Reduction of white matter integrity correlates with apathy in Parkinson's disease.

BACKGROUND: Apathy is a common non-motor symptom in Parkinson's disease (PD), but little is known about apathy and white matter (WM) change. In this study, we investigated whether fractional anisotropy (FA) of the WM can distinguish apathetic patients from non-apathetic PD patients, and whether the FA value correlates with the severity of apathy in PD.

METHODS: Thirty-nine PD patients participated in our study, of which 18 participants were with apathy symptom, and 21 without apathy symptom. Diffusion tensor imaging was performed on all the subjects.

RESULTS: Compared to non-apathetic PD patients, the apathetic group had reduced FA values in the genu and body of corpus callosum, bilateral anterior corona radiata, left superior corona radiata and left cingulum. Furthermore, in these WM regions, the FA values were negatively correlated with the Lille Apathy Rating Scale scores in apathetic subjects.

CONCLUSION: The WM change is associated with apathy in PD patients. In addition, the FA values of specific regions of WM could be a promising marker to predict the severity of apathy.