Stereo-electroencephalography (SEEG) in pediatric epilepsy: Utility in children with and without prior epilepsy surgery failure.

BACKGROUND: When noninvasive modalities fail to adequately localize the seizure onset zone (SOZ) in children with medically refractory epilepsy, invasive interrogation with stereo-electroencephalography (SEEG) or subdural electrodes may be required. Our center utilizes SEEG for invasive monitoring in a carefully selected population of children, many of whom have seizures despite a prior surgical resection. We describe the cohort of patients who underwent SEEG in the first 5 years of its employment in our institution, almost half of which had a history of a failed epilepsy surgery. METHODS: We retrospectively reviewed the records of the first 44 consecutive children who underwent SEEG at Nicklaus Children's Hospital (Miami, Florida), a large, level 4 epilepsy referral center. Patient demographic, clinical, radiographic, and electrophysiological information was collected prospectively. Student's t-test was used for sampling of means and analysis of variance (ANOVA) for evaluation of variance beyond 2 means; chi-square test of independence was used to assess the relationship between categorical variables. RESULTS: There were 44 patients in this cohort, of whom 17 (38.6 %) were male. The mean age of seizure onset was 6.2 years. Twenty-one patients (47.7 %) had previously failed an epilepsy surgery. Patients with a history of prior epilepsy surgery failure were older at SEEG implantation (17.6 vs. 13.7 years; p = 0.043), were more likely to have SEEG for identification of resection margins (9 vs. 4; p = 0.034), and had fewer electrodes placed (5.9 vs. 7.5; p = 0.016). No difference was seen in complication rates between groups with only 3/297 electrodes placed associated with complications, all of which were minor. Post-SEEG, 29 (65.9 %) patients underwent focal resection, 7 patients had VNS insertion, 3 underwent RNS placement, and 5 had no further intervention. The majority of patients that underwent resection in both groups experienced an improvement in seizures (Engel class I-III), reported by 13/15 (86.7 %) in those naive to surgery and 10/14 (71.4 %) in those with prior surgical failure. Seizure-freedom was much lower in those with prior epilepsy surgery, seen in only 4/14 (28.6 %) versus 8/15 (53.3 %). CONCLUSION: Our data supports current literature on SEEG as a safe and effective method of electrophysiological evaluation in children naive to surgery and adds that it is a safe technique in children with a history of failed epilepsy surgery. There was no difference in complication rates, which were <1 % in both groups. A favorable outcome was seen in the majority of patients in both groups; the seizure freedom rate, however, was much lower in those with prior epilepsy surgery.

Electroclinical characteristics and syndromic associations of "eye-condition" related visual sensitive epilepsies-A cross-sectional study.

PURPOSE: The systematic study of visual phenomena such as eye closure (ECLS), eye-closed/fixation-off sensitivity (FOS) [terminology proposed as eye-condition sensitive (ECS) epilepsy] distinct from photosensitivity is rarely explored in literature. METHODS: Clinical, electroencephalographic (EEG) and imaging records of patients attending an epilepsy clinic were screened. Inclusion criterion was demonstrable electrographic visual sensitivitiy in the form of ECS parameters with/without photosensitivity. Subsequently, detailed analysis of their data was undertaken. RESULTS: Fifty two patients had one or more ECS parameters. Mean age of onset of epilepsy of the cohort was 10.26 ±â€¯7.79 yrs. A family history of seizures was noted in 17% of the cohort. ECLS, FOS, combination of both, co-existent scotosensitivity and photosensitivity were noted in 32.6%, 48.1%, 19.2%, 23.1% and 30.8% respectively. Epilepsy syndromes included late-onset childhood occipital epilepsy-Gastaut variant (23.1%), reflex occipital lobe epilepsy with ECS without photosensitivity (21.2%), idiopathic photosensitive occipital epilepsy (13.5%), genetic generalized epilepsy (13.5%) and symptomatic epilepsy (28.7%) predominated by patients with posterior cortex gliosis or who were imaging negative. The idiopathic group also had lower seizure score and marked sleep activation of epileptiform abnormalities. Co-existent phostosensitivity was associated with a significantly higher predisposition for female gender, ECLS, generalized seizures and spikes with lower prevalence of FOS and extra-occipital spikes. Parieto-occipital spikes were noted in 88.4% patients. CONCLUSION: Syndromic heterogeneity is evident in ECS epilepsies. These form a unique subset of visual-sensitive epilepsy syndromes with focal or generalized seizure subtypes of idiopathic or symptomatic etiologies, with and without associated photosensitivity.

Epilepsy with myoclonic absences: Electroclinical characteristics in a distinctive pediatric epilepsy phenotype.

PURPOSE: The purpose of this article was to study the electroclinical characteristics and seizure outcome of children with epilepsy with myoclonic absences (EMA). METHOD: In this descriptive cohort study, we reviewed clinical records of patients who met the criteria for EMA. Each patient's demographic data, birth/developmental history, seizure semiology/pattern, antiepileptic drugs (AED), clinical examination, video-electroencephalography (VEEG), and neuroimaging data were reviewed. Response to AED and change in seizure frequency/pattern on follow-up were noted. Responders were defined by seizure freedom/>50% reduction in seizure frequency on follow-up. RESULT: Twelve children were diagnosed with EMA between 2008 and 2013 [50% male; mean age of onset: 3.5years]. Main seizure types were the characteristic myoclonic absences (100%) and generalized tonic-clonic seizures (42%). Ictal correlate on VEEG was 3- to 3.5-Hz spike-and-wave discharges (82%) and fast recruiting bifrontal rhythm (25%). One patient had specific MRI abnormalities. Mean duration of follow-up was 23.9months. Seizure frequency had significantly improved on follow-up (p=0.005), and at last follow-up, nine patients were in the responder group: four seizure-free for at least 1year, two with >90%, and three with >50% reduction in seizure frequency. The number of AED reduced significantly between initial visit and last follow-up among responders. Two patients on follow-up developed different seizure patterns, with generalized tonic and complex partial seizures. One responder expired because of unprovoked generalized convulsive status epilepticus. CONCLUSION: This cohort, the largest from the Indian subcontinent on the rare syndrome of EMA, suggests mild heterogeneity in a seemingly homogenous electroclinical phenotype. Clinical semiology while unique may demonstrate focality and variable ictal patterns. Most patients respond to either valproate monotherapy or valproate-lamotrigine combination; however, the prognosis remains guarded. The seizures of a minority of patients remain drug-refractory and may evolve into tonic or complex partial seizures.

Epilepsia partialis continua in mitochondrial dysfunction: Interesting phenotypic and MRI observations.

An 11-year-old girl manifested with photophobia, ptosis, external ophthalmoplegia, hypotonia, weakness of proximal limb muscles, hyporeflexia, and generalized seizures (six months). Her elder sister had had uncontrolled seizures and photophobia and died at seven years of age. In the patient, serum lactate was high (55 mg/dl). Muscle biopsy revealed characteristic ragged red and ragged blue fibers, diagnostic of mitochondrial cytopathy. Sequencing of the complete mitochondrial genome of the DNA obtained from the muscle biopsy of the patient did not show any characteristic mutation. Four months later, the girl was admitted with a one-week history of epilepsia partialis continua (EPC). EEG revealed Periodic Lateralized Epileptiform Discharges (PLEDs), once in 2-4 seconds, over the right temporo-occipital leads. MRI revealed signal change of right motor cortex, which had restricted diffusion. MR spectroscopy (MRS) from this region revealed lactate peak. EPC remained refractory to multiple anti-epileptic drugs, immuno-modulators, coenzyme-Q, and carnitine. This thought provoking report expands the spectrum of mitochondrial cytopathies.