Structural Abnormalities in Early Tourette Syndrome Children: A Combined Voxel-Based Morphometry and Tract-Based Spatial Statistics Study

Abstract

Tourette Syndrome (TS) is characterized with chronic motor and vocal tics beginning in childhood. Abnormality of both gray (GM) and white matter (WM) has been observed in cortico-striato-thalamo-cortical circuits and sensory-motor cortex of adult TS patient. It is not clear if these morphological changes are also present in TS children and if there are any microstructural changes of WM. To understand the developmental cause of such changes, we investigated volumetric changes of GM and WM using VBM and microstructural changes of WM using DTI, and correlated these changes with tic severity and duration. T1 images and Diffusion Tensor Images (DTI) from 21 TS children were compared with 20 age and gender matched health control children using a 1.5T Philips scanner. All of the 21 TS children met the DSM-IV-TR criteria. T1 images were analyzed using DARTEL-VBM in conjunction with statistical parametric mapping (SPM). Diffusion tensor imaging (DTI) analysis was performed using Tract-Based Spatial Statistics (TBSS). Brain volume changes were found in left superior temporal gyrus, left and right paracentral gyrus, right precuneous cortex, right pre- and post- central gyrus, left temporal occipital fusiform cortex, right frontal pole, and left lingual gyrus. Significant axial diffusivity (AD) and mean diffusivity (MD) increases were found in anterior thalamic radiation, right cingulum bundle projecting to the cingulate gurus and forceps minor. Decreases in white matter volume (WMV) in the right frontal pole were inversely related with tic severity (YGTSS), and increases in AD and MD were positively correlated with tic severity and duration, respectively. These changes in TS children can be interpreted as signs of neural plasticity in response to the experiential demand. Our findings may suggest that the morphological and microstructural measurements from structural MRI and DTI can potentially be used as a biomarker of the pathophysiologic pattern of early TS children.

Randomized Sham Controlled Double-blind Trial of Repetitive Transcranial Magnetic Stimulation for Adults With Severe Tourette Syndrome

“…Other studies suggest abnormal brain activity in the right hemisphere of TS patients [41], and particularly in the right frontal pole [42], with findings of hyper- excitability of motor regions [43–47]. The fact that 1-Hz rTMS resulted in a decrease in motor cortex excitability might suggest a possible failure of the active treatment in affecting inhibitory circuits that could not have been up-regulated by the parameters used in our study.…”

Putting the Pieces Together in Gilles de la Tourette Syndrome: Exploring the Link Between Clinical Observations and the Biological Basis of Dysfunction

“…Alteration of brain morphological parameters in adults includes changes in both gray and white matter (Liu et al 2013). Structural changes have been reported in the prefrontal cortex, limbic structures and basal ganglia of individuals with GTS, consistent with the dysfunction and natural history characteristic of the disorder (Singer et al 1993; Hyde et al 1995; Peterson et al 2003; Bloch et al 2005; Plessen et al 2009).…”

“…Tic severity has been reported to be inversely proportional with white matter volume in the right frontal pole and positively correlated with increases in axial diffusivity in children (Liu et al 2013). These subjects also showed a positive correlation with mean diffusivity and tic duration.…”

“…These subjects also showed a positive correlation with mean diffusivity and tic duration. In adults, intensity of premonitory sensations was negatively correlated with fractional anisotropy (FA) values in the parietal portion of the superior longitudinal fascicle (Draganski et al 2010; Liu et al 2013). Adults also showed significant FA decrease in the genu of the corpus callosum, and FA increase with mean diffusivity decrease was observed bilaterally in the somatosensory area (Draganski et al 2010).…”

“…Adults also showed significant FA decrease in the genu of the corpus callosum, and FA increase with mean diffusivity decrease was observed bilaterally in the somatosensory area (Draganski et al 2010). Significant axial diffusivity and mean diffusivity increases were reported in children in the anterior thalamic radiation, right cingulum bundle projecting to the cingulate gyrus, and forceps minor (Liu et al 2013). …”