Thalamic Atrophy in Childhood Absence Epilepsy

Abstract

Summary:Purpose: Patients with childhood absence epilepsy (CAE) have normal clinical magnetic resonance imaging (MRI) studies. The presence of abnormalities in corticothalamic networks has been suggested to be the functional basis of absence seizure generation. We assessed whether structural grey and white matter volume changes of these areas occurred in patients with absence seizures by using optimized voxel-based morphometry (VBM).Methods: We recruited 13 patients with a clinical and EEG diagnosis of CAE (mean age at examination, 17 ± 8 years) and compared them with a consecutive series of 109 controls (mean age, 29 ± 9 years). The 3 tesla MRI examination included a 3D T 1 -weighted sequence, which was analyzed with an optimized VBM protocol using the SPM2 package. The threshold was set at p < 0.05, corrected for multiple comparisons.Results: Compared with controls, CAE patients showed areas of grey matter decrease in both thalami and in the subcallosal gyrus. White matter decrease was found in the extranuclear subcortical area and in the white matter of the basal forebrain. Grey and white matter increase was restricted to small clusters of cortical and subcortical areas.Conclusions: Evidence exists of subcortical grey and white matter volume reduction in CAE patients. Bilateral thalamic atrophy may be either a result of damage from seizures (as in hippocampal sclerosis) or a reflection of a primary underlying pathology as the cause of absence seizures.

Thalamic volume reduction in drug‐naive patients with new‐onset genetic generalized epilepsy

“…In a group of patients with juvenile myoclonic epilepsy (JME), shape analysis showed surface reduction in the medial and lateral nuclei of bilateral thalami25 and decreased gray matter volume in the anteromedial thalamus has also been found in patients with JME11 and in a group of mixed GGE patients 26. Similarly, gray matter volume reduction in bilateral thalami has been reported in patients with CAE 9. However, inconsistent results of increased thalamic gray matter volume was reported in CAE27; and no difference between GGE patients and healthy controls has also been reported 4…”

“…The thalamus has shown the most consistent differences, typically volume loss3, 4, 6, 7 in patients with GGE. Morphologic abnormalities of cortex, in particular prefrontal, precentral, and posterior cingulate, have also been reported, although inconsistently 6, 8, 9, 10, 11…”

Multi-site voxel-based morphometry: Methods and a feasibility demonstration with childhood absence epilepsy

“…It was applied by at least two experienced epileptologists at all sites as described in Chan et al (2006) (Site A) and Berg et al (1999) (Site B and Site C).…”

“…Typically, structural MRI's in these patients show no obvious abnormalities on visual inspection; however, subtle abnormalities, specifically statistically demonstrable thalamic atrophy have been revealed by quantitative analysis of groups of patients (Chan et al, 2006).…”

Resting functional connectivity between the hemispheres in childhood absence epilepsy

“…In addition, resting functional connectivity analysis may provide a promising biomarker to improve our understanding of altered brain function in CAE during the interictal period. Neurology Childhood absence epilepsy (CAE) is increasingly recognized as a disorder characterized by impaired function both during seizures, and in the interictal period.1-4 Notably, 3-4 Hz spikewave discharges (SWD) seen in CAE 5-7 and their associated blood oxygenation level-dependent (BOLD) fMRI changes [8][9][10][11][12][13][14][15][16] are bilateral and fairly symmetric. Evidence from animal models indicates that this bihemispheric synchrony during SWD is mediated by the corpus callosum.…”