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Meas."],"published-print":{"date-parts":[[2025,12,31]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    <jats:italic>Objective<\/jats:italic>\n                    . sleep staging is essential for diagnosing sleep disorders and managing sleep health. Traditional methods require time-consuming manual scoring. Recent photoplethysmography (PPG)-based deep learning models perform well on local datasets but struggle with external generalization due to data drift.\n                    <jats:italic>Approach<\/jats:italic>\n                    . this study evaluates multi-source domain training for improving out-of-distribution generalization in four-class sleep staging (wake, light, deep, rapid eye movement) from raw PPG time-series. The trained deep learning model is denoted SleepPPG-Net2. Additionally, we examined the impact of demographic factors, ethnicity, and obstructive sleep apnea (OSA) on performance. SleepPPG-Net2 was benchmarked against two state-of-the-art models.\n                    <jats:italic>Main results<\/jats:italic>\n                    . SleepPPG-Net2 outperformed benchmark models, improving generalization performance (Cohen\u2019s kappa) by up to 21%. Performance disparities were observed in relation to age, sex, and OSA severity.\n                    <jats:italic>Significance<\/jats:italic>\n                    . SleepPPG-Net2 enhances PPG-based sleep staging and provides insights into demographic and clinical influences on model performance.\n                  <\/jats:p>","DOI":"10.1088\/1361-6579\/ae1a34","type":"journal-article","created":{"date-parts":[[2025,10,31]],"date-time":"2025-10-31T22:52:48Z","timestamp":1761951168000},"page":"125001","update-policy":"https:\/\/doi.org\/10.1088\/crossmark-policy","source":"Crossref","is-referenced-by-count":10,"title":["SleepPPG-Net2: deep learning generalization for sleep staging from photoplethysmography"],"prefix":"10.1088","volume":"46","author":[{"given":"Shirel","family":"Attia","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5786-0077","authenticated-orcid":true,"given":"Revital","family":"Shani Hershkovich","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alissa","family":"Tabakhov","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angeleene","family":"Ang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arie","family":"Oksenberg","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6574-3601","authenticated-orcid":false,"given":"Riva","family":"Tauman","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5956-7034","authenticated-orcid":true,"given":"Joachim A","family":"Behar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"266","published-online":{"date-parts":[[2025,12,8]]},"reference":[{"key":"pmeaae1a34bib1","article-title":"University of California, Los Angeles. 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