Hippocampal asymmetries and white matter abnormalities on MRI in benign childhood epilepsy with centrotemporal spikes

Purpose: To look for brain abnormalities by using magnetic resonance imaging (MRI) in patients with benign childhood epilepsy with centrotemporal spikes (BCECTS), which is the most common epilepsy syndrome in children. Methods: Eighteen children, aged 6-12 years, with typical BCECTS were examined with MRI, six of them twice. Results: Some hippocampal abnormality was found in six (33%) of the children, all with the syndrome's typical electroencephalogram (EEG) pattern ipsilaterally. Hippocampal size asymmetry was found in five (28%) children (right side < left in two and left < right in three), and high signal intensities on T-2-weighted images were found in three (17%). Two children also had other abnormalities; one had a heterotopic nodule near the contralateral frontal horn, and one had an Arnold-Chiari malformation. The hippocampal asymmetry remained un-changed in three of the children who were reexamined after 2 years. High signal intensities on T-2-weighted images were seen beneath the cortex-white matter junction in the frontal and temporal lobes of five (28%) children, one of whom also had a hippocampal asymmetry. MRIs were normal in eight (44%) children. Conclusion: For the first time, hippocampal asymmetries and white-matter abnormalities have been detectable on the MRIs of children with typical BCECTS. The etiology of the former is unclear, whereas the latter may be a result of a maturational delay involving a defective myelination. Long-term follow-up studies are needed to evaluate the relation between these findings and the clinical course of BCECTS.