Low-Cost Sensors and Biological Signals

Many sensors are currently available at prices lower than USD 100 and cover a wide range of biological signals: motion, muscle activity, heart rate, etc. Such low-cost sensors have metrological features allowing them to be used in everyday life and clinical applications, where gold-standard material is both too expensive and time-consuming to be used. The selected papers present current applications of low-cost sensors in domains such as physiotherapy, rehabilitation, and affective technologies. The results cover various aspects of low-cost sensor technology from hardware design to software optimization

Promoting a healthy ageing workforce: use of Inertial Measurement Units to monitor potentially harmful trunk posture under actual working conditions

Musculoskeletal disorders, particularly those involving the low back, represent a major health concern for workers, and originate significant consequences for the socio-economic system. As the average age of the population is gradually (yet steadily) increasing, such phenomenon directly reflects on labor market raising the need to create the optimal conditions for jobs which must be sustainable for the entire working life of an individual, while constantly ensuring good health and quality of life. In this context, prevention and management of low back disorders (LBDs) should be effective starting from the working environment. To this purpose, quantitative, reliable and accurate tools are needed to assess the main parameters associated to the biomechanical risk. In the last decade, the technology of wearable devices has made available several options that have been proven suitable to monitor the physical engagement of individuals while they perform manual or office working tasks. In particular, the use of miniaturized Inertial Measurement Units (IMUs) which has been already tested for ergonomic applications with encouraging results, could strongly facilitate the data collection process, being less time- and resources-consuming with respect to direct or video observations of the working tasks. Based on these considerations, this research intends to propose a simplified measurement setup based on the use of a single IMUs to assess trunk flexion exposure, during actual shifts, in occupations characterized by significant biomechanical risk. Here, it will be demonstrated that such approach is feasible to monitor large groups of workers at the same time and for a representative duration which can be extended, in principle, to the entire work shift without perceivable discomfort for the worker or alterations of the performed task. Obtained data, which is easy to interpret, can be effectively employed to provide feedback to workers thus improving their working techniques from the point of view of safety. They can also be useful to ergonomists or production engineers regarding potential risks associated with specific tasks, thus supporting decisions or allowing a better planning of actions needed to improve the interaction of the individual with the working environment

Diseño en tres niveles en el ámbito de la salud. Captura de movimiento para análisis de la marcha en rehabilitación.

En el ámbito de la salud, tecnologías como la captura de movimiento, la dinamometría, o la electromiografía de superficie, entre otras, ofrecen amplias posibilidades para objetivar la capacidad musculoesquelética de los pacientes, favoreciendo el diagnóstico o el seguimiento del proceso de rehabilitación. No obstante, conseguir que estas tecnologías se adapten e integren adecuadamente en el contexto de los servicios sanitarios implica un reto complejo de abordar. En esta tesis se presenta un compendio de publicaciones que dan respuesta a diferentes retos detectados durante el diseño, desarrollo y uso de tecnologías de evaluación del sistema musculoesquelético en el ámbito biosanitario. Particularmente, nos centramos en los sistemas de captura de movimiento; su complejidad a nivel operativo (colocación de diferentes elementos sobre el cuerpo), tecnológico (multitud de dispositivos electrónicos inalámbricos), y de análisis (generación de gran volumen de información) pone de manifiesto la necesidad de abordar esta investigación. - La primera publicación presenta las necesidades que han motivado esta tesis, exponiendo las bases y objetivos de la misma, que se enmarcan en healthcare, biomechanics, y usability. - La segunda introduce la metodología desarrollada Octopus, dirigida a apoyar el diseño de sistemas de captura de movimiento. Esta investigación clasifica y esquematiza los factores que deben considerarse durante el diseño y propone la idea de “Diseño en tres niveles”: servicio, producto y software; que son las principales líneas de trabajo a la hora de desarrollar aplicaciones dirigidas a evaluar el sistema musculoesquelético. Llegados a este punto, y fruto de diferentes colaboraciones del grupo de investigación con hospitales públicos de nuestra comunidad, así como una revisión exhaustiva del estado del arte, los trabajos de investigación se dirigieron hacia un nicho o caso de estudio enmarcado en el contexto de rehabilitación hospitalaria. En concreto, diseñar una prueba clínica de análisis de la marcha basada en captura de movimiento para monitorizar tratamientos de rehabilitación mediante sesiones de medición previas y posteriores a los tratamientos.- Como resultado se elaboró una publicación encuadra en el primer nivel de Octopus, el diseño de servicios. Esta investigación estudia cómo integrar el test de análisis de la marcha en la rehabilitación hospitalaria. Incorporar un micro-servicio (test de análisis de la marcha) en un macro-servicio como es la rehabilitación, no es una tarea sencilla de abordar. Por ello, se propone un enfoque metodológico para evaluar cualitativamente el test de marcha en su contexto, cuya aplicación permitió obtener guías de diseño que proporcionan conocimiento multidisciplinar para integrar el test en la rehabilitación.- Asimismo, se realizó una publicación que responde a otro de los niveles de Octopus, el diseño de producto. Este trabajo presenta un sistema de captura de movimiento llamado Move-Human Sensors (MH) que permite realizar pruebas de análisis de la marcha. Este sistema responde a las necesidades detectadas en el estudio del servicio, e incorpora dos funcionalidades clave: un procedimiento de calibración anatómica que evita las perturbaciones magnéticas las cuales tienen efectos negativos en la captura de movimiento inercial; así como un algoritmo que detecta gait events a partir de los datos de movimiento sin requerir de instrumentación complementaria. - Finalmente, se desarrolla una publicación enmarcada en el último nivel de Octopus, el diseño de software. Este estudio propone un método para gestionar los datos resultantes del test de análisis de la marcha. Dicho método permite comparar las capturas pre- y post-tratamiento para realizar el seguimiento de pacientes en rehabilitación, proporcionando información visual y específica al facultativo que puede apoyar la toma de decisiones clínicas.Esta tesis contribuye al ámbito del diseño, aportando una perspectiva global basada en tres niveles: producto, servicio, y software. En esta línea, se presenta un sistema de captura de movimiento, cuyo diseño y desarrollo recorre los tres niveles y da solución a los retos clave detectados. Conforme se profundiza en el propio caso de estudio de análisis de la marcha, se avanza en wearables, biomecánica, tecnología de captura de movimiento, usabilidad y algoritmos de análisis de datos. Las implicaciones que tiene esta investigación van más allá de las publicaciones descritas, ya que se enmarca en diferentes proyectos más amplios que dan sentido a la unidad temática de los capítulos abordados. En consecuencia, este trabajo está apoyado por otras comunicaciones científicas, desarrollos y colaboraciones que se han elaborado de manera paralela. Asimismo, los resultados de esta investigación están siendo extrapolados a otras áreas relacionadas; tanto en el propio sector sanitario -para la realización pruebas de valoración funcional- como en el sector industrial -para la realización de evaluación ergonómica de puestos de trabajo-, donde esta tecnología puede aportar valor.<br /

Commercially available pressure sensors for sport and health applications: A comparative review

Pressure measurement systems have numerous applications in healthcare and sport. The purpose of this review is to: (a) describe the brief history of the development of pressure sensors for clinical and sport applications, (b) discuss the design requirements for pressure measurement systems for different applications, (c) critique the suitability, reliability, and validity of commercial pressure measurement systems, and (d) suggest future directions for the development of pressure measurements systems in this area. Commercial pressure measurement systems generally use capacitive or resistive sensors, and typically capacitive sensors have been reported to be more valid and reliable than resistive sensors for prolonged use. It is important to acknowledge, however, that the selection of sensors is contingent upon the specific application requirements. Recent improvements in sensor and wireless technology and computational power have resulted in systems that have higher sensor density and sampling frequency with improved usability – thinner, lighter platforms, some of which are wireless, and reduced the obtrusiveness of in-shoe systems due to wireless data transmission and smaller data-logger and control units. Future developments of pressure sensors should focus on the design of systems that can measure or accurately predict shear stresses in conjunction with pressure, as it is thought the combination of both contributes to the development of pressure ulcers and diabetic plantar ulcers. The focus for the development of in-shoe pressure measurement systems is to minimise any potential interference to the patient or athlete, and to reduce power consumption of the wireless systems to improve the battery life, so these systems can be used to monitor daily activity. A potential solution to reduce the obtrusiveness of in-shoe systems include thin flexible pressure sensors which can be incorporated into socks. Although some experimental systems are available further work is needed to improve their validity and reliability

Concurrent Validity of the Inertial Measurement Unit Vmaxpro in Vertical Jump Estimation

The aim of this study was to evaluate if the inertial measurement unit (IMU) Vmaxpro is a valid device to estimate vertical jump height (VJH) when compared to a motion capture system (MoCAP). Thirteen highly trained female volleyball players participated in this study which consisted of three sessions. After a familiarization session, two sessions comprised a warm-up followed by ten countermovement jumps, resting two min between each attempt. Jump height was measured simultaneously by Vmaxpro using take-off velocity and MoCAP using center-of-mass vertical excursion. Results show significant differences in jump height between devices (10.52 cm; p < 0.001; ES = 0.9), a very strong Spearman’s correlation (rs = 0.84: p < 0.001), and a weak concordance correlation coefficient (CCC = 0.22; ρ = 0.861; Cb= 0.26). Regression analysis reveals very high correlations, high systematic error (8.46 cm), and a nonproportional random error (SEE = 1.67 cm). Bland–Altman plots show systematic error (10.6 cm) with 97.3 % of the data being within the LoA. In conclusion, Vmaxpro can be considered a valid device for the estimation of VJH, being a cheaper, portable, and manageable alternative to MoCAP. However, the magnitude of systematic error discourages its use where indistinguishable data from Vmaxpro and MoCAP are used unless the corresponding specific fitting equation is applied.This work was supported by Generalitat Valenciana (grant number GV/2021/098)

Development of a mobile technology system to measure shoulder range of motion

In patients with shoulder movement impairment, assessing and monitoring shoulder range of motion is important for determining the severity of impairments due to disease or injury and evaluating the effects of interventions. Current clinical methods of goniometry and visual estimation require an experienced user and suffer from low inter-rater reliability. More sophisticated techniques such as optical or electromagnetic motion capture exist but are expensive and restricted to a specialised laboratory environment.;Inertial measurement units (IMU), such as those within smartphones and smartwatches, show promise as tools bridge the gap between laboratory and clinical techniques and accurately measure shoulder range of motion during both clinic assessments and in daily life.;This study aims to develop an Android mobile application for both a smartphone and a smartwatch to assess shoulder range of motion. Initial performance characterisation of the inertial sensing capabilities of both a smartwatch and smartphone running the application was conducted against an industrial inclinometer, free-swinging pendulum and custom-built servo-powered gimbal.;An initial validation study comparing the smartwatch application with a universal goniometer for shoulder ROM assessment was conducted with twenty healthy participants. An impaired condition was simulated by applying kinesiology tape across the participants shoulder girdle. Agreement, intra and inter-day reliability were assessed in both the healthy and impaired states.;Both the phone and watch performed with acceptable accuracy and repeatability during static (within ±1.1°) and dynamic conditions where it was strongly correlated to the pendulum and gimbal data (ICC > 0.9). Both devices could perform accurately within optimal responsiveness range of angular velocities compliant with humerus movement during activities of daily living (frequency response of 377°/s and 358°/s for the phone and watch respectively).;The concurrent agreement between the watch and the goniometer was high in both healthy and impaired states (ICC > 0.8) and between measurement days (ICC > 0.8). The mean absolute difference between the watch and the goniometer were within the accepted minimal clinically important difference for shoulder movement (5.11° to 10.58°).;The results show promise for the use of the developed Android application to be used as a goniometry tool for assessment of shoulder ROM. However, the limits of agreement across all the tests fell out with the acceptable margin and further investigation is required to determine validity. Evaluation of validity in clinical impairment patients is also required to assess the feasibility of the use of the application in clinical practice.In patients with shoulder movement impairment, assessing and monitoring shoulder range of motion is important for determining the severity of impairments due to disease or injury and evaluating the effects of interventions. Current clinical methods of goniometry and visual estimation require an experienced user and suffer from low inter-rater reliability. More sophisticated techniques such as optical or electromagnetic motion capture exist but are expensive and restricted to a specialised laboratory environment.;Inertial measurement units (IMU), such as those within smartphones and smartwatches, show promise as tools bridge the gap between laboratory and clinical techniques and accurately measure shoulder range of motion during both clinic assessments and in daily life.;This study aims to develop an Android mobile application for both a smartphone and a smartwatch to assess shoulder range of motion. Initial performance characterisation of the inertial sensing capabilities of both a smartwatch and smartphone running the application was conducted against an industrial inclinometer, free-swinging pendulum and custom-built servo-powered gimbal.;An initial validation study comparing the smartwatch application with a universal goniometer for shoulder ROM assessment was conducted with twenty healthy participants. An impaired condition was simulated by applying kinesiology tape across the participants shoulder girdle. Agreement, intra and inter-day reliability were assessed in both the healthy and impaired states.;Both the phone and watch performed with acceptable accuracy and repeatability during static (within ±1.1°) and dynamic conditions where it was strongly correlated to the pendulum and gimbal data (ICC > 0.9). Both devices could perform accurately within optimal responsiveness range of angular velocities compliant with humerus movement during activities of daily living (frequency response of 377°/s and 358°/s for the phone and watch respectively).;The concurrent agreement between the watch and the goniometer was high in both healthy and impaired states (ICC > 0.8) and between measurement days (ICC > 0.8). The mean absolute difference between the watch and the goniometer were within the accepted minimal clinically important difference for shoulder movement (5.11° to 10.58°).;The results show promise for the use of the developed Android application to be used as a goniometry tool for assessment of shoulder ROM. However, the limits of agreement across all the tests fell out with the acceptable margin and further investigation is required to determine validity. Evaluation of validity in clinical impairment patients is also required to assess the feasibility of the use of the application in clinical practice

Wearable and Nearable Biosensors and Systems for Healthcare

Biosensors and systems in the form of wearables and “nearables” (i.e., everyday sensorized objects with transmitting capabilities such as smartphones) are rapidly evolving for use in healthcare. Unlike conventional approaches, these technologies can enable seamless or on-demand physiological monitoring, anytime and anywhere. Such monitoring can help transform healthcare from the current reactive, one-size-fits-all, hospital-centered approach into a future proactive, personalized, decentralized structure. Wearable and nearable biosensors and systems have been made possible through integrated innovations in sensor design, electronics, data transmission, power management, and signal processing. Although much progress has been made in this field, many open challenges for the scientific community remain, especially for those applications requiring high accuracy. This book contains the 12 papers that constituted a recent Special Issue of Sensors sharing the same title. The aim of the initiative was to provide a collection of state-of-the-art investigations on wearables and nearables, in order to stimulate technological advances and the use of the technology to benefit healthcare. The topics covered by the book offer both depth and breadth pertaining to wearable and nearable technology. They include new biosensors and data transmission techniques, studies on accelerometers, signal processing, and cardiovascular monitoring, clinical applications, and validation of commercial devices

Three-Dimensional Motion Analysis for Occupational Therapy Upper Extremity Assessment and Rehabilitation: A Scoping Review

Background: Three-dimensional (3D) human motion analysis provides objective, quantitative, and reliable kinematic data that are valuable in rehabilitation. Clinicians, including occupational therapists and other specialists, can apply this technology to quantify patients’ upper extremity (UE) motion during functional tasks. A better comprehension of altered body mechanics serves to guide clinical reasoning, develop evidence-based interventions, and monitor patients’ progress through follow-up. However, the scientific literature has yet to emphasize the practicality of using 3D motion analysis as a clinical measurement tool. Method: This scoping review appraised 20 articles that used 3D motion analysis to quantify UE movements for individuals with and without mechanical pathologies. The articles were evaluated based on their quality and clinically relevant applications of UE kinematics. Results: This scoping review revealed that 3D motion analysis has already been implemented in rehabilitation but the variability across protocols and facilities can complicate the comparison of results. Conclusion: To further expand clinical use of 3D motion analysis, an introduction of more accessible, inexpensive, and user-friendly kinematic systems is critical. Future research should also aim to establish a standardized protocol of 3D motion analysis in UE assessments to produce clinically relevant results and maximize patients’ independence when engaging in daily activities

Wearables for Movement Analysis in Healthcare

Quantitative movement analysis is widely used in clinical practice and research to investigate movement disorders objectively and in a complete way. Conventionally, body segment kinematic and kinetic parameters are measured in gait laboratories using marker-based optoelectronic systems, force plates, and electromyographic systems. Although movement analyses are considered accurate, the availability of specific laboratories, high costs, and dependency on trained users sometimes limit its use in clinical practice. A variety of compact wearable sensors are available today and have allowed researchers and clinicians to pursue applications in which individuals are monitored in their homes and in community settings within different fields of study, such movement analysis. Wearable sensors may thus contribute to the implementation of quantitative movement analyses even during out-patient use to reduce evaluation times and to provide objective, quantifiable data on the patients’ capabilities, unobtrusively and continuously, for clinical purposes