Observations on juvenile myoclonic epilepsy amongst ethnic Bengalees in West Bengal—An Eastern Indian State

Current Concepts in the Management of Idiopathic Generalized Epilepsies

Idiopathic generalized epilepsies (IGEs) are a group of epilepsies characterized by an underlying genetic predisposition and a good response to antiseizure medicines (ASMs) in the majority of the patients. Of the various broad-spectrum ASMs, valproate is the most effective medicine for the control of seizures in IGEs. However, with the availability of many newer ASMs and evidence showing the high teratogenic potential of valproate, the choice of ASMs for IGEs has become increasingly difficult, especially in women of the child-bearing age group. In this article, we review the current evidence regarding the efficacy and safety of various ASMs in patients with IGEs and provide practical guidelines for choosing appropriate ASMs in various subgroups of patients with IGEs.

Juvenile myoclonic epilepsy: Long-term prognosis and risk factors

OBJECTIVE

Our goal was to investigate the long-term clinical course of juvenile myoclonic epilepsy (JME) in a cohort of patients and to identify prognostic factors for refractoriness and seizure relapse after anti-seizure medications (ASMs) withdrawal. A literature review is also presented to consolidate and compare our findings with the previously reported cases.

METHODS

We retrospectively studied a series of patients diagnosed with JME with 15 years or more of evolution. We collected clinical, neurophysiological and neuroimaging data from patients who met defined inclusion and exclusion criteria.

RESULTS

Study involved 61 patients (65.5% female) with mean age at study of 37.6 years, and mean age at its outset of 14.8 years. Median follow-up was 31.0 years (mean 28.9, range 15-53). They presented more frequently with a combination of myoclonic and generalized tonic-clonic seizures (GTCS) (65.6%). Sixty-five percent of patients (n = 40) had a 5-year terminal remission with a mean age at last seizure of 27.4 years. Thirty-two percent of seizure-free patients (n = 13) withdrew ASMs: 6 out of 13 had a recurrence of the seizures while 7 remained seizure-free (mean age at ASMs withdrawal 21.0 versus 35.7 years, p < 0.05). In the multivariate model, a high GTCS frequency at onset (p = 0.026) was a prognostic factor of drug resistance.

CONCLUSION

JME is often regarded as a benign epileptic syndrome, although a quarter of the individuals have refractory epilepsy. The possibility of withdrawing ASMs in patients who have been free of seizures over an extended time seems feasible.

Source localization of epileptiform discharges in juvenile myoclonic epilepsy (JME) using magnetoencephalography (MEG)

OBJECTIVE

The purpose of this study is to localize the sources of epileptiform discharges (EDs), in juvenile myoclonic epilepsy (JME) using Magnetoencephalography (MEG), at three different time instances and analyze the propagation of EDs, from onset to offset, for inferring the cortical and subcortical region of involvement.

METHODS

Twenty patients (age 23.5±6.3years old) with JME were recruited in this prospective study. MEG source analysis was performed on the independently collected EDs of each patient. The distributed source model was employed for source localization using low resolution electromagnetic brain tomography (LORETA). In each EDs, the onset (leading edge of the spike from baseline), peak and offset (trailing edge of the spike), with time window of 8ms, were subjected for source localization in order to study the propagation of the EDs. The obtained source location coordinates, from each individual MRI, were transformed in Talairach space and the distribution of region of source involvement was analysed.

RESULTS

The frequency pattern of lobar distribution at onset, peak and offset respectively suggest that discharges most commonly localized at onset from sublobar region, at peak from frontal lobe and at offset from the sublobar region. It was observed that the maximum involvement of sources from the sublobar, limbic and frontal lobes at different time instances. It indicates that the restricted cortical-subcortical involvement during the generation and propagation of EDs in JME.

SIGNIFICANCE

This MEG study supported the cortical-subcortical region of involvement and provided further insights in our understanding the network involvement in generation and propagation of EDs in JME.

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.

Epidemiology of juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is a widely recognized presumed genetic, electroclinical idiopathic generalized epilepsy syndrome. The prevalence of JME in large cohorts has been estimated to be 5% to 10% of all epilepsies and around 18% of idiopathic generalized epilepsies but may be lower in some settings. There is a marked female predominance. However, some of the basic epidemiology of JME is not well known, possibly because the syndrome is not sharply defined. A questionnaire study about the diagnostic criteria for JME suggests that diagnosis of JME can be made with the history of myoclonus plus a single generalized tonic-clonic seizure plus generalized fast spike-waves or polyspike-waves on the EEG. However, until these diagnostic criteria are fully accepted, the detailed epidemiology of JME will remain imprecise.

Juvenile myoclonic epilepsy

Juvenile myoclonus epilepsy (JME) is a common epileptic syndrome, the etiology of which is genetically determined. Its onset occurs from 6 through 22 years of age, and affected patients present with myoclonic jerks, often associated with generalized tonic-clonic seizures - the most common association - and absence seizures. JME is non-progressive, and there are no abnormalities on clinical examination or intellectual deficits. Psychiatric disorders may coexist. Generalized polyspike-and-waves are the most characteristic electroencephalographic pattern. Usual neuroimaging studies show no abnormalities. Atypical presentations should be entertained, as they are likely to induce misdiagnosis. Prevention of precipitating factors and therapy with valproic acid (VPA) are able to control seizures in the great majority of patients. Whenever VPA is judged to be inappropriate, other antiepileptic drugs such as lamotrigine may be considered. Treatment should not be withdrawn, otherwise recurrences are frequent.