A Particular Type of Epilepsy in Children with Congenital Hemiparesis Associated with Unilateral Polymicrogyria

Abstract

Summary: 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 poly‐microgyria 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 appears to be age specific and responsive to antiepileptic drug (AED) treatment. Despite limited follow‐up time, a good outcome was observed in most cases.