Voxel-based meta-analysis of gray matter abnormalities in idiopathic generalized epilepsy

This meta-analysis aims to investigate the convergent gray matter alterations observed in idiopathic generalized epilepsy through voxel-based morphometry studies. Voxel-based morphometry studies investigating the whole-brain gray matter alterations between patients with idiopathic generalized epilepsy and healthy controls were systematically searched. A coordinate-based meta-analysis of gray matter alterations was performed utilizing the anisotropic effect size-based signed differential mapping. Subgroup analyses were also conducted to further validate these findings and identify specificities. Twenty-two studies including 913 idiopathic generalized epilepsy patients and 887 healthy controls were enrolled. Patients with idiopathic generalized epilepsy exhibited increased gray matter in the right cuneus cortex, precuneus, superior frontal gyrus, middle frontal gyrus, parahippocampal gyrus, and fusiform gyrus, while exhibiting decreased gray matter in the bilateral thalami, left caudate nucleus, and right insula. Subgroup analyses revealed overlapping gray matter alterations in the bilateral thalami, with specific involvement of frontal lobe and insula in juvenile myoclonic epilepsy, right superior temporal gyrus in generalized tonic-clonic seizures alone, and bilateral paracentral lobules in absence epilepsy. This meta-analysis identified that both cortical and subcortical structural abnormalities especially thalamo-cortical circuit was involved in patients with idiopathic generalized epilepsy, while overlapped and disassociated gray matter alterations were identified across different idiopathic generalized epilepsy subsyndromes.