Objective: To investigate skin temperature dynamics in the peri-sleep onset period in patients with isolated REM Sleep Behavior Disorder (iRBD).

Background: Increases in peripheral skin temperature reflect thermoregulatory and circadian processes linked to sleep onset and autonomic control (1). While altered thermoregulation is a core feature of Parkinson’s Disease (2), and disturbed circadian rhythms have been recently associated with risk markers for neurodegeneration in prodromal stages such as iRBD (3), temperature dynamics around sleep onset have been scarcely explored in this population (4).

Method: Forty-two patients with iRBD and twenty-three healthy controls (HC) underwent six-day ambulatory circadian monitoring of wrist skin temperature (KronowiseTM) and clinical assessment (3). Temperature values were aligned to individual sleep onset and analyzed within a ±120-minute window. Daily normalization was applied to control for inter-night variability. Group differences between HC and iRBD were assessed using linear mixed-effects models (LMEM), using subject as a random-factor to account for intra-individual variability. Individual linear and quadratic coefficients describing temperature dynamics after sleep onset were extracted, and correlations with clinical variables were explored.

Results: Patients with iRBD exhibited greater burden of non-motor symptoms. LMEM revealed that temperature increased significantly with sleep onset transitions in both groups (linear component: β = 63.80, p < 0.001; quadratic component: β = −3.83, p < 0.001). Significant interactions between group and time were observed, with iRBD patients showing a reduced temperature increase (β = −7.52, p < 0.001) and a flatter trajectory (β = −4.00, p < 0.001) compared with HC (Figure 1). No significant correlations were observed between trajectory components and clinical variables.

Conclusion: Skin temperature dynamics surrounding sleep onset are altered in iRBD, suggesting early disruption of sleep-related thermoregulatory processes. Future studies should address the clinical correlates of ambulatorily-recorded skin temperature to assess its potential value as a biomarker in prodromal α-synucleinopathies.

Figure 1.

Table 1.

References: 1. Szymusiak R. Body temperature and sleep. Handbook of Clinical Neurology [Internet]. Elsevier B.V.; 2018. 341–351 p. Available from: http://dx.doi.org/10.1016/B978-0-444-63912-7.00020-5 doi:10.1016/B978-0-444-63912-7.00020-5 PubMed PMID: 30454599.
2. Pressnell ZS, Neilson LE, Tupone D, Pfeiffer RF, Safarpour D. Thermoregulatory Dysfunction in Parkinson’s Disease: Mechanisms, Implications, and Therapeutic Perspectives. Cells. 2025 Dec 2;14(23):1910. doi:10.3390/cells14231910 PubMed PMID: 41369399; PubMed Central PMCID: PMC12691499.
3. Roura I, Pardo J, Martín-Barceló C, Pacheco-Jaime L, García-Vicente C, Falcon C, et al. Circadian alterations in isolated Rapid-Eye-Movement sleep behavior disorder: associations with clinical, glymphatic, and dopaminergic imaging markers. Sleep. 2026 Jan 6;zsaf418. doi:10.1093/sleep/zsaf418
4. Zhong G, Bolitho S, Grunstein R, Naismith SL, Lewis SJG. The relationship between thermoregulation and REM sleep behaviour disorder in Parkinson’s disease. PloS One. 2013;8(8):e72661. doi:10.1371/journal.pone.0072661 PubMed PMID: 23991135; PubMed Central PMCID: PMC3749164.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/isolated-rem-sleep-behavior-disorder-is-associated-with-altered-nocturnal-skin-temperature-dynamics/