Ravindra Arya

Adverse events related to extraoperative invasive EEG monitoring with subdural grid electrodes: A systematic review and meta-analysis

Implantation of subdural grids and invasive electroencephalography (EEG) monitoring is important to define the ictal‐onset zone and eloquent cortex in selected patients with medically refractory epilepsy. The objective of this systematic review is to summarize data about adverse events related to this procedure.

Intranasal versus intravenous lorazepam for control of acute seizures in children: A randomized open-label study

Purpose:  Intravenous lorazepam is considered the drug of first choice for control of acute convulsive seizures. However, resource or personnel constraints necessitate the study of alternative routes and medications. This study compared the efficacy and adverse effects of intranasal versus intravenous lorazepam in children aged 6–14 years who presented with acute seizures.

Gaps and opportunities in refractory status epilepticus research in children: A multi-center approach by the Pediatric Status Epilepticus Research Group (pSERG)

Purpose: Status epilepticus (SE) is a life-threatening condition that can be refractory to initial treatment. Randomized controlled studies to guide treatment choices, especially beyond first-line drugs, are not available. This report summarizes the evidence that guides the management of refractory convulsive SE (RCSE) in children, defines gaps in our clinical knowledge and describes the development and works of the ‘pediatric Status Epilepticus Research Group’ (pSERG). Methods: A literature review was performed to evaluate current gaps in the pediatric SE and RCSE literature. In person and online meetings helped to develop and expand the pSERG network. Results: The care of pediatric RCSE is largely based on extrapolations of limited evidence derived from adult literature and supplemented with case reports and case series in children. No comparative effectiveness trials have been performed in the pediatric population. Gaps in knowledge include risk factors for SE, biomarkers of SE and RCSE, second-and third-line treatment options, and long-term outcome. Conclusion: The care of children with RCSE is based on limited evidence. In order to address these knowledge gaps, the multicenter pSERG was established to facilitate prospective collection, analysis, and sharing of de-identified data and biological specimens from children with RCSE. These data will allow identification of treatment strategies associated with better outcomes and delineate evidence-based interventions to improve the care of children with SE.

Epilepsy in children with Down syndrome

This review discusses the various aspects of epilepsy in Down syndrome (DS) from the perspective of paediatric neurology. DS is the most common genetic cause of mental retardation (MR) with a reported prevalence of epilepsy of 1–13%. Infantile spasms (IS) or West syndrome (WS) is the most frequent epilepsy syndrome in children with DS. IS occur in 0.6–13% of children with DS, representing 4.5–47% of seizures in these children. Curiously, these patients have electroencephalographic (EEG) characteristics of idiopathic rather than symptomatic WS. Despite a lack of consensus on therapeutic approach, no significant difference has been reported among the different regimens with regards to achieving clinical remission or EEG normalisation. It appears that DS patients have better seizure control compared to other patients with symptomatic IS, and early initiation of appropriate treatment may contribute to the prevention of late seizure development and better developmental outcome. Lennox-Gastaut syndrome (LGS) also exhibits some distinctive features in children with DS including later onset and high incidence of reflex seizures. Other seizure types including partial and generalised tonic clonic seizures have also been described in children with DS. There is a high rate of EEG abnormalities in children with DS, even among children without epilepsy, however, no patterns specific to DS have been identified and EEG does not correlate with outcome. Various cellular and molecular mechanisms contribute to epileptogenesis in DS and offer an interesting field of study.

Time from convulsive status epilepticus onset to anticonvulsant administration in children

Objective: To describe the time elapsed from onset of pediatric convulsive status epilepticus (SE) to administration of antiepileptic drug (AED). Methods: This was a prospective observational cohort study performed from June 2011 to June 2013. Pediatric patients (1 month–21 years) with convulsive SE were enrolled. In order to study timing of AED administration during all stages of SE, we restricted our study population to patients who failed 2 or more AED classes or needed continuous infusions to terminate convulsive SE. Results: We enrolled 81 patients (44 male) with a median age of 3.6 years. The first, second, and third AED doses were administered at a median (p25–p75) time of 28 (6–67) minutes, 40 (20–85) minutes, and 59 (30–120) minutes after SE onset. Considering AED classes, the initial AED was a benzodiazepine in 78 (96.3%) patients and 2 (2–3) doses of benzodiazepines were administered before switching to nonbenzodiazepine AEDs. The first and second doses of nonbenzodiazepine AEDs were administered at 69 (40–120) minutes and 120 (75–296) minutes. In the 64 patients with out-of-hospital SE onset, 40 (62.5%) patients did not receive any AED before hospital arrival. In the hospital setting, the first and second in-hospital AED doses were given at 8 (5–15) minutes and 16 (10–40) minutes after SE onset (for patients with in-hospital SE onset) or after hospital arrival (for patients with out-of-hospital SE onset). Conclusions: The time elapsed from SE onset to AED administration and escalation from one class of AED to another is delayed, both in the prehospital and in-hospital settings.

Sample size estimation in prevalence studies.

Estimation of appropriate sample size for prevalence surveys presents many challenges, particularly when the condition is very rare or has a tendency for geographical clustering. Sample size estimate for prevalence studies is a function of expected prevalence and precision for a given level of confidence expressed by the z statistic. Choice of the appropriate values for these variables is sometimes not straight-forward. Certain other situations do not fulfil the assumptions made in the conventional equation and present a special challenge. These situations include, but are not limited to, smaller population size in relation to sample size, sampling technique or missing data. This paper discusses practical issues in sample size estimation for prevalence studies with an objective to help clinicians and healthcare researchers make more informed decisions whether reviewing or conducting such a study.

Folic acid supplementation prevents phenytoin-induced gingival overgrowth in children

Objective: Gingival overgrowth is an important adverse effect of phenytoin (PHT) therapy, occurring in about half of the patients. This study aimed to evaluate the effect of oral folic acid supplementation (0.5 mg/day) for the prevention of PHT-induced gingival overgrowth (PIGO) in children with epilepsy aged 6–15 years on PHT monotherapy for 6 months. Methods: This was a randomized, double-blind, placebo-controlled trial conducted at a tertiary level hospital from May 2008 to June 2009. Children aged 6–15 years started on PHT monotherapy within last 1 month were eligible for inclusion. Preexisting gingival overgrowth, use of other folic acid antagonists, and macrocytic anemia were exclusion criteria. Trial subjects were randomized to receive either folic acid or placebo. The primary outcome measure was incidence of any degree of gingival overgrowth after 6 months of PHT monotherapy. The trial was registered with clinicaltrials.gov (NCT00781196). Results: A total of 120 children were recruited, 62 and 58, respectively, in folic acid and placebo arms. The 2 arms were comparable at baseline. Twenty-one percent of patients in the folic acid arm developed PIGO, as compared with 88% receiving placebo (p < 0.001). Absolute risk reduction of PIGO by folic acid was 67% (95% confidence interval 54%–80%), and relative risk reduction was 0.76. Conclusions: Oral folic acid was found to decrease the incidence of PIGO in children on PHT monotherapy, in a statistically significant and clinically relevant manner. Classification of evidence: This study provides Class I evidence that folic acid supplementation, 0.5 mg/day, is associated with prevention of gingival overgrowth in children taking PHT monotherapy.

Corticosteroids for the Treatment of Infantile Spasms A Systematic Review

Adrenocorticotropic hormone (ACTH) and corticosteroids are the usual first-line treatment options for infantile spasms. Despite significant differences, these agents are often lumped together in this context. There is a need to systematically explore the efficacy of corticosteroids in the treatment of infantile spasms, especially in comparison to ACTH. This review identified and analyzed corticosteroid clinical trials and summarized their short-term efficacy and tolerability. Primary outcome was cessation of spasms and abolition of hypsarrhythmia on prolonged video electroencephalographic monitoring. Eight corticosteroid clinical trials were found with only 2 fulfilling the criteria for adequate design. The weighted-mean efficacy of corticosteroids to achieve primary outcome was 31% for these 2 methodologically adequate studies. Including reanalyzed data from 3 other studies, the corticosteroid efficacy was found to be 42%. On the basis of the available evidence, the efficacy of high-dose corticosteroids is similar to low-dose ACTH and inferior to high-dose ACTH, the current standard treatment.

Efficacy of nonvenous medications for acute convulsive seizures: A network meta-analysis

Objective: This is a network meta-analysis of nonvenous drugs used in randomized controlled trials (RCTs) for treatment of acute convulsive seizures and convulsive status epilepticus. Methods: Literature was searched according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines for RCTs examining treatment of acute convulsive seizures or status epilepticus with at least one of the study arms being a nonvenous medication. After demographic and outcome data extraction, a Bayesian network meta-analysis was performed and efficacy results were summarized using treatment effects and their credible intervals (CrI). We also calculated the probability of each route–drug combination being the most clinically effective for a given outcome, and provided their Bayesian hierarchical ranking. Results: This meta-analysis of 16 studies found that intramuscular midazolam (IM-MDZ) is superior to other nonvenous medications regarding time to seizure termination after administration (2.145 minutes, 95% CrI 1.308–3.489), time to seizure cessation after arrival in the hospital (3.841 minutes, 95% CrI 2.697–5.416), and time to initiate treatment (0.779 minutes, 95% CrI 0.495–1.221). Additionally, intranasal midazolam (IN-MDZ) was adjudged most efficacious for seizure cessation within 10 minutes of administration (90.4% of participants, 95% CrI 79.4%–96.9%), and persistent seizure cessation for ≥1 hour (78.5% of participants, 95% CrI 59.5%–92.1%). Paucity of RCTs produced evidence gaps resulting in small networks, routes/drugs included in some networks but not others, and some trials not being connected to any network. Conclusions: Despite the evidence gaps, IM-MDZ and IN-MDZ exhibit the best efficacy data for the nonvenous treatment of acute convulsive seizures or status epilepticus.

Vagus nerve stimulation for medically refractory absence epilepsy

PURPOSE A proportion of patients with childhood and juvenile absence epilepsies (CAE, JAE) are likely to be classified as medically refractory. In view of evidence gap for the treatment of such patients, this series is reported to generate estimate for efficacy of vagus nerve stimulation (VNS) in this patient population. METHODS Patients were identified by a chart review of all VNS recipients between January 1, 2006 and December 31, 2011. The diagnosis of CAE and JAE was based on conventional criteria. Details of demography, epilepsy phenomenology, management and outcomes were extracted. The outcome measures included reduction in daily seizure frequency measured as a percentage of pre-VNS seizure frequency and classified on International League Against Epilepsy (ILAE) outcome scale. RESULTS Nine patients (7 CAE, 2 JAE) with a mean age of seizure onset of 5.4 years (±3.9) were identified. Mean duration of epilepsy prior to VNS implant was found to be 3.9 years (±1.4). These patients had failed a median of 5 anti-epileptic drugs before being referred for consideration of surgical treatment. After a mean follow-up of 33.9 months (±25.5, minimum 4 months), 1 patient attained complete seizure freedom (ILAE class 1), 6 had ILAE class 4 and 2 had ILAE class 5 outcomes, respectively. Mean reduction in daily seizure frequency was found to be 53.5±60.3% (1-sided p-value for paired t-test=0.04), with a 50% responder rate of 55.6%. CONCLUSION VNS may be considered as a therapeutic option in patients with medically refractory absence epilepsy.