Abstract
Background: Studies reported a relationship between white matter alterations and apathy in patients with Cerebral Small Vessel Disease (CSVD), the reported lesions are heterogeneously distributed. To identify microstructural alterations associated with apathy in CSVD patients using tract-based spatial statistics (TBSS).
Methods:Forty-eight CSVD patients underwent structural magnetic resonance imaging (MRI) and completed clinical assessments of symptoms, which were divided into apathy and non-apathy groups. We used TBSS to assess the integrity of the white matter tracts and mediation analysis was performed to test the relationship between emotional disorders, neuroimaging features, and the disruption of white matter tracts.
Result：TBSS showed decreased fractional anisotropy (FA) and increased mean diffusivity (MD) in the apathy group in specific structural regions, including anterior thalamic radiation, corticospinal tract, cingulate gyrus, hippocampus, inferior fronto-occipital fasciculus, inferior/superior longitudinal fasciculus, and uncinate fasciculus. The mediation analyses reported FA and MD values significantly mediated the intervention effect on apathy and neuroimaging markers (white matter hyperintensities WHM and cerebral microbleeds CMB). In addition, mediation analyses indicated that depression partially but significantly mediated the intervention effect on apathy and MD values.
Limitations: Full follow-up data for apathy are not available in CSVD to perform the longitudinal analysis. Moreover, clinical information regarding the presence or absence of apathy prior to CSVD was unavailable for the present analysis.
Conclusions: TBSS revealed that apathy in CSVD is associated with disruption of white matter tracts in wider brain regions, and white matter damage underlies the relationship between neuroimaging markers of CSVD (WHM and CMB) and apathy. Depression may be a precursor to apathy due to the loss of special white matter tracts.