Subclinical epileptiform activity in children with electrical status epilepticus during sleep: effects on cognition and behavior before and after treatment with levetiracetam

Thalamic epileptic spikes disrupt sleep spindles in patients with epileptic encephalopathy

In severe epileptic encephalopathies, epileptic activity contributes to progressive cognitive dysfunction. Epileptic encephalopathies share the trait of spike-wave activation during non-REM sleep (EE-SWAS), a sleep stage dominated by sleep spindles, which are brain oscillations known to coordinate offline memory consolidation. Epileptic activity has been proposed to hijack the circuits driving these thalamocortical oscillations, thereby contributing to cognitive impairment. Using a unique dataset of simultaneous human thalamic and cortical recordings in subjects with and without EE-SWAS, we provide evidence for epileptic spike interference of thalamic sleep spindle production in patients with EE-SWAS. First, we show that epileptic spikes and sleep spindles are both predicted by slow oscillations during stage two sleep (N2), but at different phases of the slow oscillation. Next, we demonstrate that sleep-activated cortical epileptic spikes propagate to the thalamus (thalamic spike rate increases after a cortical spike, P ≈ 0). We then show that epileptic spikes in the thalamus increase the thalamic spindle refractory period (P ≈ 0). Finally, we show that in three patients with EE-SWAS, there is a downregulation of sleep spindles for 30 s after each thalamic spike (P < 0.01). These direct human thalamocortical observations support a proposed mechanism for epileptiform activity to impact cognitive function, wherein epileptic spikes inhibit thalamic sleep spindles in epileptic encephalopathy with spike and wave activation during sleep.

Movement Termination of Slow-Wave Sleep-A Potential Biomarker?

The duration of slow-wave sleep (SWS) is related to the reported sleep quality and to the important variables of mental and physical health. The internal cues to end an episode of SWS are poorly understood. One such internal cue is the initiation of a body movement, which is detectable as electromyographic (EMG) activity in sleep-electroencephalography (EEG). In the present study, we characterized the termination of SWS episodes by movement to explore its potential as a biomarker. To this end, we characterized the relation between the occurrence of SWS termination by movement and individual characteristics (age, sex), SWS duration and spectral content, chronotype, depression, medication, overnight memory performance, and, as a potential neurological application, epilepsy. We analyzed 94 full-night EEG-EMG recordings (75/94 had confirmed epilepsy) in the video-EEG monitoring unit of the EpiCARE Centre Salzburg, Austria. Segments of SWS were counted and rated for their termination by movement or not through the visual inspection of continuous EEG and EMG recordings. Multiple linear regression was used to predict the number of SWS episodes that ended with movement by depression, chronotype, type of epilepsy (focal, generalized, no epilepsy, unclear), medication, gender, total duration of SWS, occurrence of seizures during the night, occurrence of tonic-clonic seizures during the night, and SWS frequency spectra. Furthermore, we assessed whether SWS movement termination was related to overnight memory retention. According to multiple linear regression, patients with overall longer SWS experienced more SWS episodes that ended with movement (t = 5.64; p = 0.001). No other variable was related to the proportion of SWS that ended with movement, including no epilepsy-related variable. A small sample (n = 4) of patients taking Sertraline experienced no SWS that ended with movement, which was significant compared to all other patients (t = 8.00; p < 0.001) and to n = 35 patients who did not take any medication (t = 4.22; p < 0.001). While this result was based on a small subsample and must be interpreted with caution, it warrants replication in a larger sample with and without seizures to further elucidate the role of the movement termination of SWS and its potential to serve as a biomarker for sleep continuity and for medication effects on sleep.

The effects of slow wave sleep characteristics on semantic, episodic, and procedural memory in people with epilepsy

Slow wave sleep (SWS) is highly relevant for verbal and non-verbal/spatial memory in healthy individuals, but also in people with epilepsy. However, contradictory findings exist regarding the effect of seizures on overnight memory retention, particularly relating to procedural and non-verbal memory, and thorough examination of episodic memory retention with ecologically valid tests is missing. This research explores the interaction of SWS duration with epilepsy-relevant factors, as well as the relation of spectral characteristics of SWS on overnight retention of procedural, verbal, and episodic memory. In an epilepsy monitoring unit, epilepsy patients (N = 40) underwent learning, immediate and 12 h delayed testing of memory retention for a fingertapping task (procedural memory), a word-pair task (verbal memory), and an innovative virtual reality task (episodic memory). We used multiple linear regression to examine the impact of SWS duration, spectral characteristics of SWS, seizure occurrence, medication, depression, seizure type, gender, and epilepsy duration on overnight memory retention. Results indicated that none of the candidate variables significantly predicted overnight changes for procedural memory performance. For verbal memory, the occurrence of tonic-clonic seizures negatively impacted memory retention and higher psychoactive medication load showed a tendency for lower verbal memory retention. Episodic memory was significantly impacted by epilepsy duration, displaying a potential nonlinear impact with a longer duration than 10 years negatively affecting memory performance. Higher drug load of anti-seizure medication was by tendency related to better overnight retention of episodic memory. Contrary to expectations longer SWS duration showed a trend towards decreased episodic memory performance. Analyses on associations between memory types and EEG band power during SWS revealed lower alpha-band power in the frontal right region as significant predictor for better episodic memory retention. In conclusion, this research reveals that memory modalities are not equally affected by important epilepsy factors such as duration of epilepsy and medication, as well as SWS spectral characteristics.

Effect of Levetiracetam on Cognition: A Systematic Review and Meta-analysis of Double-Blind Randomized Placebo-Controlled Trials

BACKGROUND

Studies have suggested that levetiracetam may help improve cognitive function in patients with epilepsy. Recently, its efficacy in improving cognitive function was reported in patients with amnestic mild cognitive impairment, schizophrenia, and Alzheimer's disease. However, the specific cognitive domains affected and the degree of evidence supporting these effects remain unclear. This systematic review and meta-analysis aimed to explore the effects of levetiracetam on different cognitive domains.

METHODS

This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. We defined our inclusion criteria for the systematic review as: (1) randomized placebo-controlled trials (RCTs) involving human subjects, (2) double-blinded RCTs, and (3) RCTs evaluating the quantitative differences in cognitive function between levetiracetam and placebo. We excluded: (1) non-RCT studies, (2) open-label studies, and (3) RCTs lacking cognitive assessments for either intervention. Two authors independently searched electronic databases, including PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov, from inception until 2 July 2023. The methodological quality of the included studies was assessed using the Cochrane risk of bias tool. Meta-analytic techniques were applied to examine the impact of levetiracetam on cognitive domain tests, with Hedges' g facilitating the comparison with placebo. The domains analyzed comprised multi-domain, executive function, processing speed, working memory, verbal memory/learning (verbal ML), visuospatial memory/learning (visuospatial ML), and language. We used odds ratios to compare the incidence of treatment-emergent adverse events between the groups, including somnolence, fatigue, dizziness, headache, irritability, and cognitive adverse events.

RESULTS

A random-effects model was utilized to perform a meta-analysis of 16 RCTs including 545 participants. Compared with a placebo, levetiracetam was associated with improved executive function [Hedges'g = - 0.390, 95% confidence interval (CI) = - 0.609 to - 0.172, p < 0.001, I2 = 24.0%]. Subgroup analysis showed that levetiracetam outperformed placebo in patients without epilepsy (Hedges' g = - 0.419, 95% CI = - 0.647 to - 0.191, p < 0.001, I2 = 26.2%). Meanwhile, low-dose levetiracetam showed a moderate favorable effect over placebo (Hedges' g = -0.544, 95% CI = - 1.085 to - 0.003, p = 0.049, I2 = 65.3%). In patients without epilepsy, low-dose levetiracetam was associated with improved executive function (Hedges'g = - 0.544, 95% CI = - 1.085 to - 0.003, p = 0.049, I2 = 65.3%). Concurrently, levetiracetam was associated with more frequent somnolence than a placebo (odds ratio = 4.654, 95% CI = 1.533 to 14.124, p = 0.007, I2 = 32.9%). Potential publication bias was observed in the executive function domain.

CONCLUSIONS

This exploratory study suggests that levetiracetam might improve executive function in specific populations. However, the diversity in study populations and potential publication bias warrant caution.

Unmet needs in epileptic encephalopathy with spike-and-wave activation in sleep: A systematic review

INTRODUCTION

Developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep (D/EE-SWAS), also referred to as electrical status epilepticus during sleep (ESES) or epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS or EE-CSWS), is a spectrum of rare childhood epileptic encephalopathies that can lead to long-term cognitive impairment. Despite the importance of early diagnosis and intervention for D/EE-SWAS, there is a paucity of well-controlled clinical trial data to inform treatment, and no approved treatments are available. To assess correlations between diagnosis, treatment, and outcomes in D/EE-SWAS, we carried out a systematic review of the literature.

METHODS

In August 2020, we conducted comprehensive database searches using search terms including "electrical status epilepticus," "ESES," "CSWS," and "Landau-Kleffner syndrome." Two or more independent reviewers screened titles, abstracts, and full-text articles for those that met the following criteria: prospective studies (randomized controlled trials [RCTs] or open-label trials), retrospective studies (drug evaluations or observational studies/chart reviews), and case series with ≥ 10 participants. Both interventional and non-interventional studies were included (i.e., drug intervention was not an inclusion criterion). Articles published before 2012, review articles, animal studies, and studies of surgical or dietary interventions were excluded. Standardized data extraction templates were used to capture data on study design, patient characteristics, interventions, and outcomes from each of the selected publications. Study quality was assessed using the Cochrane Risk of Bias Tool for RCTs and the Newcastle-Ottawa Scale (NOS) or the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for retrospective, observational studies.

RESULTS

A total of 34 studies were included for full data extraction, most of which were uncontrolled and observational. Interpretation of study outcomes was limited by small study populations, variability in inclusion criteria, and inconsistency in methods of assessment and reporting of outcomes, which resulted in large heterogeneity in patients and their presenting symptoms. Despite these limitations, some patterns could be discerned. Several studies found that longer duration of ESES and younger age at onset were correlated with more severe language and cognitive deficits. In addition, several studies reported an association between improvement in cognitive outcomes and reduction in electroencephalogram (EEG) abnormalities and/or seizure frequency. In the 16 prospective or retrospective studies that evaluated drug treatments (e.g., antiseizure medications, corticosteroids, and high-dose diazepam), there was some improvement in EEG, seizure, and/or cognitive outcomes, although the specific outcomes and rates of improvement reported varied from study to study.

CONCLUSION

Long-term cognitive deficits remain common in D/EE-SWAS, and data gaps exist in the literature that preclude an evidence-based approach to managing this complex epilepsy indication. Early intervention with more effective medications is needed to optimize long-term outcomes. Sufficiently powered, randomized, double-blind, controlled trials with standardized methods and predefined primary and secondary outcomes are needed.

Preliminary evidence of a relationship between sleep spindles and treatment response in epileptic encephalopathy

OBJECTIVE

Epileptic encephalopathy with spike-wave activation in sleep (EE-SWAS) is a challenging neurodevelopmental disease characterized by abundant epileptiform spikes during non-rapid eye movement (NREM) sleep accompanied by cognitive dysfunction. The mechanism of cognitive dysfunction is unknown, but treatment with high-dose diazepam may improve symptoms. Spike rate does not predict treatment response, but spikes may disrupt sleep spindles. We hypothesized that in patients with EE-SWAS: (1) spikes and spindles would be anti-correlated, (2) high-dose diazepam would increase spindles and decrease spikes, and (3) spindle response would be greater in those with cognitive improvement.

METHODS

Consecutive EE-SWAS patients treated with high-dose diazepam that met the criteria were included. Using a validated automated spindle detector, spindle rate, duration, and percentage were computed in pre- and post-treatment NREM sleep. Spikes were quantified using a validated automated spike detector. The cognitive response was determined from a chart review.

RESULTS

Spindle rate was anti-correlated with the spike rate in the channel with the maximal spike rate (p = 0.002) and averaged across all channels (p = 0.0005). Spindle rate, duration, and percentage each increased, and spike rate decreased, after high-dose diazepam treatment (p ≤ 2e-5, all tests). Spindle rate, duration, and percentage (p ≤ 0.004, all tests) were increased in patients with cognitive improvement after treatment, but not those without. Changes in spindle rate but not changes in spike rate distinguished between groups.

INTERPRETATION

These findings confirm thalamocortical disruption in EE-SWAS, identify a mechanism through which benzodiazepines may support cognitive recovery, and introduce sleep spindles as a promising mechanistic biomarker to detect treatment response in severe epileptic encephalopathies.

Preliminary evidence of a relationship between sleep spindles and treatment response in epileptic encephalopathy

Objective

Epileptic encephalopathy with spike wave activation in sleep (EE-SWAS) is a challenging neurodevelopmental disease characterized by abundant epileptiform spikes during non-rapid eye movement (NREM) sleep accompanied by cognitive dysfunction. The mechanism of cognitive dysfunction is unknown, but treatment with high-dose diazepam may improve symptoms. Spike rate does not predict treatment response, but spikes may disrupt sleep spindles. We hypothesized that in patients with EE-SWAS: 1) spikes and spindles would be anticorrelated, 2) high-dose diazepam would increase spindles and decrease spikes, and 3) spindle response would be greater in those with cognitive improvement.

Methods

Consecutive EE-SWAS patients treated with high-dose diazepam that met criteria were included. Using a validated automated spindle detector, spindle rate, duration, and percentage were computed in pre- and post-treatment NREM sleep. Spikes were quantified using a validated automated spike detector. Cognitive response was determined from chart review.

Results

Spindle rate was anticorrelated with spike rate in the channel with the maximal spike rate ( p =0.002) and averaged across all channels ( p =0.0005). Spindle rate, duration, and percentage each increased, and spike rate decreased, after high-dose diazepam treatment ( p≤ 2e-5, all tests). Spindle rate, duration, and percentage ( p ≤0.004, all tests) were increased in patients with cognitive improvement after treatment, but not those without. Changes in spike rate did not distinguish between groups.

Interpretation

These findings confirm thalamocortical disruption in EE-SWAS, identify a mechanism through which benzodiazepines may support cognitive recovery, and introduce sleep spindles as a promising mechanistic biomarker to detect treatment response in severe epileptic encephalopathies.

Does epileptic activity impair sleep-related memory consolidation in epilepsy? A critical and systematic review

STUDY OBJECTIVES

People with epilepsy often complain about disturbed sleep and cognitive impairment. Beyond seizures, the occurrence of interictal epileptic activity during sleep is also increasingly recognized to negatively impact cognitive functioning, including memory processes. The aim of this study was to critically review the effect of interictal epileptic activity on sleep-related memory consolidation.

METHODS

PubMed and PsychINFO databases were systematically searched to identify experimental studies that investigated sleep-related memory consolidation and the relationships between sleep-related epileptic activity and memory in adults and children with epilepsy. This review also highlights hypotheses regarding the potential pathophysiological mechanisms.

RESULTS

A total of 261 studies were identified; 27 of these met selection criteria. Only 13 studies prospectively assessed the effect of sleep on memory in epilepsy. Most studies reported no alteration of sleep-related memory consolidation in patients, with either similar retention levels following a period containing sleep (n = 5) or improved memory performance postsleep (n = 4). Two studies in children with epilepsy found impaired sleep-related memory consolidation. Ten studies, of which 6 were in childhood epilepsy syndromes, reported a debilitating effect of sleep-related epileptic activity on memory functioning.

CONCLUSIONS

Conclusions from existing studies were hampered by small sample sizes, heterogeneous patient groups, and variations in memory assessment techniques. Overall, results to date preclude any definitive conclusions on the alteration of sleep-related memory consolidation in epilepsy. We discuss methodological considerations specific to people with epilepsy and provide suggestions on how to best investigate the relationship between epileptic activity, sleep, and memory consolidation in future studies.

CITATION

Latreille V, Schiller K, Peter-Derex L, Frauscher B. Does epilepticimpair sleep-related memory consolidation in epilepsy? A critical and systematic review. J Clin Sleep Med. 2022;18(10):2481-2495.

Electroencephalographic changes in purified pharmaceutical cannabidiol therapy

OBJECTIVE

Evaluate electroencephalographic changes in patients receiving purified pharmaceutical cannabidiol (CBD).

METHODS

A total of 104 EEG studies from 52 patients with pediatric-onset refractory epilepsy, who were enrolled in the FDA-approved expanded access investigational new drug program, were retrospectively analyzed for electroencephalographic changes in the background, interictal epileptiform discharges (IEDs), ictal findings, and sleep architecture after CBD treatment.

RESULTS

Patients were between 18 months and 52 years of age. After CBD treatment, 88.4% (46/52) of patients had EEG changes. Eighty-nine percent of these patients had changes in their background, 74% in IEDs, 46% in ictal findings, and 17% in sleep architecture. Seven out of 52 patients had modified hypsarrhythmia on their pre-treatment EEG. The pattern resolved in 2/7 patients (29%), diminished in prevalence in 4/7 (57%) subjects, and remained unchanged in 1/7 (14%) cases. Electrographic improvement was seen in 70% (32/46) of the patients, and worsening in 7% (3/46) of the cases. At the post-CBD EEG, 83% had a reduction in the frequency of the most predominant seizure type, and 25% reported subjective cognitive improvement. Of these patients, 88% (p = 0.09) and 92% (p = 0.45) had corresponding EEG changes, respectively.

CONCLUSION

Our results revealed electrographic changes in association with the CBD treatment. Despite these changes, a substantial association between specific electrographic findings and clinical outcomes was not established.

Diazepam induced sleep spindle increase correlates with cognitive recovery in a child with epileptic encephalopathy

BACKGROUND

Continuous spike and wave of sleep with encephalopathy (CSWS) is a rare and severe developmental electroclinical epileptic encephalopathy characterized by seizures, abundant sleep activated interictal epileptiform discharges, and cognitive regression or deceleration of expected cognitive growth. The cause of the cognitive symptoms is unknown, and efforts to link epileptiform activity to cognitive function have been unrevealing. Converging lines of evidence implicate thalamocortical circuits in these disorders. Sleep spindles are generated and propagated by the same thalamocortical circuits that can generate spikes and, in healthy sleep, support memory consolidation. As such, sleep spindle deficits may provide a physiologically relevant mechanistic biomarker for cognitive dysfunction in epileptic encephalopathies.

CASE PRESENTATION

We describe the longitudinal course of a child with CSWS with initial cognitive regression followed by dramatic cognitive improvement after treatment. Using validated automated detection algorithms, we analyzed electroencephalograms for epileptiform discharges and sleep spindles alongside contemporaneous neuropsychological evaluations over the course of the patient's disease. We found that sleep spindles increased dramatically with high-dose diazepam treatment, corresponding with marked improvements in cognitive performance. We also found that the sleep spindle rate was anticorrelated to spike rate, consistent with a competitively shared underlying thalamocortical circuitry.

CONCLUSIONS

Epileptic encephalopathies are challenging electroclinical syndromes characterized by combined seizures and a deceleration or regression in cognitive skills over childhood. This report identifies thalamocortical circuit dysfunction in a case of epileptic encephalopathy and motivates future investigations of sleep spindles as a biomarker of cognitive function and a potential therapeutic target in this challenging disease.

Focal Sleep Spindle Deficits Reveal Focal Thalamocortical Dysfunction and Predict Cognitive Deficits in Sleep Activated Developmental Epilepsy

Childhood epilepsy with centrotemporal spikes (CECTS) is the most common focal epilepsy syndrome, yet the cause of this disease remains unknown. Now recognized as a mild epileptic encephalopathy, children exhibit sleep-activated focal epileptiform discharges and cognitive difficulties during the active phase of the disease. The association between the abnormal electrophysiology and sleep suggests disruption to thalamocortical circuits. Thalamocortical circuit dysfunction resulting in pathologic epileptiform activity could hinder the production of sleep spindles, a brain rhythm essential for memory processes. Despite this pathophysiologic connection, the relationship between spindles and cognitive symptoms in epileptic encephalopathies has not been previously evaluated. A significant challenge limiting such work has been the poor performance of available automated spindle detection methods in the setting of sharp activities, such as epileptic spikes. Here, we validate a robust new method to accurately measure sleep spindles in patients with epilepsy. We then apply this detector to a prospective cohort of male and female children with CECTS with combined high-density EEGs during sleep and cognitive testing at varying time points of disease. We show that: (1) children have a transient, focal deficit in spindles during the symptomatic phase of disease; (2) spindle rate anticorrelates with spike rate; and (3) spindle rate, but not spike rate, predicts performance on cognitive tasks. These findings demonstrate focal thalamocortical circuit dysfunction and provide a pathophysiological explanation for the shared seizures and cognitive symptoms in CECTS. Further, this work identifies sleep spindles as a potential treatment target of cognitive dysfunction in this common epileptic encephalopathy.SIGNIFICANCE STATEMENT Childhood epilepsy with centrotemporal spikes is the most common idiopathic focal epilepsy syndrome, characterized by self-limited focal seizures and cognitive symptoms. Here, we provide the first evidence that focal thalamocortical circuit dysfunction underlies the shared seizures and cognitive dysfunction observed. In doing so, we identify sleep spindles as a mechanistic biomarker, and potential treatment target, of cognitive dysfunction in this common developmental epilepsy and provide a novel method to reliably quantify spindles in brain recordings from patients with epilepsy.

Response to clobazam in continuous spike-wave during sleep

AIM

To evaluate the efficacy of clobazam treatment in reducing epileptiform discharges and modifying neuropsychological function in continuous spike-wave during slow wave sleep.

METHOD

We performed a prospective clinical trial in patients with continuous spike-wave during sleep aged 4 to 10 years. Patients underwent neuropsychological assessment and overnight electroencephalographic monitoring before treatment, and subsequent repeat assessment and overnight electroencephalographic monitoring 3 months after treatment. Treatment consisted of 1mg/kg clobazam up to a maximum dose of 30mg during the first night, followed by 0.5mg/kg nightly for 3 months.

RESULTS

Nine patients completed the study and had pre- and post-neuropsychological evaluation. There was a qualitative reduction in median (p₂₅ -p₇₅ ) spike percentage after 3 months (72.2 [68.0-75.8] vs 32.7 [4.7-81.7]). There were no marked changes in median (p₂₅ -p₇₅ ) IQ comparing pre- and post-clobazam treatment (80.0 [74.0-88.0] vs 80.0 [67.0-89.0]). There was a qualitative increase in Verbal IQ (83.0 [69.0-92.0] vs 95.0 [83.0-99.0]) and a qualitative decrease in Non-verbal IQ (84.0 [74.0-87.0] vs 71.0 [60.0-84.0]).

INTERPRETATION

Qualitative improvements in epileptiform activity and cognition occurred in patients treated with clobazam for 3 months and the relationship between epileptiform activity and cognitive outcome should be studied in larger studies.

WHAT THIS PAPER ADDS

Verbal IQ in patients with continuous spike-wave during sleep improved following short-term treatment with clobazam. Other neuropsychological improvements were observed, but varied by patient. Cognitive improvement was observed despite some worsening of epileptiform discharges.

Watch the language! Language and linguistic-cognitive abilities in children with nocturnal epileptiform activity

We studied the language and linguistic-cognitive abilities of a group of children with nocturnal epileptiform activity (NEA; N=33) who were hospitalized at a tertiary epilepsy hospital. The children were compared with two groups: one age- and gender-matched group (N=33) and one group matched on language ability (vocabulary) and gender (N=66). We also examined how NEA-related variables affected language abilities. Overall, the children with NEA showed delayed language abilities and a trend for specific difficulties with phonology and naming speed. We did not find firm evidence that the amount of NEA, the use of antiepileptic drugs (AEDs), and the lateralization and localization of NEA had an effect on language. However, we found that children with right-lateralized epileptiform activity seemed to have specific difficulties with naming speed. Additionally, our results indicated that NEA located in the centrotemporal areas particularly affected phonology and orthographic skills.

Pharmacological interventions for epilepsy in people with intellectual disabilities

BACKGROUND

The prevalence of epilepsy among people with intellectual disabilities is much higher than in the general population. Seizures in this population are often complex and refractory to treatment and antiepileptic medication may have a profound effect upon behaviour (Kerr 1997).This is an updated version of a Cochrane Review first published in Issue 3, 2007.

OBJECTIVES

To assess the data available from randomised controlled trials (RCTs) of the efficacy of antiepileptic drug (AED) interventions in people with epilepsy and intellectual disabilities.

SEARCH METHODS

For the latest update of this review, we searched the Cochrane Epilepsy Group Specialised Register (2 September 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO) (2 September 2014), MEDLINE (Ovid, 1946 to 3 September 2014) and PsycINFO (EBSCOhost, 1887 to 3 September 2014).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials (RCTs) of pharmacological interventions for people with epilepsy and a learning disability.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information. We assessed epilepsy/seizure, behavioural and cognitive outcomes, as well as quality of life and adverse effects.

MAIN RESULTS

We included 14 RCTs (1116 participants) in the present review. Data were heterogenous and a descriptive analysis is presented. In the majority of cases where antiepileptic drugs (AEDs) were trialled in this population, we found moderate reductions in seizure frequency in that there was a significantly higher rate of responders (reduction of 50% or more) in the treatment group compared with the placebo group, with some studies reporting a higher incidence of seizure freedom in the treatment group. In general, AEDs that are proven to be effective in the general epilepsy population are also effective for refractory epilepsy in people with intellectual disability. It is not possible to comment on the relative efficacy of medications, making clinical decisions difficult.In trial settings patients continued on treatment in the majority of cases. Placebo groups often experienced fewer adverse events. Where adverse events were experienced they appeared similar to those in the general population. The methods by which adverse events were recorded and reported appeared to be inconsistent, resulting in very large variation between studies. This is problematic as clinically relevant interpretation of these findings is limited.The quality of evidence provided in the present review is low to moderate. Additionally the majority of studies lacked or used non-reliable measures of behavioural exacerbation. However, where measured, little obvious impact on behaviour was seen in terms of behaviour disorder.

AUTHORS' CONCLUSIONS

This review broadly supports the use of AEDs to reduce seizure frequency in people with refractory epilepsy and intellectual disability. The evidence suggests that adverse events are similar to those in the general population and that behavioural adverse events leading to discontinuation are rare; however, other adverse effects are under-researched.

Long-term response to high-dose diazepam treatment in continuous spikes and waves during sleep

BACKGROUND

This study evaluated whether the reduction in epileptiform activity after treatment with high-dose diazepam in continuous spikes and waves during sleep persists over time.

PATIENTS

Patients aged 1 to 21 years with continuous spikes and waves during sleep who received high-dose nocturnal diazepam and who had electroencephalogram follow-up were included. Twenty-nine patients met the inclusion criteria and underwent a total of 48 high-dose diazepam treatment cycles.

RESULTS

An overnight reduction of the spike wave percentage of at least 25% (i.e., 75-50%) occurred in 29 cycles (20 patients), and persisted within 6 months in 16 of 29 cycles (12 patients), but returned to baseline in three of 29 cycles (three patients). An overnight reduction of at least 50% (i.e., 75-25%) occurred in 15 cycles (13 patients), and persisted within 6 months in eight of 15 cycles (eight patients), but returned to baseline in three cycles (three patients). Twenty of 29 cycles that responded in the short term had persistent response on follow-up. Thirteen cycles of treatment were associated with mild side effects that did not recur with repeated treatment cycles.

CONCLUSIONS

Treatment with high-dose diazepam reduced epileptiform activity in continuous spikes and waves during sleep in the short term, and improvement persisted for several months in most cycles. Short-term response predicted persistence of this effect on subsequent follow-up.