Myoclonic epilepsy in infancy: An electroclinical study and long‐term follow‐up of 38 patients

Abstract

SUMMARYPurpose: 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 selflimited and pharmacosensitive mainly to valproic acid.

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)

“…They occur several times daily, usually in isolation, but also in clusters, and are easily controlled by antiepileptic medication, especially valproic acid. Reflex myoclonus can be seen along with spontaneous MS. A rare coexistence of MS with absences during the active course of MEI has been described (Caraballo et al, 2013). A variant with predominantly nocturnal MS has also been described (Prabhu et al, 2014).…”

“…GPSWD/GSWD and photoparoxysmal responses may persist for many years after the clinical remission of MEI (Caraballo et al, 2013). However, a given sleep EEG may be normal.…”

“…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.…”

The relationship between epilepsy, sleep disorders, and attention deficit hyperactivity disorder (ADHD) in children: A review of the literature

“…After, 3 articles were excluded secondary to unspecified findings (1), EEG specified objective (1) and inclusion of patients with neurological and cognitive deficits (1). Eight articles were considered relevant for this study [15], [16], [17], [18], [19], [20], [21], [22].…”

“…Caraballo et al [22] realized a follow-up of 38 patients with MEI. After a mean follow-up of 13.5 years, 32 patients had normal neurologic and neuropsychological evaluations.…”