Reliability of seizure classification using a semistructured interview

Familial aggregation of seizure outcomes in four familial epilepsy cohorts

OBJECTIVE

To assess the possible effects of genetics on seizure outcome by estimating the familial aggregation of three outcome measures: seizure remission, history of ≥4 tonic-clonic seizures, and seizure control for individuals taking antiseizure medication.

METHODS

We analyzed families containing multiple persons with epilepsy in four previously collected retrospective cohorts. Seizure remission was defined as being 5 and 10 years seizure-free at last observation. Total number of tonic-clonic seizures was dichotomized at <4 and ≥4 seizures. Seizure control in patients taking antiseizure medication was defined as no seizures for 1, 2, and 3 years. We used Bayesian generalized linear mixed-effects model (GLMM) to estimate the intraclass correlation coefficient (ICC) of the family-specific random effect, controlling for epilepsy type, age at epilepsy onset, and age at last data collection as fixed effects. We analyzed each cohort separately and performed meta-analysis using GLMMs.

RESULTS

The combined cohorts included 3644 individuals with epilepsy from 1463 families. A history of ≥4 tonic-clonic seizures showed strong familial aggregation in three separate cohorts and meta-analysis (ICC .28, 95% confidence interval [CI] .21-.35, Bayes factor 8 × 1016). Meta-analyses did not reveal significant familial aggregation of seizure remission (ICC .08, 95% CI .01-.17, Bayes factor 1.46) or seizure control for individuals taking antiseizure medication (ICC .13, 95% CI 0-.35, Bayes factor 0.94), with heterogeneity among cohorts.

SIGNIFICANCE

A history of ≥4 tonic-clonic seizures aggregated strongly in families, suggesting a genetic influence, whereas seizure remission and seizure control for individuals taking antiseizure medications did not aggregate consistently in families. Different seizure outcomes may have different underlying biology and risk factors. These findings should inform the future molecular genetic studies of seizure outcomes.

Epilepsy and seizures in young people with 22q11.2 deletion syndrome: Prevalence and links with other neurodevelopmental disorders

OBJECTIVE

The true prevalence of epileptic seizures and epilepsy in 22q11.2 deletion syndrome (22q11.2DS) is unknown, because previous studies have relied on historical medical record review. Associations of epilepsy with other neurodevelopmental manifestations (eg, specific psychiatric diagnoses) remain unexplored.

METHODS

The primary caregivers of 108 deletion carriers (mean age 13.6 years) and 60 control siblings (mean age 13.1 years) completed a validated epilepsy screening questionnaire. A subsample (n = 44) underwent a second assessment with interview, prolonged electroencephalography (EEG), and medical record and epileptologist review. Intelligence quotient (IQ), psychopathology, and other neurodevelopmental problems were examined using neurocognitive assessment and questionnaire/interview.

RESULTS

Eleven percent (12/108) of deletion carriers had an epilepsy diagnosis (controls 0%, P = 0.004). Fifty-seven of the remaining 96 deletion carriers (59.4%) had seizures or seizurelike symptoms (controls 13.3%, 8/60, P < 0.001). A febrile seizure was reported for 24.1% (26/107) of cases (controls 0%, P < 0.001). One deletion carrier with a clinical history of epilepsy was diagnosed with an additional type of unprovoked seizure during the second assessment. One deletion carrier was newly diagnosed with epilepsy, and two more with possible nonmotor absence seizures. A positive screen on the epilepsy questionnaire was more likely in deletion carriers with lower performance IQ (odds ratio [OR] 0.96, P = 0.018), attention-deficit/hyperactivity disorder (ADHD) (OR 3.28, P = 0.021), autism symptoms (OR 3.86, P = 0.004), and indicative motor coordination disorder (OR 4.56, P = 0.021).

SIGNIFICANCE

Even when accounting for deletion carriers diagnosed with epilepsy, reports of seizures and seizurelike symptoms are common. These may be "true" epileptic seizures in some cases, which are not recognized during routine clinical care. Febrile seizures were far more common in deletion carriers compared to known population risk. A propensity for seizures in 22q11.2DS was associated with cognitive impairment, psychopathology, and motor coordination problems. Future research is required to determine whether this reflects common neurobiologic risk pathways or is a consequence of recurrent seizures.

Sodium valproate versus phenytoin monotherapy for epilepsy: an individual participant data review

BACKGROUND

Epilepsy is a common neurological condition in which abnormal electrical discharges from the brain cause recurrent unprovoked seizures. It is believed that with effective drug treatment up to 70% of individuals with active epilepsy have the potential to become seizure-free, and to go into long-term remission shortly after starting drug therapy with a single antiepileptic drug in monotherapy.Worldwide, sodium valproate and phenytoin are commonly used antiepileptic drugs for monotherapy treatment. It is generally believed that phenytoin is more effective for focal onset seizures, and that sodium pvalproate is more effective for generalised onset tonic-clonic seizures (with or without other generalised seizure types). This review is one in a series of Cochrane Reviews investigating pair-wise monotherapy comparisons. This is the latest updated version of the review first published in 2001, and updated in 2013 and 2016.

OBJECTIVES

To review the time to treatment failure, remission and first seizure of sodium valproate compared to phenytoin when used as monotherapy in people with focal onset seizures or generalised tonic-clonic seizures (with or without other generalised seizure types).

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform ICTRP on 19 February 2018. We handsearched relevant journals, contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing monotherapy with either sodium valproate or phenytoin in children or adults with focal onset seizures or generalised onset tonic-clonic seizures DATA COLLECTION AND ANALYSIS: This was an individual participant data (IPD) review. Our primary outcome was time to treatment failure and our secondary outcomes were time to first seizure post-randomisation, time to six-month, and 12-month remission, and incidence of adverse events. We used Cox proportional hazards regression models to obtain trial-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs), using the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

We included 11 trials in this review and IPD were available for 669 individuals out of 1119 eligible individuals from five out of 11 trials, 60% of the potential data. Results apply to focal onset seizures (simple, complex and secondary generalised tonic-clonic seizures), and generalised tonic-clonic seizures, but not other generalised seizure types (absence or myoclonus seizure types). For remission outcomes, a HR of less than 1 indicates an advantage for phenytoin, and for first seizure and treatment failure outcomes a HR of less than 1 indicates an advantage for sodium valproate.The main overall results were: time to treatment failure for any reason related to treatment (pooled HR adjusted for seizure type 0.88, 95% CI 0.61 to 1.27; 5 studies; 528 participants; moderate-quality evidence), time to treatment failure due to adverse events (pooled HR adjusted for seizure type 0.77, 95% CI 0.44 to 1.37; 4 studies; 418 participants; moderate-quality evidence), time to treatment failure due to lack of efficacy (pooled HR for all participants 1.16 (95% CI 0.71 to 1.89; 5 studies; 451 participants; moderate-quality evidence). These results suggest that treatment failure for any reason related to treatment and treatment failure due to adverse events may occur earlier on phenytoin compared to sodium valproate, while treatment failure due to lack of efficacy may occur earlier on sodium valproate than phenytoin; however none of these results were statistically significant.Results for time to first seizure (pooled HR adjusted for seizure type 1.08, 95% CI 0.88 to 1.33; 5 studies; 639 participants; low-quality evidence) suggest that first seizure recurrence may occur slightly earlier on sodium valproate compared to phenytoin. There were no clear differences between drugs in terms of time to 12-month remission (pooled HR adjusted for seizure type 1.02, 95% CI 0.81 to 1.28; 4 studies; 514 participants; moderate-quality evidence) and time to six-month remission (pooled HR adjusted for seizure type 1.05, 95% CI 0.86 to 1.27; 5 studies; 639 participants; moderate-quality evidence).Limited information was available regarding adverse events in the trials and we could not make comparisons between the rates of adverse events on sodium valproate and phenytoin. Some adverse events reported with both drugs were drowsiness, rash, dizziness, nausea and gastrointestinal problems. Weight gain was also reported with sodium valproate and gingival hypertrophy/hyperplasia was reported on phenytoin.The methodological quality of the included trials was generally good, however four out of the five trials providing IPD for analysis were of an open-label design, therefore all results were at risk of detection bias. There was also evidence that misclassification of seizure type may have confounded the results of this review, particularly for the outcome 'time to first seizure' and heterogeneity was present in analysis of treatment failure outcomes which could not be explained by subgroup analysis by epilepsy type or by sensitivity analysis for misclassification of seizure type. Therefore, for treatment failure outcomes we judged the quality of the evidence to be moderate to low, for 'time to first seizure' we judged the quality of the evidence to be low, and for remission outcomes we judged the quality of the evidence to be moderate.

AUTHORS' CONCLUSIONS

We have not found evidence that a significant difference exists between valproate and phenytoin for any of the outcomes examined in this review. However detection bias, classification bias and heterogeneity may have impacted on the results of this review. We did not find any outright evidence to support or refute current treatment policies. We recommend that future trials be designed to the highest quality possible with consideration of masking, choice of population, classification of seizure type, duration of follow-up, choice of outcomes and analysis, and presentation of results.

Familial aggregation of focal seizure semiology in the Epilepsy Phenome/Genome Project

OBJECTIVE

To improve phenotype definition in genetic studies of epilepsy, we assessed the familial aggregation of focal seizure types and of specific seizure symptoms within the focal epilepsies in families from the Epilepsy Phenome/Genome Project.

METHODS

We studied 302 individuals with nonacquired focal epilepsy from 149 families. Familial aggregation was assessed by logistic regression analysis of relatives' traits (dependent variable) by probands' traits (independent variable), estimating the odds ratio for each symptom in a relative given presence vs absence of the symptom in the proband.

RESULTS

In families containing multiple individuals with nonacquired focal epilepsy, we found significant evidence for familial aggregation of ictal motor, autonomic, psychic, and aphasic symptoms. Within these categories, ictal whole body posturing, diaphoresis, dyspnea, fear/anxiety, and déjà vu/jamais vu showed significant familial aggregation. Focal seizure type aggregated as well, including complex partial, simple partial, and secondarily generalized tonic-clonic seizures.

CONCLUSION

Our results provide insight into genotype-phenotype correlation in the nonacquired focal epilepsies and a framework for identifying subgroups of patients likely to share susceptibility genes.

Ictal fear: Associations with age, gender, and other experiential phenomena

PURPOSE

The aim of this study was to determine the relationship of fear to other auras and to gender and age using a large database.

METHODS

The Epilepsy Phenome/Genome Project (EPGP) is a multicenter, multicontinental cross-sectional study in which ictal symptomatology and other data were ascertained in a standardized series of questionnaires then corroborated by epilepsy specialists. Auras were classified into subgroups of symptoms, with ictal fear, panic, or anxiety as a single category.

RESULTS

Of 536 participants with focal epilepsy, 72 were coded as having ictal fear/panic/anxiety. Reviewing raw patient responses, 12 participants were deemed not to have fear, and 24 had inadequate data, leaving 36 (7%) of 512 with definite ictal fear. In univariate analyses, fear was significantly associated with auras historically considered temporal lobe in origin, including cephalic, olfactory, and visceral complaints; déjà vu; and derealization. On both univariate and multivariate stepwise analyses, fear was associated with jamais vu and auras with cardiac symptoms, dyspnea, and chest tightening. Expressive aphasia was associated with fear on univariate analysis only, but the general category of aphasias was associated with fear only in the multivariate model. There was no age or gender relationship with fear when compared to the overall population with focal epilepsy that was studied under the EPGP. Patients with ictal fear were more likely to have a right hemisphere seizure focus.

CONCLUSIONS

Ictal fear was strongly associated with other auras considered to originate from the limbic system. No relationship of fear with age or gender was observed.

Phenytoin versus valproate monotherapy for partial onset seizures and generalised onset tonic-clonic seizures: an individual participant data review

BACKGROUND

Worldwide, phenytoin and valproate are commonly used antiepileptic drugs. It is generally believed that phenytoin is more effective for partial onset seizures, and that valproate is more effective for generalised onset tonic-clonic seizures (with or without other generalised seizure types). This review is one in a series of Cochrane reviews investigating pair-wise monotherapy comparisons. This is the latest updated version of the review first published in 2001 and updated in 2013.

OBJECTIVES

To review the time to withdrawal, remission and first seizure of phenytoin compared to valproate when used as monotherapy in people with partial onset seizures or generalised tonic-clonic seizures (with or without other generalised seizure types).

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialised Register (19 May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library; 2015, Issue 4), MEDLINE (1946 to 19 May 2015), SCOPUS (19 February 2013), ClinicalTrials.gov (19 May 2015), and WHO International Clinical Trials Registry Platform ICTRP (19 May 2015). We handsearched relevant journals, contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in children or adults with partial onset seizures or generalised onset tonic-clonic seizures with a comparison of valproate monotherapy versus phenytoin monotherapy.

DATA COLLECTION AND ANALYSIS

This was an individual participant data (IPD) review. Outcomes were time to: (a) withdrawal of allocated treatment (retention time); (b) achieve 12-month remission (seizure-free period); (c) achieve six-month remission (seizure-free period); and (d) first seizure (post-randomisation). We used Cox proportional hazards regression models to obtain study-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs), and the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

IPD were available for 669 individuals out of 1119 eligible individuals from five out of 11 trials, 60% of the potential data. Results apply to partial onset seizures (simple, complex and secondary generalised tonic-clonic seizures), and generalised tonic-clonic seizures, but not other generalised seizure types (absence or myoclonus seizure types). For remission outcomes: HR > 1 indicates an advantage for phenytoin; and for first seizure and withdrawal outcomes: HR > 1 indicates an advantage for valproate.The main overall results (pooled HR adjusted for seizure type) were time to: (a) withdrawal of allocated treatment 1.09 (95% CI 0.76 to 1.55); (b) achieve 12-month remission 0.98 (95% CI 0.78 to 1.23); (c) achieve six-month remission 0.95 (95% CI 0.78 to 1.15); and (d) first seizure 0.93 (95% CI 0.75 to 1.14). The results suggest no overall difference between the drugs for these outcomes. We did not find any statistical interaction between treatment and seizure type (partial versus generalised).

AUTHORS' CONCLUSIONS

We have not found evidence that a significant difference exists between phenytoin and valproate for the outcomes examined in this review. However misclassification of seizure type may have confounded the results of this review. Results do not apply to absence or myoclonus seizure types. No outright evidence was found to support or refute current treatment policies.

Genetic effects on sleep/wake variation of seizures

OBJECTIVE

There is a complex bidirectional relationship between sleep and epilepsy. Sleep/wake timing of seizures has been investigated for several individual seizure types and syndromes, but few large-scale studies of the timing of seizures exist in people with varied epilepsy types. In addition, the genetic contributions to seizure timing have not been well studied.

METHODS

Sleep/wake timing of seizures was determined for 1,395 subjects in 546 families enrolled in the Epilepsy Phenome/Genome Project (EPGP). We examined seizure timing among subjects with different epilepsy types, seizure types, epilepsy syndromes, and localization. We also examined the familial aggregation of sleep/wake occurrence of seizures.

RESULTS

Seizures in nonacquired focal epilepsy (NAFE) were more likely to occur during sleep than seizures in generalized epilepsy (GE), for both convulsive (odds ratio [OR] 5.2, 95% confidence interval [CI] 3.59-7.52) and nonconvulsive seizures (OR 4.2, 95% CI 2.48-7.21). Seizures occurring within 1 h of awakening were more likely to occur in patients with GE than with NAFE for both convulsive (OR 2.3, 95% CI 1.54-3.39) and nonconvulsive (OR 1.7, 95% CI 1.04-2.66) seizures. Frontal onset seizures were more likely than temporal onset seizures to occur during sleep. Sleep/wake timing of seizures in first-degree relatives predicted timing of seizures in the proband.

SIGNIFICANCE

We found that sleep/wake timing of seizures is associated with both epilepsy syndrome and seizure type. In addition, we provide the first evidence for a genetic contribution to sleep/wake timing of seizures in a large group of individuals with common epilepsy syndromes.

Using a structured questionnaire improves seizure description by medical students

OBJECTIVE

The purpose of this study was to evaluate a structured questionnaire for improving a medical students' ability to identify, describe and interpret a witnessed seizure.

METHODS

Ninety two 3rd year medical students, blinded to seizure diagnosis, viewed videos of a primary generalized seizure and a complex partial seizure. Students next completed an unstructured questionnaire that asked the students to describe the seizure video recordings. The students then completed a structured questionnaire that asked the student to respond to 17 questions regarding specific features occurring during the seizures. We determined the number and types of correct responses for each questionnaire.

RESULTS

Overall, the structured questionnaire was more effective in eliciting an average of 9.25 correct responses compared to the unstructured questionnaire eliciting an average of 5.30 correct responses (p < 0.001). Additionally, 10 of the 17 seizure features were identified more effectively with the structured questionnaire. Potentially confounding factors, prior knowledge of someone with epilepsy or a prior experience of viewing a seizure, did not predict the student's ability to correctly identify any of the 17 features.

CONCLUSIONS

A structured questionnaire significantly improves a medical student's ability to provide an accurate clinical description of primary generalized and complex partial witnessed seizures. Our analysis identified the 10 specific features improved by using the structured questionnaire.

Sex differences in seizure types and symptoms

BACKGROUND

Despite the increasing interest in sex differences in disease manifestations and responses to treatment, very few data are available on sex differences in seizure types and semiology. The Epilepsy Phenome/Genome Project (EPGP) is a large-scale, multi-institutional, collaborative study that aims to create a comprehensive repository of detailed clinical information and DNA samples from a large cohort of people with epilepsy. We used this well-characterized cohort to explore differences in seizure types as well as focal seizure symptoms between males and females.

METHODS

We reviewed the EPGP database and identified individuals with generalized epilepsy of unknown etiology (GE) (n = 760; female: 446, male: 314), nonacquired focal epilepsy (NAFE) (n = 476; female: 245, male: 231), or both (n = 64; female: 33, male: 31). Demographic data along with characterization of seizure type and focal seizure semiologies were examined.

RESULTS

In GE, males reported atonic seizures more frequently than females (6.5% vs. 1.7%; p < 0.001). No differences were observed in other generalized seizure types. In NAFE, no sex differences were seen for seizure types with or without alteration of consciousness or progression to secondary generalization. Autonomic (16.4% vs. 26.6%; p = 0.005), psychic (26.7% vs. 40.3%; p = 0.001), and visual (10.3% vs. 19.9%; p = 0.002) symptoms were more frequently reported in females than males. Specifically, of psychic symptoms, more females than males endorsed déjà vu (p = 0.001) but not forced thoughts, derealization/depersonalization, jamais vu, or fear. With corrections for multiple comparisons, there were no significant differences in aphasic, motor, somatosensory, gustatory, olfactory, auditory, vertiginous, or ictal headache symptoms between sexes.

CONCLUSIONS

Significant differences between the sexes were observed in the reporting of atonic seizures, which were more common in males with GE, and for autonomic, visual, and psychic symptoms associated with NAFE, which were more common in females.

Epileptic encephalopathies: new genes and new pathways

Epileptic encephalopathies represent a group of devastating epileptic disorders that occur early in life and are often characterized by pharmaco-resistant epilepsy, persistent severe electroencephalographic abnormalities, and cognitive dysfunction or decline. Next generation sequencing technologies have increased the speed of gene discovery tremendously. Whereas ion channel genes were long considered to be the only significant group of genes implicated in the genetic epilepsies, a growing number of non-ion-channel genes are now being identified. As a subgroup of the genetically mediated epilepsies, epileptic encephalopathies are complex and heterogeneous disorders, making diagnosis and treatment decisions difficult. Recent exome sequencing data suggest that mutations causing epileptic encephalopathies are often sporadic, typically resulting from de novo dominant mutations in a single autosomal gene, although inherited autosomal recessive and X-linked forms also exist. In this review we provide a summary of the key features of several early- and mid-childhood onset epileptic encephalopathies including Ohtahara syndrome, Dravet syndrome, Infantile spasms and Lennox Gastaut syndrome. We review the recent next generation sequencing findings that may impact treatment choices. We also describe the use of conventional and newer anti-epileptic and hormonal medications in the various syndromes based on their genetic profile. At a biological level, developments in cellular reprogramming and genome editing represent a new direction in modeling these pediatric epilepsies and could be used in the development of novel and repurposed therapies.

Genetic testing preferences in families containing multiple individuals with epilepsy

OBJECTIVE

To examine genetic testing preferences in families containing multiple individuals with epilepsy.

METHODS

One hundred forty-three individuals with epilepsy and 165 biologic relatives without epilepsy from families containing multiple affected individuals were surveyed using a self-administered questionnaire. Four genetic testing scenarios were presented, defined by penetrance (100% vs. 50%) and presence or absence of clinical utility. Potential predictors of genetic testing preferences were evaluated using generalized estimating equations with robust Poisson regression models. The influence of 21 potential testing motivations was also assessed.

RESULTS

For the scenario with 100% penetrance and clinical utility, 85% of individuals with epilepsy and 74% of unaffected relatives responded that they would definitely or probably want genetic testing. For the scenario with 100% penetrance but without clinical utility, the proportions who responded that they would want testing were significantly lower in both affected individuals (69%) and unaffected relatives (57%). Penetrance (100% vs. 50%) was not a significant predictor of genetic testing interest. The highest-ranking motivations for genetic testing were the following: the possibility that the results could improve health or health care, the potential to know if epilepsy in the family is caused by a gene, and the possibility of changing behavior or lifestyle to prevent seizures.

SIGNIFICANCE

Interest in epilepsy genetic testing may be high in affected and unaffected individuals in families containing multiple individuals with epilepsy, especially when testing has implications for improving clinical care.

Auras in generalized epilepsy

OBJECTIVE

We studied the frequency of auras in generalized epilepsy (GE) using a detailed semistructured diagnostic interview.

METHODS

In this cross-sectional study, participants with GE were drawn from the Epilepsy Phenome/Genome Project (EPGP). Responses to the standardized diagnostic interview regarding tonic-clonic (grand mal) seizures were then examined. This questionnaire initially required participants to provide their own description of any subjective phenomena before their "grand mal seizures." Participants who provided answers to these questions were considered to have an aura. All participants were then systematically queried regarding a list of specific symptoms occurring before grand mal seizures, using structured (closed-ended) questions.

RESULTS

Seven hundred ninety-eight participants with GE were identified, of whom 530 reported grand mal seizures. Of these, 112 (21.3%) reported auras in response to the open-ended question. Analysis of responses to the closed-ended questions suggested that 341 participants (64.3%) experienced at least one form of aura.

CONCLUSIONS

Auras typically associated with focal epilepsy were reported by a substantial proportion of EPGP subjects with GE. This finding may support existing theories of cortical and subcortical generators of GE with variable spread patterns. Differences between responses to the open-ended question and closed-ended questions may also reflect clinically relevant variation in patient responses to history-taking and surveys. Open-ended questions may underestimate the prevalence of specific types of auras and may be in part responsible for the underrecognition of auras in GE. In addition, structured questions may influence participants, possibly leading to a greater representation of symptoms.

Phenytoin versus valproate monotherapy for partial onset seizures and generalised onset tonic-clonic seizures

BACKGROUND

This is an updated version of the previously published Cochrane review (Issue 4, 2009)Worldwide, phenytoin and valproate are commonly used antiepileptic drugs. It is generally believed that phenytoin is more effective for partial onset seizures, and that valproate is more effective for generalised onset tonic-clonic seizures with or without other generalised seizure types.

OBJECTIVES

To review the best evidence comparing phenytoin and valproate when used as monotherapy in individuals with partial onset seizures or generalised onset tonic-clonic seizures with or without other generalised seizure types.

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialised Register (19 February 2013), the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, The Cochrane Library, January 2013), MEDLINE (1946 to 18 February 2013), SCOPUS (19 February 2013), ClinicalTrials.gov (19 February 2013), and WHO International Clinical Trials Registry Platform ICTRP (19 February 2013). We handsearched relevant journals, contacted pharmaceutical companies, original trial investigators and experts in the field.

SELECTION CRITERIA

Randomised controlled trials in children or adults with partial onset seizures or generalised onset tonic-clonic seizures with a comparison of valproate monotherapy versus phenytoin monotherapy.

DATA COLLECTION AND ANALYSIS

This was an individual patient data review. Outcomes were time to (a) treatment withdrawal (b) 12-month remission (c) six-month remission and (d) first seizure post randomisation. Cox proportional hazards regression models were used to obtain study-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs) with the generic inverse variance method used to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

Individual patient data were available for 669 individuals out of 1119 eligible individuals from five out of 11 trials, 60% of the potential data. Results apply to generalised tonic-clonic seizures, but not absence or myoclonus seizure types. For remission outcomes, HR > 1 indicates an advantage for phenytoin and for first seizure and withdrawal outcomes HR > 1 indicates an advantage for valproateThe main overall results (pooled HR adjusted for seizure type, 95% CI) were time to (a) withdrawal of allocated treatment 1.09 (0.76 to 1.55); (b) 12-month remission 0.98 (0.78 to 1.23); (c) six-month remission 0.95 (0.78 to 1.15) and (d) first seizure 0.93 (0.75 to 1.14). The results suggest no overall difference between the drugs for these outcomes. No statistical interaction between treatment and seizure type (partial versus generalised) was found, but misclassification of seizure type may have confounded the results of this review.

AUTHORS' CONCLUSIONS

We have not found evidence that a significant difference exists between phenytoin and valproate for the outcomes examined in this review. However misclassification of seizure type may have confounded the results of this review. Results do not apply to absence or myoclonus seizure types. No outright evidence was found to support or refute current treatment policies.

Evidence for a shared genetic susceptibility to migraine and epilepsy

PURPOSE

Although epilepsy and migraine are known to co-occur within individuals, the contribution of a shared genetic susceptibility to this comorbidity remains unclear. We investigated the hypothesis of shared genetic effects on migraine and epilepsy in the Epilepsy Phenome/Genome Project (EPGP) cohort.

METHODS

We studied prevalence of a history of migraine in 730 EPGP participants aged ≥ 12 years with nonacquired focal epilepsy (NAFE) or generalized epilepsy (GE) from 501 families containing two or more individuals with epilepsy of unknown cause. Information on migraine without aura (MO) and migraine with aura (MA) was collected using an instrument validated for individuals ≥ 12 years. Because many individuals have both MO and MA, we considered two nonoverlapping groups of individuals with migraine: those who met criteria for MA in any of their headaches (MA), and those who did not ("MO-only"). EPGP participants were interviewed about the history of seizure disorders in additional nonenrolled family members. We evaluated associations of migraine prevalence in enrolled subjects with a family history of seizure disorders in additional nonenrolled relatives, using generalized estimating equations to control for the nonindependence of observations within families.

KEY FINDINGS

Prevalence of a history of MA (but not MO-only) was significantly increased in enrolled participants with two or more additional affected first-degree relatives.

SIGNIFICANCE

These findings support the hypothesis of a shared genetic susceptibility to epilepsy and MA.

Recruitment for genetic studies of epilepsy

Virtually nothing has been published about recruitment of adults with sporadic temporal lobe epilepsy (TLE) for genetic studies. We examined eligibility, recruitment, participation rates, and reasons for exclusion in a genetic study of TLE. Participants with non-acquired TLE with onset ≤35 were recruited through review of records and screening of incoming patients at Columbia University Medical Center (CUMC). Eligible patients were asked to participate in an interview about seizures and give a blood sample for DNA extraction. Medical records were sought for each participant. Of 2974 patients screened 252 (8.5%) were eligible, and 40 (15.9% of eligible) participated. Leading reasons for ineligibility included an antecedent cause of epilepsy, syndrome other than TLE, and seizure onset after age 35. Those declining participation cited concerns about confidentiality, lack of compensation, and fear of phlebotomy. Although TLE is common and patients were recruited from a major surgical epilepsy center, a small proportion of potential participants participated. Large numbers need to be screened to reach the target sample size. Obtaining permission from treating physicians to contact their patients directly can improve recruitment. Saliva DNA collection, monetary incentives and patient education can improve participation. This information can facilitate study design in epilepsy genetics.

Accuracy of family history information on epilepsy and other seizure disorders

BACKGROUND

In epilepsy as in other disorders, family history information is often obtained by asking patients about the medical histories of their relatives rather than interviewing or examining the relatives directly. The accuracy of this type of information for epilepsy and other seizure disorders is unclear.

METHODS

This study used data from the Genetic Epidemiology of Seizure Disorders in Rochester study, a population-based investigation including all Rochester, MN, residents born ≥1920 with incidence of unprovoked seizures from 1935 to 1994 (case probands) and control probands matched by age, gender, and prior Rochester residency period. Seizure disorders in the first-degree relatives of case and control probands were ascertained by reviewing the relatives' medical records. Case and control probands were interviewed about seizures in their first-degree relatives using a validated 9-question screening interview. Interviewers were blinded to case-control status.

RESULTS

Sensitivity of the family history (i.e., proportion of relatives with medical record-documented seizures who screened positive in the proband interview) was 62% (32/52) for epilepsy, 50% (7/14) for isolated unprovoked seizures, and 56% (9/16) for febrile seizures. Sensitivity did not differ by case/control status of the proband. Sensitivity was much higher for probands reporting on their offspring or siblings than their parents. Among relatives with epilepsy, 90% of offspring and 80% of siblings but only 32% of parents screened positive.

CONCLUSIONS

Family histories of epilepsy are reasonably accurate for siblings and offspring, but are underreported in parents. Family histories of other seizure disorders are underreported.

Adaptive phase I study of OROS methylphenidate treatment of attention deficit hyperactivity disorder with epilepsy

OBJECTIVE

The goal of this study was to pilot a randomized controlled trial of OROS methylphenidate (OROS-MPH) to treat attention deficit hyperactivity disorder (ADHD) plus epilepsy.

METHODS

Thirty-three patients, 6-18years of age, taking antiepileptic drugs and with a last seizure 1-60months prior were assigned to a maximum daily dose of 18, 36, or 54mg of OROS-MPH in a double-blind placebo-controlled crossover trial.

RESULTS

There were no serious adverse events and no carryover effects in the crossover trial. OROS-MPH reduced ADHD symptoms more than did placebo treatment. There were too few seizures during the active (5) and placebo arms (3) to confidently assess seizure risk; however, considering exposure time, we observed an increased daily risk of seizures with increasing dose of OROS-MPH, suggesting that potential safety concerns require further study.

CONCLUSION

A larger study to assess the effect of OROS-MPH on seizure risk is needed. A crossover design including subjects with frequent seizures could maximize power and address high patient heterogeneity and recruitment difficulties.

Novel susceptibility locus at chromosome 6q16.3-22.31 in a family with GEFS+

BACKGROUND

Genetic epilepsy with febrile seizures plus (GEFS+) is a familial epilepsy syndrome with extremely variable expressivity. Mutations in 5 genes that raise susceptibility to GEFS+ have been discovered, but they account for only a small proportion of families.

METHODS

We identified a 4-generation family containing 15 affected individuals with a range of phenotypes in the GEFS+ spectrum, including febrile seizures, febrile seizures plus, epilepsy, and severe epilepsy with developmental delay. We performed a genome-wide linkage analysis using microsatellite markers and then saturated the potential linkage region identified by this screen with more markers. We evaluated the evidence for linkage using both model-based and model-free (posterior probability of linkage [PPL]) analyses. We sequenced 16 candidate genes and screened for copy number abnormalities in the minimal genetic region.

RESULTS

All 15 affected subjects and 1 obligate carrier shared a haplotype of markers at chromosome 6q16.3-22.31, an 18.1-megabase region flanked by markers D6S962 and D6S287. The maximum multipoint lod score in this region was 4.68. PPL analysis indicated an 89% probability of linkage. Sequencing of 16 candidate genes did not reveal a causative mutation. No deletions or duplications were identified.

CONCLUSIONS

We report a novel susceptibility locus for genetic epilepsy with febrile seizures plus at 6q16.3-22.31, in which there are no known genes associated with ion channels or neurotransmitter receptors. The identification of the responsible gene in this region is likely to lead to the discovery of novel mechanisms of febrile seizures and epilepsy.

Interview accuracy in partial epilepsy

The statistical concept of accuracy has never been applied to verify the history data collected on seizure disorders by open format interview. We compared patients'/witnesses' descriptions of epileptic seizures with videotaped seizure characteristics and analyzed the accuracy (ACC), sensitivity (SN), specificity (SP), false-positive rate (FPR), and false-negative rate (FNR) of various components of the semiology in patients with partial epilepsy. Language disturbances, complex automatisms, and autonomic signs have high ACC and intermediate FNRs. This means that these manifestations are most obvious to the witness/patient and, therefore, are memorized easily. Dystonic posturing and upper limb automatisms have the highest FNRs, leading to low ACC. These are very subtle signs, not vigorous enough to be paid attention to, but their predictive value in partial epilepsy syndromes is relatively high. We believe these signs need to be directly sought in the interview, because often the patient/witness pays limited attention to them.

Validation of a brief screening instrument for the ascertainment of epilepsy

PURPOSE

To validate a brief screening instrument for identifying people with epilepsy in epidemiologic or genetic studies.

METHODS

We designed a nine-question screening instrument for epilepsy and administered it by telephone to individuals with medical record-documented epilepsy (lifetime history of >or=2 unprovoked seizures, n = 168) or isolated unprovoked seizure (n = 54), and individuals who were seizure-free on medical record review (n = 120), from a population-based study using Rochester Epidemiology Project resources. Interviewers were blinded to record-review findings.

RESULTS

Sensitivity (the proportion of individuals who screened positive among affected individuals) was 96% for epilepsy and 87% for isolated unprovoked seizure. The false positive rate (FPR, the proportion who screened positive among seizure-free individuals) was 7%. The estimated positive predictive value (PPV) for epilepsy was 23%, assuming a lifetime prevalence of 2% in the population. Use of only a single question asking whether the subject had ever had epilepsy or a seizure disorder resulted in sensitivity 76%, FPR 0.8%, and estimated PPV 66%. Subjects with epilepsy were more likely to screen positive with this question if they were diagnosed after 1964 or continued to have seizures for at least 5 years after diagnosis.

DISCUSSION

Given its high sensitivity, our instrument may be useful for the first stage of screening for epilepsy; however, the PPV of 23% suggests that only about one in four screen-positive individuals will be truly affected. Screening with a single question asking about epilepsy yields a higher PPV but lower sensitivity, and screen-positive subjects may be biased toward more severe epilepsy.

Incidence of epilepsy in a racially diverse, community-dwelling, elderly cohort: results from the Einstein aging study

OBJECTIVE

To determine age-specific incidence and cumulative incidence of epilepsy in a well-defined cohort of elderly people, and to examine how rates of epilepsy are modified by sex, race, stroke, dementia, head injury, and depression.

METHODS

The authors examined data from a reconstructed cohort based on 1919 community-dwelling volunteers, followed as part of a large ongoing prospective aging study.

RESULTS

Age-specific incidence was 10.6 (per 100,000 person-years) between ages 45 and 59, 25.8 between ages 60 and 74, and 101.1 between ages 75 and 89. Cumulative incidence was 0.15% from age 45 to age 60, 0.38% to age 70, 1.01% to age 80, and 1.47% to age 90. In addition, the difference in cumulative incidence among African-American subjects approached statistical significance (57.6/100,000 person-years versus 26.1 in Caucasian, p=0.10), and the difference in incidence among subjects reporting a history of stroke was significantly elevated (p=0.029). Incidence of epilepsy was not statistically elevated among males, those with dementia, or individuals reporting a history of head injury or treatment for depression. Among "healthy" subjects without history of stroke, head injury, or dementia, we observed a cumulative risk of epilepsy with onset after age 60 of only 1.1%.

CONCLUSIONS

The incidence of epilepsy was low in this relatively healthy cohort of elderly people, especially among subjects without known risk factors. In this study we identified African-American race as a risk factor in the elderly for epilepsy independent of stroke.

Classification of partial seizure symptoms in genetic studies of the epilepsies

OBJECTIVES

To develop standardized definitions for classification of partial seizure symptoms for use in genetic research on the epilepsies, and evaluate inter-rater reliability of classifications based on these definitions.

METHODS

The authors developed the Partial Seizure Symptom Definitions (PSSD), which include standardized definitions of 41 partial seizure symptoms within the sensory, autonomic, aphasic, psychic, and motor categories. Based on these definitions, two epileptologists independently classified partial seizures in 75 individuals from 34 families selected because one person had ictal auditory symptoms or aphasia. The data used for classification consisted of standardized diagnostic interviews with subjects and family informants, and medical records obtained from treating neurologists. Agreement was assessed by kappa.

RESULTS

Agreement between the two neurologists using the PSSD was "substantial" or "almost perfect" for most symptom categories.

CONCLUSIONS

Use of standardized definitions for classification of partial seizure symptoms such as those in the Partial Seizure Symptom Definitions should improve reliability and accuracy in future genetic studies of the epilepsies.

Familial clustering of seizure types within the idiopathic generalized epilepsies

OBJECTIVE

To examine the genetic relationships among epilepsies with different seizure types--myoclonic, absence, and generalized tonic-clonic--within the idiopathic generalized epilepsies (IGEs).

BACKGROUND

Careful phenotype definition in the epilepsies may allow division into groups that share susceptibility genes. Examination of seizure type, a phenotypic characteristic less complex than IGE syndrome, may help to define more homogeneous subgroups.

METHODS

Using the approach that found evidence of distinct genetic effects on myoclonic vs absence seizures in families from the Epilepsy Family Study of Columbia University, the authors examined an independent sample of families from Australia and Israel. They also examined the familial clustering of generalized tonic-clonic seizures (GTCs) within the IGEs in two combined data sets. Families were defined as concordant if all affected members had the same type of seizure or IGE syndrome, as appropriate for the analysis performed.

RESULTS

The proportion of families concordant for myoclonic vs absence seizures was greater than expected by chance in the Australian families. In addition, GTCs clustered in families with IGEs to a degree greater than expected by chance.

CONCLUSIONS

These results provide additional evidence for distinct genetic effects on myoclonic vs absence seizures in an independent set of families and suggest that there is a genetic influence on the occurrence of generalized tonic-clonic seizures within the idiopathic generalized epilepsies.

Incidence of unprovoked seizures and epilepsy in Iceland and assessment of the epilepsy syndrome classification: a prospective study

BACKGROUND

No population-based incidence studies of epilepsy have studied syndrome classification from the outset. We prospectively studied the incidence of a single unprovoked seizure and epilepsy in the population of Iceland, and applied the syndrome classification endorsed by the International League Against Epilepsy to this population.

METHODS

We used a nationwide surveillance system to prospectively identify all residents of Iceland who presented with a first diagnosis of a single unprovoked seizure or epilepsy between December 1995 and February 1999. All cases were classified by seizure type, cause or risk factors, and epilepsy syndrome.

RESULTS

The mean annual incidence of first unprovoked seizures was 56.8 per 100,000 person-years, 23.5 per 100,000 person-years for single unprovoked seizures, and 33.3 per 100,000 person-years for epilepsy (recurrent unprovoked seizures). Incidence was similar in males and females. Partial seizures occurred in 40% and a putative cause was identified in 33%. Age-specific incidence was highest in the first year of life (130 per 100,000 person-years) and in those 65 years and older (110.5 per 100,000 person-years). Using strict diagnostic criteria for epilepsy syndromes, 58% of cases fell into non-informative categories. Idiopathic epilepsy syndromes were identified in 14% of all cases.

INTERPRETATION

Findings are consistent with incidence studies from developed countries. Although the epilepsy syndrome classification might be useful in tertiary epilepsy centers, it has limited practicality in population studies and for use by general neurologists.

Recruitment of families for genetic studies of epilepsy

PURPOSE

Study of families containing multiple affected individuals is essential for genetic research on the epilepsies, yet practically nothing has been published about methods for identification and recruitment of families or expected participation rates. Here we describe the strategy used for data collection in a genetic linkage study, to provide guidelines for efficient design of new studies.

METHODS

Potentially eligible families were ascertained from private physicians, clinics, and self-referrals. Participation rates were examined at each step of the recruitment process, according to ascertainment source, initial contact method, gender, and ethnicity.

RESULTS

Among 320 potentially eligible families identified, only 68 (21%) were successfully enrolled. Contact was established with an index subject in 83% of families, and a screen for eligibility was completed in 88% of these. However, only 54% of screened families were confirmed to be eligible, and of these, only 54% were enrolled. In eligible families, 79% of index subjects agreed to participate; the low family enrollment rates resulted largely from refusals by other family members whose participation was needed for linkage analysis. At each step in the recruitment process, the participation rate was higher in self-referred than in other families.

CONCLUSIONS

Recruitment of families for genetic studies is labor-intensive; many potentially eligible families may have to be screened for each family enrolled. Recruitment is easier with self-referred families than with those identified through other methods. The introduction of standardized methods for identification of eligible families from clinical settings can improve efficiency.

LGI1 mutations in autosomal dominant partial epilepsy with auditory features

OBJECTIVE

S: Mutations in LGI1 cause autosomal dominant partial epilepsy with auditory features (ADPEAF), a form of familial temporal lobe epilepsy with auditory ictal manifestations. The authors aimed to determine what proportion of ADPEAF families carries a mutation, to estimate the penetrance of identified mutations, and to identify clinical features that distinguish families with and without mutations.

METHODS

The authors sequenced LGI1 in 10 newly described ADPEAF families and analyzed clinical features in these families and others with mutations reported previously.

RESULTS

Three of the families had missense mutations in LGI1 (C42R, I298T, and A110D). Penetrance was 54% in eight families with LGI1 mutations the authors have identified so far (five reported previously and three reported here). Excluding the original linkage family, the authors have found mutations in 50% (7/14) of tested families. Families with and without mutations had similar clinical features, but those with mutations contained significantly more subjects with auditory symptoms and significantly fewer with autonomic symptoms. In families with mutations, the most common auditory symptom type was simple, unformed sounds (e.g., buzzing and ringing). In two of the newly identified families with mutations, some subjects with mutations had idiopathic generalized epilepsies.

CONCLUSIONS

LGI1 mutations are a common cause of autosomal dominant partial epilepsy with auditory features. Current data do not reveal a clinical feature that clearly predicts which families with autosomal dominant partial epilepsy with auditory features have a mutation. Some families with LGI1 mutations contain individuals with idiopathic generalized epilepsies. This could result from either an effect of LGI1 on risk for generalized epilepsy or an effect of co-occurring idiopathic generalized epilepsy-specific genes in these families.

Interrater agreement of the diagnosis and classification of a first seizure in childhood. The Dutch Study of Epilepsy in Childhood

OBJECTIVE

To assess the interrater agreement of the diagnosis and the classification of a first paroxysmal event in childhood.

METHODS

The descriptions of 100 first paroxysmal events were submitted to two panels each consisting of three experienced paediatric neurologists. Each observer independently made a diagnosis based on clinical judgment and thereafter a diagnosis based on predefined descriptive criteria. Then, the observers discussed all patients within their panel. The agreement between the six individual observers was assessed before discussion within each panel and after that, between the two panels.

RESULTS

Using their clinical judgement, the individual observers reached only fair to moderate agreement on the diagnosis of a first seizure (mean (SE) kappa 0.41 (0.03)). With use of defined descriptive criteria the mean (SE) kappa was 0.45 (0.03). The kappa for agreement between both panels after intra-panel discussion increased to 0.60 (0.06). The mean (SE) kappa for the seizure classification by individual observers was 0.46 (0.02) for clinical judgment and 0.57 (0.03) with use of criteria. After discussion within each panel the kappa between the panels was 0.69 (0.06). In 24 out of 51 children considered to have had a seizure, agreement was reached between the panels on a syndrome diagnosis. However, the epileptic syndromes were in most cases only broadly defined.

CONCLUSIONS

The interrater agreement on the diagnosis of a first seizure in childhood is just moderate. This phenomenon hampers the interpretation of studies on first seizures in which the diagnosis is only made by one observer. The use of a panel increased the interrater agreement considerably. This approach is recommended at least for research purposes. Classification into clinically relevant syndromes is possible only in a very small minority of children with a single seizure.

Genetic influences on myoclonic and absence seizures

OBJECTIVE

To examine the relationship between genotype and phenotype in idiopathic generalized epilepsies (IGEs) using a novel approach that focuses on seizure type rather than syndrome.

METHODS

The authors evaluated whether the genetic effects on myoclonic seizures differ from the genetic effects on absence seizures. For this purpose, they studied 34 families containing 2 or more members with IGEs and assessed whether the number of families concordant for seizure type exceeded that expected by chance. The authors performed a similar analysis to examine the genetic contributions to juvenile myoclonic epilepsy (JME), juvenile absence epilepsy (JAE), and childhood absence epilepsy (CAE).

RESULTS

The observed number of families concordant for seizure type (myoclonic, absence, or both) was greater than expected (20 vs 7.51; p < 0.0001). The observed number of families concordant for syndrome was greater than expected when JME was compared with absence epilepsies (JAE+CAE) (17 vs 11.9; p < 0.012) but not when JAE was compared with CAE (8 vs 6.82; p = 0.516).

CONCLUSIONS

These results provide evidence for distinct genetic effects on absence and myoclonic seizures, suggesting that examining the two seizure types separately would be useful in linkage studies of idiopathic generalized epilepsies. The approach presented here can also be used to discover other clinical features that could direct division of epilepsies into groups likely to share susceptibility genes.

Poststroke Epilepsy

Seizures and status epilepticus can be a presenting feature of acute stroke. They may occur in its early (<7 days) clinical course or be a remote (>7 days) complication. Most seizures are single, either partial or generalised. Early and remote seizures seem to have different predictors and pathogenesis. Seizures are more frequent in severe and disabling strokes, haemorrhagic strokes and those with cortical involvement. The risk of epilepsy is higher for patients with early seizures, cortical infarctions and lobar haemorrhages and in dependent patients. Early or remote seizures do not have a significant influence on dependency or mortality, although seizures and status epilepticus can be a direct cause of death. Treatment can be started after a first or a recurrent seizure. Treatment options include phenytoin, carbamazepine, valproic acid (valproate sodium) and the new antiepileptic drugs (AEDs). New AEDs can be used to decrease the likelihood of drug interactions and adverse effects in patients who do not tolerate the classic AEDs and in treatment failures with classic AEDs. Large observational studies to define prognostic factors for poststroke seizures in specific stroke subtypes are needed. Randomised controlled trials of AED prophylaxis for acute and remote seizures are essential to improve the evidence level of current guidelines and recommendations.

How accurate are witness descriptions of epileptic seizures?

PROBLEM

The diagnosis of epilepsy largely relies on the seizure description by a witness. Our aim was to assess the accuracy of seizure descriptions.

METHODS

Twenty volunteers (10 medical students, 4 junior doctors working on a neurological ward and 6 non-medical students) viewed a video of a partial then secondary, i.e. generalised seizure, and were then asked to provide a written account of the event. The seizure had eight key features. Volunteers scored one mark for each described key feature. One mark was deducted for each false observation.

RESULTS

The mean positive score was 3.5 (range 1 to 6). Unresponsiveness and lateralising features were often missed. The mean negative score was -0.8 (range 0 to -3). Erroneously described features included 'patient rolled over', 'agitated' or 'arms flopped about' as part of the tonic clonic seizure. Left and right were sometimes confused. The mean total score was 2.7 (range -2 to 6). A medical and a non-medical student achieved the highest scores, a doctor the lowest score.

CONCLUSIONS

The accuracy of seizure descriptions by witnesses was generally low and there were wide variations.

Evidence for distinct genetic influences on generalized and localization-related epilepsy

PURPOSE

Determining the existence of syndrome-specific genetic factors in epilepsy is essential for phenotype definition in genetic linkage studies, and informs research on basic mechanisms. Analysis of concordance of epilepsy syndromes in families has been used to assess shared versus distinct genetic influences on generalized epilepsy (GE) and localization-related epilepsy (LRE). However, it is unclear how the results should be interpreted in relation to specific genetic hypotheses.

METHODS

To assess evidence for distinct genetic influences on GE and LRE, we examined concordance of GE and LRE in 63 families containing multiple individuals with idiopathic or cryptogenic epilepsy, drawn from the Epilepsy Family Study of Columbia University. To control for the number of concordant families expected by chance, we used a permutation test to compare the observed number with the number expected from the distribution of individuals with GE and LRE in the study families.

RESULTS

Of the families, 62% were concordant for epilepsy type, and 38% were discordant. In all analyses, the proportion of concordant families was significantly greater than expected.

CONCLUSIONS

This suggests that some genetic influences predispose specifically to either GE or LRE. Because of the ascertainment bias resulting from the selection of families containing multiple individuals with epilepsy, we could not test whether there are also shared genetic influences on these two epilepsy subtypes. Population-based studies will be needed to explore these results further.

Development of diagnostic reference frames for seizures. Part 1: inter-participant agreement in the selection of symptoms

OBJECTIVE

Our aim is to develop reliable descriptions of various seizure types, which will be used as a basis for decision support. We use expert opinions in this process. In this contribution we evaluate the inter-participant agreement in the selection of frequently occurring symptoms for the description of seizure types.

METHOD

We compared the actual agreement among participants with the agreement that would result from random symptom selection as well as with the maximal agreement attainable. For each seizure type we calculated the reliability coefficients of the responses.

RESULTS

For all seizure types we found that the agreement in symptom selection among the participants is significantly higher than expected by chance, but not reaching the maximum agreement attainable. The reliability coefficients varied between 0.56 and 0.74 for the various seizure types.

CONCLUSION

Although the participants do not reach the maximum agreement attainable in the selection of symptoms, the majority agreement on characteristic frequently occurring symptoms for the different seizure types does approach the maximum agreement attainable. Therefore, we conclude that expert opinions can be used for building descriptions of seizure types. However, to derive a reliable set of symptoms for the construction of the diagnostic reference frames (DRFs) more participants are needed.

Carbamazepine versus valproate monotherapy for epilepsy: a meta-analysis

PURPOSE

To provide an overview of the evidence comparing carbamazepine (CBZ) and valproate (VPA) monotherapy for epilepsy, investigating whether existing data support the current practice of preferring CBZ for partial-onset and VPA for generalized-onset seizures.

METHODS

We performed meta-analysis of randomized controlled trials by using individual patient data. Our strategy included searches of (a) Medline, 1966-2000; (b) The Cochrane Library 2000, issue 4; and (c) the pharmaceutical industry. Outcome measures were time to discontinuation of allocated treatment, time to 12-month remission, and time to first seizure after randomization. Results are expressed as hazard ratios (HRs; 95% CI), where HR>1 indicates that an event is more likely with VPA. A test for an interaction between treatment and seizure type (partial vs. generalized onset) also was undertaken.

RESULTS

Data were available for 1,265 patients from five trials. Overall results (HR, 95% CI) were Time to treatment discontinuation, 0.97 (0.79-1.18); 12-Month remission, 0.87 (0.74-1.02); and First seizure, 1.09 (0.96-1.25), suggesting no overall difference for these outcomes. The test for an interaction between Treatment and Seizure type was significant for time to first seizure, but for no other outcome. The age distribution of adults classified as having generalized seizures indicated that significant numbers of patients may have had their seizures misclassified.

CONCLUSIONS

We found some evidence to support the preference of CBZ for partial-onset seizures, but no evidence to support the preference of VPA for generalized-onset seizures. Confidence intervals are too wide to infer equivalence. Misclassification of patients may have confounded our results and has important implications for future trials.

Four new families with autosomal dominant partial epilepsy with auditory features: clinical description and linkage to chromosome 10q24

PURPOSE

Autosomal dominant partial epilepsy with auditory features (ADPEAF) is a rare form of nonprogressive lateral temporal lobe epilepsy characterized by partial seizures with auditory disturbances. The gene predisposing to this syndrome was localized to a 10-cM region on chromosome 10q24. We assessed clinical features and linkage evidence in four newly ascertained families with ADPEAF, to refine the clinical phenotype and confirm the genetic localization.

METHODS

We genotyped 41 individuals at seven microsatellite markers spanning the previously defined 10-cM minimal genetic region. We conducted two-point linkage analysis with the ANALYZE computer package, and multipoint parametric and nonparametric linkage analyses as implemented in GENEHUNTER2.

RESULTS

In the four families, the number of individuals with idiopathic epilepsy ranged from three to nine. Epilepsy was focal in all of those with idiopathic epilepsy who could be classified. The proportion with auditory symptoms ranged from 67 to 100%. Other ictal symptoms also were reported; of these, sensory symptoms were most common. Linkage analysis showed a maximum 2-point LOD score of 1.86 at (theta=0.0 for marker D10S603, and a maximum multipoint LOD score of 2.93.

CONCLUSIONS

These findings provide strong confirmation of linkage of a gene causing ADPEAF to chromosome 10q24. The results suggest that the susceptibility gene has a differential effect on the lateral temporal lobe, thereby producing the characteristic clinical features described here. Molecular studies aimed at the identification of the causative gene are underway.

Risk of epilepsy in offspring of affected women: association with maternal spontaneous abortion

BACKGROUND

Previously, the authors found that risk of spontaneous abortion was increased in the pregnancies of women with epilepsy compared with their same-sex siblings, which could have implications for risk of epilepsy in their offspring. An association between a history of spontaneous abortion in the mother and risk of epilepsy in her live-born offspring may arise through selective loss of fetuses with a genetic susceptibility to epilepsy or through intrauterine environmental factors that may predispose the mother to a spontaneous abortion and to epilepsy in her live-born children.

METHOD

The authors examined the relation of a history of spontaneous abortion to the risk of idiopathic or cryptogenic epilepsy in 791 live-born offspring of 385 women with cryptogenic localization-related epilepsy (probands) ascertained from voluntary organizations. A semistructured telephone interview with probands and additional family informants, supplemented by medical record review, was used to obtain information on seizures and other risk factors in probands and relatives.

RESULTS

Live-born offspring of women with a history of spontaneous abortion were four or five times as likely to develop epilepsy as were children of women without (12.8% versus 4.7%; rate ratio = 4.6, 95% CI: 2.3-9.0). Cumulative incidence of epilepsy was 21.9% in offspring of women with a history of spontaneous abortion and a family history of epilepsy, compared with 4.7% in offspring of women with neither risk factor.

CONCLUSIONS

These results suggest that a history of spontaneous abortion is associated with increased risk of epilepsy in live-born offspring and may be a marker for genetic susceptibility for epilepsy in the mother.

Phenytoin versus valproate monotherapy for partial onset seizures and generalized onset tonic-clonic seizures

BACKGROUND

Phenytoin and valproate are commonly used antiepileptic drugs. It is generally believed that phenytoin is more effective for partial onset (simple partial, complex partial and secondary generalized tonic-clonic seizures) seizures whilst valproate is more effective in generalized onset seizures (generalized tonic-clonic seizures, absence, myoclonus) although there is no evidence from randomized controlled trials to support this belief. The use of individual patient data meta-analysis enabled us to examine time to event outcomes which are important in epilepsy monotherapy trials, and also to examine treatment-covariate interactions.

OBJECTIVES

To review the best evidence comparing phenytoin and valproate when used as monotherapy in subjects with partial onset seizures, or generalized onset tonic-clonic seizures with or without other generalized seizure types.

SEARCH STRATEGY

Our search strategy included: (i) the Cochrane Epilepsy Group trial register, (ii) MEDLINE 1966-2000, (iii) hand-searching relevant journals, (iv) the pharmaceutical industry, and (v) researchers in the field.

SELECTION CRITERIA

Randomized controlled trials in children or adults with partial onset seizures or generalized onset tonic-clonic seizures. Trials must have included a comparison of phenytoin monotherapy with valproate monotherapy.

DATA COLLECTION AND ANALYSIS

This was an individual patient data review. Outcomes were time to (i) withdrawal of allocated treatment, (ii) 12 month remission, (iii) six month remission, and (iv) first seizure post randomization. Data were analysed using stratified logrank analysis with results expressed as hazard ratios (HR) and 95% confidence intervals (95% CI), where a HR>1 indicates an event is more likely on phenytoin. A test for interaction between treatment and seizure type (partial onset versus generalized onset) was also undertaken for each outcome.

MAIN RESULTS

Data were available for 669 subjects from five trials, representing 60% of the subjects recruited into the eleven trials that met our inclusion criteria. One important limitation of these data is that in four of the five trials, for patients classified as having generalized onset seizures, tonic-clonic seizures were the only seizure types recorded at follow up, despite the fact that some patients will have been experiencing other generalized seizure types such as absence or myoclonus. Their results for the generalized seizures therefore relate only to generalized onset tonic-clonic seizures. The main overall results were as follows (HR(95% CI), HR>1 indicates a clinical advantage for phenytoin for both remission outcomes and a clinical advantage for valproate for the outcomes time to withdrawal and time to first seizure) (i) time to withdrawal of allocated treatment 1.10(0.79-1.54), (ii) time to 12 month remission 1.04(0.78-1.38), (iii) time to six month remission 0.89(0.71-1.11), and (iv) time to first seizure 0.92(0.74-1.14). The results suggest no overall difference between drugs for these outcomes. The test for an interaction between treatment and seizure type (generalized versus partial onset) was non significant for all outcomes.

REVIEWER'S CONCLUSIONS

We have not found evidence that a significant difference exists between phenytoin and valproate for the outcomes examined in this review. As generalized seizures such as absence and myoclonus were counted in only one trial, results do not address the treatment of these seizure types. We found no unequivocal evidence to overthrow or support the policy of using valproate in generalized onset tonic-clonic seizures and phenytoin in partial onset seizures.

The impact of epilepsy from the patient's perspective I. Descriptions and subjective perceptions

This study surveyed the perceptions about and subjective experience of 1023 people with epilepsy in two community-based samples: one from a national postal survey; the other callers to the Epilepsy Foundation. Response to a mail survey was 49%. In comparison with US Census Bureau norms, respondents had received less education, were less likely to be employed or married, and came from lower income households. Complex partial seizures were the most prevalent seizure type, but a convulsion had occurred in 61%. Fifty percent of respondents reported incomplete control of their seizure disorder, although 25% of these had a seizure in the prior year. Thirteen percent had a longest inter-seizure interval of a year or greater, 37% of 3 months, 22% of 1 month, 10% of 1 week and 4% of 1 day. Respondents listed uncertainty and fear of having a seizure as the worst thing about having epilepsy. Lifestyle, school, driving, and employment limits were also listed as major problems. When asked to rank a list of potential problems, cognitive impairment was ranked highest. These data indicate that ongoing medical and psychosocial problems continue for those with epilepsy in the view of those questioned and their families, even in a sample where the majority report good control of their epilepsy.

Carbamazepine versus valproate monotherapy for epilepsy

BACKGROUND

Carbamazepine and valproate are drugs of first choice for epilepsy. Despite the lack of hard evidence from individual randomized controlled trials, there is strong clinical belief that valproate is the drug of choice for generalized epilepsies and carbamazepine for partial epilepsies.

OBJECTIVES

To overview the best evidence comparing carbamazepine and valproate monotherapy

SEARCH STRATEGY

Our search strategy included: (a) MEDLINE 1966-99, (b) The Cochrane Library 1999 issue 4, (c) The trial register of the Cochrane Epilepsy Group (d) the pharmaceutical industry.

SELECTION CRITERIA

Randomized controlled trials comparing carbamazepine and valproate monotherapy for epilepsy.

DATA COLLECTION AND ANALYSIS

This was an individual patient data review. Outcome measures were time to withdrawal of allocated treatment, time to 12 month remission, and time to first seizure post randomization. Data were analysed using the stratified Logrank test with results expressed as hazard ratios (HR) (95% CI), where HR>1 indicates an event is more likely on valproate. A test for an interaction between treatment and epilepsy type (partial versus generalized) was also undertaken.

MAIN RESULTS

Results Data were available for 1265 patients from five trials, representing 85% of the patients recruited into the eight trials that met our inclusion criteria. The main overall results (HR 95% CI) were: Time to treatment withdrawal 0.97 (0.79-1.18), 12 month remission 0.87 (0.74-1.02), first seizure 1.09 (0.96-1.25) suggesting no overall difference for these outcomes. The test for an interaction between treatment and epilepsy type was non significant for time to treatment withdrawal and 12 month remission, but significant for time to first seizure. The age distribution of adults classified as having a generalized epilepsy indicate that significant numbers of patients may have had their epilepsy misclassified.

REVIEWER'S CONCLUSIONS

We have found some evidence to support the policy of using carbamazepine as the first treatment of choice in partial epilepsies, but no evidence to support the choice of valproate in generalized epilepsies, but confidence intervals are too wide to confirm equivalence. Misclassification of patients may have confounded our results, and has important implications for the design and conduct of future trials.

Classification of childhood epilepsy syndromes in newly diagnosed epilepsy: interrater agreement and reasons for disagreement

PURPOSE

The International League Against Epilepsy (ILAE) classification of the epilepsies is in increasingly widespread use. The following analysis was done to assess the interrater agreement in classifying epilepsy syndromes in children with newly diagnosed epilepsy.

METHODS

In a prospective, community-based study, 613 children with newly diagnosed epilepsy were recruited. Based on information available at diagnosis or generated as part of the initial diagnostic assessment, three pediatric neurologists independently classified epilepsy syndromes. Interrater agreement was assessed with kappa.

RESULTS

Interrater agreement was extremely good, with kappa scores > or = 0.80 for almost all comparisons. Relatively limited quality of the EEG and seizure information in some cases, as well as discrepancies between the two, were associated with a tendency for more disagreement.

CONCLUSIONS

A high degree of interrater agreement was obtained in this study, indicating that the system for classifying syndromes can be meaningfully used in a community-based sample. Quality of the information, which is often, by necessity, less than optimal in newly diagnosed epilepsy, is a potential barrier to identification of syndromes. A substantial proportion of children were classified into relatively nonspecific syndromes. Over time, additional information may come to light to allow more precise identification of their forms of epilepsy. In an epidemiologic setting, the ILAE classification of the epilepsies can be successfully used with a high degree of reliability to classify newly diagnosed epilepsy in children.

Are generalized and localization-related epilepsies genetically distinct?

BACKGROUND

Whether the genetic influences are distinct for generalized and localization-related epilepsies or whether some susceptibility genes raise the risk for both types of epilepsy is uncertain.

OBJECTIVE

To evaluate genetic heterogeneity in epilepsy.

METHODS

We used Cox proportional hazards analysis to compute rate ratios (RRs) for generalized and localization-related idiopathic or cryptogenic epilepsy in the first-degree relatives of 1498 adult probands with idiopathic or cryptogenic epilepsy ascertained from voluntary organizations. The reference group comprised the first-degree relatives of 362 probands from the same study with postnatal symptomatic epilepsy in whom the genetic contributions appear to be minimal.

RESULTS

In the parents and siblings, the risk for all idiopathic or cryptogenic epilepsy was greater if the proband's epilepsy was generalized than if it was localization-related (RR, 4.7 vs 2.4). However, in the parents and siblings of each group of probands, the increased risk was not restricted to the same type of epilepsy as in the proband. The results differed in offspring, with a greater risk for all types of epilepsy if the proband's epilepsy was localization-related than if it was generalized (RR, 4.2 vs 1.6) and a greater risk for localization-related epilepsy than for generalized epilepsy (RR, 7.8 vs 1.8) if the proband's epilepsy was localization-related.

CONCLUSIONS

These findings in parents and siblings suggest that some susceptibility genotypes raise the risk for both generalized and localization-related epilepsies but are more common in persons affected with generalized epilepsy. The different findings in offspring may reflect a different influence on susceptibility in that subgroup.

Segregation analysis of cryptogenic epilepsy and an empirical test of the validity of the results

We used POINTER to perform segregation analysis of cryptogenic epilepsy in 1,557 three-generation families (probands and their parents, siblings, and offspring) ascertained from voluntary organizations. Analysis of the full data set indicated that the data were most consistent with an autosomal dominant (AD) model with 61% penetrance of the susceptibility gene. However, subsequent analyses revealed that the patterns of familial aggregation differed markedly between siblings and offspring of the probands. Risks in siblings were consistent with an autosomal recessive (AR) model and inconsistent with an AD model, whereas risks in offspring were inconsistent with an AR model and more consistent with an AD model. As a further test of the validity of the AD model, we used sequential ascertainment to extend the family history information in the subset of families judged likely to carry the putative susceptibility gene because they contained at least three affected individuals. Prevalence of idiopathic/cryptogenic epilepsy was only 3.7% in newly identified relatives expected to have a 50% probability of carrying the susceptibility gene under an AD model. Approximately 30% (i.e., 50% x 61%) were expected to be affected under the AD model resulting from the segregation analysis. These results suggest that the familial distribution of cryptogenic epilepsy is inconsistent with any conventional genetic model. The differences between siblings and offspring in the patterns of familial risk are intriguing and should be investigated further.

Is the comorbidity of epilepsy and migraine due to a shared genetic susceptibility?

We tested the hypothesis that the comorbidity of migraine and epilepsy results from a shared genetic susceptibility to the two disorders. We used semistructured telephone interviews to collect information on migraine and epilepsy in the families (parents, siblings, and offspring) of 1,967 adult probands with epilepsy. Epilepsy was defined as a lifetime history of two or more unprovoked seizures, and migraine as self-reported severe headaches with two or more of the following symptoms: unilateral pain, throbbing pain, visual aura, or nausea. As a first test of the hypothesis of shared susceptibility, we assessed risk of migraine in relatives of probands with genetic versus nongenetic forms of epilepsy, using two proxy measures of genetic susceptibility-a first-degree family history of epilepsy and idiopathic/cryptogenic (versus postnatal symptomatic) etiology. Neither of these two measures was associated with risk of migraine in relatives. As a second test, we assessed risk of epilepsy in the relatives of probands with versus without migraine. With the exception of one subgroup (sons of female probands), risk of epilepsy in relatives was not associated with the proband's history of migraine. This pattern of results is inconsistent with the hypothesis of a shared genetic susceptibility to migraine and epilepsy.

Interobserver variability in the classification of neonatal seizures based on medical record data

This population-based, retrospective cohort study of neonatal seizures included all 16,428 neonates born to residents of Fayette County, Kentucky, from 1985 to 1989. Eighty potential cases were ascertained by computer search of hospital-based medical record systems, birth certificate data files, and multiple-cause-of-death mortality data files. Medical records for potential cases were abstracted, and relevant portions were reviewed independently by three neurologists using prospectively determined criteria. Both unweighted and weighted kappa statistics were used to measure agreement between each pair of observers in the classification of potential cases as seizures, possible seizures, or not seizures, adjusting for the proportion of agreement expected by chance. Agreement in the classification of potential cases was excellent (kappa = 0.72-0.79, average = 0.76; weighted kappa = 0.85-0.88, average = 0.87). The kappa extension statistic of Kraemer was used to assess agreement in the classification of seizure types by a simplification of the classification scheme of Volpe. This documented excellent agreement between raters in the classification of seizure types (kappa e = 0.72). Experienced raters can reliably classify potential cases of neonatal seizures using seizure descriptions transcribed from medical records.

Behavioral descriptors that differentiate between seizure and nonseizure events in a pediatric population

The diagnosis and treatment of epilepsy relies heavily on descriptions of behavioral changes noted during seizure episodes. A pilot study was completed to determine the frequency of occurrence of behaviors commonly associated with seizures in a pediatric population (n = 153). Caretakers of the children (ages = 4 months to 19 years) were asked to respond to a checklist containing 40 behavioral descriptors. Thirteen descriptors were found to differentiate between seizure and nonseizure events. Twelve of these behaviors were endorsed significantly more frequently by caretakers of children with seizures including the following: does not remember what happened, moves mouth funny, drools, jerking/twitching, becomes stiff, changes in breathing, stares off, bites or chews tongue, eyes look glassy, will not respond, mumbles or slurs words, and eyes or head turn to one side. One behavior, fidgets in seat, was significantly more associated with nonseizure episodes. The behavioral descriptors may be presented in a checklist format or incorporated within a clinical interview in primary care settings for initial screening of children with possible seizure disorders.

Relations of genetic and environmental factors in the etiology of epilepsy

We assessed the relations of genetic and environmental factors in the etiology of epilepsy. The study population comprised 9,705 first-degree relatives of 1,951 adults with epilepsy ascertained from voluntary organizations. We calculated standardized morbidity ratios for specific etiologies of epilepsy in the relatives of probands with the same etiologies, using population incidence rates from Rochester, MN, as the reference. Relatives of probands with idiopathic/cryptogenic epilepsy had increased risk for idiopathic/cryptogenic epilepsy and for epilepsy associated with neurological deficit presumed present at birth (cerebral palsy or mental retardation) but not for symptomatic epilepsy associated with postnatal central nervous system insults. Relatives of probands with neurodeficits had increased risks for idiopathic/cryptogenic epilepsy. Risk for epilepsy was not increased among relatives of probands with postnatal symptomatic epilepsy. The degree of increased risk of idiopathic/cryptogenic epilepsy in relatives of probands with idiopathic/cryptogenic epilepsy diminished with increasing age of the relatives; risk was not increased at age 35 or older. These findings support the possibility of shared genetic susceptibility to epilepsy and cerebral palsy, and suggest that the genetic contributions to postnatal symptomatic epilepsy are minimal.

A clinical approach to the classification of seizures and epileptic syndromes

Seizures and epilepsies are heterogeneous. Their classifications are essential for clinicians to achieve a common understanding of the disorders. The diagnosis, treatment, and prognosis of seizure disorders depend on the correct identification of the types of seizures and epilepsy. The two currently accepted classifications are the International Classification of Epileptic Seizures and the International Classification of Epilepsies and Epileptic Syndromes. Both are based on clinical and electrophysiologic data, and both maintain a basic dichotomy between partial (focal, localization-related) and generalized epileptic disorders. Partial seizures are further classified into those that are simple partial, complex partial, and partial with secondary generalization. Generalized seizures are classified predominantly on the basis of their motor manifestations. Epilepsies are divided into idiopathic, cryptogenic, and symptomatic types. The utility and the limitations of these two classifications are discussed. A simplified system that encompasses neuroradiologic advances is offered to enhance the clinical usefulness of classifying epileptic disorders.

Clinical indicators of genetic susceptibility to epilepsy

We evaluated clinical indicators of genetic susceptibility to epilepsy in the families of 1,957 adults with epilepsy (probands) ascertained from voluntary organizations. Very few of the probands in this series had idiopathic epilepsy syndromes. Among relatives of probands with postnatal CNS insults, risks of epilepsy were no higher than in the general population. Risk was increased in relatives of probands without identified CNS insults (i.e., those with idiopathic/cryptogenic epilepsy) or with neurological deficit presumed present at birth, compared with relatives of probands with postnatal CNS insults. Among relatives of probands with idiopathic/cryptogenic epilepsy, risks were higher in parents and siblings, but not in offspring, of probands with generalized onset as compared with partial onset seizures. Risks in offspring were higher if the probands had onset of idiopathic/cryptogenic epilepsy before age 10 as compared with age > or = 10 years, but risks in parents and siblings were not associated with the probands's age at onset. These results suggest that genetic susceptibility increases risk of some forms of cryptogenic epilepsy and of epilepsy associated with neurological deficit presumed present at birth, but not of postnatal symptomatic epilepsy. The influences on risk in offspring may differ from those in parents and siblings.