Objective: To determine whether mismatch between participant (PT) self-perceived and bed partner (BP)–reported sleep symptoms is associated with risk of phenoconversion to synucleinopathy.

Background: Patients with Parkinson’s disease (PD) commonly underreport sleep symptoms, but whether this occurs in isolated REM sleep behavior disorder (iRBD) is unclear.

Method: We analyzed SCOPA-Sleep scale scores from 175 iRBD PTs with ≥ 2 visits in the North American Prodromal Synucleinopathy (NAPS) Consortium database. Baseline signed differences (BP – PT) were examined separately for nighttime sleep (NS) and daytime sleepiness (DS), and classified as PT overestimator (≤ -2), concordant with BP (-1 to 1), or PT underestimator (≥ 2). Longitudinally consistent classifications were defined as maintaining the same classification across all visits. Associations with phenoconversion to synucleinopathy (PD, dementia with Lewy bodies, or multiple system atrophy) were examined using multivariable Cox proportional hazards models for baseline and longitudinally consistent classifications, adjusting for age, sex, disease duration, and education. Stability was quantified using Cohen’s κ for local (visits 1–3) and long-range (visit 1 and last visit) agreement.

Results: Mismatch classifications demonstrated instability across visits for NS (local: κ = 0.19–0.28, long-range: κ = 0.22) and DS (local: κ = 0.29–0.38, long-range: κ = 0.33), with fewer than half retaining their classification to last visit (consistent NS: 34.8%; DS: 45.2%). Baseline classification was not associated with phenoconversion to synucleinopathy. For longitudinally consistent classifications, only NS underestimation by PTs was associated with increased risk of phenoconversion to synucleinopathy (HR 3.11, 95% CI 1.32–7.31, p = 0.009). Consistent DS underestimators and consistent overestimators (NS or DS) were not associated with phenoconversion risk.

Conclusion: Persistent PT underestimation of nighttime sleep symptoms in iRBD was associated with increased risk of phenoconversion to synucleinopathy. Whether this reflects vulnerability to motor, cognitive, or combined phenoconversion requires further study.

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References: [1] Elliott JE, Lim MM, Keil AT, Postuma RB, Pelletier A, Gagnon JF, St Louis EK, Forsberg LK, Fields JA, Huddleston DE, Bliwise DL, Avidan AY, Howell MJ, Schenck CH, McLeland J, Criswell SR, Videnovic A, During EH, Miglis MG, Shprecher DR, Lee-Iannotti JK, Boeve BF, Ju YS; North American Prodromal Synucleinopathy (NAPS) Consortium. Baseline characteristics of the North American prodromal Synucleinopathy cohort. Ann Clin Transl Neurol. 2023 Apr;10(4):520-535. doi: 10.1002/acn3.51738. Epub 2023 Feb 8. PMID: 36751940; PMCID: PMC10109527.
[2] Zolfaghari S, Thomann AE, Lewandowski N, Trundell D, Lipsmeier F, Pagano G, Taylor KI, Postuma RB. Self-Report versus Clinician Examination in Early Parkinson’s Disease. Mov Disord. 2022 Mar;37(3):585-597. doi: 10.1002/mds.28884. Epub 2021 Dec 13. PMID: 34897818; PMCID: PMC9299700.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/underestimation-of-nighttime-sleep-symptoms-in-isolated-rbd-is-associated-with-increased-risk-of-phenoconversion-to-synucleinopathy-a-north-american-prodromal-synucleinopathy-consortium-study/