Thalamic and functional correlates of processing speed in pediatric epilepsy syndromes: an exploratory neuroimaging...

Children with self-limited epilepsy with centrotemporal spikes (SeLECTS) and childhood absence epilepsy (CAE) often have favorable seizure outcomes, but cognitive inefficiencies may persist and affect school functioning. Whether choice reaction time (CRT) is related to somatomotor connectivity and thalamic or hippocampal volumes in these syndromes remains unclear.

We performed an exploratory secondary analysis of public pediatric epilepsy neuroimaging data. After excluding one participant with SeLECTS because of FreeSurfer segmentation failure, the final structural and functional samples included 25 children with SeLECTS and 10 with CAE. CRT was the primary behavioral outcome. We tested whether SomMot connectivity-CRT coupling differed between syndromes and whether thalamic or hippocampal volumes were associated with CRT within the combined epilepsy sample.

The SomMot connectivity × syndrome interaction was nominally significant in the linear-age model (p = 0.039), yet was attenuated after quadratic age adjustment (p = 0.065). In the linear-age structural models, larger bilateral thalamic volumes were associated with shorter CRT within combined epilepsy sample, even after false discovery rate (FDR) correction. The estimates remained directionally consistent after quadratic age adjustment, yet no longer survived FDR correction.

Bilateral thalamic volumes were associated with CRT across combined epilepsy sample, while SomMot connectivity exhibited a candidate syndrome-dependent coupling pattern, suggesting complementary structural and functional correlates of reaction speed in pediatric epilepsy. Their sensitivity to age model specification warrants further validation in larger, age-balanced cohorts.