Smartphone-derived digital motor measures to monitor progression in idiopathic REM sleep behavior disorder
Sensitive and scalable biomarkers are critical for tracking progression during the prodromal phase of Parkinson's disease, particularly in idiopathic REM sleep behavior disorder (iRBD). We evaluated the Roche PD Mobile Application version 2, a smartphone-based platform, in 51 individuals with polysomnography-confirmed iRBD, 89 patients with early Parkinson's disease, and 22 healthy controls over 12 months. Participants completed daily active tasks generating validated digital summary measures. Adherence was high (73%). Baseline digital bradykinesia scores discriminated between groups (p < 0.001) and were higher in phenoconverters versus non-converters (p = 0.003; Cohen's d = 1.10). Over 50 weeks, bradykinesia (Cohen's d = 0.50) and speech (Cohen's d = 0.79) scores worsened significantly. Sample size modeling showed that digital bradykinesia required 132 participants per arm to detect a 50% treatment effect, fewer than the best-performing clinical measure. These findings support digital bradykinesia as a sensitive endpoint for prodromal Parkinson's disease trials.
Authors
- Kirsten I. Taylor (ORCID: https://orcid.org/0000-0002-2480-3137)
- Antoine Duquette (ORCID: https://orcid.org/0000-0002-8313-4068)
- Martin J. McKeown (ORCID: https://orcid.org/0000-0002-4048-0817)
- Michael Lindemann (ORCID: https://orcid.org/0000-0003-1010-3890)
- Barbara S. Connolly (ORCID: https://orcid.org/0000-0002-0757-1557)
- Damian Kwaśny (ORCID: https://orcid.org/0000-0002-2276-5288)
- Sarah Bouhadoun (ORCID: https://orcid.org/0009-0000-5500-3151)
- Nicolas Dupré (ORCID: https://orcid.org/0000-0001-7270-6115)
- David Grimes
- Kerrie Schoffer
- Stefan Lambrecht
- Werner L. Popp
- Valerie Soland
- Nicolas Jodoin
- Julius Anang
- Ronald B. Postuma
Institutions
- Roche (Switzerland) (CH)
- Montreal Neurological Institute and Hospital (CA)
- Dalhousie University (CA)
- University of British Columbia (CA)
- Ottawa Hospital (CA)
- Beatrice Hunter Cancer Research Institute (CA)
- Centre hospitalier universitaire de Québec (CA)
- Centre Hospitalier de l’Université de Montréal (CA)
- Université Laval (CA)
- McGill University (CA)
- Université de Saint-Boniface (CA)
- Hamilton Health Sciences (CA)
Publication Details
- Journal
- npj Parkinson s Disease
- Published
- 2026-06-26
- DOI
- https://doi.org/10.1038/s41531-026-01440-6
- Primary Topic
- Restless Legs Syndrome Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Roche
- Canadian Institutes of Health Research