Myoclonic epilepsy in infancy: an electroclinical study and long-term follow-up of 38 patients.

PURPOSE: Myoclonic epilepsy in infancy (MEI) is characterized by brief generalized myoclonic seizures associated with generalized spike-wave paroxysms without other seizure types occurring in the first 3 years of life in developmentally normal children. In this study we analyze the electroclinical features, treatment, and outcome of 38 patients with MEI. METHODS: A retrospective chart review was conducted in 38 patients followed at the Neurology Department of the Pediatric Hospital Juan P. Garrahan in Buenos Aires, Argentina, between 1990 and 2012. KEY FINDINGS: A total of 24 boys and 14 girls were identified. The mean and median ages at seizure onset were 16 and 18 months, respectively (range 3-40 months). Ten patients (28.9%) had a family history of epilepsy, and six (15.8%) had a family history of febrile seizures. All patients had several daily brief and isolated myoclonic seizures during wakefulness and predominantly in the first two stages of sleep. Twelve children (31.5%) had reflex myoclonus, triggered by a tactile stimulus in 10 and additionally by noise and light in 2. The remaining two had photosensitive myoclonic jerks. The interictal electroencephalography (EEG) recordings evidenced generalized spike waves, polyspikes, and polyspike-wave paroxysms. The interictal EEG was normal in 12 patients. The abnormalities on the ictal EEG were similar to those on the interictal EEG. Most of the patients responded well to valproic acid. After a mean follow-up of 13.5 years, 24 patients (63%) were without treatment. At the last examination, 32 patients had normal neurologic and neuropsychological evaluations. Two patients (5.2%) had significant cognitive impairment (an IQ of 60 and 63, respectively) despite good seizure control. Four patients (10.4%) had significant learning impairment, two of whom also had attention deficit hyperactivity disorder. SIGNIFICANCE: MEI is a well-defined epileptic syndrome of unknown etiology, but likely of a genetic cause. It is self-limited and pharmacosensitive mainly to valproic acid.

Encephalopathy with status epilepticus during sleep or continuous spikes and waves during slow sleep syndrome: a multicenter, long-term follow-up study of 117 patients.

PURPOSE: To retrospectively analyze the electroclinical features, etiology, treatment and prognosis of 117 patients with encephalopathy with status epilepticus during sleep (ESES) or continuous spike and waves slow sleep (CSWSS) syndrome with a long-term follow-up. METHODS: Charts of 117 patients with ESES/CSWSS syndrome followed between 1990 and 2012 were analyzed. Inclusion criteria were: (1) focal seizures or apparently generalized seizures and focal EEG epileptiform discharges; (2) further occurrence of atypical absences, and myoclonic, atonic, and/or generalized seizures; (3) cognitive impairment and/or behavior disturbances; (4) continuous spike-and-wave discharges during slow sleep in more than 85% of non-REM sleep. Patients with spike-and-wave discharges in less than 85% of slow sleep were also analyzed. KEY FINDINGS: 'Mean follow-up from onset of ESES/CSWSS was 13 years (range, 2-22 years) in the symptomatic/structural and non-idiopathic group consisting of 79 children and 10.5 years (range, 2-21 years) in the idiopathic group consisting of 38 children. The comparison of clinical findings and localization of paroxysmal EEG abnormalities (focal, multifocal, or generalized) at the different stages (before, during, and after ESES/CSWSS) and the percentage of spike-wave index during ESES/CSWSS between the symptomatic/structural and non-idiopathic and the idiopathic group was not statistically significant. SIGNIFICANCE: ESES/CSWSS syndrome is an epileptic encephalopathy with similar electroclinical findings in children with a >85% spike-wave index and those with a <85% spike-wave index. In this series of patients, the most commonly used treatments were clobazam, ethosuximide, sulthiame, alone or in combination. In refractory cases, high-dose steroids were administered. Among the AED responders, the idiopathic cases returned to normality and the structural cases returned to baseline cognitive development.