Previous studies have emphasized the role of CSF circulation in the clearance of brain waste products, with recent findings demonstrating increased CSF flow during sleep. CSF circulation impairment could play a major role in neurodegenerative proteinopathies such as PD, a commonly encountered feature of which is disrupted sleep. Here, we assessed the relationship between patient-reported sleep quality and imaging assays of CSF flow.

To investigate the relationship between sleep quality and cerebrospinal fluid (CSF) flow in individuals with Parkinson’s disease (PD).

Imaging and clinical assessments were completed in 23 PD participants aged 56 to 79 (M_age=66.70; 16 males). The Montreal Cognitive Assessment (MoCA) and Unified Parkinson’s Disease Rating Scale (UPDRS) were administered; subjective sleep measurements were recorded using the Sleep Disturbance (SD) and Sleep-Related Impairment (SRI) items from the Patient-Reported Outcomes Measurement Information System (PROMIS) scale. MRI phase contrast sequences quantified CSF flux (mL/min) via the cerebral aqueduct. Net CSF flow was defined as the difference between caudal and cranial flow, whereas absolute flow was calculated as the sum of total caudal and cranial flow per cardiac cycle.

Participants had mean MoCA scores of 24.17 (range 13-30) and UPDRS scores of 30.70 (7-59). PROMIS scores for SD and SRI were 20.14 (9-32) and 15.00 (8-24), respectively. Mean CSF measurements were 0.25 mL/min (-0.29-0.88) for net and 8.11 mL/min (3.55-16.34) for absolute flow. Higher SRI scores correlated with greater net CSF flow while awake (r=0.531, p=0.023). Additionally, SRI and age explained 73.4% of variation in absolute CSF flow in a linear regression model (F(3,15)=24.5, p<0.0001).

Self-reported sleep impairment is associated with increased CSF flow in awake individuals with PD. This study is the first to link patient-reported measures of sleep with alterations to CSF flow. These data support novel outcomes for clinical studies that improve sleep.