Michelle Bureau

Idiopathic photosensitive occipital lobe epilepsy.

Summary: We studied 10 neurologically normal patients (8 females, 2 males) aged 8–30 years (mean 17 years) who had recurrent episodes of visually induced occipital seizures. Television and computer screens were the main triggers. Seizure onset occurred between the ages of 5 and 17 years (mean 11 years). All seizures were stimulus related and began with elementary visual symptoms, followed in most patients by a slow clustering of cephalicpain, epigastric discomfort, and vomiting, with either normal or only mildly impaired responsiveness. EEG fea‐tures included normal background activity, occipital spikes and waves, and a photoparoxysmal response which could be occipital, generalized, or both. Four pa‐tients also showed spontaneous generalized epileptiform abnormalities, and 3 had rolandic spikes. An Oz electrode was critical in identifying epileptiform activity in some patients. Complete seizure control was achieved in most patients with monotherapy, although occasional stimulus‐related seizures occurred in 3 patients who showed a wider range of photosensitivity. These patients have an idiopathic localization‐related epilepsy with age‐related onset and specific mode of precipitation. Although this type of epilepsy has been reported previously, it has remained underrecognized, probably because it is difficult to differentiate clinically from migraine or from nonreflex childhood idiopathic occipital epilepsy.

Multilobar polymicrogyria, intractable drop attack seizures, and sleep-related electrical status epilepticus.

Background and Objective: Patients with cortical malformations often have intractable seizures and are candidates for epilepsy surgery. Within an unselected series of patients with various forms of cortical malformation, nine patients with multilobar polymicrogyria had electrical status epilepticus during sleep (ESES) accompanied by infrequent focal motor seizures. Eight patients also had intractable atonic drop attack seizures. Because ESES usually is accompanied by a good long-term seizure prognosis, the objective of this study was to examine ESES outcome among patients with a structural lesion that is usually highly epileptogenic and has a low seizure remission trend. Methods: The nine patients had follow-up periods lasting 4 to 19 years. All underwent brain MRI, serial sleep EEG recordings, and cognitive testing during and after ESES. Results: ESES and drop attack seizures appeared between the ages of 2 and 5 years(mean, 4 years) and ceased between the ages of 5 and 12 years (mean, 8 years). At the last visit patients were 8 to 23 years of age (mean, 14.5 years) and were either seizure free or had very infrequent focal motor seizures during sleep. Three patients were free from antiepileptic drugs. In no patient was definite cognitive deterioration apparent after ESES in comparison with earlier evaluations. Conclusions: Age-related secondary bilateral synchrony underlying ESES may be facilitated in multilobar polymicrogyria. The good seizure outcome contrasts with that usually found in the presence of cortical malformations. For children with polymicrogyria and drop attack seizures, surgical treatment of the epilepsy should be considered cautiously, and sleep EEG recordings should be performed systematically.

EPILEPSY AND FOCAL GYRAL ANOMALIES DETECTED BY MRI: ELECTROCLINICO-MORPHOLOGICAL CORRELATIONS AND FOLLOW-UP

The authors studied 10 patients (mean age 15 years 6 months) with localized developmental gyral disorder detected by MRI. There were two groups of major malformations. Seven patients (group 1) had unilateral ‘macrogyric‐like’ insulo‐opercular changes, one of whom died early in life and had extensive microgyria. The six others had mental retardation and epilepsy, three of whom had focal neurological signs. Age at onset of epilepsy varied greatly. Clinical arid EEG data suggested a wider cerebral involvement than recognized on MRI. The remaining three patients (group 2) had abnormal gyri of variable topography and extension, with bulging grey matter and ventricular deformity. One had mental retardation, another had neurological signs. All had intractable complex partial seizures and focal EEG anomalies correlating with the MRI lesion site, pointing to a well‐defined epileptogenic zone. No clinical or EEG evidence of significant malformation in the remaining brain tissue was observed. Ablative surgery was beneficial for one patient; focal cortical dysplasia was the pathological substrate.

Epileptic negative myoclonus

Five patients with partial epilepsy of diverse etiology insidiously developed action-activated jerks. The disorder was limited to one arm in two patients and to the legs in another, and was multifocal in the remaining two. Each jerk was related to an EMG silent period lasting 100 to 400 msec, causing a lapse followed by resumption of posture. Simultaneous EEG-EMG recording showed each postural lapse to be time-locked with a sharp or spike and slow-wave transient over the contralateral sensorimotor cortex, where almost continuous paroxysmal activity occurred. The three patients who were able to cooperate during neurologic evaluation also exhibited motor neglect in the most affected body segment and decreased awareness of the disorder. In three patients, the phenomenon was medically resistant, and in two of them it was continuous and could be defined as epilepsia partialis continua. In the other two, medical treatment induced remission of EEG, motor, and neuropsychological abnormalities. This disabling movement disorder can be classified as “epileptic negative myoclonus” and may result from focal-discharge-related transient disruption of cortical function in the sensorimotor cortex.

Neurological findings and seizure outcome in children with bilateral opercular macrogyric-like changes detected by MRI.

The authors studied 10 patients aged between six and 23 years (mean age 14 years 5 months) with magnetic resonance imaging, which detected bilateral ‘macrogyric‐like’ maldevelopment of the insulo‐opercular regions. The data confirm that biopercular gyral anomaly, associated with mental retardation, pseudobulbar palsy (cortical or central) and epilepsy, represents an anatomo‐clinical syndrome. Nevertheless, a wide clinical spectrum was found varying from pictures correlating with the topography and extent of the MRI‐detected anomaly to conditions indicating wider cerebral involvement. Epilepsy, varying greatly in age at onset and severity, consistently influenced the prognosis for five patients with diffuse EEG abnormalities and intractable seizures with falls. Anterior callosotomy relieved such seizures in one case.

A Study of the Rhythm of Petit Mai Absences in Children in Relation to Prevailing Situations: The Use of EEG Telemetry during Psychological Examinations, School Exercises and Periods of Inactivity

A telemetric EEG study was made of 30 patients with petit mal in the course of various activities (intelligence tests, projective tests and interviews, drawing and school exercises) and in periods of inactivity. The frequency of epileptic paroxysms was found to vary significantly with the various situations in which the subject was placed.

Partial Epilepsies in Infancy: A Study of 40 Cases

Summary: Forty patients with partial epilepsy that began before they were aged 3 years were recorded at the Centre Saint‐Paul between 1981 and 1986 with a follow‐up ranging from 1 year 9 months to 20 years. We analyzed the following data: age at onset, clinical features of seizures at onset and during the follow‐up period, ictal and interictal EEG features, etiologic circumstances, evolution of the epilepsy, and psychomotor development. The age of onset was mostly between 2 months and 2 years (more than two thirds of cases). Most had partial symptomatic epilepsy. In nine cases, epilepsy was preceded by febrile convulsions. Seizures at onset were of the following type (in order of decreasing occurrence): unilateral seizures, complex partial seizures, elementary partial seizures, and other seizures, often difficult to classify. A few patients with infantile spasms associated with focal or multifocal EEG abnormalities, differing from Wests syndrome, were included in this study. We discuss the problem arising from the classification of infantile seizures and epilepsies.

Multiple defects of the mitochondrial respiratory chain in a mitochondrial encephalopathy (MERRF): a clinical, biochemical and molecular study.

We describe a young man with a progressive neurological disorder including myoclonus, mental retardation, muscle weakness and a mitochondrial myopathy (myoclonus epilepsy and ragged red fibres--MERRF). Multiple abnormalities of the mitochondrial respiratory chain in skeletal muscle are shown by direct measurement of the flux through the individual complexes, low-temperature redox spectroscopy and decreased immunodetectable subunits of complexes I and IV by immunoblotting. No abnormality of mitochondrial DNA was found. This is the first report of combined defects of complexes I, III and IV as a cause of this clinical syndrome. However, we propose that the occurrence of multiple respiratory chain defects may be more common than previously recognised and that this particular combination of defects, involving complexes I, III and IV, may be the predominant biochemical abnormality in MERRF.

Abnormal neuroimaging in patients with benign epilepsy with centrotemporal spikes.

Summary:  Purpose: Neuroimaging procedures are usually unnecessary in benign epilepsy of childhood with centrotemporal spikes (BECTS) but are often performed before a specific diagnosis has been reached. By definition, BECTS occurs in normal children; however, recent reports have shown that it also can affect children with static brain lesions. We evaluated the prevalence of abnormal neuroimaging in BECTS and assessed whether the lesions had influenced the clinical and EEG expression of this epilepsy.

Reflex Seizures are Frequent in Patients with Down Syndrome and Epilepsy

Summary: In a retrospective study of 30 Down syndrome (DS) patients with epilepsy, we found 6 cases (20%) with reflex seizures. One patient had benign myoclonic epilepsy of infancy with clinical photosensitivity. The other 5 cases had all startle‐induced epileptic seizures and a form of symptomatic epilepsy. Three patients had a Len‐nox‐Gastaut syndrome, one had generalized symptomatic epilepsy, and one had partial symptomatic epilepsy (PSE). Reflex epilepsy was also used as a classification category in the PSE case, as most or all seizures were stimulus‐related in this patient. Seizures precipitated by stimuli were stereotyped in 4 patients, but 2 patients responded to stimuli with different types of seizures. The actual occurrence of reflex seizures in DS patients with epilepsy is probably underestimated. These cases seem to confirm previous reports showing deficiencies in cortical inhibition in the brain of DS patients.