The multidisciplinary management of Parkinson’s disease (PD) demands an appreciation for the prevalence and etiology of non-motor aspects of the disease, including impairments in executive function, memory, visuospatial skills, attention, and language. These symptoms, which must factor into surgical decision-making, are likely due to degradation of projection fibers associated with the underlying neurodegenerative process.

     In this study, we use diffusion tensor imaging (DTI) to evaluate the relationship between measures of white matter integrity in predefined regions-of-interest (ROIs) and performance in 5 distinct cognitive domains in 13 PD patients.

       Thirteen patients provided the data.

     Using FSL tools, fractional anisotropy (FA) and mean diffusivity (MD) values were calculated for 40 ROIs, as defined by the John Hopkins University’s white matter atlas, and were regressed against neuropsychological scores in each domain. P<0.01 was considered significant.

     Executive function directly correlated with FA and inversely correlated with MD of frontal white matter tracts, including the fronto-occipital fasciculus and the anterior corona radiata. Memory, visuospatial skills, and attention likewise demonstrated correlations with frontal white matter tracts but uniquely correlated with FA and inversely correlated with MD of the uncinate fasciculae and the posterior thalamic radiations. Finally, language performance was significantly related to diffusivity measures in the left anterior corona radiata.

     This is a retrospective study.

     Unique patterns of white matter disease underlie impairments in distinct cognitive domains in patients with PD.

     Importantly, this study identifies an important imaging correlate of cognitive impairment that when coupled with neuropsychological measures may be used as an enhanced diagnostic tool for cognitive impairments in PD.