Multifocal Discharges Research Articles

Long-term follow-up study of vigabatrin in pretreated children with west syndrome

A multicentre, long-term, open-label, add-on study of vigabatrin was undertaken in 23 pretreated children with infantile spasms. After 3 months of vigabatrin therapy 11 of the 23 patients had become seizure-free. At this time two-thirds of these 11 children still received other antiepileptic drugs (AEDs) in addition to vigabatrin (mostly valproic acid and/or dexamethasone). After a mean follow-up time of 5 1/4 years (range: 4 1/4-6 1/2) 72% of 18 evaluable patients (two children died, three were lost to follow-up) revealed seizure freedom for at least 1 year. The mean duration of vigabatrin therapy had been 2 1/2 years (range: 2 weeks to 4 3/4 years). Two-thirds of the 18 children continued to take AEDs, three of them undergoing vigabatrin monotherapy. Relapses of infantile spasms had occurred in 14% of the children. The rate of vigabatrin side effects (10%) was low. At follow-up, the EEG of 13 and the 18 patients demonstrated focal or multifocal epileptic discharges. Fifty-five percent had developed another epilepsy (focal epilepsy, secondary generalized epilepsy or myoclonic-astatic epilepsy). With respect to mental functions, three children were normal or slightly retarded, four showed moderate retardation and 11 revealed severe or very severe retardation. This long-term result is comparable to that in ACTH studies with unselected patients. The conclusions are: (1) vigabatrin is an effective drug for the short-term and long-term treatment of refractory infantile spasms; (2) the relapse rate is low; (3) vigabatrin is well tolerated; (4) with respect to secondary epilepsies and mental functions the long-term outcome in these pretreated children is similar to that in earlier studies with ACTH or corticosteroids.

Anterior corpus callosotomy: effects in a patient with congenital bilateral perisylvian syndrome and oromotor seizures

Anterior corpus callosotomy was performed in a patient with pseudobulbar palsy, mild mental retardation and intractable epilepsy related to congenital bilateral perisylvian cortical dysplasia. Before surgery, she had daily atonic drop attacks, rare and mainly sleep-related oromotor seizures, and multifocal and diffuse paroxysmal EEG discharges; after callosotomy, less abrupt atonic drop attacks recurred monthly and the EEG epileptiform abnormalities disappeared. Video-EEG sleep recordings revealed the clinically unsuspected serial recurrence of oromotor seizures, probably related to the clinically observed aggravation of dysarthria. New surgical techniques, in addition or alternative to callosotomy, should be developed in order to avoid or reduce the risk of aggravating some types of partial seizures in patients with bilateral cortical displastic lesions, intractable epilepsy and epileptic falls.

The epileptic spectrum in the congenital bilateral perisylvian syndrome. CBPS Multicenter Collaborative Study.

We studied the frequency, clinical and EEG characteristics, and outcome of the epileptic syndrome in 31 patients with a congenital neurologic syndrome characterized by pseudobulbar palsy, cognitive deficits, and bilateral perisylvian polymicrogyria. Seizures were present in 27 of 31 patients (87%) and usually began between the ages of 4 and 12 years; they commonly consisted of atypical absence, atonic/tonic, and generalized tonic-clonic seizures. Partial attacks were present in 26%. EEG demonstrated generalized spike and wave abnormalities and, less frequently, multifocal discharges, predominantly in centro-parietal regions. Seizures were poorly controlled in 65%, with the remaining patients well controlled. Seven patients underwent callosotomy, which resulted in seizure improvement. This study indicates that the epileptic spectrum in this syndrome is broad but follows predictable patterns. Callosotomy is a valuable treatment strategy in those with intractable drop attacks.

Infant-Onset Progressive Myoclonus Epilepsy

We report the clinical, electroencephalographic, neurophysiologic, and neuroimaging findings in eight children with infant-onset progressive myoclonus epilepsy, all of whom had muscle biopsies performed as as part of the diagnostic evaluation. Each child had myoclonic seizures, generalized tonic-clonic seizures, and neurologic regression or marked developmental delay. Four children died before 3 years of age. Electroencephalograms in seven children showed an abnormally slow background with bilateral multifocal paroxysmal discharges but no burst suppression pattern or photoparoxysmal response. Muscle biopsy specimens were submitted for histopathology and respiratory-chain enzyme studies. Nonspecific abnormalities on light microscopy or electron microscopy were found in seven samples, including increased subsarcolemmal deposits of mitochondria or morphologic mitochondrial changes, but no ragged-red fibers were seen. Respiratory-chain enzyme studies were performed on five samples and in three children (all of whom had a history of elevated lactate in serum or cerebrospinal fluid), there were low levels of rotenone-sensitive reduced nicotinamide adenine dinucleotide (NADH) cytochrome c reductase characteristic of a defect in the complex I part of the respiratory-chain pathway. This study has shown that infant-onset progressive myoclonus epilepsy can be distinguished from other myoclonic epilepsy syndromes of infancy by clinical and electrographic features. Furthermore, respiratory-chain enzyme defects are a relatively common cause of infant-onset progressive myoclonus epilepsy. The absence of ragged-red fibers on muscle histopathology does not preclude a mitochondrial enzyme abnormality.

Changes in Cerebral White Matter in a Case of Congenital Muscular Dystrophy (Non-Fukuyama Type)

A 3-year-old Japanese boy with congenital muscular dystrophy (CMD) and normal intelligence is presented. He had not learned to crawl, shuffled on his bottom, and could not walk. At 7 months, his CT-scan had showed periventricular low density and mild ventricular dilatation, and spike or sharp wave discharges were seen on EEG. At three years of age, his CT-scan revealed wide-spread hypodensity in the cerebral white matter, EEG showed multifocal discharges, and MRI showed abnormal high density area in the cerebrum on spin echo image. These findings suggest the existence of an intermediate form of CMD between the Fukuyama type of CMD and the classical occidental type of CMD. The combination of repeated CT and MRI scans seems necessary for the evaluation of CNS abnormalities in CMD.

Complex partial seizures of infancy.

Ictal manifestations of complex partial seizures in infancy have not been described previously. Using long-term video/electroencephalographic and telemetric monitoring techniques, 187 seizures were recorded in 14 infants under 2 years of age. With one exception, the infants were profoundly delayed with intractable seizures. Nine had marked bilateral abnormalities on computed tomographic scan. The seizure manifestations noted most frequently consisted of behavioral arrest with forced lateralized deviation of the head and eyes and tonic upper-extremity extensor stiffening. Complex facial automatisms such as chewing, sucking, mouthing, and blinking were relatively common. Ictal paroxysmal onset was always lateralized on electroencephalograms, whereas the interictal recordings revealed multifocal epileptic discharges, generalized slowing, and voltage attenuation. The ictal behavioral manifestations and electric seizure patterns were quite distinctive yet were often undiagnosed on routine evaluations.

Neurophysiological and neuroradiological features preceding infantile spasms

Neonatal EEG, cerebral evoked potentials, CT scan findings and their evolution were investigated in 42 neonates who eventually developed the West syndrome. In infants with perinatal hypoxia, the EEG displayed most often marked or maximal depression in the first week of life. The highly abnormal initial EEG improved progressively with time. The most frequent findings in early infancy was discontinuous tracing and persistent alternating tracing at 1-2 months, and absent sigma rhythms at 3-4 months. The VEP, AEP and CT scan also showed findings suggesting severe degree of brain damage. In infants with meningitis, the initial EEG was less depressed but the EEG abnormality persisted or worsened. In infants with prenatal causes the neonatal EEG was variable, ranging from a normal background EEG to specific abnormalities. The evolution of paroxysmal abnormalities was similar in all groups. There were no epileptiform discharges in early months. The appearance of hypsarrhythmia was preceded by focal and then multifocal spike or sharp wave discharges.

Tuberous sclerosis: long-term follow-up and longitudinal electroencephalographic study.

We analyzed 320 electroencephalograms done on 60 patients having tuberous sclerosis. The main features in EEGs were diffuse slowing in the background activity, slow spike-wave discharges, focal and multifocal spike discharges, and amplitude asymmetries. No significant changes occurred in EEGs during the follow-up. No characteristic pattern was identified for diagnosing TS. Severe abnormalities were seen in patients who had infantile spasms and frequent seizures, and who were mentally retarded. Slow spike-wave abnormality was less frequent in patients who had mild mental retardation and few seizures. The pathological findings did not offer any clue to the frequently recorded EEG abnormalities.

Electrophysiologic studies in neonatal adrenoleukodystrophy

Recent electrophysiologic studies have focussed attention on the X-linked adrenoleukodystrophy (ALD) and its myeloneuropathic variant. No organized studies are, however, yet available on its relatively recently described neonatal variant. We conducted electroencephalographic, electroretinographic and evoked response studies in 2 patients with neonatal ALD. In one patient, an infant, initial EEG, hypsarrhythmic in waking and somewhat periodic in sleep, showed dramatic improvement on ACTH therapy accompanied with a seizure-free status. The EEG and clinical improvement, however, were temporary. No improvement occurred following pyridoxine therapy. Her electroretinogram (ERG), visual evoked responses (VERs) and far-field short latency brain-stem auditory evoked responses were also abnormal. The latter studies probably reflected photoreceptor degeneration, optic nerve involvement, cochlear and/or auditory nerve involvement respectively in neonatal ALD. The other patient, a 3.5-year-old girl, also had an EEG characterized by a moderate- to high-amplitude slow background activity and high-amplitude multifocal, generalized or periodic paroxysmal discharges, but presence of some better formed theta frequencies in background activity precluded a hypsarrhythmic label on her EEG. Her ERGs and VERs were totally extinct but in contrast to the first patient, she had clear-cut optic atrophy and retinitis pigmentosa on ophthalmological examination.

Les Epilepsies a foyers EEG intercritiques multiples

Retrospective data on 77 epileptic patients allowed the following conclusions: Epilepsies with EEG independent multifocal spike discharges are mainly observed in children. Partial unilateral or generalized seizures are encountered. No relationship exists between the EEG foci and the seizure pattern. Acquired cerebral lesions are common. Multifocal spike discharges are functional foci, appearing and disappearing without close correlation with the evolution of seizures. They are an age-dependent expression of a disease which extends far beyond the seizures. They have to be absolutely distinguished from stable epileptic foci found in multifocal epilepsies.

Slow spike‐wave activity in EEG and associated clinical features

Clinical features were studied in 83 patients with slow spike-wave activity in the EEG. Epileptic seizures, usually intractable, occurred in 82 patients. The majority had the onset of seizures during the first 2 years of life. Minor motor seizures alone or in combination with other types of seizures occurred in 80 percent, and most had more than one type of seizure. The combination of tonic-clonic, minor motor, and absence seizures was the commonest, occurring in 37 percent. Sixty-six patients were definitely retarded and 49 showed definite motor impairment. Etiologic factors responsible for cerebral insult were identified in 53 patients. Serial EEG studies showed a close relationship between the EEG patterns of hypsarrhythmia, independent multifocal spike discharges, and slow spike-wave activity. The eponym "Lennox-Gastaut" syndrome is appropriate for a patient who has slow spike-wave activity in the EEG, exhibits mental retardation, and has intractable seizures of various types. However, the syndrome does not imply a pathologic entity because many diverse processes, both static and progressive, can produce this syndrome.

Clinical and electroencephalographic correlation of independent multifocal spike discharges.

One hundred and eight patients with independent, multifocal, spike discharges in the EEG were studied. The abnormality occurred at all ages but was more frequent between 4 and 7 years. The basic EEG activity in wake tracing was invariably slow for the age of the patient. The majority of the patients with independent multifocal spike discharges had extensive bilateral cerebral lesions that occurred in the prenatal, perinatal, or postnatal periods. Clinical seizures were of different types, and patients had varying degrees of intellectural and neurologic deficits. A significant number had had previous tracings with either hypsarrhythmic or slow spike-wave patterns, suggesting a close relationship of these three EEG abnormalities.