{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T22:31:29Z","timestamp":1772749889720,"version":"3.50.1"},"reference-count":49,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2020,8,13]],"date-time":"2020-08-13T00:00:00Z","timestamp":1597276800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004085","name":"Ministry of Education, Science and Technology","doi-asserted-by":"publisher","award":["2017M3C1B6070526"],"award-info":[{"award-number":["2017M3C1B6070526"]}],"id":[{"id":"10.13039\/501100004085","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004085","name":"Ministry of Education, Science and Technology","doi-asserted-by":"publisher","award":["2018R1A2A2A05023299"],"award-info":[{"award-number":["2018R1A2A2A05023299"]}],"id":[{"id":"10.13039\/501100004085","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004085","name":"Ministry of Education, Science and Technology","doi-asserted-by":"publisher","award":["2018K1A3A1A20026539"],"award-info":[{"award-number":["2018K1A3A1A20026539"]}],"id":[{"id":"10.13039\/501100004085","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003052","name":"Ministry of Trade, Industry and Energy","doi-asserted-by":"publisher","award":["R0004840, 2020"],"award-info":[{"award-number":["R0004840, 2020"]}],"id":[{"id":"10.13039\/501100003052","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Biomedical Research Institute of Chonbuk National University Hospital","award":["N\/A"],"award-info":[{"award-number":["N\/A"]}]},{"name":"Korean Health Technology R&amp;D Project, Ministry of Health &amp; Welfare","award":["HI10C0626"],"award-info":[{"award-number":["HI10C0626"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Existing swallowing evaluation methods using X-ray or endoscopy are qualitative. The present study develops a swallowing monitoring and assessment system (SMAS) that is nonintrusive and quantitative. The SMAS comprises an ultrasonic Doppler sensor array, a microphone, and an inertial measurement unit to measure ultrasound signals originating only from swallowing activities. Ultrasound measurements were collected for combinations of two viscosity conditions (water and yogurt) and two volume conditions (3 mL and 9 mL) from 24 healthy participants (14 males and 10 females; age = 30.5 \u00b1 7.6 years) with no history of swallowing disorders and were quantified for 1st peak amplitude, 2nd peak amplitude, peak-to-peak (PP) time interval, duration, energy, and proportion of two or more peaks. The peak amplitudes and energy significantly decreased by viscosity and the PP time interval and duration increased by volume. The correlation between the time measures were higher (r = 0.78) than that of the amplitude measures (r = 0.30), and the energy highly correlated with the 1st peak amplitude (r = 0.86). The proportion of two or more peaks varied from 76.8% to 87.9% by viscosity and volume. Further research is needed to examine the concurrent validity and generalizability of the ultrasonic Doppler sensor-based SMAS.<\/jats:p>","DOI":"10.3390\/s20164529","type":"journal-article","created":{"date-parts":[[2020,8,13]],"date-time":"2020-08-13T09:23:44Z","timestamp":1597310624000},"page":"4529","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Development of an Ultrasonic Doppler Sensor-Based Swallowing Monitoring and Assessment System"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7894-3787","authenticated-orcid":false,"given":"Younggeun","family":"Choi","sequence":"first","affiliation":[{"name":"Department of Industrial and Management Engineering, Pohang University of Science and Technology, Pohang 37673, Korea"}]},{"given":"Minjae","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Industrial and Management Engineering, Pohang University of Science and Technology, Pohang 37673, Korea"}]},{"given":"Baekhee","family":"Lee","sequence":"additional","affiliation":[{"name":"Body Test Team 3, Hyundai Motor Company, Hwaseong 18280, Korea"}]},{"given":"Xiaopeng","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Artificial Intelligence and Computer Science, Jiangnan University, Wuxi 214122, China"}]},{"given":"Jinwon","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Industrial and Management Engineering, Pohang University of Science and Technology, Pohang 37673, Korea"}]},{"given":"Dohoon","family":"Kwon","sequence":"additional","affiliation":[{"name":"Department of Industrial and Management Engineering, Pohang University of Science and Technology, Pohang 37673, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2766-8791","authenticated-orcid":false,"given":"Sang-Eok","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation Medicine, Pohang Stroke and Spine Hospital, Pohang 37659, Korea"}]},{"given":"HyangHee","family":"Kim","sequence":"additional","affiliation":[{"name":"Graduate Program in Speech-Language Pathology, Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul 03722, Korea"}]},{"given":"Seok In","family":"Nam","sequence":"additional","affiliation":[{"name":"Graduate School of Social Welfare, Yonsei University, Seoul 03722, Korea"}]},{"given":"Saewon","family":"Hong","sequence":"additional","affiliation":[{"name":"R&amp;D Research Team, Digital Echo Co., Hwaseong 18385, Korea"}]},{"given":"Giltae","family":"Yang","sequence":"additional","affiliation":[{"name":"R&amp;D Research Team, SEED Tech. Co., Bucheon 14523, Korea"}]},{"given":"Duk L.","family":"Na","sequence":"additional","affiliation":[{"name":"Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1914-5774","authenticated-orcid":false,"given":"Heecheon","family":"You","sequence":"additional","affiliation":[{"name":"Department of Industrial and Management Engineering, Pohang University of Science and Technology, Pohang 37673, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2020,8,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1007\/s00455-001-0113-5","article-title":"Social and psychological burden of dysphagia: Its impact on diagnosis and treatment","volume":"17","author":"Ekberg","year":"2002","journal-title":"Dysphagia"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"189","DOI":"10.2147\/CIA.S97481","article-title":"Oropharyngeal dysphagia in older persons\u2014From pathophysiology to adequate intervention: A review and summary of an international expert meeting","volume":"11","author":"Wirth","year":"2016","journal-title":"Clin. Interv. Aging"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1007\/BF00385794","article-title":"Prepharyngeal dysphagia in Parkinson\u2019s disease","volume":"11","author":"Leopold","year":"1996","journal-title":"Dysphagia"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1111\/j.1365-2842.2007.01741.x","article-title":"Evaluation of chewing and swallowing disorders among frail community-dwelling elderly individuals","volume":"34","author":"Miura","year":"2007","journal-title":"J. Oral Rehabil."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/S0003-9993(98)90200-3","article-title":"Aspiration in patients with acute stroke","volume":"79","author":"Daniels","year":"1998","journal-title":"Arch. Phys. Med. Rehab."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1505","DOI":"10.1589\/jpts.28.1505","article-title":"The duration of stage transition during pharyngeal swallowing among young-elderly, and mid-elderly individuals","volume":"28","author":"Byeon","year":"2016","journal-title":"J. Phys. Ther. Sci."},{"key":"ref_7","first-page":"665","article-title":"Effect of age and bolus variables on the coordination of the glottis and upper esophageal sphincter","volume":"88","author":"Ren","year":"1993","journal-title":"Am. J. Gastroenterol."},{"key":"ref_8","first-page":"16","article-title":"Interaction of swallowing and control of breathing","volume":"28","author":"Nishino","year":"1990","journal-title":"Nihon Kyobu Shikkan Gakkai Zasshi"},{"key":"ref_9","first-page":"179","article-title":"Swallow apnea: Rhinomanometric manifestation and classification","volume":"4","author":"Loch","year":"1982","journal-title":"Rhinology"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Adkins, C., Takakura, W., Spiegel, B.M.R., Lu, M., Vera-Llonch, M., Williams, J., and Almario, C.V. (2020). Prevalence and characteristics of dysphagia based on a population-based survey. Clin. Gastroenterol. H.","DOI":"10.1016\/j.cgh.2019.10.029"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1111\/j.1532-5415.2010.03227.x","article-title":"Prevalence of oropharyngeal dysphagia and impaired safety and efficacy of swallow in independently living older persons","volume":"59","author":"Hinojosa","year":"2011","journal-title":"J. Am. Geriatr. Soc."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1534","DOI":"10.3346\/jkms.2013.28.10.1534","article-title":"Oropharyngeal dysphagia in a community-based elderly cohort: The korean longitudinal study on health and aging","volume":"28","author":"Yang","year":"2013","journal-title":"J. Korean Med. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"632","DOI":"10.21037\/jtd.2016.02.60","article-title":"Dysphagia, dystussia, and aspiration pneumonia in elderly people","volume":"8","author":"Ebihara","year":"2016","journal-title":"J. Thorac. Dis."},{"key":"ref_14","first-page":"1227","article-title":"Management of respiratory diseases in the elderly","volume":"29","author":"Sasaki","year":"1991","journal-title":"Nihon Kyobu Shikkan Gakkai Zasshi"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1033","DOI":"10.1148\/radiographics.21.4.g01jl271033","article-title":"Fluoroscopy: Patient radiation exposure issues","volume":"21","author":"Mahesh","year":"2001","journal-title":"RadioGraphics"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.anl.2018.04.005","article-title":"A novel fluoroscopic method for multidimensional evaluation of swallowing function","volume":"46","author":"Arai","year":"2019","journal-title":"Auris Nasus Larynx"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1080\/21681163.2015.1046190","article-title":"Semi-automatic tracking of hyolaryngeal coordinates in videofluoroscopic swallowing studies","volume":"5","author":"Natarajan","year":"2017","journal-title":"Comput. Methods Biomech. Biomed. Eng. Imaging Vis."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1007\/s00455-011-9368-7","article-title":"Evaluation of dysphagia after cervical surgery using laryngeal electromyography","volume":"27","author":"Ryu","year":"2012","journal-title":"Dysphagia"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1007\/s00455-011-9352-2","article-title":"Measurement of hyoid and laryngeal displacement in video fluoroscopic swallowing studies: Variability, reliability, and measurement error","volume":"27","author":"Sia","year":"2012","journal-title":"Dysphagia"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1007\/s00455-010-9321-1","article-title":"Videofluoroscopic evaluation of swallowing in Chagas\u2019 disease","volume":"26","author":"Cassiani","year":"2011","journal-title":"Dysphagia"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1007\/s12070-018-1275-x","article-title":"Fiberoptic endoscopic evaluation of swallow (FEES) in intensive care unit patients post extubation","volume":"71","author":"Ambika","year":"2019","journal-title":"Indian J. Otolaryngol. Head Neck Surg."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1111\/coa.13331","article-title":"Feasibility and outcomes of fibreoptic endoscopic evaluation of swallowing following prophylactic swallowing rehabilitation in head and neck cancer","volume":"44","author":"Patterson","year":"2019","journal-title":"Clin. Otolaryngol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1007\/s00455-013-9447-z","article-title":"Evaluation of dysphagia in early stroke patients by bedside, endoscopic, and electrophysiological methods","volume":"28","author":"Umay","year":"2013","journal-title":"Dysphagia"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1007\/s004559910008","article-title":"The safety of flexible endoscopic evaluation of swallowing with sensory testing (FEESST): An analysis of 500 consecutive evaluations","volume":"15","author":"Aviv","year":"2000","journal-title":"Dysphagia"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1007\/PL00009559","article-title":"Predictors of aspiration pneumonia: How important is dysphagia?","volume":"13","author":"Langmore","year":"1998","journal-title":"Dysphagia"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1007\/PL00009544","article-title":"Fiberoptic endoscopic evaluation of dysphagia to identify silent aspiration","volume":"13","author":"Leder","year":"1998","journal-title":"Dysphagia"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1007\/BF00301919","article-title":"Indications and techniques of endoscopy in evaluation of cervical dysphagia: Comparison with radiographic techniques","volume":"9","author":"Kidder","year":"1994","journal-title":"Dysphagia"},{"key":"ref_28","unstructured":"Carrau, R.L., Murry, T., and Rebecca, J. (2017). Comprehensive Management of Swallowing Disorders, Plural Publishing."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Kuramoto, N., Jayatilake, D., Hidaka, K., and Suzuki, K. (2016, January 16\u201320). Smartphone-based swallowing monitoring and feedback device for mealtime assistance in nursing homes. Proceedings of the 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Orlando, FL, USA.","DOI":"10.1109\/EMBC.2016.7592041"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Jayatilake, D., Ueno, T., Teramoto, Y., Nakai, E., Hidaka, K., Ayuzawa, S., Eguchi, K., Matsumura, A., and Suzuki, K. (2015). Smartphone-based real-time assessment of swallowing ability from the swallowing sound. IEEE J. Transl. Eng. Health Med., 3.","DOI":"10.1109\/JTEHM.2015.2500562"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"706","DOI":"10.1590\/S1808-86942009000500016","article-title":"Doppler sonar analysis of swallowing sounds in normal pediatric individuals","volume":"75","author":"Cagliari","year":"2009","journal-title":"Braz. J. Otorhinolar."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"639","DOI":"10.2340\/16501977-0384","article-title":"Acoustic analysis of swallowing sounds: A new technique for assessing dysphagia","volume":"41","author":"Santamato","year":"2009","journal-title":"J. Rehabil. Med."},{"key":"ref_33","first-page":"182","article-title":"Sonar Doppler as an instrument of deglutition evaluation","volume":"10","author":"Santos","year":"2006","journal-title":"Ann. Otol. Rhinol. Laryngol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1007\/s00455-001-0100-x","article-title":"Detection of swallowing sounds: Methodology revisited","volume":"17","author":"Cichero","year":"2002","journal-title":"Dysphagia"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"749","DOI":"10.1177\/000348949009900916","article-title":"Interpreting the sounds of swallowing: Fluid flow through the cricopharyngeus","volume":"99","author":"Hamlet","year":"1990","journal-title":"Ann. Otol. Rhinol. Laryngol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1093\/ageing\/18.3.168","article-title":"Respiratory patterns associated with swallowing: Part 1. The normal adult pattern and changes with age","volume":"18","author":"Selley","year":"1989","journal-title":"Age Ageing"},{"key":"ref_37","unstructured":"You, H. (2018, January 11). Development of a swallowing monitoring technology based on a wearable ultrasound Doppler sensor. Proceedings of the 2018 Spring Conference of the Korean Gerontological Society, Seoul, Korea."},{"key":"ref_38","unstructured":"Choi, Y., Lee, H., Oh, G., and You, H. (2017, January 26\u201328). Development of a swallowing monitoring device for early screening of dysphagia. Proceedings of the 2017 Spring Conference of the Korean Institute of Industrial Engineers, Yeosoo, Korea."},{"key":"ref_39","unstructured":"Lee, B., Yang, G., Hong, S., Na, D., and You, H. (2015, January 10\u201316). Development of a swallowing screening algorithm using ultrasonic Doppler sensor and microphone. Proceedings of the 2015 Fall Conference of the Ergonomic Society of Korea, Busan, Korea."},{"key":"ref_40","unstructured":"Lee, B., Lee, H., Yun, M., Seo, M., Na, D.L., and You, H. (2013, January 23\u201324). Comparison of swallowing characteristics in normal controls and patients with dysphagia. Proceedings of the 2013 Spring Conference of Ergonomics Society of Korea, Ulsan, Korea."},{"key":"ref_41","unstructured":"Lee, B., Lee, H., Seo, M., Na, D.L., and You, H. (2013, January 23\u201327). Comparison of swallowing characteristics in patients with dysphagia and normal controls. Proceedings of the 20th IAGG World Congress of Gerontology and Geriatrics, Seoul, Korea."},{"key":"ref_42","unstructured":"Lee, B., Jung, K., Yang, G., Seo, M., Na, D.L., and You, H. (2012, January 10\u201311). Development of a quantitative assessment system for dysphagia using Doppler ultrasound. Proceedings of the 2012 Spring Conference of the Korean Institute of Industrial Engineers, Gyeongju, Korea."},{"key":"ref_43","unstructured":"Lee, B. (2015). A Quantitative Assessment Methodology of Pharyngeal Swallow. [Ph.D. Thesis, Pohang University of Science and Technology]."},{"key":"ref_44","unstructured":"Gjendemsj\u00d8, A., Selik, M., and Baraniuk, R. (2006). Energy and power. Information and Signal Theory, Rice University."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Soria, F., Silva, R.G., and Furkim, A.M. (2015). Acoustic analysis of oropharyngeal swallowing using Sonar Doppler. Braz. J. Otorhinolar., 82.","DOI":"10.1016\/j.bjorl.2015.12.001"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1016\/j.ces.2015.05.011","article-title":"Oil-water two-phase flow velocity measurement with continuous wave ultrasound Doppler","volume":"135","author":"Dong","year":"2015","journal-title":"Chem. Eng. Sci."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"735","DOI":"10.1016\/j.ijrobp.2012.07.2370","article-title":"Evaluating swallowing muscles essential for hyolaryngeal elevation by using muscle functional magnetic resonance imaging","volume":"85","author":"Pearson","year":"2013","journal-title":"Int. J. Radiat. Oncol. Biol. Phys."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"78","DOI":"10.5056\/jnm14055","article-title":"Effect of bolus volume and consistency on swallowing events duration in healthy subjects","volume":"21","author":"Nascimento","year":"2015","journal-title":"J. Neurogastroenterol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1007\/s00455-005-0013-1","article-title":"An acoustic profile of normal swallowing","volume":"20","author":"Youmans","year":"2005","journal-title":"Dysphagia"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/16\/4529\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:59:58Z","timestamp":1760176798000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/16\/4529"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,8,13]]},"references-count":49,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2020,8]]}},"alternative-id":["s20164529"],"URL":"https:\/\/doi.org\/10.3390\/s20164529","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,8,13]]}}}