Impaired cerebrovascular-cerebrospinal fluid coupling is associated with non-motor features of Lewy body disease

The temporal coupling between cortical blood-oxygen-level-dependent (BOLD) activity and CSF inflow has recently been proposed as a non-invasive marker of glymphatic function, a brain-wide clearance system closely linked to sleep, neuromodulatory regulation and neurodegeneration. Reduced BOLD-CSF coupling has been previously reported in Parkinsons disease but its characterization in dementia with Lewy bodies, regional specificity and relevance to shared neuropsychiatric symptoms remain unclear. Using resting-state functional MRI, we quantified global and regional BOLD-CSF coupling in 39 participants, including 17 with Parkinsons disease (mean age 61.4 years), 10 with dementia with Lewy bodies