Cyclic Alternating Pattern and Sleep Microstructure in Parkinson’s Disease: A Systematic Review and Meta-Analysis
Cyclic Alternating Pattern and Sleep Microstructure in Parkinson’s Disease: A Systematic Review and Meta-Analysis
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Original abstract
Jiajun Jiang,1,* Yi Huang,1,* Min Wang,1 Zixuan Zeng,2 Jing Li1â 3 1School of Psychiatry, North Sichuan Medical College, Nanchong, 637000, Peopleâs Republic of China; 2Sichuan Provincial Center for Mental Health, Sichuan Provincial Peopleâs Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, Peopleâs Republic of China; 3Key Laboratory of Psychosomatic Medicine, Chinese Academy of Medical Sciences, Chengdu, 610072, Peopleâs Republic of China*These authors contributed equally to this workCorrespondence: Jing Li, Sichuan Provincial Center for Mental Health, Sichuan Provincial Peopleâs Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, Peopleâs Republic of China, Email lijingjingjing222@163.comObjective: To systematically review polysomnographic sleep differences, with emphasis on cyclic alternating pattern (CAP) microstructure, between patients with Parkinsonâs disease (PD) and healthy controls (HC).Methods: We searched MEDLINE (via OVID), EMBASE (via OVID), CINAHL (via EBSCOhost), APA PsycArticles (via EBSCOhost), and Evidence-Based Medicine databases (via EBSCOhost) for studies published from January 1, 2020, to September 15, 2025. Eligible studies enrolled adults with idiopathic PD, included an internal HC group, used overnight polysomnography, and reported extractable CAP-related outcomes. Study quality was assessed with the Newcastle-Ottawa Scale. Random-effects meta-analyses were performed using Hedgesâ g with restricted maximum-likelihood estimation, and certainty of evidence was appraised with GRADE.Results: Four studies were included. PD patients showed significant reductions in CAP rate, CAP sequence duration, and CAP index (all p< 0.05), with low statistical heterogeneity. Macrostructural parameters showed no statistically significant pooled differences, and several had moderate-to-high heterogeneity. GRADE certainty was very low because the evidence came from a small number of observational studies.Conclusion: Within a limited evidence base, CAP-related microstructure shows a consistent pattern of reduction in clinically diagnosed PD, whereas macrostructural alterations were not stable across the included studies. CAP measures may provide complementary information in future PD sleep research, but the present evidence is insufficient to support their use as validated biomarkers.Keywords: Parkinsonâs disease, sleep microstructure, polysomnography, cyclic alternating pattern, meta-analysis