Altered spontaneous activity in treatment-naive childhood absence epilepsy revealed by Regional Homogeneity

To explore the differences in regional spontaneous activities throughout the whole brain by the Regional Homogeneity (ReHo) method in untreated childhood absence epilepsy (CAE), in order to understand the neuro-pathophysiological mechanism of function impairments in CAE.

The rest-functional MRI was used to measure the ReHo in 16 patients with untreated CAE and 16 age- and sex-matched healthy controls. The correlations between the ReHo at each voxel of the whole brain and duration of epilepsy were analyzed.

Compared with healthy controls, we found that ReHo was decreased in bilateral thalamus, caudate, posterior lobe of cerebellum and areas mainly in the default mode network (DMN) (including precuneus and posterior cingulate cortex-PCC, bilateral inferior lateral parietal lobule). The increase of ReHo was found in bilateral insula, left occipital cortex. Moreover, a correlation analysis of the ReHo measurement versus the epilepsy duration was performed, and highly positive correlation was observed in precuneus/PCC and supplementary motor area (SMA).

The current findings demonstrated alterations of ReHo in the striato-thalamo-cortical network in drug naïve CAE subjects during interictal resting state. Some regions with decreased ReHo followed the pattern of 'default' state of brain function. In addition, positive correlations between the ReHo values in the precuneus/PCC and SMA and the disease duration were identified. These results indicate that the involvement of these regions may be related to the pathomechanisms of seizure generation and the neurological deficits observed in CAE patients. ReHo has demonstrated the capability to characterize spontaneous brain dysfunction in epilepsy.