{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T16:57:02Z","timestamp":1770915422518,"version":"3.50.1"},"reference-count":22,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2021,9,25]],"date-time":"2021-09-25T00:00:00Z","timestamp":1632528000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Bijzonder Onderzoeksfonds KU Leuven","award":["C24\/18\/097"],"award-info":[{"award-number":["C24\/18\/097"]}]},{"DOI":"10.13039\/501100003130","name":"Fonds Wetenschappelijk Onderzoek","doi-asserted-by":"publisher","award":["150466"],"award-info":[{"award-number":["150466"]}],"id":[{"id":"10.13039\/501100003130","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100011878","name":"Vlaamse regering","doi-asserted-by":"publisher","award":["AI research program"],"award-info":[{"award-number":["AI research program"]}],"id":[{"id":"10.13039\/501100011878","id-type":"DOI","asserted-by":"publisher"}]},{"name":"imec funds","award":["2019-2020"],"award-info":[{"award-number":["2019-2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Obstructive sleep apnea (OSA) patients would strongly benefit from comfortable home diagnosis, during which detection of wakefulness is essential. Therefore, capacitively-coupled electrocardiogram (ccECG) and bioimpedance (ccBioZ) sensors were used to record the sleep of suspected OSA patients, in parallel with polysomnography (PSG). The three objectives were quality assessment of the unobtrusive signals during sleep, prediction of sleep\u2013wake using ccECG and ccBioZ, and detection of high-risk OSA patients. First, signal quality indicators (SQIs) determined the data coverage of ccECG and ccBioZ. Then, a multimodal convolutional neural network (CNN) for sleep\u2013wake prediction was tested on these preprocessed ccECG and ccBioZ data. Finally, two indices derived from this prediction detected patients at risk. The data included 187 PSG recordings of suspected OSA patients, 36 (dataset \u201cTest\u201d) of which were recorded simultaneously with PSG, ccECG, and ccBioZ. As a result, two improvements were made compared to prior studies. First, the ccBioZ signal coverage increased significantly due to adaptation of the acquisition system. Secondly, the utility of the sleep\u2013wake classifier increased as it became a unimodal network only requiring respiratory input. This was achieved by using data augmentation during training. Sleep\u2013wake prediction on \u201cTest\u201d using PSG respiration resulted in a Cohen\u2019s kappa (\u03ba) of 0.39 and using ccBioZ in \u03ba = 0.23. The OSA risk model identified severe OSA patients with a \u03ba of 0.61 for PSG respiration and \u03ba of 0.39 using ccBioZ (accuracy of 80.6% and 69.4%, respectively). This study is one of the first to perform sleep\u2013wake staging on capacitively-coupled respiratory signals in suspected OSA patients and to detect high risk OSA patients based on ccBioZ. The technology and the proposed framework could be applied in multi-night follow-up of OSA patients.<\/jats:p>","DOI":"10.3390\/s21196409","type":"journal-article","created":{"date-parts":[[2021,9,27]],"date-time":"2021-09-27T22:16:38Z","timestamp":1632780998000},"page":"6409","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Capacitively-Coupled ECG and Respiration for Sleep\u2013Wake Prediction and Risk Detection in Sleep Apnea Patients"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0500-9894","authenticated-orcid":false,"given":"Dorien","family":"Huysmans","sequence":"first","affiliation":[{"name":"STADIUS Center for Dynamical Systems, Signal Processing and Data Analytics, Department of Electrical Engineering (ESAT), KU Leuven, 3001 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3852-2379","authenticated-orcid":false,"given":"Ivan","family":"Castro","sequence":"additional","affiliation":[{"name":"Circuits and Systems for Health, Imec-Leuven, 3001 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8292-3532","authenticated-orcid":false,"given":"Pascal","family":"Borz\u00e9e","sequence":"additional","affiliation":[{"name":"Department of Pneumology, UZ Leuven, 3000 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3814-1872","authenticated-orcid":false,"given":"Aakash","family":"Patel","sequence":"additional","affiliation":[{"name":"Circuits and Systems for Health, Imec-Leuven, 3001 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1302-3346","authenticated-orcid":false,"given":"Tom","family":"Torfs","sequence":"additional","affiliation":[{"name":"Circuits and Systems for Health, Imec-Leuven, 3001 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2482-7139","authenticated-orcid":false,"given":"Bertien","family":"Buyse","sequence":"additional","affiliation":[{"name":"Department of Pneumology, UZ Leuven, 3000 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7303-9799","authenticated-orcid":false,"given":"Dries","family":"Testelmans","sequence":"additional","affiliation":[{"name":"Department of Pneumology, UZ Leuven, 3000 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5939-0996","authenticated-orcid":false,"given":"Sabine","family":"Van Huffel","sequence":"additional","affiliation":[{"name":"STADIUS Center for Dynamical Systems, Signal Processing and Data Analytics, Department of Electrical Engineering (ESAT), KU Leuven, 3001 Leuven, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9581-0676","authenticated-orcid":false,"given":"Carolina","family":"Varon","sequence":"additional","affiliation":[{"name":"STADIUS Center for Dynamical Systems, Signal Processing and Data Analytics, Department of Electrical Engineering (ESAT), KU Leuven, 3001 Leuven, Belgium"},{"name":"Service de Chimie-Physique E.P., Universit\u00e9 Libre de Bruxelles, 1050 Brussels, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1016\/j.smrv.2016.07.002","article-title":"Prevalence of obstructive sleep apnea in the general population: A systematic review","volume":"34","author":"Senaratna","year":"2017","journal-title":"Sleep Med. 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