Moving towards stability: Sleep and cognition across six years of community dance in Parkinsons disease

Background: Non-motor symptoms, including sleep and cognitive dysfunction, are major contributors to reduced quality of life in people with Parkinsons disease (PwPD). Dance has been proposed as a promising intervention to improve quality of life in PwPD. Previously, we reported longitudinal trajectories of global cognition following community-based dance; however, little is known about its long-term influence on sleep-related non-motor symptoms and their relationship with global cognitive performance. Objective: We examined the six-year trajectories of sleep and overall non-motor symptom severity among PwPD participating in weekly community-based dance classes compared to a sedentary Reference group. As a secondary objective, we evaluated their association with global cognitive performance as a functional outcome. Methods: This longitudinal observational study followed PwPD engaged in community dance participation as well as a matched sedentary control group from the Parkinsons Progression Markers Initiative database over six years. Generalized estimating equations (GEE) were used to model group-level trends, with sensitivity analyses conducted to assess the robustness of the findings. Results: Non-motor outcomes showed that insomnia worsened significantly within the Reference group (p = .003) but improved among dancers (p = .005), with daytime sleepiness remaining stable across both groups. When sleep was used as a predictor of cognition, global cognitive performance trended to improve in the Dance group (p = .078) and declined mid-period in the Reference group (p = .014). In addition, overall non-motor symptom severity worsened in the Reference group (p = .011) but remained stable in the Dance group. Constipation also worsened significantly in the Reference group (p = .012) compared to the Dance group. Conclusion: The present study demonstrates that community-based dance may support select non-motor symptoms, including insomnia, and cognitive resilience in PwPD. Findings reinforce dance as a valuable, real-world, non-pharmacological approach to slow functional decline in PD.