Event-based modeling in temporal lobe epilepsy demonstrates progressive atrophy from cross-sectional data.

Area of Science:

• Neuroimaging
• Epilepsy Research
• Brain Morphology

Background:

• Common epilepsies exhibit characteristic, potentially progressive cortical thinning patterns.
• Previous studies suggest sequential changes in brain structure in epilepsy.

Purpose of the Study:

• To investigate the sequential nature of regional morphometric changes in mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE-HS).
• To correlate these neuroimaging changes with clinical features of MTLE-HS.

Main Methods:

• Utilized T1-weighted MRI scans from 804 MTLE-HS patients and 1625 controls from the ENIGMA-Epilepsy consortium.
• Employed an event-based model (EBM) trained on regional brain measures (cortical thickness, surface area, subcortical volumes) with Cohen's d ≥ 0.5.
• Assessed associations between EBM-derived disease stage and epilepsy duration, age at onset, and antiseizure medicine (ASM) resistance.

Main Results:

• Identified a sequence of brain changes in MTLE-HS: hippocampal volume reduction/asymmetry, followed by neocortical thinning, thalamus volume reduction, and ventricle enlargement.
• EBM stage correlated significantly with illness duration (ρ = 0.293), age at onset (ρ = -0.18), and ASM resistance (AUC = 0.59).
• Associations were primarily driven by early-stage MTLE-HS (EBM Stage 0) with subtle MRI abnormalities.

Conclusions:

• Reconstructed a cross-sectional MRI-based disease progression model for MTLE-HS, aligning with longitudinal findings.
• The developed model can stage MTLE-HS patients in new cohorts.
• This imaging-based staging can help link disease progression to clinical characteristics.