Altered structural-functional coupling in Parkinson's disease

BackgroundStructural-functional coupling is abnormally altered in a variety of neuropsychiatric disorders and correlates with clinical symptoms of the patients. The relationships between structural-functional coupling and clinical manifestations of Parkinsons disease (PD) remain unclear. ObjectiveThe purpose of this study is to investigate whether the structural-functional coupling changes in PD and to explore the clinical implications of this network metric. MethodsStructural 3D T1-weighted imaging, diffusion tensor imaging, and resting-state functional magnetic resonance imaging were performed in 22 control subjects and 34 PD patients. Two types of structural-functional coupling (node coupling and network coupling) were derived from structural and functional images. The associations between structural-functional network coupling and clinical characteristics and genetic variations of 73 PD patients from Parkinsons Progression Markers Initiative database were analyzed. ResultsPD patients exhibited reduced structural-functional node couplings in multiple brain networks compared to controls. Structural-functional node coupling could be shaped by age, sex, and disease severity. In addition, this metric was modified by TMEM175 rs34311866 and GPNMB rs199347, two genetic variants conferring PD risk. In contrast, network coupling was less affected in PD. Particularly, structural-functional network couplings were potential predictors of motor symptoms, non-motor symptoms and pathological markers of cerebrospinal fluid in PD patients. Additionally, structural-functional network coupling was significantly correlated with metrics of network topology. ConclusionsOur findings suggest that structural-functional decoupling is an essential network feature in PD and structural-functional network coupling may serve as a valuable trait-like biomarker for disease burden in PD.