Brain microstructural changes and cognitive correlates in patients with pure obsessive compulsive disorder

Area of Science:

• Neuroscience
• Radiology
• Psychiatry

Background:

• Obsessive compulsive disorder (OCD) is a neuropsychiatric condition characterized by obsessions and compulsions.
• Previous research suggests structural and functional brain abnormalities in OCD patients, but findings are not always consistent.
• Investigating both macrostructural and microstructural changes is crucial for a comprehensive understanding of OCD's neurobiology.

Purpose of the Study:

• To investigate macrostructural and microstructural brain changes in patients with pure OCD.
• To examine the relationship between observed brain alterations and neuropsychological deficits, particularly executive functions.
• To identify potential neuroimaging and cognitive markers for OCD.

Main Methods:

• A cohort of 20 patients diagnosed with OCD underwent a comprehensive neuropsychological assessment.
• Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) were employed to analyze gray matter (GM) and white matter (WM) differences.
• Multiple regression analyses explored correlations between cognitive performance and neuroimaging parameters.

Main Results:

• OCD patients exhibited increased mean diffusivity (MD) in GM regions of the orbitofronto-striatal loop and associative cortices.
• Decreased fractional anisotropy (FA) was observed in intrahemispheric and interhemispheric white matter tracts, including the corpus callosum.
• Semantic fluency scores, indicative of executive control, predicted OCD diagnosis and correlated with MD in temporal and parietal regions and FA in specific white matter tracts.

Conclusions:

• The study identified significant microstructural brain alterations in patients with OCD.
• Deficits in executive processes, such as semantic fluency, are associated with these neuroimaging findings.
• These combined cognitive and neurobiological changes may serve as potential behavioral and biological markers for OCD.