A particular type of epilepsy in children with congenital hemiparesis associated with unilateral polymicrogyria

Purpose: Polymicrogyria (PMG) is often associated with symptomatic focal ep ilepsy and neurologic dysfunction. We investigated the clinical and laborat ory features of a group of children with congenital hemiparesis, unilateral polymicrogyria on magnetic resonance imaging (MRI), and a peculiar epilept ic syndrome. Methods: Twelve patients (seven girls and five boys) with a mean age of 7.8 years (range, 5-13 years) were studied. All patients underwent clinical ev aluation, computed tomography (CT) and MRI scanning, and neuropsychological assessment at initial examination. Patients were followed up from 1 to 7 y ears (mean, 4.5 years). Results: Partial motor seizures with secondary generalization with onset be tween age 1 and 6 years (mean age, 2 years) were recorded in all patients. The course of epilepsy was similar in all patients with development of atyp ical absences, negative myoclonus, and gait difficulties. EEG recording dem onstrated continuous spike-wave or bilateral abnormality throughout. Freque nt relapses of the atonic and myoclonic seizures were seen in seven patient s. However, during follow-up, seven patients were seizure free, and the oth ers have not developed this particular seizure pattern. A single case under went cortical resection 23 months ago and has had no seizures since then. M ental retardation was mild in nine and moderate in three patients. Conclusions: Children with unilateral polymicrogyria may develop a syndrome of negative myoclonus seizures that ap pears to be age specific and respon sive to antiepileptic drug (AED) treatment. Despite limited follow-up time, a good outcome was observed in most cases.