Using magneto-inertial-measurement-units to track upper-limb movement during rehabilitation

Functional Electrical Stimulation (FES) can be used to support upper-limb rehabilitation after a stroke. A key aspect of FES control and also patient monitoring is the automatic tracking of upper-limb motion during intensive and functional practise of upper-limb tasks. To achieve this in a home environment, simple on-body sensors are required. A promising approach is to use Magnetic and Inertial Measurement Units (MIMUs), but they provide body-segment orientations rather than anatomical joint angles, the latter being more meaningful. To solve this problem the sensor orientation data must be interpreted anatomically, which requires that for each body-segment the orientation of its sensor coordinate frame is known with respect to its anatomical coordinate frame. Therefore, appropriate calibration must be performed to obtain the relationship between each sensor frame and its corresponding body-segment anatomical frame.While many papers have been published on anatomical calibration methods for MIMUs, there has been no comprehensive comparison of the alternative approaches to establish their relative merits. For FES supported upper-limb therapy, the need is for simple and fast donning and calibration, whilst achieving acceptable accuracy and repeatability with regards to the calculated joint kinematics. Therefore, the main objective of the PhD research was to undertake such a comparison and make recommendations for donning and calibration for the purposes of upper-limb FES.To address this problem the PhD work included:1. Undertaking a comprehensive and critical comparison of alternative anatomical calibration methods for MIMUs in terms of accuracy, speed, and simplicity.2. Finding the most appropriate anatomical calibration methods for use in upper-limb FES applications with stroke patients.3. Determining the best methods for processing MIMU outputs to provide anatomically meaningful upper-limb kinematic data.4. Experimentally assessing these methods against a gold standard (a VICON optical motion capture system).The results demonstrate that there is considerable variation between the alternative sensor defined anatomical frames and, hence, confirm the need for comprehensive comparisons. The comparisons reported in this thesis have led to tentative recommendations. Nevertheless, the methods reported are a sound foundation for future work to provide stronger recommendations, with more formal measures of confidence

Wearable inertial sensors for human movement analysis

Introduction: The present review aims to provide an overview of the most common uses of wearable inertial sensors in the field of clinical human movement analysis.Areas covered: Six main areas of application are analysed: gait analysis, stabilometry, instrumented clinical tests, upper body mobility assessment, daily-life activity monitoring and tremor assessment. Each area is analyzed both from a methodological and applicative point of view. The focus on the methodological approaches is meant to provide an idea of the computational complexity behind a variable/parameter/index of interest so that the reader is aware of the reliability of the approach. The focus on the application is meant to provide a practical guide for advising clinicians on how inertial sensors can help them in their clinical practice.Expert commentary: Less expensive and more easy to use than other systems used in human movement analysis, wearable sensors have evolved to the point that they can be considered ready for being part of routine clinical routine

Appl Ergon

Many sensor fusion algorithms for analyzing human motion information collected with inertial measurement units have been reported in the scientific literature. Selecting which algorithm to use can be a challenge for ergonomists that may be unfamiliar with the strengths and limitations of the various options. In this paper, we describe fundamental differences among several algorithms, including differences in sensor fusion approach (e.g., complementary filter vs. Kalman Filter) and gyroscope error modeling (i.e., inclusion or exclusion of gyroscope bias). We then compare different sensor fusion algorithms considering the fundamentals discussed using laboratory-based measurements of upper arm elevation collected under three motion speeds. Results indicate peak displacement errors of <4.5\ub0 with a computationally efficient, non-proprietary complementary filter that did not account for gyroscope bias during each of the one-minute trials. Controlling for gyroscope bias reduced peak displacement errors to <3.0\ub0. The complementary filters were comparable (<1\ub0 peak displacement difference) to the more complex Kalman filters.T42OH008491/ACL/ACL HHSUnited States/T42 OH008491/OH/NIOSH CDC HHSUnited States/T42 OH008436/OH/NIOSH CDC HHSUnited States/T42OH008436/ACL/ACL HHSUnited States/K01 OH011183/OH/NIOSH CDC HHSUnited States/2022-10-26T00:00:00Z32854821PMC960563612055vault:4343

Visual perceptual skills and motor performance in gymnastics : the influence of task constraints

Esta dissertação teve como principal objetivo investigar a influência dos constrangimentos da tarefa nos comportamentos visual e motor de ginastas de nível elite. Para recolher dados dos comportamentos visual e motor num contexto ecológico representativo, foi validado um sistema de sensores inerciais para medir os ângulos articulares em 3D, durante uma tarefa gímnica. Três estudos foram realizados. O primeiro estudo investigou o comportamento visual durante a realização de quatro tarefas no mini trampolim e no mini-trampolim com mesa de saltos, aumentando progressivamente o nível de complexidade. O segundo estudo analisou a validade de um sistema de sensores inerciais na medição de ângulos articulares em 3D durante a realização de uma tarefa gímnica, utilizando um sistema optoelectrónico como referência. O estudo final examinou a influência dos constrangimentos da tarefa (presença e ausência da mesa de saltos) nos comportamentos visual e motor de ginastas de elite, durante a fase de corrida para o mini trampolim e mini-trampolim com mesa de saltos. O primeiro estudo sugeriu que os ginastas adaptaram o comportamento visual à complexidade da tarefa. O mini-trampolim foi a área de interesse mais fixada. O segundo estudo mostrou que o sistema de sensores inerciais apresentou boas correlações, erros aceitáveis e que não apresenta diferenças significativas para a maioria das articulações, comparando com o sistema optoelectrónico. O último estudo revelou que a presença da mesa de saltos influenciou o comportamento visual dos ginastas com menor expertise, enquanto que o comportamento motor foi diferentes nas duas tarefas para todos dos ginastas. Estas conclusões sugerem que o sistema de sensores inerciais é válido para fornecer dados cinemáticos aos treinadores e ginastas, e que os constrangimentos da tarefa influenciam o comportamento visual de ginastas de elite de forma distinta, consoante o nível de expertise.The main aim of this dissertation was to investigate the influence of task constraints on gaze and motor behaviours in elite gymnasts. To collect gaze and motor data in an ecological and representative context, an inertial measurement units system to measure 3D joint angles outside the laboratory was validated. To accomplish these goals, three studies were completed. In the first study, gaze behaviour was investigated during the performance of four gymnastics tasks on mini-trampoline and on mini-trampoline with vaulting table, while increasing the level of complexity. The second study analysed the validity of an inertial measurement units system in measuring 3D joint angles during a gymnastics task, using an optoelectronic system as a reference. The final study examined the influence of task constraint (i.e., presence and absence of vaulting table) on gaze and motor behaviours of elite gymnasts, during the approach run phase to the mini-trampoline and mini-trampoline with vaulting table. The first study showed that gymnasts adapted their gaze behaviours according to the level of complexity of the task and that the most fixated area of interest was the mini-trampoline. The second study demonstrated that the inertial measurement units system has very good and acceptable correlations, acceptable errors and no significant differences for the majority of the joint ankles. Finally, the last study revealed that the presence of the vaulting table influenced gaze behaviour only in elite gymnasts (compared to super-elite gymnasts), while different motor behaviours occurred across the two tasks, irrespective of gymnasts’ level of expertise. The findings indicate that the inertial measurement units system is valid to provide kinematics data, and task constraints (i.e., presence and absence of vaulting table) influence gaze behaviours of elite gymnasts differently, across varying levels of expertise

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

Postures et mouvements du membre supérieur à partir de capteurs inertiels : une évaluation méthodologique

This PhD work is focused on the estimation of joint angles and segment positions of the upper limb based on inertial sensor technology (MIMU). Despite much interest from the scientific community in this topic, several aspects of research deserve more investigation. This work contributes to the enhancement of scientific knowledge related to (1) the kinematic modeling associated to MIMU and (2) the validation of final kinematic outputs (joint angles and segment positions). Based on an exhaustive methodological approach, recommendations related to the anatomical calibration of MIMU are highlighted. Moreover, key-values related to the characterization of kinematic outputs are proposed, such as a precision of joint angles of 5-10° and a hand positioning error of 7-15 cm. The aim of this study is the development of an ambulatory system for the assessment of postures and movements of the upper limb, in a general context of musculoskeletal disorders risk assessment at work. From now on, an advanced kinematic modeling that uses a MIMU placed on the scapula as well as a characterization of the system under magnetic disturbances represent two of the main scientific questions to exploreCe travail de thèse s’intéresse à l’estimation des angles articulaires et des positions segmentaires du membre supérieur à partir de capteurs inertiels (MIMU). Malgré l’intérêt grandissant de la communauté scientifique pour cette technologie, plusieurs questions de recherche restent en suspens. Ce travail de thèse contribue à l’avancée de connaissances scientifiques à la fois au niveau de la modélisation cinématique du membre supérieur associée aux capteurs inertiels et au niveau de la validation même des données cinématiques de sortie (angles articulaires et positions segmentaires). Au travers d’une approche méthodologique complète, des recommandations de calibration anatomique sont avancées. De plus, des valeurs clefs de caractérisation sont proposées, telles qu’une reproductibilité des données angulaires de l’ordre de 5-10° et une erreur de positionnement de la main de 7-15 cm. La finalité de ce travail de thèse est la mise à disposition d’un système ambulatoire pour l’évaluation des postures et des mouvements du membre supérieur dans une optique d’évaluation des risques de troubles musculo-squelettiques en milieu professionnel. Une modélisation cinématique avancée prenant en compte un capteur inertiel sur la scapula et la caractérisation du système en milieu perturbé magnétiquement apparaissent comme une suite logique à ce travail de thès