way interhemispheric propagation in four. The age of the patients at the time of surgery ranged from 3.6-9.9 years. Focal resection (two patients) or hemispherotomy (one patient with postoperative EEG) either terminated SES or restricted the discharge to one region. Either reduced SES propagation area or source strength was found in four of eight callosotomy patients with postoperative EEG. Of patients who had seizures preoperatively, Engel class I-II seizure outcome was observed in two of three children after focal resection or hemispherotomy and in two of eight children after callosotomy. None of these patients with Engel class I-II outcome had SES with two-way interhemispheric propagation on preoperative EEG. Cognitive deterioration was halted postoperatively in all except one patient. Cognitive catch-up of more than 10 IQ points was seen in three patients, all of whom had shown a first measured IQ of >75. SIGNIFICANCE: Patients with pharmacoresistant ESES based on symptomatic etiology may benefit from resective surgery or corpus callosotomy regarding both seizure outcome and cognitive prognosis.

Long-term outcome of 32 children with encephalopathy with status epilepticus during sleep, or ESES syndrome.

PURPOSE: To prospectively evaluate the efficacy of drug treatment and long-term cognitive outcome in children with encephalopathy with status epilepticus during sleep (ESESS). METHODS: Thirty-two children were diagnosed and prospectively followed up for at least 3 years at our unit between 1991 and 2007. Twenty-seven children were included in the prospective treatment study with valproate (VPA) and 17 with VPA combined with ethosuximide (ESM). Treatment response of disappearance of electrical status epilepticus during sleep (SES) was documented with overnight EEG recordings. Neuropsychological follow up for at least 5 years was available in 18 patients. RESULTS: Six children had atypical rolandic (AR) epilepsy, nine Landau-Kleffner syndrome (LKS), and 17 symptomatic epilepsy. Before ESESS, 20 children were cognitively normal. Prospective treatment with VPA and ESM was effective in 3 of the 17 children (18%) treated. Abolition of SES with drug treatment was observed in 16 patients. In all, 10 children (31%), 4 with AR (67%), 3 with LKS (33%), and 3 with symptomatic etiology (19%), including 9 with treatment response regained the pre-ESESS cognitive level. Unfavorable cognitive outcome was predicted by younger age at ESESS diagnosis, lower IQ at the time of the diagnosis, and no response to drug treatment when compared with those with favorable cognitive outcome. Eight of the 16 nonresponders underwent epilepsy surgery. DISCUSSION: Treatment response with VPA combined with ESM was observed more often than with other drug combinations. Most children with ESESS experienced permanent cognitive impairment. Cognitive outcome depends on treatment response on electroencephalography (EEG) and seizures, and on underlying etiology.

Two-year follow-up of intelligence after pediatric epilepsy surgery.

Research findings concerning cognitive effects of pediatric epilepsy surgery form an important basis for decisions about surgery. However, most follow-up studies have been of limited duration. In this study, a 2-year follow-up of intelligence was undertaken. Risk factors were analyzed. Included were 38 patients aged 3 to 17 years. Surgery was left in 19 patients and right in 19 patients. Types of surgery included temporal lobe resection (n = 23), extratemporal or multilobar resection (n = 8), and hemispherectomy (n = 7). The Wechsler Scales of Intelligence were administered presurgically, 6 months postsurgically, and 2 years postsurgically. No significant change in verbal or performance intelligence quotient (IQ) was demonstrated on a group level. Lateralization, type of surgery, age at surgery, sex, and presurgical IQ did not affect outcome. Across assessments, IQ scores of left-hemisphere patients were lower than those of right-hemisphere patients. Scores of patients in the hemispherectomy group were lower than those of the extratemporal or multilobar resection group, which were lower than the temporal lobe resection group. Scores improved significantly in six patients and deteriorated in seven. In conclusion, epilepsy surgery in children and adolescents does not, in general, have a significant impact on cognitive development in a 2-year perspective. In individual patients, poor seizure control and extensive surgery for Rasmussen's encephalitis were related to a deterioration of IQ.

Dichotic listening in children with focal epilepsy: effects of structural brain abnormality and seizure characteristics.

The study examined performance on a dichotic listening test in children with focal epilepsy. The aim of the study was to explore how factors related to brain pathology would affect ear advantage. The effects of lateralization of epileptogenic area, size and localization of structural abnormality on MRI findings, and seizure characteristics were studied. Children treated for focal epileptic seizures took part in the study (N = 35). The dichotic test consisted of pairs of words, nonwords, syllables and vowels. Results demonstrated that large congenital structural abnormality in the left hemisphere altered ear advantage whereas smaller abnormality and right-hemisphere abnormality did not. Further, epileptic seizures of left-hemisphere origin that had started at an early age affected ear advantage whereas seizure frequency at the time of the assessment did not. Children with early onset of seizures of right-hemisphere origin had a strong right-ear advantage. The total score did not differ between the groups. There was a strong negative correlation between the scores for the right-ear and the left-ear. The findings were interpreted to indicate altered functional dominance for perception of auditory, linguistic stimuli following early left-hemisphere pathology rather than unilateral functional suppression.

Low-grade gliomas and focal cortical developmental malformations: differentiation with proton MR spectroscopy.

PURPOSE: To assess proton magnetic resonance (MR) spectroscopy in differentiating between low-grade gliomas and focal cortical developmental malformations (FCDMs). MATERIALS AND METHODS: Eighteen patients with seizures and a cortical brain lesion on MR images were studied with proton MR spectroscopy. A metabolite ratio analysis was performed, and the metabolite signals in the lesion core were compared with those in the contralateral centrum semiovale and in the corresponding brain sites in 18 control subjects to separately obtain the changes in N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine-phosphocreatine (Cr). Ten patients had a low-grade glioma (three, oligodendrogliomas; three, oligoastrocytomas; three, astrocytomas; and one, pilocytic astrocytoma), and eight had FCDM (five, focal cortical dysplasias and three, dysembryoplastic neuroepithelial tumors). Linear discriminant analysis and Student t test were used for statistical comparisons. RESULTS: Loss of NAA and increase of Cho were more pronounced in low-grade gliomas than in FCDMs (NAA, -72% +/- 15 [+/- SD] vs -29% +/- 22, P <.001; Cho, 117% +/- 56 vs 21% +/- 66, P <.01). Changes in NAA and Cho helped differentiate low-grade gliomas from FCDMs, and changes in Cho and Cr helped differentiate astrocytomas from oligodendrogliomas and oligoastrocytomas. Metabolite NAA/Cho and NAA/Cr ratios helped differentiate low-grade gliomas from FCDMs but did not differentiate glioma subtypes. CONCLUSION: MR spectroscopy allows distinction between low-grade gliomas and FCDMs and between low-grade glioma subtypes. Metabolite changes are more informative than are metabolite ratios.

Visual field constriction in 91 Finnish children treated with vigabatrin.

PURPOSE: To study the prevalence and features of visual field constrictions (VFCs) associated with vigabatrin (VGB) in children. METHODS: A systematic collection of all children with any history of VGB treatment in fifteen Finnish neuropediatric units was performed, and children were included after being able to cooperate reliably in repeated visual field tests by Goldmann kinetic perimetry. This inclusion criterion yielded 91 children (45 boys; 46 girls) between ages 5.6 and 17.9 years. Visual field extent <70 degrees in the temporal meridian was considered abnormal VFC. RESULTS: There was a notable variation in visual field extents between successive test sessions and between different individuals. VFCs <70 degrees were found in repeated test sessions in 17 (18.7%) of 91 children. There was no difference in the ages at the study, the ages at the beginning of treatment, the total duration of the treatment, general cognitive performance, or neuroradiologic findings between the patients with normal visual fields and those with VFC, but the patients with VFC had received a higher total dose of VGB. In linear regression analysis, there were statistically significant inverse correlations between the temporal extent of the visual fields and the total dose and the duration of VGB treatment. The shortest duration of VGB treatment associated with VFC was 15 months, and the lowest total dose 914 g. CONCLUSIONS: Because of a wide variation in normal visual-field test results in children, the prevalence figures of VFCs are highly dependent on the definition of normality. Although our results confirm the previous findings that VFC may occur in children treated with VGB, our study points out the need to reevaluate critically any suspected VFC to avoid misdiagnosis. Nevertheless, our study suggests that the prevalence of VFC may be lower in children than in adults, and that the cumulative dose of VGB or length of VGB therapy may add to the personal predisposition for developing VFC.