Gray matter structural compromise is equally distributed in left and right temporal lobe epilepsy

Area of Science:

• Neuroimaging
• Epilepsy Research
• Structural Brain Analysis

Background:

• Drug-resistant temporal lobe epilepsy (TLE) is associated with mesiotemporal and neocortical structural changes.
• The impact of seizure focus lateralization on the extent of structural damage in TLE remains unclear.

Purpose of the Study:

• To investigate whether the side of seizure focus (left vs. right) influences the degree of mesiotemporal and neocortical structural damage in TLE patients.
• To compare structural brain alterations between left TLE (LTLE) and right TLE (RTLE) patients who achieved seizure freedom post-surgery.

Main Methods:

• Surface-based morphometry and voxel-based morphometry were used to analyze preoperative 1.5 T and 3 T MRI scans.
• Patients with seizure freedom (Engel-I outcome) after surgery were compared to age- and sex-matched healthy controls.
• Statistical analyses included direct contrasts between LTLE and RTLE groups, bootstrap simulations, and power analysis.

Main Results:

• Both LTLE and RTLE groups exhibited ipsilateral mesiotemporal atrophy and bilateral cortical thinning compared to controls.
• No significant differences in structural damage were found between LTLE and RTLE groups.
• Bootstrap simulations indicated low reproducibility for detecting between-group differences, requiring over 110 patients.

Conclusions:

• Gray matter compromise is equivalent in left and right TLE, irrespective of seizure focus lateralization.
• The observed morphological profile (ipsilateral mesiotemporal and bilateral cortical atrophy) in seizure-free patients supports developing outcome neuromarkers.
• Future research should consider both mesiotemporal and neocortical structures for predicting epilepsy surgery outcomes.