Yield and risk associated with prolonged presurgical video-EEG monitoring: a systematic review

OBJECTIVE: Presurgical long-term video-EEG monitoring (LT-VEEG) is an important part of the presurgical evaluation in patients with focal epilepsy. Multiple seizures need to be recorded, often in limited time and with the need to taper anti-seizure medication (ASM). The aim of this study was to systematically study the yield – in terms of success – and risks associated with presurgical LT-VEEG, and to identify all previously reported contributing variables. METHODS: A systematic review of the databases of PubMed Medline, Embase, Cochrane Central, and the Cochrane Database of Systematic Reviews were searched following the Preferred Reporting Items for Systematic Reviews (PRISMA) guideline. Publications about presurgical LT-VEEG reporting on variables contributing to yield and risk were included. Study characteristics of all included studies were extracted following a standardized template. Within these articles, studies presenting multivariable analyses of factors contributing to the risk of adverse events or the success of LT-VEEG were identified. RESULTS: We found 36 articles reporting on LT-VEEG, including 4,703 presurgical patients, both children and adults. Presurgical LT-VEEG monitoring led to an average yield of 85%. Adverse events occurred with an averaged total event rate of 17%, but the type of included events was variable among studies. Factors reported to independently contribute to successful LT-VEEG were: baseline seizure frequency, a shorter interval from the most recent seizure, extratemporal lobe epilepsy, and no requirement for ASM reduction. Factors independently contributing to the occurrence of adverse events were: ASM tapering, a history of status epilepticus, a history of focal to bilateral tonic-clonic seizures, psychiatric comorbidity, and ASM taper rate. SIGNIFICANCE: This study reveals that the data on factors contributing to yield and risk of adverse events is significant and variable, and often reported with inadequate statistics. Future research is warranted to develop guidelines for ASM withdrawal during presurgical video-EEG monitoring, taking predefined factors for success and risks of adverse events into account

The relation between cortisol and functional connectivity in people with and without stress-sensitive epilepsy

OBJECTIVE: The most common reported seizure-precipitant is stress. We recently showed a biologic basis for stress sensitivity of seizures: cortisol levels in people with stress-sensitive epilepsy correlated with focal interictal epileptiform discharges (IEDs) on electroencephalography (EEG). Here we aimed to determine whether the effect of cortisol on the epileptic brain is global or focal, and whether cortisol affects all brains or just those of stress-sensitive people. Because epilepsy is associated with changes in functional brain connectivity, we studied the relationship between cortisol and changes in global and focal (node-centered) functional connectivity measures for individuals with stress-sensitive and non-stress-sensitive epilepsy. METHODS: Seventeen people with epilepsy underwent long-term (>24 h) EEG recording. During the first 5 h after waking, saliva was collected every 15 min for cortisol measurements. Theta-band functional connectivity was assessed for every 15 min of the recording. We calculated the average phase-lag index (PLI) between all channels as a measure of global functional connectivity. We used network Strength, the averaged PLI per channel, as focal functional connectivity measure. We correlated cortisol, global, and focal functional connectivity (Strength) with IED frequency using linear mixed models. Analyses were split for people with and without stress-sensitivity of seizures. RESULTS: Cortisol was negatively correlated with global functional connectivity in people with stress-sensitive seizures (estimate -0.0020; P < .01), whereas not in those without stress-sensitivity (estimate -0.0003; P = .46). This relationship occurred irrespective of the presence of IEDs on a channel (channels without IEDs and stress-sensitivity: estimate -0.0019; P < .01, non-stress-sensitive -0.0003; P = .41). Global and focal functional connectivity were negatively correlated with IED frequency, irrespective of stress sensitivity of seizures or channel type. SIGNIFICANCE: People with stress-sensitive epilepsy have a whole-brain neuronal response to cortisol that is different from that of people with non-stress-sensitive epilepsy. This offers a basis for understanding seizure genesis in stress-sensitive epilepsy, which might require a different treatment approach

Diagnostic and prognostic value of noninvasive long-term video-electroencephalographic monitoring in epilepsy surgery: A systematic review and meta-analysis from the E-PILEPSY consortium

OBJECTIVE: The European Union–funded E‐PILEPSY network (now continuing within the European Reference Network for rare and complex epilepsies [EpiCARE]) aims to harmonize and optimize presurgical diagnostic procedures by creating and implementing evidence‐based guidelines across Europe. The present study evaluates the current evidence on the diagnostic accuracy of long‐term video‐electroencephalographic monitoring (LTM) in identifying the epileptogenic zone in epilepsy surgery candidates. METHODS: MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov were searched for relevant articles. First, we used random‐effects meta‐analytical models to calculate pooled estimates of sensitivity and specificity with respect to postsurgical seizure freedom. In a second phase, we analyzed individual patient data in an exploratory fashion, assessing diagnostic accuracy within lesional and nonlesional temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE) patients. We also evaluated seizure freedom rate in the presence of “localizing” or “nonlocalizing” LTM within each group. The quality of evidence was assessed using the QUADAS‐2 tool and the GRADE approach. RESULTS: Ninety‐four studies were eligible. Forty‐four were included in sensitivity meta‐analysis and 34 in specificity meta‐analysis. Pooled sensitivity was 0.70 (95% confidence interval [CI] = 0.60‐0.80) and specificity was 0.40 (95% CI = 0.27‐0.54). Subgroup analysis was based on individual data of 534 patients (41% men). In lesional TLE patients, sensitivity was 0.85 (95% CI = 0.81‐0.89) and specificity was −0.19 (95% CI = 0.13‐0.28). In lesional ETLE patients, a sensitivity of 0.47 (95% CI = 0.36‐0.58) and specificity of 0.35 (95% CI = 0.21‐0.53) were observed. In lesional TLE, if LTM was localizing and concordant with resection site, the seizure freedom rate was 247 of 333 (74%), whereas in lesional ETLE it was 34 of 56 (61%). The quality of evidence was assigned as “very low.” SIGNIFICANCE: Long‐term video‐electroencephalographic monitoring is associated with moderate sensitivity and low specificity in identification of the epileptogenic zone. Sensitivity is remarkably higher in lesional TLE compared to lesional ETLE. Substantial heterogeneity across the studies indicates the need for improved design and quality of reporting

A survey of the European Reference Network EpiCARE on clinical practice for selected rare epilepsies

Objective: Clinical care of rare and complex epilepsies is challenging, because evidence‐based treatment guidelines are scarce, the experience of many physicians is limited, and interdisciplinary treatment of comorbidities is required. The pathomechanisms of rare epilepsies are, however, increasingly understood, which potentially fosters novel targeted therapies. The objectives of our survey were to obtain an overview of the clinical practice in European tertiary epilepsy centers treating patients with 5 arbitrarily selected rare epilepsies and to get an estimate of potentially available patients for future studies. / Methods: Members of the European Reference Network for rare and complex epilepsies (EpiCARE) were invited to participate in a web‐based survey on clinical practice of patients with Dravet syndrome, tuberous sclerosis complex (TSC), autoimmune encephalitis, and progressive myoclonic epilepsies including Unverricht Lundborg and Unverricht‐like diseases. A consensus‐based questionnaire was generated for each disease. / Results: Twenty‐six of 30 invited epilepsy centers participated. Cohorts were present in most responding centers for TSC (87%), Dravet syndrome (85%), and autoimmune encephalitis (71%). Patients with TSC and Dravet syndrome represented the largest cohorts in these centers. The antiseizure drug treatments were rather consistent across the centers especially with regard to Dravet syndrome, infantile spasms in TSC, and Unverricht Lundborg / Unverricht‐like disease. Available, widely used targeted therapies included everolimus in TSC and immunosuppressive therapies in autoimmune encephalitis. Screening for comorbidities was routinely done, but specific treatment protocols were lacking in most centers. / Significance: The survey summarizes the current clinical practice for selected rare epilepsies in tertiary European epilepsy centers and demonstrates consistency as well as heterogeneity in the treatment, underscoring the need for controlled trials and recommendations. The survey also provides estimates for potential participants of clinical trials recruited via EpiCARE, emphasizing the great potential of Reference Networks for future studies to evaluate new targeted therapies and to identify novel biomarkers

Refractory juvenile myoclonic epilepsy: A meta-analysis of prevalence and risk factors

BACKGROUND: Juvenile myoclonic epilepsy (JME) is a common epilepsy syndrome for which treatment response is generally assumed to be good. We aimed to determine the prevalence and prognostic risk factors for refractoriness of JME. METHODS: We systematically searched PubMed and Embase and included 43 eligible studies, reporting seizure outcome after anti-epileptic drug treatment JME cohorts. We defined refractory JME as persistence of any seizure despite AED treatment and performed a random-effects meta-analysis to assess the prevalence of refractory JME and of seizure-recurrence after AED withdrawal in individuals with well-controlled seizures. Studies reporting potential prognostic risk factors in relation to seizure outcome were included for subsequent meta-analysis of risk factors for refractoriness. RESULTS: Overall 35% (95%CI: 29 - 41%) of individuals (n=3311) were refractory. There was marked heterogeneity between studies. Seizures recurred in 78% (95%-CI: 52-94%) of individuals who attempted to withdraw treatment after a period of seizure-freedom (n=246). Seizure outcome by publication year suggests that prognosis has not improved over time. Meta-analysis suggested six variables as prognostic factors for refractoriness: having three seizure types, absence seizures, psychiatric comorbidities, earlier age at seizure onset, history of childhood absence epilepsy, and having praxis-induced seizures. CONCLUSION: A third of people with JME were refractory, which is more prevalent than expected. Risk factors were identified and can be used to guide treatment and counselling of people with JME. This article is protected by copyright. All rights reserved

Individualized prediction of seizure relapse and outcomes following antiepileptic drug withdrawal after pediatric epilepsy surgery

The objective of this study was to create a clinically useful tool for individualized prediction of seizure outcomes following antiepileptic drug withdrawal after pediatric epilepsy surgery. We used data from the European retrospective TimeToStop study, which included 766 children from 15 centers, to perform a proportional hazard regression analysis. The 2 outcome measures were seizure recurrence and seizure freedom in the last year of follow-up. Prognostic factors were identified through systematic review of the literature. The strongest predictors for each outcome were selected through backward selection, after which nomograms were created. The final models included 3 to 5 factors per model. Discrimination in terms of adjusted concordance statistic was 0.68 (95% confidence interval [CI] 0.67-0.69) for predicting seizure recurrence and 0.73 (95% CI 0.72-0.75) for predicting eventual seizure freedom. An online prediction tool is provided on www.epilepsypredictiontools.info/ttswithdrawal. The presented models can improve counseling of patients and parents regarding postoperative antiepileptic drug policies, by estimating individualized risks of seizure recurrence and eventual outcome

Parents experience problems in psychological and family functioning two to four years after their child's epilepsy surgery

Objectives: The objective of this study was to explore whether parents experience problems in their own psychological wellbeing and their family functioning two to four years after their child's epilepsy surgery and whether these problems are associated with epilepsy variables, demographic and cognitive variables, and parent-observed behavior problems of the child. Methods: Of the 65 approached families, parents of 31 children participated by completing the Brief Symptom Inventory (BSI), the Family Questionnaire, and the Child Behavior Checklist (CBCL). High scores indicating clinically relevant problems were reported and called ‘problem scores’. Correlations between results of questionnaires and demographic and illness variables (abstracted from medical files) were computed for fathers and mothers separately. By comparing the group with at least one problem score with the group without problem scores, risk factors for parent-perceived problems in their own psychological functioning and in family functioning were explored. Results: Thirty percent of the mothers had problem scores on hostility and on communication within their family. Only a few fathers obtained problem scores, most of these pertaining to their family's organization. Not one parent had a problem score regarding their partner relationship. Many parents had problem scores on behavior problems in their child. Brain area of surgery was the only epilepsy variable related to parents’ wellbeing and family functioning, with lowest problem scores for the hemispherotomy group. Scores on behavior problems in the child were also lowest for children after hemispherotomy and for those who had achieved freedom of seizures and antiepileptic drugs (AEDs). Fathers of older children experienced more problems than those of young children. Conclusions: Parent's wellbeing and family functioning cannot be understood from epilepsy or epilepsy surgery variables only but are related to the child's age and behavior. Having epilepsy is associated with emotional and behavior problems and limits children in developing age-appropriate self-dependence. These problems are not resolved after achieving seizure freedom and have great influence on the family. Professionals should set realistic expectations of epilepsy surgery and should assess, acknowledge, and follow up problems of parental psychological wellbeing and family functioning, regardless of the outcome

Parents experience problems in psychological and family functioning two to four years after their child's epilepsy surgery

Objectives: The objective of this study was to explore whether parents experience problems in their own psychological wellbeing and their family functioning two to four years after their child's epilepsy surgery and whether these problems are associated with epilepsy variables, demographic and cognitive variables, and parent-observed behavior problems of the child. Methods: Of the 65 approached families, parents of 31 children participated by completing the Brief Symptom Inventory (BSI), the Family Questionnaire, and the Child Behavior Checklist (CBCL). High scores indicating clinically relevant problems were reported and called ‘problem scores’. Correlations between results of questionnaires and demographic and illness variables (abstracted from medical files) were computed for fathers and mothers separately. By comparing the group with at least one problem score with the group without problem scores, risk factors for parent-perceived problems in their own psychological functioning and in family functioning were explored. Results: Thirty percent of the mothers had problem scores on hostility and on communication within their family. Only a few fathers obtained problem scores, most of these pertaining to their family's organization. Not one parent had a problem score regarding their partner relationship. Many parents had problem scores on behavior problems in their child. Brain area of surgery was the only epilepsy variable related to parents’ wellbeing and family functioning, with lowest problem scores for the hemispherotomy group. Scores on behavior problems in the child were also lowest for children after hemispherotomy and for those who had achieved freedom of seizures and antiepileptic drugs (AEDs). Fathers of older children experienced more problems than those of young children. Conclusions: Parent's wellbeing and family functioning cannot be understood from epilepsy or epilepsy surgery variables only but are related to the child's age and behavior. Having epilepsy is associated with emotional and behavior problems and limits children in developing age-appropriate self-dependence. These problems are not resolved after achieving seizure freedom and have great influence on the family. Professionals should set realistic expectations of epilepsy surgery and should assess, acknowledge, and follow up problems of parental psychological wellbeing and family functioning, regardless of the outcome