Myoclonic-atonic Seizures Research Articles

Myoclonic epilepsy in a child with 17q22–q23.1 deletion

Interstitial deletions of the long arm of the chromosome 17 are relatively rare. Up to 17 cases involving the q22-q23.3 band have been reported so far. A common phenotype has not yet been delineated and epilepsy has been reported in only 2 out of 17 cases. We describe a clinical phenotype of epilepsy characterized by myoclonic atonic and absence seizures in a 6-year-old boy carrying a de novo 17q22q23 deletion detected by oligonucleotide array comparative genomic hybridization (aCGH).

Epilepsy With Myoclonic Atonic Seizures: An Electroclinical Study of 69 Patients

Epilepsy with myoclonic-atonic seizures is characterized by myoclonic-atonic, absence, tonic-clonic, and eventually tonic seizures, appearing in previously normal children at ages 18-60 months. We analyzed the electroclinical features, treatment, and outcome of 69 patients with myoclonic-atonic seizures; these patients were followed between 1990 and 2012 at the Juan P. Garrahan Pediatric Hospital, Buenos Aires, Argentina. No structural or metabolic etiology was identified. Based on the electroclinical features and evolution, two groups could be distinguished. The first group of 39 patients with myoclonic and myoclonic-atonic seizures with or without generalized tonic-clonic seizures and absences associated with generalized spike- and polyspike-and-wave paroxysms had excellent prognoses. The second group of 30 patients had myoclonic jerks and myoclonic-atonic seizures associated with other seizure types including tonic seizures; some had myoclonic status epilepticus andcognitive deterioration. The interictal EEG showed frequent generalized spike- and polyspike-and-wave paroxysms. In 16 patients, the seizures remitted within 3.6 years. The two groups were distinguished in retrospect, when enough time had elapsed to evaluate cognitive deterioration and different seizure types. In conclusion, epilepsy with myoclonic atonic seizures is an epileptic syndrome with a broad clinical spectrum and variable prognosis.

Is the ketogenic diet effective in specific epilepsy syndromes?

Is the ketogenic diet (KD) more effective in certain epilepsy syndromes? The KD has been shown to be effective in treating multiple seizure types and epilepsy syndromes. We review the effectiveness of the KD in Dravet syndrome, epilepsy with myoclonic-atonic seizures, mitochondrial disease, tuberous sclerosis, late infantile and juvenile neuronal ceroid lipofuscinosis, and febrile infection-related epilepsy syndrome. In certain epilepsy syndromes, like epilepsy with myoclonic-atonic seizures, the diet should be considered early in the course of treatment.

Efficacy of the ketogenic diet: Which epilepsies respond?

We report the efficacy of the ketogenic diet in refractory epilepsies focusing on outcomes with regard to epilepsy syndromes and etiology in children and adults with refractory epilepsy. Sixty-four consecutive children and four adults were prospectively enrolled from 2002 to 2009; seven were excluded from analysis. The classical ketogenic diet was initiated on an inpatient basis with dietary ratios ranging from 2:1 to 4:1 fat to carbohydrate and protein. Patients were classified according to syndrome and etiology using the 1989 and more recent 2010 International League Against Epilepsy (ILAE) classification systems. Responders were defined as >50% reduction in seizure frequency compared to baseline. Syndromes included symptomatic generalized (52), genetic (idiopathic) generalized (7), and focal epilepsies (2) and etiologies included structural (24), genetic (18), and unknown (19). Twenty-nine (48%) of 61 patients were responders at 3 months. Two children became seizure-free: one with focal epilepsy of unknown etiology and another with refractory childhood absence epilepsy. Responsive syndromes included migrating partial epilepsy of infancy, childhood absence epilepsy, focal epilepsy, epilepsy with myoclonic-atonic seizures, and Dravet syndrome. Children with lissencephaly and hypoxic ischemic encephalopathy had surprisingly good responses. The ketogenic diet is an effective treatment for children and adults with refractory epilepsy. The response is predicted by type of epilepsy syndrome. Accurate characterization of the electroclinical syndrome is an important factor in decisions about timing of initiation of the ketogenic diet.

Electroclinical features of myoclonic-atonic epilepsy

To summarize the electroclinical characteristics of myoclonic atonic epilepsy (MAE) in children. The clinical data, video electroencephalogram (EEG) and simultaneous electromyography (EMG) of MAE patients were analyzed. The treatment and its effects were followed up. In 47 MAE patients, 25 had a history of febrile seizures (FS), 20 had a family history of FS or epilepsy. All patients had a normal development before the illness. The age of afebrile seizure onset was between 1.4 years to 5.8 years. The first seizure was generalized tonic-clonic seizure (GTCS) in 41 patients (87.2%). All patients had multiple seizure types, including 47 GTCS (97.9%), 34 myoclonic atonic seizures (72.3%), 47 myoclonic seizures (100%), 32 atonic seizures (68.1%), 36 atypical absences (76.6%) and 3 tonic seizures (6.4%). EEG backgrounds were slow or parietal θ rhythm, interictal EEG showed 1-4 Hz (predominant 2-3 Hz) generalized spike and wave or poly spike and wave discharges in all cases. Seizures were controlled by antiepileptic drugs (AEDs) in 41 patients (87.2%). Valproate was used in 37. Lamotrigine was used in 26. Mild mental retardation was observed in 10 children after the onset of the illness. The clinical features of MAE included the following: the development was normal before the onset of the illness; the onset of seizure type was often GTCS. All patients had multiple generalized seizure types. Myoclonic atonic seizure was its characteristic seizure type. EEG showed generalized discharges. Early diagnosis and rational choice of AEDs are important for getting a better prognosis.

Does genotype determine phenotype?

The field of epilepsy genetics has made huge leaps in the last decade and now forms part of the clinician's diagnostic armamentarium. The gene with the greatest clinical import to date is undoubtedly SCN1A , which encodes the α1 subunit of the neuronal sodium channel. Mutations were first identified in this pore-forming subunit gene in genetic epilepsy with febrile seizures plus (GEFS+).1 This followed the initial discovery of mutations in a sodium channel auxiliary subunit gene SCN1B , encoding the β1 subunit, in GEFS+.2 GEFS+ is a familial epilepsy syndrome with a spectrum of characteristic yet heterogeneous phenotypes with febrile seizures followed by patterns of generalized and sometimes focal seizures. While generally a benign disorder, the GEFS+ spectrum encompasses epileptic encephalopathies including epilepsy with myoclonic-atonic seizures and Dravet syndrome (DS).3 DS begins with infantile onset of febrile hemiclonic status epilepticus and evolves to a pattern of multiple seizure types including focal, myoclonic, absence, and atonic seizures. Development is normal during the first year with subsequent slowing, poor outcome, and intellectual disability in most cases. The predilection to febrile seizures led to mutational analysis of SCN1A in DS in 2001 and, as they say, the rest is history.4 SCN1A is now a diagnostic test for DS, with >70% of patients having mutations detectable by …

Doose syndrome (myoclonic–astatic epilepsy): 40 years of progress

Doose syndrome, otherwise traditionally known as myoclonic-astatic epilepsy, was first described as a unique epilepsy syndrome by Dr Hermann Doose in 1970. In 1989, the International League Against Epilepsy classified it formally as a symptomatic generalized epilepsy, and 20 years later it was renamed 'epilepsy with myoclonic-atonic seizures'. In this review, we discuss the components of this unique disorder including its incidence, clinical features, and electroencephalographic findings. Recent evidence has suggested possible genetic links to the GEFS+ (generalized epilepsy with febrile seizures plus) family, and, additionally, some children with structural brain lesions can mimic the Doose syndrome phenotype. Treatment strategies such as corticosteroids, ethosuximide, and valproate have been described as only partially effective, but newer anticonvulsants, such as levetiracetam and zonisamide, may provide additional seizure control. The most effective treatment reported to date appears to be the ketogenic diet. Prognosis is quite varied in this disorder; however, many children can have a remarkably normal neurodevelopmental outcome.

Electrophysiological characterisation of myoclonicatonic seizures in symptomatic continuous spike‐waves during slow sleep syndrome

Sudden epileptic falls are frequently reported in continuous spike-waves during slow sleep (CSWS) syndrome. Inhibitory seizures are usually considered as the underlying mechanism. However, published polygraphic recordings are rare. We report the case of a 22 month-old boy suffering from a symptomatic CSWS syndrome associated with a perinatal stroke involving the right middle cerebral artery territory. He presented with psychomotor regression and daily multiple falls related to myoclonic-atonic seizures. Neurophysiological examination showed secondary generalized myoclonus systematically correlated with a bilateral spike spreading from the right central area. This confirms that positive myoclonus, in addition to negative myoclonus, may be responsible for epileptic falls in CSWS syndrome. [Published with video sequences].

Lipofuscinosis neuronal ceroidea infantil tardía: aspectos clínicos y electroencefalográficos

In this paper we describe the clinical characteristics, and particularly the epileptic seizures and electroencephalographic findings, in 15 patients with a pathology diagnosis of late infantile neuronal ceroid lipofuscinosis (NCL). Nine female and six male patients were studied and their clinical records covering the period February 1990 to June 2003 were analysed. Neuroimaging, neurometabolic studies, ERG, PE and repeated EEG were carried out in all cases. The mean age on onset of the disease was 3 years (range: 1-5 years). The initial symptom was epilepsy in all cases. Massive myoclonias and myoclonic-atonic seizures were the most frequent kinds of attacks. Focal myoclonias were observed in six patients. Other types of epileptic seizures observed included generalised tonic-clonic, absence, motor focal and complex focal. The epileptic seizures were resistant to therapy. Progressive neurological and visual impairment, pyramidal and cerebellar signs, as well as mental retardation were present in all cases. Intercritical EEG recordings showed diffuse paroxysms with spike and polyspike waves, multifocal spikes and, less often, focal spikes that were predominant in posterior regions. Photostimulation showed high amplitude (300-450) occipital spikes during the application of light stimulation between 1 and 8 Hz. ERG, VEP and SSEP results were pathological. Images showed signs of brain and cerebellar atrophy. Seven of the patients died between 8.5 and 11 years of age. Late infantile NCL must be considered in the case of a child aged between 1 and 5 years who presents seizures that are predominantly generalised myoclonias and myoclonic-atonic, in association with progressive neurological deterioration including pyramidal, cerebellar and visual signs and an EEG trace showing occipital paroxysms triggered by low frequency photostimulation.

Twenty years of ictal EEG-EMG.

This study aimed to evaluate the use of ictal EEG recordings combined with simultaneous surface EMG in the diagnosis and analysis of motor events, both epileptic and nonepileptic. All ictal registrations were performed utilizing radio/cable telemetry. Routine recordings consisted of 18-channel EEG plus 8-channels bipolar surface EMG in freely moving patients. Combined ictal EEG-EMG recordings in freely moving patients enabled us to identify and define the following pathomechanisms of epileptic drop seizures, epileptic axial spasms, atonic, myoclonic-atonic, and akinetic seizures. Precise differentiation could be made between tonic and nontonic postural seizures and between startle-induced reflex seizures and hyperekplexia. The findings from telemetered ictal recordings in freely moving patients with combined EEG and surface EMG offer the only means of identifying, defining, and differentiating motor events, both epileptic and nonepileptic, of a short duration that cannot be properly differentiated by clinical examination alone.

Epileptic Syndromes in Infancy and Childhood: Recent Advances

Epileptic syndromes are more reliable than etiology in determining prognosis and optimal treatment in infants and children. Benign neonatal and infantile convulsions are either idiopathic or dominantly inherited, the latter being genetically nonallelic. Forms of idiopathic generalized epilepsy (IGE) include absence epilepsy, benign myoclonic epilepsy of infancy, and epilepsy with generalized myoclonic atonic seizures. Forms of idiopathic partial epilepsy include benign partial epilepsy with centrotemporal spikes (BECT), benign partial epilepsy with occipital paroxysms, idiopathic partial epilepsy with affective seizures, and benign partial epilepsies with extreme somatosensory evoked potentials (SEPS). These idiopathic epilepsies appear to result from a multifactorial genetic predisposition. The diagnosis is based on strict clinical and EEG criteria. In epileptogenic encephalopathies, cognitive disorders are the main feature and are linked to so-called interictal abnormalities. Some epileptic syndromes, particularly myoclonic epilepsies, remain unclassifiable because of poor understanding of nosology or heterogeneous outcome.

Electroclinical seizures in Lennox-Gastaut syndrome.

We analyzed electroclinical seizures observed by long video split-screen recording in 21 patients with Lennox-Gastaut syndrome (LGS). All patients had atypical absence seizures, 18 (81%) had tonic seizures, and 4 (21%) had myoclonic-atonic seizures. Tonic seizures were axial with flexion or extension of the head or trunk, or global with generalized tonic spasm mimicking infantile spasm, or involved the eyeballs only (either brief, with upward deviation of eyeballs or long, with oscillatory nystagmus). EEG showed either a bilateral 10-13-Hz rhythm or generalized synchronous spike wave at 3 Hz. Myoclonic-atonic seizures involving limbs, trunk, or neck were either brief or massive; the discharges were 2-3.5-Hz spike wave. Atypical absence seizures evolved gradually, terminated abruptly, and manifested alone or with subtle motor activity or oral automatism. EEG discharges were variable and of different types: (a) Diffuse irregular spike wave at 2-2.5 Hz with or without fragmentation (consciousness was regained during fragmentation or when spike wave discharges were < 2 Hz), (b) irregular diffuse fast activity at 10-13 Hz, or (c) a combination of fast spike wave or sharp waves of increasing amplitude followed by synchronous spike wave discharges at 3 Hz.

Video-EEG analysis of drop seizures in myoclonic astatic epilepsy of early childhood (Doose syndrome).

We studied 36 drop seizures in 5 patients with myoclonic astatic epilepsy of early childhood (MAEE) with simultaneous split-screen video recording and polygraph. Sixteen were falling attacks and 20 were either less severe attacks exhibiting only deep head nodding or seizures equivalent to drop attacks in terms of ictal pattern but recorded in the supine position. All seizures except those that occurred in patients in the supine position showed sudden momentary head dropping or collapse of the whole body downward. Recovery to the preictal position was observed in 0.3-1 s. As a result of carefully repeated observations, the 36 seizures were classified as myoclonic flexor type in 9, myoclonic atonic type in 2, and atonic type, with and without transient preceding symptoms in the remaining 25. The MF seizure was characterized by sudden forward flexion of the head and trunk as well as both arms, which caused the patient to fall. In the myoclonic atonic seizure, patients showed brief myoclonic flexor spasms, immediately followed by atonic falling. The AT seizure showed abrupt atonic falling, with and without transient preceding facial expression change and/or twitching of extremities. The ictal EEGs of all 36 seizures exhibited generalized bilaterally synchronous single or multiple spike(s) and wave discharges. Atonic drop attacks appear to be a common cause of ictal epileptic falling in MAEE.

The axial spasm--the predominant type of drop seizure in patients with secondary generalized epilepsy.

In 45 patients suffering from secondary generalized epilepsy, we have recorded 239 drop seizures both by radio-telemetered EEG/split-screen video taping and polygraphically. Twenty of these patients had pure tonic drop seizures. Nine patients each had myoclonic-atonic or pure atonic seizures, whereas seven had slow falls that occurred during gradually developing tonic or akinetic seizures. We term the pure tonic drop seizure "axial spasm." It consists of a uniform pattern of movement lasting from 0.5 to 0.8 s and leading to a specific bearing characterized by a moderate flexion of the hips, the upper trunk, and the head. The arms are almost always involved being abducted, elevated and in a semiflexed position. A fall is provoked by the rapidity and violence of the flexion in the hips. The spasms can occur independently (pure axial spasm) or in connection with other seizure manifestations (combined axial spasm). In pure spasms, no disturbance of consciousness and no significant EEG changes--apart from a slight attentuation--are seen. In the combined axial spasms, distinct epileptic phenomena, in close connection with the axial spasms, can be observed, appearing either in the postspasm phase or in both the pre- and the afterphases. The prephase consists always of an absence and spike-and-wave activity. The onset of the spasm coincides with the last generalized spike, which is followed by a biphasic high-voltage slow wave. In the afterphases, various seizure patterns can be seen; quite characteristic are arrest states during which the patients are completely immobile and take up a postural-like or athetoid position. Almost as frequent are absences or absence-like states and tonic seizures. The afterphase can be compounded by two or three of these seizure patterns, the most common sequence of events in these cases being tonic--arrest state--absence. From the clinical and neurophysiological points of view, axial spasms can be regarded as a more mature form of infantile spasms. Clinical and experimental findings suppose a brainstem origin.