Juvenile myoclonic epilepsy: clinical and EEG features

We aimed to characterize the clinical profile and EEG features of 43 patients with juvenile myoclonic epilepsy. In a retrospective design we studied the records of, and re-interviewed, 43 patients diagnosed with JME from the epilepsy clinic data base. Furthermore, available EEGs were re-evaluated. Of the patients 72% were female and 28% male. Average age of onset was 13 (5.5–22) years for absences, 16 (5.2–25) years for myoclonic seizures, and 16 (8–29) years for generalized tonic–clonic seizures. Forty-two percent reported asymmetric or unilateral myoclonic jerks. Commonly reported precipitating factors were sleep deprivation (84%), stress (70%), and alcohol consumption (51%). EEG findings included rapid spike-wave and polyspike-wave.     

Juvenile myoclonic epilepsy: a study in Sri Lanka.

Juvenile myoclonic epilepsy (JME) has a distinct clinical profile. Often JME is not recognized, with the result that proper treatment is not instituted, leading to poor control of seizures. This study is an attempt to identify the factors that contribute to the delay in diagnosing this condition. During a period of 3 years 40 patients (21 females) with JME were identified and all were included in a prospective follow-up study. The age range was 12-58 years. Twenty-seven patients (67%) had already seen at least one specialist; however, diagnosis had not been made despite the presence of characteristic features. The duration of delay in diagnosis varied from months to years with a mean of 11 years. Myoclonic jerks were the most characteristic feature, but only six volunteered this information spontaneously. The response to treatment with sodium valproate was excellent, although only three were taking it when first seen. As a result of treatment with other drugs all patients were having recurrent seizures. The main reasons for the delay in diagnosis found in our study were that the physicians were unaware of the condition, the occurrence of myoclonic jerks were overlooked either because the patients were not directly questioned about them or because the patients did not volunteer the information.     

Juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy is an age-related form of idiopathic generalized epilepsy (mean age of onset: 12-14 years). The diagnosis is based on a cluster of clinical features: types of seizures, namely myoclonic jerks associated with generalized tonic-clonic or clonic-tonic-clonic seizures in 90% of the cases, absence seizures in one third of the cases; triggering factors and circadian rhythm of seizures on awakening or after sleep deprivation; a characteristic EEG pattern, i.e. bilateral symmetrical polyspike-waves. The clinical pattern is so suggestive that in clinical practice EEG is not necessary. Seventy percent of the patients are seizure-free with one-drug therapy. Treatment must be life-long, as relapse occurs in most cases after drug withdrawal, whatever the duration of control.     

Juvenile myoclonic epilepsy of Janz: clinical observations in 60 patients.

We studied 60 patients with juvenile myoclonic epilepsy (JME). There was a high positive family history for epilepsy (33.3%). Age at onset of epilepsy ranged from 4 to 18 years with an average of 13.9 years. 88.3% of patients were seizure-free. The most effective drug was valproate. In eight patients drug withdrawal was attempted but all patients relapsed during a follow-up period of 1 year. Video-EEG studies were performed in eight newly diagnosed patients; myoclonic jerks were recorded in five patients.     

Juvenile myoclonic epilepsy misdiagnosed as focal epilepsy: variability of myoclonic seizures

We report two male patients with juvenile myoclonic epilepsy. They had been diagnosed as having partial epilepsy for three years. They had various myoclonic seizures characterized by truncal and head torsion, stepping backward, and inability to reach objects, as well as asymmetric myoclonic jerks of the upper extremities. For early diagnosis of juvenile myoclonic epilepsy, it is important to take account of the variability of myoclonic seizures.     

Sleep disturbances in juvenile myoclonic epilepsy: a sleep questionnaire-based study

Sleep and epilepsy share a complex pathophysiological association. Juvenile myoclonic epilepsy (JME) is a common sleep-sensitive epilepsy in which the effect of seizures could have therapeutic implications in terms of sleep disturbances and seizure control. This study aimed to analyze the effect of epilepsy on sleep in patients with JME. Fifty patients on valproic acid (VPA) monotherapy, and age- and gender-matched controls were recruited into this prospective, hospital-based, case-control study after informed consent and screening for inclusion criteria. They underwent a detailed clinical assessment, electroencephalogram (EEG) and neuroimaging, and were administered validated sleep questionnaires, which included the Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI) and NIMHANS Sleep Disorders Questionnaire. The patient and control groups had identical numbers of males and females (M: F=22: 28), without any significant difference in the age and body mass index (BMI). The clinical profile of JME was similar to published literature while the prevalence of EEG abnormalities was less compared to similar studies. The mean ESS and PSQI scores and the number of subjects with abnormal scores on one or both questionnaires were significantly more in patients. Patients had a higher prevalence of sleep disturbances, insomnia and excessive daytime somnolence. No significant seizure- or treatment-related factors influencing sleep could be identified. This study, the first of its kind, revealed that patients with JME have significant sleep disturbances characterized by excessive daytime sleepiness and disturbed night sleep, despite adequate medications and good seizure control. The role of VPA in the genesis of these symptoms needs clarification.     

Juvenile myoclonic epilepsy of Janz

We studied 43 patients, aged 15 to 69 years, whose convulsive seizures were uncontrolled because the syndrome of juvenile myoclonic epilepsy was not recognized. Awakening myoclonic jerks appeared with tonic-clonic (18 patients), clonic-tonic-clonic (24 patients), and absence seizures (17 patients), with a mean age at onset of 13.6 years. Generalized seizures were present in relatives of 17 patients. All patients had diffuse 3 1/2- to 6-Hz multispike-wave complexes. Valproic acid stopped convulsions in 86% of patients. After being free of seizures for 2 years, withdrawal of valproic acid was followed by relapse of convulsions in 12 patients.     

Some clinical and EEG aspects of benign juvenile myoclonic epilepsy

Twelve patients with benign juvenile myoclonic epilepsy (BJME) representing 4% of our population of epileptics (n = 275) are presented. Only two patients (17%) had myoclonic jerks as the only seizure type. Seven (58%) had generalized tonic-clonic seizures (GTCS) and myoclonus. Three patients (25%) had absence seizures (AS), GTCS, and myoclonic jerks. Electroencephalographic evidence of photosensitivity was found in four (33%). Auditory precipitation of seizures was found in one patient. As is the case with other primary generalized epilepsies, the onset of BJME seems to be age specific. In our series the mean age of onset in years was 4.3 for AS, 14.75 for myoclonic jerks, and 16.4 for GTCS. It took an average of 8.5 years from the onset of BJME (range, 2-20 years) and 6.5 years from the onset of GTCS (range, 2 months-6 years) until the condition was properly recognized. Five patients experienced at least one episode of myoclonic status epilepticus. Generalized, paroxysmal, symmetric polyspike and slow wave discharges are the typical EEG finding. These complexes, however, showed considerable interpatient variability. Sleep deprivation proved to be the most valuable activating procedure. Valproic acid monotherapy effectively controlled myoclonic jerks as well as associated GTCS in most patients.     

Juvenile myoclonic epilepsy – a generalized epilepsy syndrome?

Juvenile myoclonic epilepsy (JME) has been classified as a syndrome of idiopathic generalized epilepsy and is characterized by specific types of seizures, showing a lack of pathology using magnetic resonance imaging (MRI) and computed tomography scanning. However, JME is associated with a particular personality profile, and behavioral and neuropsychologic studies have suggested the possible involvement of frontal lobe dysfunction. The development of highly sensitive neuroimaging techniques has provided a means of elucidating the underlying mechanisms of JME. For example, positron emission tomography has demonstrated neurotransmitter changes in the cerebral cortex, quantitative MRI has revealed significant abnormalities of cortical gray matter in medial frontal areas, and ¹H-magnetic resonance spectroscopy has shown evidence of thalamic dysfunction, which appears to be progressive. Such techniques provide evidence of multi-focal disease mechanisms, suggesting that JME is a frontal lobe variant of a multi-regional, thalamocortical 'network' epilepsy, rather than a generalized epilepsy syndrome.     

Absences in juvenile myoclonic epilepsy: a clinical and video-electroencephalographic study

We report a prospective clinical and electroencephalographic study of 19 patients with juvenile myoclonic epilepsy and absence seizures. Absences began 1 to 9 (4.5 +/- 2.5) years before myoclonic jerks and generalized tonic-clonic seizures. Clinical manifestations during the absence ictus showed great variation, ranging from subtle or no overt features to severe impairment of consciousness, and severity was age related. Simple and complex absence seizures can occur in the same patient. The electroencephalographic features were distinct, with many interictal discharges, fragmentation of the paroxysms, and frequent polyspikes of varying numbers and amplitude for each spike-slow wave component. The combined clinical-electroencephalographic manifestations were characteristic and allow differentiation of absences in juvenile myoclonic epilepsy from typical absence seizures in other epileptic syndromes.     

Juvenile myoclonic epilepsy: an autosomal recessive disease

We undertook genetic study of patients with juvenile myoclonic epilepsy (JME) from 17 families. There was a mean of 8 children in each sibship. Siblings were affected in 8 sibships, and some families had more than 2 members affected by JME. Half-siblings and parental involvement were found in only 1 sibship each. The segregation ratio was 0.123 but increased to 0.18 with correction for age of onset. Parental consanguinity was found in 9 (45%) of the sibships. The evidence establishes an autosomal recessive mode of inheritance for JME.     

Juvenile myoclonic epilepsy: Long-term prognosis and risk factors

ObjectiveOur 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.MethodsWe 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.ResultsStudy 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.ConclusionJME 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.     

Juvenile myoclonic epilepsy: non-classic electroencephalographical presentation in adult patients.

Although diagnosis of juvenile myoclonic epilepsy (JME), a common form of idiopathic generalized epilepsy, is based on clinical and electroencephalogram (EEG) criteria, at times clinical symptoms may be misleading, like the occurrence of asymmetric myoclonic jerks. Thus EEG assumes an important role in these cases, it can fail to show the classical polyspike and slow wave (PSW) discharges of JME, specially in a routine evaluation in older patients. We analyzed retrospectively EEG results of 35 patients with JME [Commission on Classification and Terminology of the International League Against Epilepsy (ILAE) Epilepsia 1989; 30: 389] aged 12-44 years. (mean 22.7 years) at first medical evaluation. EEG findings of 35 patients (19 females, 16 males) with JME consisted of normal tracings in 22.9 and 54.3% had at least one normal exam. EEG abnormalities present in 27 patients (77.1%) consisted of isolated generalized slowing in two and generalized discharges in 25: irregular spike and wave complexes (SWC) in 76%; PSW in 48%; SWC faster than 3 Hz in 20%; spikes, sharp waves, and irregular slow waves in 24%; asymmetric generalized epileptiform discharges in 40%; and associated focal paroxysms in 12%. Thus JME is classically associated to PSW on EEG, the most frequent abnormality was irregular SWC. Generalized paroxysms could occur in an asymmetric fashion and rarely associated to focal activity.     

Juvenile myoclonic epilepsy starting in the eighth decade.

Juvenile myoclonic epilepsy (JME) typically begins at age 10-17 years. We present two patients, with no previous history of epileptic seizures, in whom JME began after the age of 70. The clinical picture of these patients did not differ from "typical" JME except for the patient's age and age at epilepsy-onset. We suggest that not only symptomatic epilepsy, but also some idiopathic epilepsies, can begin or can be reactivated in elderly people. This may be more evidence that susceptibility to epileptic seizures is increased after 60 years of age.     

Juvenile myoclonic epilepsy in unexpected age groups

Juvenile myoclonic epilepsy is a well defined, age related epileptic syndrome. Case reports are presented, demonstrating the onset of this syndrome very early in life as well as in old age. Consequently, since the correct diagnosis is of decisive importance with regard to optimal treatment, the search for this syndrome should not be confined to juvenile patients.