The Impact of Sleep Disorders on Glymphatic Function in Parkinson's Disease Using Diffusion Tensor MRI

To investigate the impact of sleep disorders on glymphatic system in Parkinson's disease (PD) using a non-invasive imaging technique called diffusion tensor image analysis along perivascular space (DTI-ALPS).

A total of 114 PD patients and 54 healthy controls (HCs) underwent sleep questionnaires and MRI examinations as part of data collection from the Parkinson's Progression Markers Initiative cohort. An automated pipeline was proposed for ALPS calculation to reduce biases from manually region delineation. ALPS indices were compared between PD and HCs, as well as between PD with and without sleep disorders. Correlation was assessed between ALPS index and clinical characteristics. Furthermore, a 2-year follow-up analysis was performed to explore longitudinal impact of sleep disorders on glymphatic function.

PD patients showed significantly decreased ALPS indices compared with HCs (P = 0.038). PD patients with sleep disorders showed slightly but not significantly decreased ALPS index compared with those with normal sleep (P = 0.058). However, PD patients who transitioned from normal sleep to sleep disorders showed significantly decreased ALPS index at follow-up compared to baseline (P = 0.047). In contrast, patients who maintained normal sleep showed no significant difference in ALPS index between follow-up and baseline (P = 0.934). In addition, PD patients who transitioned from normal sleep to sleep disorders showed significantly increased ΔMDS-UPDRS Part I score (P = 0.004), ΔMDS-UPDRS total score (P = 0.040) and ΔSCOPA-AUT (P = 0.048) compared with PD who remained normal sleep.

Sleep disorders accelerate dysfunction of glymphatic system as indicated by ALPS index in PD patients, which may be associated with symptom progression in follow-up analysis. Therefore, more attention should be devoted to prevent sleep disorders in early PD.