Postoperative multichannel magnetoencephalography in patients with recurrent seizures after epilepsy surgery

Objectives - Juvenile myoclonic epilepsy (JME) is a common, age related, idiopathic generalized epileptic syndrome. We aimed to define the expression of JME in Indian probands and study the occurrence of seizures/ epileptic syndromes in their family members. Methods - We studied 225 JME probands with a uniform protocol, recording the type and frequency of seizures, precipitating factors, EEG data, and family history. Detailed family pedigrees were drawn to include all the 1st- and 2nd-degree relatives of probands. The seizures/epileptic syndromes in relatives examined were classified in a uniform way. Results - The clinical and EEG characteristics of 225 JME probands from India were similar to those reported in probands from different ethnic backgrounds. The incidence of febrile convulsions in probands with JME was similar to that of the general population but was much lower (0.2%) among their relatives. A positive family history of seizures among 1st- or 2nd-degree relatives was noted in 79 of 225 (35%) probands. The risk of relatives being affected as well as their risk of expressing a type of idiopathic generalized epilepsy (IGE) varied as a function of the degree of relation with the probands. Conclusions - The clinical expression of JME among probands from India is fairly similar to that reported in probands of different ethnic backgrounds. The risk of relatives being affected as well as their risk of expressing a type of IGE (including JME) varies as a function of the degree of relation with the probands. The reduced occurrence of febrile convulsions among the relatives of JME probands probably represents an ascertainment bias. A much larger database of this type should be helpful in understanding the interactions of different genes that are believed to be responsible for some of the inherited human epileptic syndromes like JME and other IGEs.     

Electroencephalographic studies of family members of patients with juvenile myoclonic epilepsy]

Juvenile myoclonic epilepsy (JME) is a common idiopathic generalized epilepsy (IGE); it has a clinical and probably a strong genetic relation to the other IGE forms. Generalized spike/polyspike-wave discharges (SW/PSW) are typical of all IGEs. The aim of our study was to determine the incidence of epilepsy and SW/PSW in EEG of family members of 12 JME patients. 35 first degree relatives aged over 15 years were examined. 40 min EEG with 5 min HV were recorded. IGE was diagnosed in 3 (8.6%) persons: JME in 2 and childhood absence epilepsy (CAE) in 1 person. Six more relatives (17.1%) had typical SW/PSW traits in EEG. Thus the IGE features were found in 9 (25.7%) individuals--members of 7 out of 12 families (58%). EEG of 7 other relatives (20%) revealed non-specific episodic diffuse or focal abnormalities. The above results reveal higher incidence of different kinds of ICEs and typical EEG traits in families of JME patients. This findings confirm familial susceptibility to IGE and may be helpful in genetical counselling.     

Complex inheritance and parent-of-origin effect in juvenile myoclonic epilepsy

BACKGROUND: Juvenile myoclonic epilepsy (JME) is an idiopathic generalized epilepsy (IGE) with complex inheritance. Previous studies have suggested maternal inheritance and female excess in IGEs but have not been specific for JME. We investigated evidence for maternal inheritance, female excess and patterns of familial seizure risk in a well-characterized sample of JME families. METHODS: We ascertained 89 families through a JME proband and 50 families through a non-JME IGE proband. JME families were divided into those with and without evidence of linkage to the EJM1 susceptibility locus on chromosome 6. We analyzed transmission in 43 multigenerational families, calculated the adjusted sex ratio for JME, and looked for evidence of seizure specific risk in 806 family members. RESULTS: We found evidence for preferential maternal transmission in both EJM1-linked and unlinked families (2.7:1), evidence even more marked when potential selection factors were excluded. The adjusted female: male risk ratio was very high in JME (RR=12.5; 95% CI: 1.9-83.7). Absence seizures in JME probands increased the overall risk of seizures in first degree relatives (15.8% vs. 7.0%, P=0.011), as well as first-degree relatives' specific risk of absence seizures (6% vs. 1.6%, P=0.01), but not myoclonic seizures. CONCLUSIONS: We have confirmed the finding of maternal inheritance in JME, which is not restricted to JME families linked to the EJM1 locus. The striking female excess in JME may relate to anatomical and/or endocrine sexual dimorphism in the brain. Evidence for independent inheritance of absence and myoclonic seizures in JME families reinforces a model in which combinations of loci confer susceptibility to the component seizure types of IGE.     

Genetic architecture of idiopathic generalized epilepsy: clinical genetic analysis of 55 multiplex families

PURPOSE: In families with idiopathic generalized epilepsy (IGE), multiple IGE subsyndromes may occur. We performed a genetic study of IGE families to clarify the genetic relation of the IGE subsyndromes and to improve understanding of the mode(s) of inheritance. METHODS: Clinical and genealogic data were obtained on probands with IGE and family members with a history of seizures. Families were grouped according to the probands' IGE subsyndrome: childhood absence epilepsy (CAE), juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and IGE with tonic-clonic seizures only (IGE-TCS). The subsyndromes in the relatives were analyzed. Mutations in genes encoding alpha1 and gamma 2 gamma-aminobutyric acid (GABA)-receptor subunits, alpha1 and beta1 sodium channel subunits, and the chloride channel CLC-2 were sought. RESULTS: Fifty-five families were studied. 122 (13%) of 937 first- and second-degree relatives had seizures. Phenotypic concordance within families of CAE and JME probands was 28 and 27%, respectively. JAE and IGE-TCS families had a much lower concordance (10 and 13%), and in the JAE group, 31% of relatives had CAE. JME was rare among affected relatives of CAE and JAE probands and vice versa. Mothers were more frequently affected than fathers. No GABA-receptor or sodium or chloride channel gene mutations were identified. CONCLUSIONS: The clinical genetic analysis of this set of families suggests that CAE and JAE share a close genetic relation, whereas JME is a more distinct entity. Febrile seizures and epilepsy with unclassified tonic-clonic seizures were frequent in affected relatives of all IGE individuals, perhaps representing a nonspecific susceptibility to seizures. A maternal effect also was seen. Our findings are consistent with an oligogenic model of inheritance.     

Clinical expression and EEG features of patients with juvenile myoclonic epilepsy (JME) from North India.

We aimed to characterize the clinical profile, EEG features and response to treatment of juvenile myoclonic epilepsy (JME) patients. We studied 103 JME probands with a standard protocol recording age of onset, type, frequency of seizures, EEG data, detailed family history and response to treatment in a superspeciality university hospital in New Delhi. The mean age of onset of disease was 14.01 +/- 3.14 years with a male to female ratio of 1.19 : 1. The myoclonic jerks were present in all the probands, generalized tonic-clonic seizures (GTCS) were present in 75.72% and 11.65% probands had absence seizures. The incidence of febrile convulsion (FC) was higher (9.7%) in our JME probands reflecting some ethnic variation or ascertainment bias. There was a considerable delay (of approximately 5.26 +/- 4.61 years) in the diagnosis of JME in our probands because most of the patients were referred from private physicians who were possibly not familiar with this epileptic syndrome in this part of the world or thought it was a milder variety of GTCS. The family history was positive in 25.24% JME probands among first- and second-degree relatives. An interictal EEG was found to be abnormal in 81 (78.64%) patients with the predominant abnormality being generalized polyspike and wave (PSW) discharges (39.80% probands). The majority of patients (80.58%) showed a good response to treatment with valproate alone. There was a subset of patients (11.65%) who required the addition of other antiepileptic drugs (AEDs) for control of GTCS: 7.76% of JME patients were diagnosed as cases of GTCS by private practitioners before they were registered in our study and their seizures were well controlled on other AEDs (without valproate) prescribed by the referring physicians (carbamazepine-4, phenytoin-2, clobazam-2). It is concluded that the clinical features and EEG data of JME probands were comparable to reports from other parts of the world except for the fact that the incidence of FC was higher in our JME patients. There was a delay in the diagnosis of JME due to unfamiliarity with the epileptic syndrome among private practitioners in this part of the world. There was a subset of JME patients who had complete seizure control on other AEDs besides valproate.     

Idiopathic Generalized Epilepsies: Do Sporadic and Familial Cases Differ?

PURPOSE: Genetic factors are the only identified cause of idiopathic generalized epilepsies (IGEs), but the majority of cases do not have affected first-degree relatives. Here we investigate whether subjects with sporadic and familial IGE differ in terms of antecedent events and clinical and EEG features. Differences would support the hypothesis of a different etiology for sporadic cases, which has implications for choice of subjects for genetic association studies. METHODS: We analyzed 98 patients with IGE, diagnosed on clinical and EEG criteria. All patients and, if possible, one relative were interviewed, with special emphasis on potential antecedent events and family history. Patients with first-degree relatives affected with epileptic seizures were regarded as "familial," and the other patients were regarded as "sporadic." RESULTS: Of the 98 IGE patients, 32 (33%) patients were familial. The risk for seizures was 13.2% for siblings, and 7.7% for parents. The distribution of the IGE subsyndromes, the presence of antecedent events, and other electroclinical features did not differ between familial and sporadic IGE groups. CONCLUSIONS: No differences were found between familial and sporadic IGE patients. This does not the support the hypothesis that sporadic and familial IGE cases have separate etiologies.     

Clinical genetic study in juvenile myoclonic epilepsy

PurposeTo evaluate clinical features of probands with juvenile myoclonic epilepsy (JME) and affected members of their families in order to study clinical genetics of JME.MethodThirteen unrelated families with at least two members with history of seizures were identified; clinical and genealogic data were collected from JME probands and family members.ResultsAll probands had myoclonic and generalized tonic–clonic seizures (GTCS), while absences occurred in 25% of them. The average age of seizure onset was 13 years. Totally 22 members from 13 families had history of seizures with average age of seizure onset at 18 years. Ten family members had JME, three had epilepsy with GTCS, two had juvenile absence epilepsy, one had adult onset myoclonic epilepsy and six of the affected individuals had unclassified type of epilepsy. In five families, JME was the solely clinical feature. JME dominated among siblings, while phenotypic heterogeneity was observed in second and third degree relatives. In three multi-generation families, members with adult onset genetic generalized epilepsies (GGE) were identified.ConclusionWe found phenotypic heterogeneity regarding epilepsy type and age of seizure onset. Using pedigree analysis, we found no evidence for preferential maternal or any other distinctive inheritance pattern. Further study is needed to confirm and clarify the results.     

How to diagnose and classify idiopathic (genetic) generalized epilepsies

Idiopathic or genetic generalized epilepsies (IGE) constitute an electroclinically well‐defined group that accounts for almost one third of all people with epilepsy. They consist of four well‐established syndromes and some other rarer phenotypes. The main four IGEs are juvenile myoclonic epilepsy, childhood absence epilepsy, juvenile absence epilepsy and IGE with generalized tonic‐clonic seizures alone. There are three main seizure types in IGE, namely generalized tonic‐clonic seizures, typical absences and myoclonic seizures, occurring either alone or in any combination. Diagnosing IGEs requires a multidimensional approach. The diagnostic process begins with a thorough medical history with a specific focus on seizure types, age at onset, timing and triggers. Comorbidities and family history should be questioned comprehensively. The EEG can provide valuable information for the diagnosis, including specific IGE syndromes, and therefore contribute to their optimal pharmacological treatment and management.     

A study of idiopathic generalised epilepsy in an Irish population.

Idiopathic generalised epilepsy (IGE) is subdivided into syndromes based on clinical and EEG features. PURPOSE: The aim of this study was to characterise all cases of IGE with supportive EEG abnormalities in terms of gender differences, seizure types reported, IGE syndromes, family history of epilepsy and EEG findings. We also calculated the limited duration prevalence of IGE in our cohort. METHODS: Data on abnormal EEGs were collected retrospectively from two EEG databases at two tertiary referral centres for neurology. Clinical information was obtained from EEG request forms, standardised EEG questionnaires and medical notes of patients. RESULTS: two hundred twenty-three patients met our inclusion criteria, 89 (39.9%) male and 134 (60.1%) females. Tonic clonic seizures were the most common seizure type reported, 162 (72.65%) having a generalised tonic clonic seizure (GTCS) at some time. IGE with GTCS only (EGTCSA) was the most common syndrome in our cohort being present in 94 patients (34 male, 60 female), with 42 (15 male, 27 female) patients diagnosed with Juvenile myoclonic epilepsy (JME), 23 (9 male, 14 female) with Juvenile absence epilepsy (JAE) and 20 (9 male, 11 female) with childhood absence epilepsy (CAE). EEG studies in all patients showed generalised epileptiform activity. CONCLUSIONS: More women than men were diagnosed with generalised epilepsy. Tonic clonic seizures were the most common seizure type reported. EGTCSA was the most frequent syndrome seen. Gender differences were evident for JAE and JME as previously reported and for EGTCSA, which was not reported to date, and reached statistical significance for EGTCA and JME.     

Idiopathic generalized epilepsies with versive or circling seizures

OBJECTIVES: To describe the electroclinical features of the idiopathic generalized epilepsies (IGEs) with versive or circling seizures. METHODS: Sixteen patients with versive or circling seizures and interictal electroclinical features of IGE were studied. Patients with insufficient clinical or imaging data, with a follow-up period less than 1 year or with partial seizures in addition to the versive or circling ones were excluded from the study. All patients underwent full interictal clinical and neurophysiological studies. The EEG patterns of 13 versive or circling seizures from 4 patients were also analyzed. RESULTS: A specific IGE syndrome was recognized in 9 out of the 16 patients (56%). More specific, 1 patient had childhood absence epilepsy (CAE), 4 had juvenile absence epilepsy (JAE), and 4 had juvenile myoclonic epilepsy (JME). No specific IGE syndrome was recognizable in the remaining 7 patients (44%). These 7 patients had a juvenile epileptic syndrome (mean age at onset of seizures was 15.7 years) characterized by versive or circling seizures followed or not by generalized tonic-clonic fits. Three main EEG patterns were identified during versive or circling seizures: 1) generalized spike-and-wave discharges at 3-4 cps; 2) generalized polyspike-and-wave discharges at 1 to 2.5 cps beginning with generalized fast activity at 12-14 cps, and 3) generalized spike-and-wave discharges at 3-4 cps intermingled with fast activity at 12-14 cps. Most patients had good response to treatment on a single drug regimen (mainly valproic acid). CONCLUSIONS: Versive or circling seizures may occur in the context of an IGE. Although many individuals share the features of different IGE syndromes including CAE, JAE and JME, a consistent number of patients, who show circling or versive seizures solely, remain without a specific syndromic diagnosis. When occurring in the context of IGE, circling or versive seizures do not worsen the prognosis.     

Idiopathic generalized epilepsy: Phenotypic and electroencephalographic observations in a large cohort from South India

Purpose:

We studied the phenotype and electroencephalographic (EEG) features, and therapeutic aspects of idiopathic generalized epilepsies (IGEs) in South Indian population.

Patients and Methods:

This prospective cross-sectional hospital-based study was carried out on non-consecutive 287 patients (age 22.2 ± 7.7 years; M:F = 139:148) with IGE syndrome. Their clinical and EEG observations were analyzed.

Results:

Majority of the patients had onset of seizures <20 years of age (n = 178; 62%). Thirty one patients (10.8%) had family history of epilepsy. Nearly half of them (49.9%) had <5 years of duration of seizures. The type of IGEs included Juvenile myoclonic epilepsy (JME): 115 (40.1%); IGE with generalized tonic-clonic seizures (GTCS) only: 102 (39.02%); childhood absence epilepsy (CAE): 35 (12.2%); GTCS on awakening: 15 (5.2%); Juvenile absence epilepsy (JAE): 11 (3.8%); and unclassified seizures: 9 (3.1%). The triggering factors noted in 45% were sleep deprivation (20%), non-compliance and stress in 5% each. The EEG (n = 280) showed epileptiform discharges in about 50% of patients. Epileptiform discharges during activation was observed in 40/249 patients (16.1%): Hyperventilation in 32 (12.8%) and photic stimulation in 19 (7.6%). The seizures were well controlled with anti-epileptic drugs (AEDs) in 232 (80.8%) patients and among them, 225 (78.4%) patients were on monotherapy. Valproate (n = 131) was the most frequently prescribed as monotherapy.

Conclusions:

This is one of the largest cohort of patients with IGE. This study reiterates the importance of segregating IGE syndrome and such analysis will aid to the current understanding and management.     

Genome scan of idiopathic generalized epilepsy: evidence for major susceptibility gene and modifying genes influencing the seizure type

Idiopathic generalized epilepsy (IGE) is a common, complex disease with an almost exclusively genetic etiology but with variable phenotypes. Clinically, IGE can be divided into different syndromes. Varying lines of evidence point to the involvement of several interacting genes in the etiology of IGE. We performed a genome scan in 91 families ascertained through a proband with adolescent-onset IGE. The IGEs included juvenile myoclonic epilepsy (JME), juvenile absence epilepsy (JAE), and epilepsy with generalized tonic clonic seizures (EGTCS). Our linkage results support an oligogenic model for IGE, with strong evidence for a locus common to most IGEs on chromosome 18 (lod score 4.4/5.2 multipoint/two-point) and other loci that may influence specific seizure phenotypes for different IGEs: a previously identified locus on chromosome 6 for JME (lod score 2.5/4.2), a locus on chromosome 8 influencing non-JME forms of IGE (lod score 3.8/2.5), and, more tentatively, two newly discovered loci for absence seizures on chromosome 5 (lod scores 3.8/2.8 and 3.4/1.9). Our data also suggest that the genetic classification of different forms of IGE is likely to cut across the clinical classification of these subforms of IGE. We hypothesize that interactions of different combinations of these loci produce the related heterogeneous phenotypes seen in IGE families.     

Clinical characteristics of a South Indian cohort of juvenile myoclonic epilepsy probands.

Despite the distinctive clinical and electroencephalographic features known for five decades, even today, juvenile myoclonic epilepsy (JME) is frequently unrecognised and misdiagnosed in both developed and developing countries. Utilising 183 JME probands belonging to the South Indian state of Kerala, assembled through a tertiary referral centre for molecular genetic studies, we explored the phenotypic peculiarities, clinical genetics, and problems and pitfalls in the diagnosis of JME. At referral, only six (3.3%) patients carried the diagnostic label of JME, default in diagnosis resulted from failure to elicit the history of myoclonic jerks by the referring physicians. During the mean delay of 8.6 +/- 7.0 years in diagnosing JME, seizure control in the majority was poor due to inappropriate antiepileptic drug (AED) therapy. A history of epileptic seizures was obtained in 6.2% of the first-degree and 2.2% of the second-degree relatives of the probands; 37.7 and 11.1% of them, respectively, were diagnosed as JME. Although most of the clinical features of our cohort were in accordance with the literature, two notable differences we observed were the relatively increased occurrence of absence seizures and low frequency of photoparoxysmal responses. Although the variability in the clinical characteristics of JME may be apparent due to differences in the ascertainment of the data, they may well be an expression of a true clinical heterogeneity, and are in accordance with the complex and variable mode of inheritance and conflicting linkage studies reported for this syndrome from different ethnic groups.     

Focal clinical and electroencephalographic features in patients with juvenile myoclonic epilepsy

Jayalakshmi SS, Srinivasa Rao B, Sailaja S. Focal clinical and electroencephalographic features in patients with juvenile myoclonic epilepsy.
Acta Neurol Scand: 2010: 122: 115–123.
© 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objective – To identify prevalence and factors associated with occurrence of focal clinical and electroencephalogram (EEG) abnormalities in patients with juvenile myoclonic epilepsy (JME). Materials and methods – Clinical asymmetries in the seizures and focal EEG abnormalities were analyzed in 266 patients with JME. Results – All the patients had myoclonic jerks (MJ) and generalized tonic‐clonic seizures (GTCS); 56 (21%) had absence seizures. Asymmetry in clinical seizures was reported in 45 (16.9%) and focal EEG abnormalities were noted in 92 (45.5%) patients. Amplitude asymmetry or focal onset of generalized discharges was noted in 41 (44.6%) and independent focal EEG abnormalities in 30 (32.6%) patients. A statistically significant association was seen with the presence of GTCS and MJ (P = 0.007), a family history of epilepsy (P = 0.001) and drug resistance (P = 0.04) and the occurrence of focal EEG abnormalities. Conclusion – Patients with JME showed focal clinical and EEG features. These features should not be misinterpreted as indicative of partial epilepsy.     

Exploration of a putative susceptibility locus for idiopathic generalized epilepsy on chromosome 8p12

PURPOSE: A recent genome-wide scan revealed a major susceptibility locus for idiopathic generalized epilepsies (IGEs) in the chromosomal region 8p12 in 32 IGE families without members with juvenile myoclonic epilepsy (JME). This study explored the presence of an IGE locus in the chromosomal region 8p12. METHODS: Our study included 176 multiplex families of probands with common IGE syndromes. Parametric and nonparametric multipoint linkage analyses were carried out between the IGE trait and six microsatellite polymorphisms encompassing the putative susceptibility locus. To explore the associated phenotype-genotype relation, two distinct subgroups of families were selected by the presence (n = 64) or absence (n = 112) of a family member with JME. To adjust the phenotypic spectrum toward adolescent-onset IGEs, a third subgroup of 28 families without JME was chosen through an IGE proband with seizure onset at age 10-20 years. RESULTS: Parametric and nonparametric multipoint linkage analyses provided no evidence for linkage between IGE and markers encompassing the putative IGE locus in the chromosomal region 8p12. Furthermore, we found no hint of linkage along the candidate region in any of the three family subgroups. CONCLUSIONS: We failed to provide evidence for a major IGE locus in the chromosomal region 8p12. On the contrary, these parametric linkage results provide strong evidence against linkage across the candidate region under a broad range of genetic models. If there is a susceptibility locus for IGE in the chromosomal region 8p12, then the size of the effect or the proportion of linked families is too small to detect linkage in the investigated family sample.     

Clinical features, EEG findings and diagnostic pitfalls in juvenile myoclonic epilepsy: a series of 63 patients

Juvenile myoclonic epilepsy (JME) is a common idiopathic generalized epileptic syndrome distinctively characterized by myoclonic jerks often associated to generalized tonic-clonic seizures (GTCS) and typical absence seizures. In spite of typical clinical and EEG profiles, JME is widely underdiagnosed. In the present study we retrospectively revised clinical and EEG data of JME patients referring to our Epilepsy Service. A diagnosis of JME could be made in 63 patients, that is 5.7% of all the epileptic patients referring to our Service and 25.9% of those suffering from an idiopathic generalized epilepsy. General features as well as modality of onset and course of the syndrome of our JME subjects were in accordance with literature. Regarding EEG findings, asymmetries were detected in 38.1% of cases. At referral to our Service only 31.7% of JME patients were correctly diagnosed. Main factors responsible for misdiagnosis were failure in eliciting a history of myoclonic jerks and misinterpretation of myoclonic jerks as simple partial seizures. EEG asymmetries were misleading in 13 patients. In conclusion, a correct JME diagnosis is strictly dependent on the knowledge of the syndrome leading the interviewer to look for and correctly interpret myoclonic jerks whereas EEG is just an ancillary diagnostic tool.     

De novo late‐onset absence status epilepticus or late‐onset idiopathic generalized epilepsy? A case report and systematic review of the literature

Aim. Idiopathic (genetic) generalized epilepsies (IGEs) are age‐related epileptic syndromes with typical age onset in childhood or adolescence. We report a patient with de novo late‐onset absence status epilepticus (ASE) occurring at the age of 64 years, with clinical and EEG features suggestive of late‐onset IGE. We also discuss the relationship between de novo late‐onset ASE and late‐onset IGE, and provide a comprehensive and critical review of the available literature on late‐onset (i.e. onset ≥60 years) IGE. Methods. MEDLINE (1966–2016 [23^th April]) was systematically searched in order to identify reports of patients with late‐onset IGE. Grey literature was also comprehensively searched. Results. We identified nine patients with electroclinical features suggestive of late‐onset IGE. Median age at seizure onset was 71 years (range: 60–80), with a female prevalence (67%). A family history of epilepsy was reported in 67% of cases. All patients had generalized tonic‐clonic seizures, and 44% also had myoclonic seizures. Treatment and outcome were reported for six patients; all of whom reached seizure freedom under monotherapy with valproic acid (83%) or lamotrigine (17%) (range of follow‐up: 3 to 24 months). Conclusion. Late‐onset IGE are entities with unknown prevalence and incidence, and should be differentiated on the basis of late‐onset reactivation of previous IGE. Late‐onset IGEs are probably unrecognized or misdiagnosed, based on a common misconception that all elderly individuals with first‐ever seizures have focal symptomatic epilepsy. Late‐onset IGE should be actively investigated by accurate history taking aimed at identifying seizures, which may have been unnoticed, and familial antecedents of epilepsy. In elderly patients presenting with de novo late‐onset ASE, a diagnosis of late‐onset IGE should be considered in the differential diagnosis, particularly in atypical cases (e.g. absence of triggering factors, coexistence of generalized tonic‐clonic or myoclonic seizures, and interictal generalized epileptiform discharges).     

Phenotypic analysis of juvenile myoclonic epilepsy in Indian families

OBJECTIVES: Phenotypic analysis of juvenile myoclonic epilepsy (JME) is presented to document the variations in disease expression. MATERIAL AND METHODS: Information on seizure type and frequency, seizure precipitating factors, electro-encephalographic (EEG) data, response to antiepileptic drugs (AEDs) and family history was collected on 500 Indian probands and 61 relatives with JME. RESULTS: The overall clinical features, EEG characteristics, and familial occurrence were similar to other reports. JME probands and relatives having absences (56 of 561, 10%), those with only myoclonic jerks (MJ) or MJ with one generalized tonic clonic seizure (GTCS) in remission without treatment (five of 561, 1%) and those who required valproic acid (VPA) and another AED for seizure control (19 of 561, 3%) are examples of differential disease expression within JME. Seizures among those having photoparoxysmal response (PPR) on EEG responded very well to VPA alone while those with all three seizure types (MJ, GTCS and absences) were poor responders. CONCLUSIONS: Recognition of clinical 'subtypes' among JME could have therapeutic implications and help improve JME phenotypic characterization for molecular studies.     

Idiopathic generalized epilepsies misdiagnosed as partial epilepsies

Idiopathic generalized epilepsy (IGE) is often not recognized with serious consequences on the sufferers. We examined factors contributing to the missed diagnosis of IGE in 41 adults attending our epilepsy clinic with diagnosis of partial epilepsy who had semiology or EEG findings suggesting a possible differential diagnosis. After careful re-evaluation, the diagnosis of IGE was established in 25 patients: 22 (88%) with JME, one with juvenile absence, one with perioral myoclonia with absences, one with eyelid myoclonia with typical absences. Myoclonic jerks, the hallmark of the JME and other IGE, were not usually reported by patients or misdiagnosed as focal motor seizures. Brief and infrequent absence seizures and focal EEG abnormalities were other factors contributing to not recognizing JME. All 25 patients did not achieve seizure control before re-evaluation of diagnosis. After appropriate diagnosis of IGE and change of AED to valproate or valproic acid, 19 (76%) became seizure free and six (24%) had a significant improvement on seizure control. Association with lamotrigine provided further improvement in three of these patients. An appropriate questioning to identify myoclonic and absence seizures and a proper interpretation in the context of whole clinical constellation are essential for a correct seizure classification and diagnosis of IGE in adults.