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

Purpose: Polymicrogyria (PMG) is often associated with symptomatic focal epilepsy and neurologic dysfunction. We investigated the clinical and laboratory features of a group of children with congenital hemiparesis, unilateral polymicrogyria on magnetic resonance imaging (MRI), and a peculiar epileptic 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 evaluation, computed tomography (CT) and MRI scanning, and neuropsychological assessment at initial examination. Patients were followed up from 1 to 7 years (mean, 4.5 years). Results: Partial motor seizures with secondary generalization with onset between 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 atypical absences, negative myoclonus, and gait difficulties. EEG recording demonstrated continuous spike-wave or bilateral abnormality throughout. Frequent relapses of the atonic and myoclonic seizures were seen in seven patients. However, during follow-up, seven patients were seizure free, and the others have not developed this particular seizure pattern. A single case underwent cortical resection 23 months ago and has had no seizures since then. Mental 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 responsive to antiepileptic drug (AED) treatment. Despite limited follow-up time, a good outcome was observed in most cases.