Neuropsychological, cognitive, and behavioral outcome was studied in a long-term follow-up of 7 patients with benign myoclonic epilepsy in infancy (BMEI) at Universita di Palermo, Italy. Mean age at onset of myoclonic seizures (MS) was 15 months (range, 7-35 months). Febrile convulsions had occurred before the onset of MS in 3 infants. Myoclonic jerks involved mainly the upper limbs, with nodding and upward gaze deviation in some, and flexing of the body and lower limbs. Ictal EEG recordings showed generalized spike-wave and/or polyspike-wave synchronous with myoclonus; interictal EEG was normal. Seizures were controlled by valproate, and medication was discontinued after a seizure-free period of 3 years. The average duration of follow-up was 6 years 9 months (range, 4yrs 9 mos-9 yrs 2 mos). At the end of follow-up, 2 children with early onset of seizures (7 months) had mild or moderate mental retardation, deficits in fine motor coordination, attention deficit disorder, and language impairment. Three children had a borderline IQ and 1 a low average IQ, with learning disorders and attention deficits. Only one patient had a normal IQ. All children were oppositional, irritable, aggressive, and hyperactive. The mean Full Scale IQ of the group was 74, 5 had ADD, and 4 had learning disorders. Early onset of seizures is a major risk factor for poor cognitive and behavioral outcome. A delay in starting treatment is an additional risk factor. 
COMMENT. BMEI, as described by Dravet and Bureau (1981), is characterized by myoclonic seizures in previously healthy infants, 4-36 months of age, and responsive to antiepileptic medication. The unfavorable outcome reported in the above study compared to previous series was linked to early onset of seizures and delay in starting treatment. Alternatively, a pre-existing mild encephalopathy may have been responsible. The authors conclude that BMEI interferes with the growth of developing neurons, resulting in long-term neuropsychological impairment.