Transient thalamic abnormality in association with seizure

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 T2-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 unchanged in three of the children who were reexamined after 2 years. High signal intensities on T2-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.