Benign Myoclonic Epilepsy in Infancy (BMEI): A Longitudinal Electroclinical Study of 22 Cases

Abstract

Summary:Purpose: Benign myoclonic epilepsy in infancy (BMEI) is a nosologically well-defined entity, characterized by myoclonic seizures (MS) in normal children younger than 3 years and by a good long term prognosis. In some cases the seizures are reflex. We studied 22 cases to better define the electroclinical semeiology and evolution of the disorder.Methods: Serial electroclinical and neuropsychological assessments, both during wakefulness and during sleep, were performed in 22 otherwise healthy children with spontaneous (17) or reflex (5) MS, recorded by video-EEG-polygraphy since clinical onset.Results: Seizure onset was between 3 months and 4 years 10 months (50% during first year, 86% before the third year); in reflex cases onset, was earlier than the 14th month. MS recurred during wakefulness and slow sleep in all cases and during REM sleep in reflex cases. MS and related EEG discharges were synchronous or asynchronous. Often ictal EEG discharges were limited to the rolandic and vertex regions (falsely focal paroxysms). Several seizures were subtle and could have escaped recognition. Unusually frequent sleep startles were recorded mostly in reflex cases. MS were well controlled by treatment. At follow-up, between ages 3 and 19 years, four patients had occasional seizures; two had cognitive impairment and three had learning difficulties. No other seizures or cognitive deficits were observed in reflex cases.Conclusions: Seizures associated with BMEI are rarely truly generalized and are often so subtle and related to falsely focal paroxysms that their frequency can be underestimated. The reflex form is a well-defined variant with an early onset, peculiar electroclinical features, and a good prognosis.

The role of EEG in the diagnosis and classification of the epilepsy syndromes: a tool for clinical practice by the ILAE Neurophysiology Task Force (Part 2)

“…Myoclonic Epilepsy in Infancy (MEI) is characterized by brief generalized myoclonic seizures (MS) that are associated with brief generalized spike/polyspike-andwave discharges (GSWD/GSPWD) and occur between three months and four years of life in previously healthy children (Auvin et al, 2006;Darra et al, 2006;Guerrini et al, 2012;Caraballo et al, 2013). There are no other seizure types.…”

Idiopathic generalized epilepsies

“…In some cases spontaneous spike-wave discharges, lasting 1 to 3 seconds, are present both while awake and during sleep (Darra et al, 2006). In some cases spontaneous spike-wave discharges, lasting 1 to 3 seconds, are present both while awake and during sleep (Darra et al, 2006).…”

“…Myoclonic jerks occur in alert stages and may also be exacerbated by drowsiness and non-REM (NREM) sleep (Auvin et al, 2006;Darra et al, 2006). The age of onset is between 4 months and 3 years.…”

“…In most of the patients, the long-term follow-up shows a benign course (Dravet and Bureau, 2005;Darra et al, 2006).…”

Yenidoğan ve sütçocuğunun epileptik sendromları

“…While no pathology is found on interictal EEG, spike, multiple spike-wave groups are observed on ictal EEG (32,33). In an importanty portion of the patients, mild cognitive involvement develops (34). Seizures usually respond well to valproic acid treatment.…”