The epileptic network and cognition: What functional connectivity is teaching us about the childhood epilepsies

Abstract

Our objective was to summarize and evaluate the rapidly expanding body of literature studying functional connectivity in childhood epilepsy. In the self‐limited childhood epilepsies, awareness of cognitive comorbidities has been steadily increasing, and recent advances in our understanding of the network effects of these disorders promise insights into the underlying neurobiology. We reviewed publications addressing functional connectivity in children with epilepsy with an emphasis on studies of children with self‐limited childhood epilepsies. The majority of studies have been published in the past 10 years and predominantly examine childhood epilepsy with centrotemporal spikes and childhood absence epilepsy. Cognitive network alterations are commonly observed across the childhood epilepsies. Some of these effects appear to be nonspecific to epilepsy syndrome or even to category of neurological disorder. Other patterns, such as changes in the connectivity of cortical language areas in childhood epilepsy with centrotemporal spikes, provide clues to the underlying cognitive deficits seen in affected children. The literature to date is dominated by general observations of connectivity patterns without a priori hypotheses. These data‐driven studies build an important foundation for hypothesis generation and are already providing useful insights into the neuropathology of the childhood epilepsies. Future work should emphasize hypothesis‐driven approaches and rigorous clinical correlations to better understand how the knowledge of network alterations can be applied to guidance and treatment for the children in our clinics.

Network characteristics of genetic generalized epilepsy: Are the syndromes distinct?

“…In contrast, functional connectivity infers connections between brain regions from the statistical relationships of their physiologic activity. [46] Interestingly, there was some discordance between the brain network structural and functional connectivity in the GGE patients. The global efficiency, local efficiency, and mean clustering coefficients in the structural connectivity were decreased, whereas the characteristic path length and the small-worldness index were increased compared to the healthy controls.…”

The brain as a complex network: assessment of EEG‐based functional connectivity patterns in patients with childhood absence epilepsy

“…Despite an increasing amount of data describing changes in network parameters in patients with CEA, the link between these parameters and clinical application remains elusive. Currently, it would appear that altered functional connectivity may help in better understanding associated cognitive comorbidities (Bear et al, 2019). Functionally decreased connectivity and deactivation in default network mode were found both in conjunction with generalised SW activity and during the interictal period, and these abnormalities in the default mode network could be related to cognitive impairment during seizures (Laufs et al, 2006;Luo et al, 2011).…”

The Role of EEG-fMRI in Studying Cognitive Network Alterations in Epilepsy

“…This was investigated in a patient with idiopathic generalized epilepsy using EEG-fMRI during a memory task, which showed that IEDs perturb the brain network recruited by the task (95). Furthermore, recent studies have found that IEDs interfere with whole brain networks (49, 51), and indeed a recent review found a consensus between studies in both BECTS and CAE patients confirming the significant impact of IEDs on FC measurements (96).…”