Risk of clinical milestones in Parkinson disease (PD) is associated with reduced glymphatic drainage, according to new research. The study of 175 people with PD showed that lower glymphatic function, measured by diffusion tensor imaging analysis of the perivascular space, was associated with increased risk of recurrent falls, wheelchair dependence and dementia. The study adds to growing evidence for a role of the glymphatic system in PD pathology that warrants further investigation.