Bilateral lesions of thalamus and basal ganglia: A peculiar type of lesional epilepsy

Objectives: Bilateral lesions of the basal ganglia and thalamus occur in children as a consequence of birth asphyxia or neonatal shock. In a previous study (Dev Med Child Neurol 2002;44:477–484) we were able to define three different degrees of MRI lesion patterns. Since pathogenesis and timing of these lesions are homogeneous, this could serve as a model to study the impact of brain lesions on the manifestation of the epilepsy. Therefore, we investigated the relationship between lesion patterns, epilepsy and EEG findings in these children.

Material and Methods: Eight children presenting with bilateral lesions of thalamus and basal ganglia and a follow-up of more than five years were included in the study. MRI and EEG data were systematically reviewed by patient-blinded raters.

Results: The only child with a mild lesion (involvement of basal ganglia and thalamus only) had no seizures, and EEG was normal. Four children with additional involvement of the pericentral region (classified intermediate) had epilepsy with which was considered controlled. All had rare secondary generalized tonic-clonic seizures and showed multifocal benign rolandic spikes in the EEG. Three children with additional involvement of the hippocampus (classified severe) had an active epilepsy with focal hypermotoric seizures. In all, EEG showed multifocal stereotyped spikes with marked activation during sleep.

Conclusions: This small cohort of children with a well defined homogeneous brain lesion shows a peculiar epilepsy and EEG pattern including features typical for benign rolandic epilepsy. In addition, a correlation between the extent of the lesion and the severity of the epilepsy is evident.