Lateral frontal cortex volume reduction in Tourette syndrome revealed by VBM

Abstract

BackgroundStructural changes have been found predominantly in the frontal cortex and in the striatum in children and adolescents with Gilles de la Tourette syndrome (GTS). The influence of comorbid symptomatology is unclear. Here we sought to address the question of gray matter abnormalities in GTS patients with co-morbid obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD) using voxel-based morphometry (VBM) in twenty-nine adult actually unmedicated GTS patients and twenty-five healthy control subjects.ResultsIn GTS we detected a cluster of decreased gray matter volume in the left inferior frontal gyrus (IFG), but no regions demonstrating volume increases. By comparing subgroups of GTS with comorbid ADHD to the subgroup with comorbid OCD, we found a left-sided amygdalar volume increase.ConclusionsFrom our results it is suggested that the left IFG may constitute a common underlying structural correlate of GTS with co-morbid OCD/ADHD. A volume reduction in this brain region that has been previously identified as a key region in OCD and was associated with the active inhibition of attentional processes may reflect the failure to control behavior. Amygdala volume increase is discussed on the background of a linkage of this structure with ADHD symptomatology. Correlations with clinical data revealed gray matter volume changes in specific brain areas that have been described in these conditions each.

Neuroimaging of tic genesis: Present status and future perspectives

“…Compared with simple tics, complex tics can be correlated with more widespread structural abnormalities in associative networks, including the frontal and the parietal cortical areas . This results shed light on the earlier reports of widespread brain structural abnormalities within both gray and white matter in patients with tics that could thus contribute to the variability of clinical presentations (Fig. A).…”

Multicenter Voxel-Based Morphometry Mega-Analysis of Structural Brain Scans in Obsessive-Compulsive Disorder

“…Smaller medial frontal gray matter volume has been reported in anxiety and depression (3,24), and in our sample it was more pronounced in patients with additional comorbid anxiety and/ or depression, which may thus be indicative of a common pathophysiological mechanism across affective disorders related to a shared deficit in emotion regulation (3,24). On the other hand, smaller inferior frontal cortex/anterior insula volumes may be a neuroanatomical characteristic more specific to OCD and related disorders (14,24,25), although this speculation awaits empirical confirmation. We found greater cerebellar gray matter volume in OCD patients relative to healthy subjects.…”

“…Assessing the effects of aging on brain structure in OCD is important, since age-by-disorder interactions may provide leads as to whether changes in brain structure are related to developing the disorder (present in young patients) or are the result of persistent OCD symptoms, compensatory processes, or treatment effects (present in older patients). Additionally, heterogeneity in clinical characteristics such as OCD illness severity (2), illness onset time or duration, medication exposure (12), comorbidity (13,14), and symptom dimensions (8, 9) may affect regional brain volume. In meta-analyses, only group-level demographic and clinical information is available, so accounting for effects of participant-level variability is problematic.…”

Obsessive-Compulsive Disorder: Diagnosis, Epidemiology, Etiology, and Treatment

“…Patients with OCD and comorbid disorders are sometimes the intended focus of research (77,78), but inadvertent inclusion of individuals with comorbidities, or difficulty in parceling out the independent effects of comorbidities, may lead to the discrepancies among neuroimaging studies. For example, major depressive disorder shares many neuroanatomical findings with OCD (79,80).…”