Benign epilepsy with centrotemporal spikes (‘BECTS’, also known as Rolandic epilepsy) is a common epilepsy syndrome that is associated with literacy and language impairments. The neural mechanisms of the syndrome are not known. The primary objective of this study was to test the hypothesis that functional connectivity within the language network is decreased in children with BECTS. We also tested the hypothesis that siblings of children with BECTS have similar abnormalities.
Echo planar MR imaging data were acquired from 25 children with BECTS, 12 siblings, and 20 healthy controls, at rest. After pre-processing with particular attention to intra-scan motion, the mean signal was extracted from each of 90 regions-of-interest. Sparse, undirected graphs were constructed from adjacency matrices consisting of Spearman's rank correlation coefficients. Global and nodal graph metrics, subnetwork and pairwise connectivity were compared between groups.
There were no significant differences in graph metrics between groups. Children with BECTS had decreased functional connectivity relative to controls within a four-node subnetwork which consisted of the left inferior frontal gyrus, the left superior frontal gyrus, the left supramarginal gyrus, and the right inferior parietal lobe (p = 0.04). A similar but non-significant decrease was also observed for the siblings. The BECTS groups had significant increases in connectivity within a five-node, five edge frontal subnetwork.
The results provide further evidence of decreased functional connectivity between key mediators of speech processing, language and reading in children with BECTS. We hypothesise that these decreases reflect delayed lateralisation of the language network and contribute to specific cognitive impairments.