Microstructural white-matter abnormalities and their relationship with cognitive dysfunction in obsessive-compulsive disorder.
In recent years, diffusion tensor imaging (DTI) studies have detected subtle microstructural abnormalities of white matter (WM) in obsessive-compulsive disorder (OCD). However, findings have been inconsistent, and it is unclear whether WM abnormalities are related to cognitive processes. The aim of this study was to explore the relationship of WM alterations with cognitive variables in OCD in order to investigate the structural correlates of behaviorally relevant features of the disorder.



We compared DTI-derived fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) measures between OCD patients (n = 16) and healthy controls (n = 18) using a whole-brain tract-based spatial statistics (TBSS) approach. We also explored the correlations of WM alterations with clinical and cognitive variables.



Patients with OCD demonstrated increases in MD in the bilateral posterior corona radiata; left anterior corona radiata; bilateral superior longitudinal fasciculus; genu, body, and splenium of the corpus callosum; and left posterior limb of the internal capsule. An increase in RD values was also found in some of the same tracts (right posterior corona radiata, right superior longitudinal fasciculus, left anterior corona radiata, and corpus callosum). Furthermore, increased MD value in the internal capsule was correlated with the percentage of errors made during a target detection task, which was greater in the OCD group overall.



These findings indicate that OCD patients show greater diffusivity in several white-matter regions. The correlation between cognitive performance and diffusivity in the internal capsule suggests that microstructural WM alternations may have functional consequences for the disorder.
Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health Section of Psychiatry University of Genoa Genoa Italy.
Paola
P
Magioncalda
Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health Section of Psychiatry University of Genoa Genoa Italy.
Matteo
M
Martino
Department of Neuroscience Icahn School of Medicine at Mount Sinai New York City New York.
Benjamin A
BA
Ely
Department of Neuroscience Icahn School of Medicine at Mount Sinai New York City New York; Department of Neurology Icahn School of Medicine at Mount Sinai New York City New York.
Matilde
M
Inglese
Department of Neuroscience Icahn School of Medicine at Mount Sinai New York City New York; Department of Psychiatry Icahn School of Medicine at Mount Sinai New York City New York.
Emily R
ER
Stern
D000328:Adult; D001921:Brain / Q000503:physiopathology; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000503:physiopathology; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000503:physiopathology*; D066127:White Matter / Q000503:physiopathology / Q000648:ultrastructure*
Cognitive dysfunction; diffusion tensor imaging; obsessive–compulsive disorder; tract‐based spatial statistics; white matter