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Objective: Assess feasibility and performance of a wearable wristband for longitudinal nocturnal monitoring of peripheral autonomic vasoreactivity and cross-validate vasoconstriction parameters against a gold-standard finger sensor. Methods: Twelve SCD patients and six controls wore a nightly PPG wrist device (Biostrap); controls were cross-validated with an AliceNightOne finger PPG system. Results: Continuous longitudinal recordings were feasible with significant variability; vasoconstriction parameters correlated within and across devices. Conclusions: Wristband PPG enables objective vasoconstriction biomarkers for predicting imminent VOC risk.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/wearable-device-photoplethysmography-as-a-viable-tool-to-longitudinally-monitor-vasoconstriction-biomarkers-for-predicting-vaso-occlusive-crisis-in-sickle-cell-disease-feasibility-and-validation-study/453616/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/wearable-device-photoplethysmography-as-a-viable-tool-to-longitudinally-monitor-vasoconstriction-biomarkers-for-predicting-vaso-occlusive-crisis-in-sickle-cell-disease-feasibility-and-validation-study/453616.png","ImageObject",300,407,{"name":92,"@type":93},"Rowan","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-31","2026-09-30",true,{"@type":102,"interactionType":103,"userInteractionCount":34},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What problem does this study address in sickle cell disease (SCD)?","Question",{"text":112,"@type":113},"The study targets vaso-occlusive crises (VOCs) that arise from obstruction of microvascular blood flow by sickled red blood cells, potentially triggered by autonomic nervous system–mediated vasoconstriction.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How does the wearable device monitor vasoconstriction biomarkers?",{"text":117,"@type":113},"A wristband (Biostrap) records nightly photoplethysmography (PPG). The study derives vasoconstriction parameters, including magnitude of vasoconstriction (Mvasoc) and PPG amplitude coefficient of variation (PPGampCV).",{"name":119,"@type":110,"acceptedAnswer":120},"What validation was performed against the gold-standard finger sensor?",{"text":121,"@type":113},"The PPGampCV parameter was cross-validated across the wristband and the finger PPG devices during nights when both sensors were worn, showing statistically significant correlations across all tested nights.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},453616,1790834312,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":34,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":139,"language":140,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":67,"update_tm":144,"read_time":41,"preview_page_count":4},1099514067415,"https://ap-avatar.wpscdn.com/avatar/100002539d78ffe74a7?x-image-process=image/resize,m_fixed,w_180,h_180&k=1779092875211072502","| JMIR HUMAN FACTORS Shah et al\u003Cbr>Original Paper\u003Cbr>Wearable Device Photoplethysmography As a Viable Tool to Longitudinally Monitor Vasoconstriction Biomarkers for Predicting Vaso-Occlusive Crisis in Sickle Cell Disease:\u003Cbr>Feasibility and Validation Study |  |  |  |  |\n| --- | --- | --- | --- | --- |\n|  |  |  |  |  |\n| Payal Shah 1 , MS; Sabrina Saranya Veluswamy 1 , MD | Sy2 , BS; Mingjing | Chen2 , BS; Michael CK | Khoo2 , PhD; Thomas D | Coates 1 , MD; |\n| 1Division of Hematology, Cancer and Blood Disease Institute, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA, United States\u003Cbr>2Alfred E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States\u003Cbr>Corresponding Author:\u003Cbr>Saranya Veluswamy, MD\u003Cbr>Division of Hematology, Cancer and Blood Disease Institute Children's Hospital Los Angeles, University of Southern California\u003Cbr>4650 Sunset Boulevard Los Angeles, CA 90027 United States\u003Cbr>Phone: 1 3233615507\u003Cbr>Email: [sveluswamy@chla.usc.edu](sveluswamy@chla.usc.edu)\u003Cbr>Abstract |  |  |  |  |\n\nBackground: Entrapment of sickled red blood cells in the microvasculature leads to sudden painful vaso-occlusive crises (VOCs) in sickle cell disease (SCD) . This is potentially triggered by autonomic nervous system–mediated vasoconstriction in the microvasculature. Indeed, vasoconstriction biomarkers derived from a single night of laboratory-based fingertip photoplethysmography (PPG) recording were predictive of a higher frequency of future VOC in SCD. Noninvasive, remote, and longitudinal monitoring of autonomic vasoreactivity will facilitate the development of predictive biomarkers of imminent VOC.  \nObjective: This study aimed to assess the feasibility and performance of a wearable wristband device to longitudinally monitor nocturnal peripheral autonomic vasoreactivity and to cross-validate the vasoconstriction parameters across the“gold-standard” finger sensor .  \nMethods: A total of 12 patients with SCD and 6 healthy controls were recruited to wear a wristband device (Biostrap) with a PPG sensor on a nightly basis. For cross-validation studies, 50%(3/6) controls wore both the wristband and asleep monitoring device (AliceNightOne) with a finger PPG sensor . We quantified autonomic vasoreactivity by processing PPG signals and deriving vasoconstriction parameters—magnitude of vasoconstriction (Mvasoc) and photoplethysmography amplitude coefficient of variation (PPGampCV) . We performed a correlation analysis of the vasoconstriction parameters within each device to investigate whether Mvasoc and PPGampCV can be used as surrogate markers of vasoconstriction, and then cross-validated the PPGampCV across the wristband and finger PPG devices.  \nResults: A total of 131 nocturnal PPG recordings were made with a wristband device (1‐19 nights per participant; patients with SCD: n=79, 60%; controls: n=52, 40%) . A total of 9 nocturnal recordings (3 nights per participant) were made with both wristband and finger sensor devices. Longitudinal continuous PPG recordings were feasible with the wearable device, with significant within-night and night-to-night variability in vasoconstriction parameters, suggesting dynamic changes in autonomic vasoreactivity. Mvasoc and PPGampCV significantly correlated within devices—the maximum overnight correlation was 0.82 (P\u003C.001) for the finger sensor and 0.69 (P\u003C.001) for the wristband sensor, suggesting that PPGampCV can serve as a surrogate for Mvasoc. Cross-validation analysis of PPGampCV across wristband and fingertip sensors showed statistically significant correlations on all 9 nights (overnight correlation coefficient ranging from 0.24‐0.7), with some nightly segments of PPGampCV showing very strong correlation across devices.  \n[https://humanfactors.jmir.org/2026/1/e75465](https://humanfactors.jmir.org/2026/1/e75465) JMIR Hum Factors 2026 | vol. 13 | e75465 | p. 1  \n(page number not for citation purposes)  \nJMIR HU","cbCaieUlEjVMKxfK","https://ap.wps.com/l/cbCaieUlEjVMKxfK","pdf",915713,12,"English","# Background\n# Objective\n# Methods\n## Participants and devices\n## Signal processing and parameters\n# Results\n## Feasibility and variability\n## Within-device correlation\n## Cross-validation across devices\n# Conclusions\n# Keywords","[{\"question\":\"What problem does this study address in sickle cell disease (SCD)?\",\"answer\":\"The study targets vaso-occlusive crises (VOCs) that arise from obstruction of microvascular blood flow by sickled red blood cells, potentially triggered by autonomic nervous system–mediated vasoconstriction.\"},{\"question\":\"How does the wearable device monitor vasoconstriction biomarkers?\",\"answer\":\"A wristband (Biostrap) records nightly photoplethysmography (PPG). The study derives vasoconstriction parameters, including magnitude of vasoconstriction (Mvasoc) and PPG amplitude coefficient of variation (PPGampCV).\"},{\"question\":\"What validation was performed against the gold-standard finger sensor?\",\"answer\":\"The PPGampCV parameter was cross-validated across the wristband and the finger PPG devices during nights when both sensors were worn, showing statistically significant correlations across all tested nights.\"}]","Wearable Device Photoplethysmography as a Viable Tool to Longitudinally Monitor Vasoconstriction Biomarkers for Predicting Vaso-Occlusive Crisis in Sickle Cell Disease - Feasibility and Validation Study | PDF",1790739230]