Postictal agitation is associated with brain-wide postictal microstructural changes after electroconvulsive...

Electroconvulsive therapy (ECT) is effective in depression, but associated with postictal agitation. Mechanisms of postictal symptoms are largely unclear. We studied whether postictal symptoms are related to immediate postictal diffusivity changes.

In a randomized cross-over clinical trial, we acquired diffusion tensor imaging (DTI) scans before the ECT-course and three times immediately postictally in 22 patients. In this secondary analysis, mixed effects models and Generalized Estimating Equations were used to assess postictal changes in mean fractional anisotropy (FA) and mean diffusivity (MD), including relations with reorientation time and occurrence of postictal agitation. Additionally, with Tract-Based Spatial Statistics (TBSS), voxel-wise changes in the white matter (WM) skeleton were examined.

Postictal agitation, but not reorientation time, was associated with decreased mean FA (β = -12.0, OR = 0.70, p = 0.02). This relationship was supported by voxel-wise analysis, that revealed associations with postictal FA reduction localized in the left anterior limb of the internal capsule. Additionally, postictal agitation was associated with increased mean MD (β = 1.02e⁴, OR = 1.42, p = 0.04) in white matter. No significant associations were observed with baseline values of MD or FA.

We show that postictal agitation is associated with brain-wide immediate postictal diffusivity changes, suggesting a clinically relevant role of changes in tissue microstructure shortly after an ECT-induced seizure.