Postictal resting-state connectivity changes after electroconvulsive therapy-induced seizures

Background: Electroconvulsive therapy (ECT) leads to brain volume and functional changes that do not seem to persist. It is unclear what changes take place shortly after the induced seizures. Here, we present the first human study on resting-state network (RNS) changes in the immediate postictal state.
Objective: Investigate brain-wide RSNs connectivity changes shortly after ECT-induced seizures.

Methods: We collected resting-state functional magnetic resonance imaging scans in 17 patients with major depression before and one hour after ECT-sessions. Data were compared to 27 age, sex, and level of education matched healthy individuals to account for test-retest effects. RSNs were extracted and changes in mean and voxel-wise RSN connectivity strength were compared between groups.

Results: Group by time interaction analyses showed postictal decreases in mean connectivity strength in the left central executive network and the auditory network in patients, compared to healthy controls (β = -0.18 [CrI95 -0.27, -0.09] and (β = -0.22 [CrI95 -0.36, -0.07], respectively). Voxel-wise analyses revealed increased between-network connectivity in the salience network with cerebellar regions compared to healthy controls, along with decreased within-network connectivity in the default mode network and left central executive network. No significant associations with clinical variables were observed.

Conclusion: ECT-induced seizures are followed by postictal decreases of connectivity strength in the left central executive network and the auditory network, while a postictal increase of connectivity was revealed between the salience network and cerebellum.