Functional and structural network disorganizations in typical ECTS and impact on cognitive neurodevelopment

Epilepsy with Centrotemporal Spikes (ECTS) is the most common form of self-limited focal epilepsy. The pathophysiological mechanisms by which ECTS induces neuropsychological impairment in 30% of affected children remain unclear. The objective is to review the current state of knowledge concerning the brain structural and functional changes that may be involved in cognitive dysfunctions in ECTS. Publication indexed in Pubmed about structural and functional brain imaging in ECTS were reviewed. Structural brain imaging suggests the presence of subtle neurodevelopmental changes over the epileptogenic zone (EZ) and over distant regions, which evolves over time, especially in patients with cognitive impairment. This suggests that the epileptogenic processes might interfere with the dynamics of the brain development. Functional brain imaging demonstrates disorganization accentuated by IES. Changes in neuronal activity are described several hundred milliseconds before the IES in over the EZ and in bilateral distant networks. This is associated with alteration of global small-world properties towards a more random network. The direction of information flow demonstrates that, the epileptogenic zone constitutes the key area at the origin of IES propagation towards distant cortical regions. Structural and functional network disorganizations, in terms of: (i) power spectral values, (ii) functional and effective connectivity, are likely to participate in the cognitive impairment reported in children with ECTS. These results suggest a central and causal role of network disorganizations related to IES in the neuropsychological impairment.