Network-based atrophy modeling in the common epilepsies: A worldwide ENIGMA study

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Epilepsy is increasingly understood as a complex network disorder affecting brain function.
• Understanding the macroscale network features underlying epilepsy pathophysiology is crucial for developing targeted treatments.

Purpose of the Study:

• To identify network associations with brain atrophy patterns in adults with epilepsy using a large-scale neuroimaging mega-analysis.
• To compare network involvement in temporal lobe epilepsy (TLE) and idiopathic generalized epilepsy (IGE) and their relationship with aging.

Main Methods:

• A cross-sectional mega-analysis integrating neuroimaging and connectome data from 1021 adults with epilepsy and 1564 healthy controls across 19 international sites.
• Analysis of atrophy patterns and their colocalization with cortical and subcortical hub regions, anchored to disease-specific connectivity profiles.
• Investigation into the influence of age on atrophy and its interaction with connectome architecture.

Main Results:

• In temporal lobe epilepsy, atrophy was concentrated in highly interconnected cortical hubs, specifically temporo-limbic regions.
• Idiopathic generalized epilepsy exhibited preferential involvement of subcortical hubs, with disease epicenters in fronto-central cortices.
• Age negatively impacted atrophy in TLE, highlighting the role of connectome architecture, an effect not observed in IGE.

Conclusions:

• Distinct network-based macroscale features characterize temporal lobe epilepsy and idiopathic generalized epilepsy, linked to specific brain regions and connectivity profiles.
• The findings, robust across sites, patients, and methods, provide deeper insights into the pathophysiology of common epilepsies.
• This collaborative effort (ENIGMA-Epilepsy) advances our understanding of epilepsy as a network disorder.