Brain Structural Alterations Was Associated With Generalized Tonic-clonic Seizures In Temporal Lobe Epilepsy

Objective:Temporal lobe epilepsy with hippocampal sclerosis(TLE-HS)is a common type of drug-resistant epilepsy and secondarily generalized tonic-clonic seizures(sGTCS)have devastating consequences for patients' safety and quality of life.To probe the pathophysiological mechanism underlying the genesis of sGTCS,we investigated the brain structural differences between patients with and without sGTCS in a cohort of unilateral TLE-HS.Methods:From April 2014 to June 2016,consecutive Chinese patients with unilateral TLE-HSwho visited epilepsy department of our hospital were included in this study.Voxel-based morphometric analysis of cortex and vertex-wise shape analysis of subcortical structures(basal ganglia and thalamus)were performed on MR images.Comparisons were initially made between sGTCS and non-sGTCS groups,and subsequently made between uncontrolled-sGTCS and controlled-sGTCS subgroups.Results:Thirty-nine patients with unilateral TLE-HS were enrolled.The mean age was 31.2±9.7 years and the mean duration was 15.6 ± 10.4 years.Twenty-one patients(53.8%)had a history of sGTCS.Regional atrophy of the ipsilateral ventral pallidum(cluster size = 450 voxels,corrected p =0.047,Max voxel coordinate = 107,120,65),medial thalamus(cluster size = 1128 voxels,corrected p =0.049,Max voxel coordinate = 107,93,67),middle frontal gyrus(cluster size = 60 voxels,corrected p<0.05,Max voxel coordinate =-30,49.5,6),and contralateral posterior cingulate cortex(cluster size ?130 voxels,corrected p<0.05,Max voxel coordinate = 16.5,-57,27)was found in the sGTCS group relative to the non-sGTCS group.Furthermore,uncontrolled-sGTCS subgroup showed more pronounced atrophy of the ipsilateral medial thalamus(cluster size =1240 voxels,corrected p =0.014,Max voxel coordinate =107,93,67)than uncontrolled-sGTCS subgroup.Conclusions:These findings indicate a central role of thalamus and pallidum in the pathophysiology of sGTCS in TLE-HS.