The glymphatic system may play a central role in cognitive impairment associated with Parkinson's disease, but its relationship with regional cortical atrophy is not fully explored. To explore associations among glymphatic dysfunction, regional cortical degeneration and cognitive impairment in Parkinson's disease participants, we evaluated 51 participants with documented Parkinson's disease (28 men
age, 61.65 ± 8.27 years) and 30 age- and sex-matched normal controls (11 men
age, 59.2 ± 5.90 years) who underwent 3.0-T MRI of the brain, including high-resolution T1-weighted imaging and diffusion-tensor imaging along the perivascular space as a surrogate for glymphatic flow. Cortical grey matter volume was segmented automatically based on three-dimensional T1-weighted sequences. Cognitive function was assessed by Mini-Mental State Examination. The relationship between glymphatic dysfunction, cognitive decline and regional cortical degeneration was explored. The participants with Parkinson's disease revealed lower diffusion-tensor imaging along the perivascular space (1.45 ± 0.17 versus 1.64 ± 0.17,