The Impact of Sleep Disorders on Parkinson’s Disease: A Deep Dive
Introduction
Parkinson’s disease (PD) is the second most common neurodegenerative condition after Alzheimer’s, affecting around 0.5‰ of the global population.
As the world’s population ages, the number of PD cases is on the rise. Beyond its well-known motor symptoms, PD is also marked by a variety of non-motor symptoms, including sleep disorders. These issues can emerge during the early stages of the disease and significantly affect patients’ day-to-day lives and cognitive health.
Specific sleep problems like insomnia, excessive daytime sleepiness, and rapid eye movement sleep behavior disorder (RBD) are particularly prevalent in PD, occurring in 60–90% of cases. These disorders not only disrupt nighttime sleep but can also accelerate PD progression, impacting both patients and caregivers.
Understanding the Research
To better understand sleep disorders in PD, researchers conducted a comprehensive bibliometric analysis. Using the Web of Science Core Collection (WoSCC) database, they identified 4,629 relevant publications between 2004 and 2024, narrowing the focus to articles and reviews.
The search strategy employed Medical Subject Headings (MeSH) terms such as “sleep disorder,” “REM sleep behavior disorder,” “insomnia,” “excessive daytime sleepiness,” and “Restless Leg Syndrome,” combined with “Parkinson” to refine the dataset.
This rigorous approach yielded 3,655 publications included in the final analysis, providing a robust foundation for examining trends and key contributors.
Data Analysis Tools
The study utilized several tools for data analysis, including CiteSpace 6.3.R1, VOSviewer 1.6.20, Bibliometrix, and Microsoft Excel 2019. These tools helped in constructing keyword mappings, identifying citation bursts, and analyzing author and institutional collaborations.
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Key Findings
Annual Publication and Citation Trends
The research shows a steady increase in publications focusing on sleep disorders in PD, indicating growing interest in this area. Citations have also risen over the past decade, highlighting the importance of these studies in the neurodegenerative disease field.
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Figure 3 Geospatial analysis of research output on sleep disorders in Parkinson’s disease. (A) Temporal trends in annual publication output from the top 10 most prolific countries. Node size reflects the annual publication count. (B) Co-occurrence network of contributing countries. Node size corresponds to the frequency of co-occurrence, while nodes encircled in purple indicate high centrality (≥ 0.1), signifying influential bridging roles. (C) Top 10 countries with strongest citation bursts. (D) Collaboration network among countries, where link thickness indicates the strength of collaboration. |
Analysis of Countries
The United States, France, and England were identified as key hubs based on their high betweenness centrality. China, with the strongest citation burst, is rapidly becoming a leader in this research area.
Collaboration between the United States and China stands out, demonstrating the impact of international partnerships.
Institutional Contributions
Université de Montréal and McGill University in Canada had the strongest collaboration among institutions. In China, Capital Medical University and Shanghai Jiao Tong University showed close partnership, though overall international collaboration remains underdeveloped.
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Top Authors and Collaborative Patterns
Werner Poewe from Austria had the longest and strongest citation burst, while Monica Puligheddu and Michela Figorilli from Italy are currently experiencing significant contributions. Authors like Fereshtehnejad SM from Canada and Michael J. Sateia from the USA have also shown strong bursts.
The collaborative patterns among these authors reveal several clusters, with K.K. Chaudhunk and Chunfeng Liu at the center of the largest cluster.
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High-Impact Journals
Journals such as NPJ Parkinson’s Disease, Nature, Frontiers in Neurology, and the Journal of Parkinson’s Disease have seen significant citation bursts, indicating their pivotal role in disseminating influential research.
The dual-map overlay of journals highlights a shift in research focus from molecular genetics to clinical neurology and neurology sports ophthalmology, reflecting the interdisciplinary nature of sleep disorders research in PD.
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Key References and Citation Bursts
The paper by Postuma et al. on the risk and predictors of dementia in idiopathic REM sleep behavior disorder has seen the strongest ongoing citation burst. This indicates the critical link between RBD and PD.
Other recent studies on sleep disorders as prodromal markers and factors affecting quality of life are also experiencing significant citation growth.
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Figure 7 Reference analysis in sleep disorders research in Parkinson’s disease. (A) Co-citation network visualization, where node size represents citation frequency. Nodes encircled in purple indicate high centrality (≥ 0.1), highlighting pivotal works that connect different research clusters. The transition from pink to blue in node color reflects the temporal distribution of publications, with pink denoting more recent works. (B) Reference clustering based on semantic similarity, with pink arrows illustrating the primary flow of citations within each cluster. (C) Landscape map of reference clusters, providing a visual representation of the research landscape. (D) Clustering of references from 2019 to 2024, focusing on semantic similarity to identify emerging trends. (E) Top 25 references with the strongest citation bursts from 2004 to 2024. Red bars signify periods of heightened citation activity, spotlighting publications that received intense scholarly focus during specific intervals. (F) Top 25 references with the strongest citation bursts from 2019 to 2024, underscoring recent influential works. |
Research Hotspots and Future Directions
Key Research Fields and Disciplines
Neurosciences, pharmacology, clinical neurology, biochemistry, and public health play crucial roles in sleep disorders research in PD.
Prominent Keywords
Keywords like “quality of life,” “diagnosis,” “risk,” and “dopamine” suggest that research focuses on the impact of sleep disorders on quality of life, underlying mechanisms, and diagnostic strategies.
Emerging topics include machine learning, COVID-19, sleep quality, and biomarkers, indicating growing interest in advanced technologies and their applications.
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Figure 8 Analytical overview of research domains and key terms in the study of sleep disorders in Parkinson’s disease. (A) Co-occurrence network  |