Language network reorganization in temporal lobe epilepsy: insights from task-based functional MRI

In temporal lobe epilepsy (TLE), recurrent seizures can cause structural and functional disruptions within the temporal lobe and nearby language regions, resulting in neural reorganization. In this study, we leverage task-based functional magnetic resonance imaging (tb-fMRI) to understand how this language reorganization process varies based on the seizure location, the timing of seizure onset, and the chronicity of epileptic activity.

84 drug-resistant TLE patients who completed a tb-fMRI sentence completion task were included in this study. Analysis included group comparison of activation and comparison of the extent of reorganization in the whole brain and standard language regions of interest (ROI) level. We also measured the impact of the age of onset and the duration of epilepsy in the reorganization process.

A significantly higher degree of language network reorganization is observed in left (L) TLE than in right (R) TLE at the whole brain level. At the regional level, a higher degree of reorganization is observed in temporal and frontal lobe ROIs in LTLE compared to RTLE, especially in the middle frontal gyrus and posterior temporal gyrus. The effects of age of onset and epilepsy duration were prominent in LTLE subjects at both the whole-brain and ROI levels.

Patients with LTLE show greater changes in the middle frontal and posterior temporal regions, particularly in those with an earlier age of onset and longer disease duration. Identifying these patterns may assist in surgical planning and personalizing treatment to protect cognitive function.