Smart Sensors for Healthcare and Medical Applications

This book focuses on new sensing technologies, measurement techniques, and their applications in medicine and healthcare. Specifically, the book briefly describes the potential of smart sensors in the aforementioned applications, collecting 24 articles selected and published in the Special Issue “Smart Sensors for Healthcare and Medical Applications”. We proposed this topic, being aware of the pivotal role that smart sensors can play in the improvement of healthcare services in both acute and chronic conditions as well as in prevention for a healthy life and active aging. The articles selected in this book cover a variety of topics related to the design, validation, and application of smart sensors to healthcare

Personalized data analytics for internet-of-things-based health monitoring

The Internet-of-Things (IoT) has great potential to fundamentally alter the delivery of modern healthcare, enabling healthcare solutions outside the limits of conventional clinical settings. It can offer ubiquitous monitoring to at-risk population groups and allow diagnostic care, preventive care, and early intervention in everyday life. These services can have profound impacts on many aspects of health and well-being. However, this field is still at an infancy stage, and the use of IoT-based systems in real-world healthcare applications introduces new challenges. Healthcare applications necessitate satisfactory quality attributes such as reliability and accuracy due to their mission-critical nature, while at the same time, IoT-based systems mostly operate over constrained shared sensing, communication, and computing resources. There is a need to investigate this synergy between the IoT technologies and healthcare applications from a user-centered perspective. Such a study should examine the role and requirements of IoT-based systems in real-world health monitoring applications. Moreover, conventional computing architecture and data analytic approaches introduced for IoT systems are insufficient when used to target health and well-being purposes, as they are unable to overcome the limitations of IoT systems while fulfilling the needs of healthcare applications. This thesis aims to address these issues by proposing an intelligent use of data and computing resources in IoT-based systems, which can lead to a high-level performance and satisfy the stringent requirements. For this purpose, this thesis first delves into the state-of-the-art IoT-enabled healthcare systems proposed for in-home and in-hospital monitoring. The findings are analyzed and categorized into different domains from a user-centered perspective. The selection of home-based applications is focused on the monitoring of the elderly who require more remote care and support compared to other groups of people. In contrast, the hospital-based applications include the role of existing IoT in patient monitoring and hospital management systems. Then, the objectives and requirements of each domain are investigated and discussed. This thesis proposes personalized data analytic approaches to fulfill the requirements and meet the objectives of IoT-based healthcare systems. In this regard, a new computing architecture is introduced, using computing resources in different layers of IoT to provide a high level of availability and accuracy for healthcare services. This architecture allows the hierarchical partitioning of machine learning algorithms in these systems and enables an adaptive system behavior with respect to the user's condition. In addition, personalized data fusion and modeling techniques are presented, exploiting multivariate and longitudinal data in IoT systems to improve the quality attributes of healthcare applications. First, a real-time missing data resilient decision-making technique is proposed for health monitoring systems. The technique tailors various data resources in IoT systems to accurately estimate health decisions despite missing data in the monitoring. Second, a personalized model is presented, enabling variations and event detection in long-term monitoring systems. The model evaluates the sleep quality of users according to their own historical data. Finally, the performance of the computing architecture and the techniques are evaluated in this thesis using two case studies. The first case study consists of real-time arrhythmia detection in electrocardiography signals collected from patients suffering from cardiovascular diseases. The second case study is continuous maternal health monitoring during pregnancy and postpartum. It includes a real human subject trial carried out with twenty pregnant women for seven months

Effects of SIDS risk factors and hypoxia on cardiovascular control in infants

Background and aims. Sudden infant death syndrome (SIDS) is a rare lethal event occurring in 0.1 to 0.3 of infants. In Finland, 10 to 20 infants die from SIDS annually. Research has defined many risk factors for SIDS, but the cascade leading to death remains unexplained. Cardiovascular recordings of infants succumbing to SIDS, as well as animal models, suggest that the final sequelae involve cardiovascular collapse resembling hypotensive shock. There is also evidence of previous hypoxia in SIDS infants. In animal studies, vestibulo-mediated cardiovascular control has been shown to be important in hypotensive shock. Hence, we hypothetized that SIDS victims may have impaired vestibulo-mediated cardiovascular control, possibly due to previous hypoxic episodes. In this thesis, we studied cardiovascular control, and especially vestibulo-mediated cardiovascular control in infants with known risk factors for SIDS at 2 to 4 months of age when the risk for SIDS is highest. Study subjects. A full polysomnographic recording with continuous blood pressure (BP) measurement was performed in 50 infants at 2-4 months of age: 20 control infants, nine infants with univentricular heart (UVH) suffering from chronic hypoxia, 10 infants with bronchopulmonary dysplasia (BPD) with intermittent postnatal hypoxic events, and 11 infants whose mothers had smoked during pregnancy, and thus had been exposed to intrauterine hypoxia and nicotine, were studied. In addition, 20 preterm infants were studied at the gestational age of 34-39 weeks to evaluate developmental aspects of cardiovascular control during head-up tilt test and vestibular stimulus. Methods. Linear side motion and 45° head-up tilt tests were performed in quiet non-rapid eye movement sleep (NREM). Heart rate (HR) and BP responses were analysed from the tests without signs of subcortical or cortical arousal. In addition, HR variability during NREM sleep was assessed. As a general marker of cardiovascular reactivity, HR response to spontaneous arousal from NREM sleep was also evaluated. Results.Side motion test. In the side motion test, control infants presented a biphasic response. First, there was a transient increase in HR and BP. This was followed by a decrease in BP to below baseline, and a return to baseline in HR. All other infant groups showed altered responses. UVH infants and preterm infants near term age had markedly reduced responses. Infants with BPD presented with variable responses: some responded similarly to controls, whereas others showed no initial increase in BP, and the following BP decrease was more prominent. Infants with intrauterine exposure to cigarette smoke showed flat initial BP responses, and the following decrease was more prominent, similarly to a subgroup of BPD infants. Tilt test. Control infants presented with a large variability in BP responses to head-up tilting. On average, systolic BP remained, at first, close to baseline, and diastolic BP increased, after which both decreased and remained below baseline even at the end of the tilt test. On average, HR showed a biphasic response with an initial increase followed by a decrease to below and, finally, a return to baseline. UVH infants showed a similar BP response, but their HR response was tachycardic. Preterm infants with BPD presented with an even greater variability in their BP responses to head-up tilts than control infants, but the overall response as a group did not differ from that of the controls. The tilt response of infants exposed to maternal cigarette smoking during pregnancy did not markedly differ from the control response. Preterm infants near term age showed attenuated responses in both cardiovascular measures, together with greater inter-subject variability compared to the control infants. Discussion. In conclusion, the studied infants with SIDS risk factors showed altered vestibulo-mediated cardiovascular control during the linear side motion test and head-up tilt test. The findings support our initial hypothesis that some infants with SIDS risk factors have defective vestibulo-mediated cardiovascular control, which may lead to death in life-threatening situations.Kätkytkuolemat ovat harvinaisia, mutta ne ovat edelleen suurin yksittäinen syy täysiaikaisena syntyneiden imeväisten kuolemaan. Suomessa kätkytkuolemaan menehtyy vuosittain 10-20 lasta. Kätkytkuoleman syytä ei tiedetä. Epidemiologisten tutkimusten avulla kätkytkuoleman riskitekijät tunnetaan hyvin; näitä ovat mm. vatsallaan nukkuminen, äidin raskaudenaikainen tupakointi ja keskosuus. Selällään nukuttamisen yleistymisen myötä kätkytkuolemien määrä on vähentynyt olennaisesti. Koe-eläintöissä ja muutamassa kätkytkuoleman aikaisessa seurantanauhoituksessa on viitteitä siitä, että kätkytkuoleman mekanismi todennäköisesti muistuttaa verenvuotosokin loppuvaiheen kaltaista verenkiertoelimistön toiminnan romahtamista. Koe-eläintöiden perusteella tällaisessa sokkitilanteessa tasapainotumakevälitteinen verenkierron säätely on tärkeää. Tämän tutkimuskokonaisuuden pääolettaman mukaan kätkytkuolleilla on puutteellinen tasapainotumakevälitteinen sykkeen ja verenpaineen säätely. Koska kätkytkuolleilla on myös todettu merkkejä hapenpuutteesta ennen kuolemaa, voi poikkeavan tasapainotumakevälitteisen verenkierron säätelyn syynä olla edeltänyt hapenpuute: riskiryhmistä esimerkiksi keskosilla lyhytkestoiset hapenpuutejaksot ja äidin raskaudenaikaiselle tupakoinnille altistuneilla lapsilla pitkäaikainen lievä hapenpuute sikiöaikana. Myös pitkäaikaisesta syntymän jälkeisestä hapenpuutteesta kärsivillä yksikammiosydämisillä imeväisillä on todettu äkillisiä, kätkytkuoleman kaltaisia kuolemia. Tutkimme imeväisen verenkierron säätelyä unen aikana rekisteröimällä verenkiertovasteita sivuttaissiirto- ja kippilavatestille täysiaikaisilla imeväisillä sekä imeväisillä, joilla on yllämainittuja kätkytkuoleman riskitekijöitä tai hapenpuutetta. Unirekisteröinti tehtiin yhteensä 70 imeväiselle. 2-4 kuukauden korjatussa iässä tutkittiin 20 täysiaikaista verrokkia, 10 bronkopulmonaalisesta dysplasiasta kärsivää keskosta, 9 yksikammiosydämistä imeväistä sekä 11 imeväistä, joiden äidit tupakoivat raskauden aikana. Lisäksi tutkimme 20 keskosta 34-39 raskausviikon iässä sykkeen ja verenpaineen säätelyn kehityksen kartoittamiseksi. Sivuttaissiirtotesti sekä 45° kippilavatesti pää ylöspäin tehtiin rauhallisessa ei-REM-unessa. Terveiden täysiaikaisten verrokkien verenpaine- ja sykevasteita käytettiin vertailukohtana muiden ryhmien vasteita arvioitaessa. Syke- ja verenpainevasteet arvioitiin testeistä, joissa ei ollut viitettä havahtumisesta tai heräämisestä. Sydämen sykkeen vaihtelevuutta ja spontaanin heräämisen aiheuttamaa sykevastetta käytettiin kuvaamaan yleistä verenkiertoelimistön säätelyn herkkyyttä. Sivuttaissiirtotestissä verrokit reagoivat kaksivaiheisella syke- ja verenpainevasteella. Sekä verenpaine että syke nousivat aluksi, jonka jälkeen verenpaine laski alle lähtötason ennen paluuta lähtötasoon, ja syke palasi lähtötasoon. Muissa tutkituissa ryhmissä vasteet poikkesivat normaalivasteista. Yksikammiosydänlapsilla sekä lähellä laskettua aikaa tutkituilla keskosilla syke- ja verenpainevasteet sivuttaissiirrolle olivat hyvin vaimeat. Puolet bronkopulmonaalisesta dysplasiasta kärsivistä imeväisistä reagoi samoin kuin verrokit, mutta puolella verenpaineen nousu puuttui ja sitä seurannut verenpaineen lasku oli selvästi normaalia syvempi. Myös imeväisillä, joiden äidit olivat tupakoineet raskauden aikana, verenpaineen alkunousu puuttui ja sitä seurannut verenpaineen lasku oli verrokkeja syvempi. Kippilavatestissä täysiaikaisten verrokkien verenpainevasteet olivat hyvin vaihtelevat. Keskimäärin testin alussa systolinen verenpaine pysyi ennallaan ja diastolinen nousi. Testin jatkuessa molemmat laskivat alle lähtötason, jossa ne pysyivät vielä testin lopettamisen jälkeenkin. Verrokkien sykevasteet olivat selkeästi yhtenevämmät ja vaste oli kaksivaiheinen: alun sykkeen nousua seurasi sykkeen lasku alle lähtötason ja paluu takaisin lähtötasoon. Yksikammiosydänlasten verenpainevasteet olivat verrokkien kaltaiset, mutta heidän sykkeensä pysyi korkeana koko testin ajan. Bronkopulmonaalisesta dysplasiasta kärsivien imeväisten verenpainevasteissa oli vielä voimakkaampaa vaihtelua kuin verrokkien vasteissa, mutta ryhmänä heidän vasteensa ei eronnut verrokeista. Raskaudenaikaiselle tupakoinnille altistuneiden imeväisten verenkiertovasteet eivät eronneet verrokeista. Lähellä laskettua aikaa tutkittujen keskosten syke- ja verenpainevasteissa oli suurta vaihtelua verrattuna täysiaikaisiin verrokkeihin, mutta ryhmänä verenkiertovasteet olivat vaimeammat kuin verrokeilla. Tässä tutkimuksessa todettiin poikkeava tasapainotumakevälitteinen verenkierron säätely imeväisillä, joilla on yllämainittuja kätkytkuoleman riskitekijöitä ja edeltäneitä hapenpuutejaksoja. Tutkimustulokset tukevat etukäteisolettamustamme, että heikentynyt tasapainotumakevälitteinen verenkierron säätely imeväisillä voi olla osaltaan johtamassa kätkytkuolemaan henkeä uhkaavassa tilanteessa

Learning about sex: Results from Natsal 2000.

11-13 September 2002

ASSESSMENT OF RISK IN PRETERM INFANTS USING POINT PROCESS AND MACHINE LEARNING APPROACHES

Preemies, infants who are born too soon, have a higher incidence of Life-Threatening Events (LTE’s) such as apnea (cessation of breathing), bradycardia (slowing of heart rate) and hypoxemia (oxygen desaturation) also termed as ABD (Apnea, Bradycardia, and Desaturation) events. Clinicians at Neonatal Intensive Care Units (NICU) are facing the demanding task of assessing the risk of infants based on their physiological signals. The aim of this thesis is to develop a risk stratification algorithm using a machine-learning framework with the features related to pathological fluctuations derived from point process model that will be embedded into the current physiological recording system to assess the risk of life-threatening events well in advance of occurrence in individual infants in the NICU. We initially propose a point process algorithm of heart rate dynamics for risk stratification of preterm infants. Based on this analysis, point process indices were tested to determine whether they were useful as precursors for life-threatening events. Finally, a machine-learning framework using point process indices as precursors were designed and tested to classify the risk of preterm infants. This work helps to predict the number of bradycardia events, N, in the subsequent hours measuring point process indices for the current hour. The model proposed uses Quadratic Support Vector Machine (QSVM), a machine learning classifier, which can solve class optimization problems and execute data at an exponential speed with higher accuracy for risk assessment that might facilitate effective management and treatment for preterm infants in NICU. The findings are relevant to risk assessment by analyzing the fluctuations in physiological signals that can act as precursors for the future life-threatening events

Advances in Non-Invasive Blood Pressure Monitoring

This paper reviews recent advances in non-invasive blood pressure monitoring and highlights the added value of a novel algorithm-based blood pressure sensor which uses machine-learning techniques to extract blood pressure values from the shape of the pulse waveform. We report results from preliminary studies on a range of patient populations and discuss the accuracy and limitations of this capacitive-based technology and its potential application in hospitals and communities

Technology applications

A summary of NASA Technology Utilization programs for the period of 1 December 1971 through 31 May 1972 is presented. An abbreviated description of the overall Technology Utilization Applications Program is provided as a background for the specific applications examples. Subjects discussed are in the broad headings of: (1) cancer, (2) cardiovascular disease, (2) medical instrumentation, (4) urinary system disorders, (5) rehabilitation medicine, (6) air and water pollution, (7) housing and urban construction, (8) fire safety, (9) law enforcement and criminalistics, (10) transportation, and (11) mine safety