Background: Knee osteoarthritis is a degenerative disease characterized by damaged joint tissues (e.g., cartilage) that leads to joint pain, and reduced mobility and quality of life. Various factors are involved in disease progression, including biomechanical, patient-reported outcome and mobility measures. This thesis provides important longitudinal data on the role of these factors in disease progression, and the trajectory of biomechanical factors in persons with knee osteoarthritis. Objectives: (1) Determine the extent to which changes over 2.5 years in knee cartilage thickness and volume in persons with knee osteoarthritis were predicted by the knee adduction and flexion moment peaks, and knee adduction moment impulse and loading frequency. (2) Determine the extent to which changes over 2 years in walking and stair-climbing mobility in women with knee osteoarthritis were predicted by quadriceps strength and power, pain and self-efficacy. (3) Estimate the relative and absolute test-retest reliabilities of biomechanical risk factors for knee osteoarthritis progression. Methods: Data were collected at 3-month intervals during a longitudinal (3-year), observational study of persons with clinical knee osteoarthritis (n=64). Magnetic resonance imaging of the study knee was acquired at the first and last assessments, and used to determine cartilage thickness and volume. Accelerometry and dynamometry data were acquired every 3 months, and used to determine knee loading frequency and knee muscle strength and power, respectively. Walking and stair-climbing mobility, as well as pain and self-efficacy data, were also collected every 3 months. Gait analyses were performed every 6 months, and used to calculate lower-extremity kinematics and kinetics. Results: (1) The knee adduction moment peak and impulse each interacted with body mass index to predict loss of medial tibial cartilage volume over 2.5 years. These interactions suggested that larger joint loads in those with a higher body mass index were associated with greater loss of cartilage volume. (2) In women, lower baseline self-efficacy predicted decreased walking and stair ascent performances over 2 years. Higher baseline pain intensity/frequency also predicted decreased walking performance. Quadriceps strength and power each interacted with self-efficacy to predict worsening stair ascent times. These interactions suggested that the impact of lesser quadriceps strength and power on worsening stair ascent performance was more important among women with lower self-efficacy. (3) Relative reliabilities were high for the knee adduction moment peak and impulse, quadriceps strength and power, and body mass index (i.e., intraclass correlation coefficients >0.80). Absolute reliabilities were high for quadriceps strength and body mass index (standard errors of measurement <15% of the mean). Data supported the use of interventions effective in reducing the knee adduction moment and body mass index, and increasing quadriceps strength, in persons with knee osteoarthritis. Conclusion: Findings from this thesis suggest that biomechanical factors play a modest independent role in the progression of knee osteoarthritis. However, in the presence of other circumstances (e.g., obesity, low self-efficacy, high pain intensity/frequency), biomechanical factors can vastly worsen the disease. Strategies aiming to curb structural progression and improve clinical outcomes in knee osteoarthritis should target biomechanical and clinical outcomes simultaneously. / Thesis / Doctor of Philosophy (PhD) / Knee osteoarthritis is a multifactorial disease whose progression involves worsening joint structure, symptoms, and mobility. Various factors are linked to the progression of this disease, including biomechanical, patient-reported outcome and mobility measures. This thesis provides important information on how these factors, separately and collectively, are involved in worsening disease over time, as well as benchmarks that are useful to clinicians and researchers in interpreting results from interventional or longitudinal research. First, we examined how different elements of knee loading were associated with changes in knee cartilage quantity over time in persons with knee osteoarthritis. Second, we examined how different elements of knee muscle capacity and patient-reported outcomes were related to changes in mobility over time in persons with knee osteoarthritis. Third, we examined the stability over time of various biomechanical risk factors for the progression of knee osteoarthritis. Novel results from this thesis showed that: (1) larger knee loads predicted cartilage loss over 2.5 years in obese individuals with knee osteoarthritis but not in persons of normal weight or overweight; (2) among women with knee osteoarthritis with lower self-efficacy (or confidence), lesser knee muscle capacity (strength, power) was an important predictor of declining stair-climbing performance over 2 years; and (3) clinical interventions that can positively alter knee biomechanics include weight loss, knee muscle strengthening, as well as specific knee surgery and alterations during walking to reduce knee loads. Interventions for knee osteoarthritis should target biomechanical and clinical outcomes simultaneously.

[ES] Los desórdenes del equilibrio y la marcha se encuentran entre los déficits motores más frecuentes entre aquellos individuos que han sufrido un ictus. En la clínica, estas habilidades son comúnmente evaluadas mediante herramientas clínicas que, pese a ser generalmente fáciles y rápidas de administrar, adolecen de poca precisión y estar sesgadas. Los sistemas instrumentados de laboratorio existentes para valorar la postura y la marcha resuelven potencialmente estas limitaciones a costa de requerir una preparación previa por parte de los evaluadores, un amplio espacio reservado en la clínica, un elevado tiempo de realización, y tener un coste muy elevado. El desarrollo tecnológico del sector del entretenimiento ha dado lugar en la última década a periféricos, como plataformas de presión y sensores de profundidad, que permiten la interacción mediante movimientos corporales manteniendo un bajo coste y una gran portabilidad y accesibilidad. Estudios iniciales han mostrado un rendimiento de estos dispositivos muy prometedor, y a veces comparable al de sistemas de laboratorio. Sin embargo, la falta de acceso a los sistemas desarrollados, la escasa investigación en personas con ictus y el desconocimiento de las propiedades psicométricas de las pruebas basadas en estos dispositivos en esta población comprometen la relevancia clínica que podrían tener estos sistemas. La hipótesis principal de este trabajo es que plataformas de fuerzas y sensores de profundidad de bajo coste, como la Nintendo Wii Balance Board y la Microsoft Kinect v2, respectivamente, pueden proporcionar información válida para cuantificar y evaluar la postura y la marcha de sujetos que han sufrido un ictus. Durante la presente tesis doctoral, por tanto, se ha llevado a cabo el desarrollo de herramientas de valoración de la postura y la marcha mediante los dispositivos nombrados, se ha posibilitado su acceso libre, se han determinado los valores normativos de las pruebas incluidas en las herramientas desarrolladas, y, finalmente, se ha investigado su sensibilidad, su validez convergente con herramientas clínicas estandarizadas y su fiabilidad inter e intraevaluador. Los resultados obtenidos de la participación de un total de 544 sujetos sanos y 173 sujetos con ictus en los cinco estudios que comprenden este trabajo evidencian que las herramientas desarrolladas permiten caracterizar satisfactoriamente la postura y la marcha de sujetos con ictus con respecto a la de sujetos sanos, poseen una validez convergente con instrumentos variables y coherente, y tienen una fiabilidad inter e intraevaluador excelente para casi todas las pruebas incluidas. Estos hallazgos sugieren que, pese a las limitaciones existentes, las herramientas desarrolladas podrían ser potencialmente usadas como una alternativa de bajo coste a los sistemas de laboratorio existentes para complementar la valoración de la postura y la marcha de sujetos con ictus. / [CA] Els desordres de l'equilibri i la marxa es troben entre els dèficits motors més freqüents entre aquells individus que han patit un ictus. A la clínica, aquestes habilitats són comunament avaluades mitjançant instruments clínics que, tot i ser generalment fàcils i ràpids d'administrar, poden tindre poca precisió i solen estar esbiaixades. Els sistemes instrumentats de laboratori existents per avaluar la postura i la marxa permeten resoldre aquestes limitacions, però requereixen una preparació prèvia per part dels avaluadors, un ampli espai reservat a la clínica, un elevat temps per realitzar cada prova i tenen un cost molt elevat. El desenvolupament tecnològic del sector de l'entreteniment ha donat lloc a plataformes de pressió i sensors de profunditat de baix cost, gran portabilitat i accessibilitat, que permeten la interacció amb entorns virtuals mitjançant moviments corporals. Estudis preliminars han mostrat un rendiment d'aquests dispositius molt prometedor i, de vegades, comparable al de sistemes de laboratori. No obstant això, la falta d'accés a les aplicacions desenvolupades, l'escassa investigació en persones amb ictus i el desconeixement de les propietats psicomètriques de les proves basades en aquests dispositius en aquesta població comprometen la rellevància clínica dels resultats obtinguts. La hipòtesi principal d'aquest treball és que plataformes de forces i sensors de profunditat de baix cost, com la Nintendo Wii Balance Board i la Microsoft Kinect v2, respectivament, poden proporcionar informació vàlida per quantificar i avaluar la postura i la marxa de subjectes amb ictus. Durant la present tesi doctoral, per tant, s'han desenvolupat eines de valoració de la postura i la marxa mitjançant els dispositius anomenats, s'ha possibilitat el seu accés lliure, s'han determinat els valors normatius de les proves incloses en les eines desenvolupades, i, finalment, s'ha investigat la seva sensibilitat, la seva validesa convergent amb instruments clínics estandarditzats i la seua fiabilitat inter i intraavaluador. Els resultats obtinguts de la participació d'un total de 544 subjectes sans i 173 subjectes amb ictus en els cinc estudis que comprenen aquest treball evidencien que les eines desenvolupades permeten caracteritzar satisfactòriament la postura i la marxa de subjectes amb ictus respecte a la de subjectes sans, tenen una validesa convergent amb instruments variable i coherent, i tenen una fiabilitat inter i intraavaluador excel·lent en gairebé totes les proves incloses. Aquestes troballes suggereixen que, tot i les limitacions existents, les aplicacions desenvolupades podrien ser potencialment usades com una alternativa de baix cost als sistemes de laboratori existents per complementar la valoració de la postura i la marxa de subjectes amb ictus. / [EN] Balance and gait disorders are common after stroke. In the clinical setting, these skills are usually assessed using clinical instruments that, despite being generally quick and easy to administer, may have limited accuracy and be biased. Instrumented laboratory-grade systems aimed at assessing posture and gait can potentially overcome these limitations. However, they require specific training to be operated and a long time to perform the assessments, and are usually bulky and expensive. In the last decade, the technological advances in the gaming industry have given rise to low-cost, portable and off-the-shelf devices, such as pressure platforms and depth sensors, which enable interaction with videogames through body movements. Previous research on the performance of these devices has shown promising results, and suggests that some measures could have comparable accuracy to those estimated by laboratory-grade systems. However, the lack of access to the software used in the experiments, the limited research in stroke patients, and the absence of knowledge about the psychometric properties of the assemment tests based on these devices, could limit the clinical relevance of the preliminary findings. The main hypothesis of this thesis is that low-cost force platforms and depth sensors, such as the Nintendo Wii Balance Board and the Microsoft Kinect v2, can provide sensitive, valid and reliable information to quantify and asses the postural control and gait of individuals with stroke, respectively. This work describes the development of two customized applications to assess posture and gait using the devices mentioned above, their publication on a dedicated website, the exploration of the normative values of tests included in the assessment, and, finally, the investigation of the sensitivity, convergent validity with standardized clinical instruments, and their inter- and intra-rater reliability. A total of 544 healthy subjects and 173 individuals with stroke have participated in the five studies that encompass this thesis. The results of these studies showed good sensitivity to motor impairment, variable and consistent convergent validity with clinical instruments, and excellent inter- and intra-rater reliability for almost all the tests examined. All these findings suggest that, despite their limitations, the developed applications interfaced with low-cost force platforms and depth sensors, could be potentially used as a low-cost alternative to instrumented laboratory-grade systems to complement the clinical assessment of the posture and gait of individuals with stroke. / Latorre Grau, J. (2022). Valoración del equilibrio y la marcha mediante sistemas de bajo coste en sujetos con ictus [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181339

Fragestellung: Die Studie soll die Frage klären, ob sich mit der elektronischen plantaren Fußdruckmessung (elektronische plantare Pedobarographie) bei Probanden mit Rheumatoider Arthritis Veränderungen der Druckverteilung an der Fußsohle nachweisen lassen. Obwohl sich Geräte zur elektronischen Fußdruckmessung seit einigen Jahren auf dem Markt befinden, gehört ihr Einsatz bei weitem noch nicht zum Standard bei der Optimierung und Kontrolle der Therapie von Fußerkrankungen. Methode: In dieser Studie werden die statischen und dynamischen Druckverteilungsmuster einer Gruppe von dreiunddreißig Rheumatikern erfasst. Diesen wird eine Vergleichgsgruppe Fußgesunder mit einunddreißig Probanden gegenübergestellt. Die Messung des Plantardruckes erfolgte mit dem elektronischen Parotec(R) – System. Ergebnisse: Die Ergebnisse der statischen Messungen zeigen eine deutliche Tendenz der Rheumatiker zur Ausbildung eines Pes planovalgus. Über eine Quotientenbildung aus zu Sensorgruppen zusammengefasstem Druckarealen können als Spreiz-, Senkfuß- und Valgusindex die entsprechenden pathologischen Veränderungen quantifiziert werden. In der dynamischen Belastung zeigt sich im Längsgewölbebereich eine Annäherung der Plantardrücke beider Gruppen. In der Referenzgruppe treten sogar vereinzelt höhere Mittelwerte auf, als bei den Rheumatikern. Dies wird hauptsächlich durch eine räumliche und zeitliche Modifikation der Gangkinematik durch den Rheumatiker erzielt: ein langsameres Gehen; eine kleinere Schrittlänge; die relative Vergrößerung der plantaren Druckverteilungsfläche durch relativ verkürzte monopedale bzw. verlängerte bipedale Belastung ; eine Modifikation der Abrollbewegung des Rheumatikers mit Reduktion der Belastung in drucksensiblen peripheren, insbesondere distalen Bereichen, vor allem im Bereich des Metatarsalköpfchen I. Folgerung: Die Ergebnisse zeigen, dass es deutliche Plantardruckunterschiede in beiden Gruppen gibt, mit Tendenz zur aequibaren Plantardruckverteilung des Rheumatikers im Sinne eines Pes planovalgus. Die funktionelle Auswirkung struktureller Veränderungen des rheumatischen Fußes lassen sich mit dem von uns verwendeten Meßsystem quantifizieren. Durch die Quantifizierbarkeit der pathologischen Veränderungen eignet sich dieses Messverfahren zur Optimierung und Kontrolle der operativen und konservativen Therapie nicht nur von rheumatischen Veränderungen des Fußes. / Question: The study shall clarify the question, whether changes of the pressure distribution at the sole of the foot can be verified by means of electronic plantar foot measurement (electronic plantar pedobarography) in probands suffering from rheumatoid arthritis. Although there are devices of electronic foot measurement on the market, the use is not standard yet in view of the optimisation and check of pedopathy therapies. Method: This study includes the static and dynamic pressure distribution patterns of a group of thirty-three rheumatics. A comparing group of thirty-one probands with healthy feet is compared with it. The measuring of the plantar pressure took place by means of the electronic Parotec(R) system. Results: The results of the static measuring turn out a clear tendency of the rheumatics to the formation of pes planovalgus. The appropriate pathologic changes can be quantified as splayfoot, flatfoot, and valgus index by means of a quotient formation of pressure areas combined in sensor groups. In the event of dynamic load, a convergence of the plantar pressures of both groups is noticed in the area of the longitudinal arch of the foot. The reference group even shows isolated higher mean average values compared with the rheumatics. This is mainly obtained by means of a spatial and temporal modification of the rheumatic’s gait kinematics: slower walking; shorter length of stride; relative increase of the plantar pressure distribution area by means of relatively shortened monopedal, resp. lengthened bipedale load; a modification of the rheumatic’s heel-toe walking motion with reduction of the load in peripheral and distal areas in particular that are sensible to pressure, especially within the area of the metatarsal head I. Conclusion: The results turn out that there are clear differences regarding the plantar pressure of both groups with a tendency to aequibar plantar pressure distribution of the rheumatic within the sense of pes planovalgus. The functional effect of structural changes of the rheumatic foot can be quantified by means of our used measuring system. This measurement method also is suitable for the optimisation and check of operative and conservative therapies other than rheumatic changes of the foot because pathologic changes are quantifiable.

Les technologies portables sont dans le processus de révolutionner le domaine de la santé en offrant des données vitales qui assistent dans la prévention et le traitement des maladies. Les appareils portables de la santé (HWDs), comme le vêtement biométrique de Hexoskin, sont à la pointe de cette innovation en offrant des données physiologiques détaillées et en ayant un impact significatif dans les domaines comme l’analyse de la démarche et la surveillance des activités. Le but de cette étude est de développer des modèles précis de machine learning et deep learning capables de prédire les activités humaines à l’aide de données provenant des technologies portables Hexoskin. Ceci implique l’analyse des données des capteurs comme la fréquence cardiaque et les mouvements du torse dans l’optique de prédire avec précision les activités telles que la marche, la course et le sommeil. Cette étude a fait l’objet d’une collecte de données des capteurs de 52 participants sur une période de deux semaines à l’aide des technologies portables Hexoskin. Plusieurs techniques avancées d’ingénierie des caractéristiques ont été appliquées pour extraire des caractéristiques critiques comme les accélérations X, Y et Z. Plusieurs algorithmes de machine learning tels que le Balanced Random Forest (BRF), XGradient Boosting et LSTM (sans ingénierie des caractéristiques) ont été utilisés pour l’analyse des données. Les modèles ont été entraînés et testés sur des données provenant d’Hexoskin pour évaluer leurs performances basées sur l’exactitude, le rappel, la précision et du score F1. Cette étude démontre que les technologies portables Hexoskin, couplées à des modèles de machine learning sophistiqués, pouvaient prédire avec une grande précision les activités humaines. La recherche valide l’efficacité des technologies portables Hexoskin dans la reconnaissance des activités humaines, en mettant en lumière leur potentielle utilisation dans le domaine de la santé, l’analyse de la démarche, et la surveillance des activités. Cette étude contribue de manière significative à l’amélioration des standards de soins médicaux et ouvre des nouvelles perspectives pour le diagnostic et le traitement des conditions liées à la démarche. L’intégration des technologies Hexoskin avec des algorithmes de machine learning représente un pas en avant significatif dans la surveillance continue et en temps réel des maladies chroniques, v positionnant ainsi Hexoskin comme un outil fiable pour une multitude d’applications dans le domaine de la santé. / Wearable technologies are revolutionizing the healthcare field by providing vital data that assists in the prevention and treatment of diseases. Health wearable devices (HWDs), like the Hexoskin biometric garment, are at the forefront of this innovation by offering detailed physiological data and significantly impacting fields such as gait analysis and activity monitoring. The aim of this study is to develop accurate machine learning and deep learning models capable of predicting human activities using data from Hexoskin wearable technologies. This involves analyzing sensor data such as heart rate and torso movements to accurately predict activities such as walking, running, and sleeping. This study involved collecting sensor data from 52 participants over a two-week period using Hexoskin wearable technologies. Several advanced feature engineering techniques were applied to extract critical features such as X, Y, and Z accelerations. Multiple machine learning algorithms, such as Balanced Random Forest (BRF), XGradient Boosting, and LSTM (without feature engineering), were used for data analysis. The models were trained and tested on data from Hexoskin to evaluate their performance based on accuracy, recall, precision, and F1 score. This study demonstrates that Hexoskin wearable technologies, coupled with sophisticated machine learning models, can predict human activities with high accuracy. The research validates the effectiveness of Hexoskin wearable technologies in human activity recognition, highlighting their potential use in healthcare, gait analysis, and activity monitoring. This study significantly contributes to improving medical care standards and opens new perspectives for the diagnosis and treatment of gait-related conditions. The integration of Hexoskin technologies with machine learning algorithms represents a significant step forward in the continuous and real-time monitoring of chronic diseases, positioning Hexoskin as a reliable tool for a multitude of applications in the healthcare field.