Diffusion Tensor Imaging Analysis Along the Perivascular Space Index in Primary Parkinson's Disease Patients with and Without Freezing of Gait

Background: Parkinson's disease (PD) is a common neurodegeneration disease associated with the abnormal deposition and spread of misfolded proteins (α-synuclein and Tau protein), which progressively damages the glymphatic system. This research intended to investigate the activity of the glymphatic system in PD individuals with freezing of gait (PD-FOG) and PD patients without it (PD-nFOG), as well as their relationship to the clinical neural scale.Methods: Diffusion tensor imaging (DTI) was performed in 28 PD-FOG individuals, 31 PD-nFOG individuals, and 34 healthy controls (HC). The DTI analysis along the perivascular space (DTI-ALPS) index was computed after post-processing of DTI images, representing brain glymphatic functions. The DTI-ALPS index was assessed for the association with the clinical variables.Results: Compared to the HC group, the DTI-ALPS index of both PD-FOG and PD-nFOG patients was significantly decreased; however, no notable difference was found between the PD-FOG and PD-nFOG group. In addition, the DTI-ALPS index of PD-nFOG patients were positively correlated with disease duration, Unified Parkinson's Disease Rating-III Right (UPDRS-III R), UPDRS-III TOTAL, UPDRS-IV.Conclusions: The present research showed that the DTI-ALPS index decreased in PD individuals, indicating the weakening of function of the glymphatic system in PD individuals. However, no difference of the DTI-ALPS index was found between PD-FOG and PD-nFOG individuals.Funding Information: This work was supported by the Guangdong Basic and Applied Basic Research Foundation (No. 2021A1515011288), the Science and Technology Planning Project of Guangzhou (No. 202102010020). Declaration of Interests: The authors declare that they have no conflict of interest. Ethics Approval Statement: The present research was accepted by the Ethical Board of our institution (Guangzhou First People’s Hospital). All participants in the experiment were provided with informed consents to the experimental procedures and precautions of this study before the experiment. All subjects (PD group and HC group) signed informed consents.