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Self-applied single-channel mastoid ExG for fully automated detection of REM sleep behaviour disorder
Skjaerbaek, C.; Damgaard, A. T.; Bertelsen, N. B.; Lillethorup, T. P.; Horsager, J.; Lowe, V.; Andersen, N. H.; Terkelsen et al.. medRxiv (preprint), 2026-08-20
Topic: Brain proteins, microglia and lab models
Isolated REM sleep behaviour disorder (RBD) is the strongest prodromal marker of Parkinsons disease (PD) and dementia with Lewy bodies, yet diagnosis requires video-polysomnography with assisted montage and expert scoring and does not scale to screening or trial enrichment. We developed a fully automated, self-applied system that detects RBD from a pair of electrodes placed behind the ears, with no manual scoring at any stage. A novel bipolar mastoid ExG derivation enables both sleep staging and quantification of REM sleep without atonia (RWA). A fine-tuned deep-learning 1-channel model staged sleep at a Cohens kappa of 0.65 in PD, iRBD and controls ({kappa} = 0.73 for the 2-channel model). Automated mastoid RWA correlated strongly with expert chin SINBAR scoring (r = 0.82). In self-applied home recordings from 76 participants, the 1-channel system detected RBD with an AUC of 0.95 (sensitivity 94%, specificity 86%), reproduced on in-lab polysomnographies (AUC 0.93, n = 378). In RBD, between-night RWA variability warrants repeated nights for prognostic monitoring. The system provides a scalable tool for RBD detection and a continuous RWA measure for longitudinal studies of neurodegeneration.
Key findings
- A fine-tuned deep-learning 1-channel model staged sleep at a Cohens kappa of 0.65 in PD, iRBD and controls ({kappa} = 0.73 for the 2-channel model).
- Automated mastoid RWA correlated strongly with expert chin SINBAR scoring (r = 0.82).
- In self-applied home recordings from 76 participants, the 1-channel system detected RBD with an AUC of 0.95 (sensitivity 94%, specificity 86%), reproduced on in-lab polysomnographies (AUC 0.93, n = 378).
- In RBD, between-night RWA variability warrants repeated nights for prognostic monitoring.
- The system provides a scalable tool for RBD detection and a continuous RWA measure for longitudinal studies of neurodegeneration.
Why it matters
A self-applied system using electrodes behind the ears detected REM sleep behaviour disorder, a prodromal marker of Parkinson's disease and dementia with Lewy bodies, with high accuracy in home recordings. The authors present it as a scalable detection tool for screening and longitudinal studies, not as a treatment or cure.
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Study details
- Study designlongitudinal study
- Participants378
- Effect sizeAUC 0.93
- Evidence strengthModerate
How this study scored 16/100
Preprint — not yet peer-reviewed. It scored 39 on the same rubric, but non-peer-reviewed sources are capped at 16, so it shows as 16. Scored zero for randomised / blinded because the record does not state it. We have no data on impact for its field and year, so that was left out: it earned 37 of the 94 points we could judge it on, which is 39 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 2 / 10 | Tier 4 — not a peer-reviewed journal (medRxiv (preprint)) |
| Journal's citation record | 0 / 4 | Not a journal article, so the journal's record does not count |
| Study design | 7 / 12 | A longitudinal study following the same people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 4 / 10 | Preprint — not yet peer-reviewed. Hosted on a preprint server. |
| How recent | 5 / 5 | 2026 — within 1 year(s) of the newest study here |
| Sample size | 2 / 4 | 378 participants |
| Effect reported | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 0 / 7 | Cited 0 times (OpenAlex, 2026-10-10) |
| Citations per year | 0 / 5 | 0.0 citations a year over 2 year(s) since 2026 |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 0 / 4 | Cited 0 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Preben Kidmose: h-index 30 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | University of Bonn: institution h-index 1,072 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 9 institution(s) in 2 countries |
| Indexed in PubMed | 1 / 2 | Not in PubMed, but has a DOI |
| Free to read | 2 / 2 | Free to read |
| Points | 37 / 94 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 37 of the 94 points we could judge it on is 39 out of 100. |
| Total | 39 / 100 | Capped to 16 because this is not a peer-reviewed article. |
What each of these 20 components measures, and what this score is not →
Read the original
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Skjaerbaek, C., Damgaard, A. T., Bertelsen, N. B., Lillethorup, T. P., Horsager, J., Lowe, V., et al. (2026). Self-applied single-channel mastoid ExG for fully automated detection of REM sleep behaviour disorder. medRxiv (preprint). https://doi.org/10.64898/2026.08.14.26360475
Vancouver
Skjaerbaek C, Damgaard AT, Bertelsen NB, Lillethorup TP, Horsager J, Lowe V, et al. Self-applied single-channel mastoid ExG for fully automated detection of REM sleep behaviour disorder. medRxiv (preprint). 2026. doi:10.64898/2026.08.14.26360475.
BibTeX
@article{skjaerbaek2026-ad526bca,
author = {Skjaerbaek, C. and Damgaard, A. T. and Bertelsen, N. B. and Lillethorup, T. P. and Horsager, J. and Lowe, V. and Andersen, N. H. and Terkelsen and others},
title = {{Self-applied single-channel mastoid ExG for fully automated detection of REM sleep behaviour disorder}},
journal = {medRxiv (preprint)},
year = {2026},
doi = {10.64898/2026.08.14.26360475},
url = {https://doi.org/10.64898/2026.08.14.26360475}
}
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