Evaluation of Arm Swing Features and Asymmetry during Gait in Parkinson’s Disease Using the Azure Kinect Sensor

Arm swinging is a typical feature of human walking: Continuous and rhythmic movement of the upper limbs is important to ensure postural stability and walking efficiency. However, several factors can interfere with arm swings, making walking more risky and unstable: These include aging, neurological diseases, hemiplegia, and other comorbidities that affect motor control and coordination. Objective assessment of arm swings during walking could play a role in preventing adverse consequences, allowing appropriate treatments and rehabilitation protocols to be activated for recovery and improvement. This paper presents a system for gait analysis based on Microsoft Azure Kinect DK sensor and its body-tracking algorithm: It allows noninvasive full-body tracking, thus enabling simultaneous analysis of different aspects of walking, including arm swing characteristics. Sixteen subjects with Parkinson’s disease and 13 healthy controls were recruited with the aim of evaluating differences in arm swing features and correlating them with traditional gait parameters. Preliminary results show significant differences between the two groups and a strong correlation between the parameters. The study thus highlights the ability of the proposed system to quantify arm swing features, thus offering a simple tool to provide a more comprehensive gait assessment

Kinematic Analysis of Lower Limb Joint Asymmetry during Gait in People with Multiple Sclerosis

The majority of people with Multiple Sclerosis (pwMS), report lower limb motor dysfunc- tions, which may relevantly affect postural control, gait and a wide range of activities of daily living. While it is quite common to observe a different impact of the disease on the two limbs (i.e., one of them is more affected), less clear are the effects of such asymmetry on gait performance. The present retrospective cross-sectional study aimed to characterize the magnitude of interlimb asymmetry in pwMS, particularly as regards the joint kinematics, using parameters derived from angle-angle di- agrams. To this end, we analyzed gait patterns of 101 pwMS (55 women, 46 men, mean age 46.3, average Expanded Disability Status Scale (EDSS) score 3.5, range 1–6.5) and 81 unaffected individ- uals age- and sex-matched who underwent 3D computerized gait analysis carried out using an eight-camera motion capture system. Spatio-temporal parameters and kinematics in the sagittal plane at hip, knee and ankle joints were considered for the analysis. The angular trends of left and right sides were processed to build synchronized angle–angle diagrams (cyclograms) for each joint, and symmetry was assessed by computing several geometrical features such as area, orientation and Trend Symmetry. Based on cyclogram orientation and Trend Symmetry, the results show that pwMS exhibit significantly greater asymmetry in all three joints with respect to unaffected individ- uals. In particular, orientation values were as follows: 5.1 of pwMS vs. 1.6 of unaffected individuals at hip joint, 7.0 vs. 1.5 at knee and 6.4 vs. 3.0 at ankle (p < 0.001 in all cases), while for Trend Sym- metry we obtained at hip 1.7 of pwMS vs. 0.3 of unaffected individuals, 4.2 vs. 0.5 at knee and 8.5 vs. 1.5 at ankle (p < 0.001 in all cases). Moreover, the same parameters were sensitive enough to discriminate individuals of different disability levels. With few exceptions, all the calculated sym- metry parameters were found significantly correlated with the main spatio-temporal parameters of gait and the EDSS score. In particular, large correlations were detected between Trend Symmetry and gait speed (with rho values in the range of –0.58 to –0.63 depending on the considered joint, p < 0.001) and between Trend Symmetry and EDSS score (rho = 0.62 to 0.69, p < 0.001). Such results suggest not only that MS is associated with significantly marked interlimb asymmetry during gait but also that such asymmetry worsens as the disease progresses and that it has a relevant impact on gait performances

Short-term effects of underwater treadmill therapy on ground reaction forces of canine orthopaedic patients

Dissertação de Mestrado Integrado em Medicina VeterináriaThis dissertation aimed to use kinetic gait analysis to study the effects of an underwater treadmill therapy (UWT) session on ground reaction forces of dogs with lameness caused by an orthopaedic condition, located in one or both contralateral limbs of a pair. Fourteen clientowned dogs presenting appendicular orthopaedic conditions were recruited. All dogs had previously undergone UWT. The nine selected candidates were divided into two groups: Group A comprised dogs diagnosed with an orthopaedic condition in the forelimbs, and Group B individuals diagnosed with orthopaedic conditions in the hindlimbs. Pressure plate gait analysis was performed to determine ground reaction forces baseline data of all individuals. Afterwards, the dogs completed an UWT session, and gait analysis was repeated to determine postsession values. Peak and impulse of vertical forces (PFz and IFz), stance phase duration (SPD), paw pressure contact area (PCA), and step length were measured. A correlation between step length and withers height was assessed using the collective data of all participants. Contralateral limb pair symmetry was calculated using a symmetry index (SI) for the parameters PFz, IFz, SPD and PCA (SIPFz, SIIFz, SISPD and SIPCA, respectively). Nonlame dogs were excluded, using a SI cut-off value of <3% for PFz and IFz between contralateral limbs. All participants presented baseline hindlimb lameness, regardless of their diagnosis. Before and after measurements were evaluated using a paired student t-test. No statistically significant alterations were observed in any of the parameters. However, baseline and post-session values showed a strong positive correlation in Group A step length and forelimb SIPFz and SIIFz, as well as in Group B step length, mean velocity, hindlimb SIPFz and forelimb SIPCA. In Group B, post-UWT measurements showed an overall decrease in hindlimb SIPFz. In both groups, mean SIPCA increased in the forelimbs and decreased in the hindlimbs. Mean step length increased in 6 dogs and remained equal in 2 dogs. Step length and withers height exponential correlation presented a R value of 0.78. After UWT, 1 out of the 9 participants was considered nonlame. Further research is required to determine the shortterm effects of UWT in temporospatial and pressure gait parameters of dogs with orthopaedic lameness.RESUMO - EFEITOS A CURTO-PRAZO DE HIDROTERAPIA EM PASSADEIRA AQUÁTICA NAS FORÇAS DE REAÇÃO AO SOLO DE CANÍDEOS COM PATOLOGIA ORTOPÉDICA - Esta dissertação teve como objetivo estudar o efeito de uma sessão de terapia em passadeira aquática (UWT) nas forças de reação ao solo de cães com claudicação de origem ortopédica, localizada em um ou ambos membros do mesmo par, através de análise de movimento. Foram pré-avaliados 14 cães que apresentavam condições ortopédicas apendiculares, e já submetidos a UWT anteriormente. Os 9 candidatos selecionados foram separados em dois grupos: o Grupo A incluiu cães com claudicação dos membros torácicos e o Grupo B indivíduos com claudicação dos membros pélvicos. Realizou-se análise de movimento com placa de pressão para determinar os valores base das forças de reação ao solo. Depois de terem completado uma sessão de UWT, os animais foram novamente submetidos a análise de movimento para determinar os valores pós-sessão. Mediu-se o pico e impulso das forças verticais (PFz e IFz), duração da fase de estação (SPD), área de contacto do membro (PCA), e comprimento da passada. A correlação entre o comprimento da passada e a altura do garrote foi avaliada usando os dados de todos os participantes. A simetria dos membros contralaterais foi calculada através de um índice de simetria (SI) para os parâmetros PFz, IFz, SPD e PCA (SIPFz, SIIFz, SISPD and SIPCA). Cães com um valor de SIPFz e SIIFz inferior a 3% foram considerados não claudicantes e excluídos. Todos os participantes apresentaram valores de claudicação nos membros pélvicos, independentemente do diagnóstico. Os valores pré e pós-UWT foram avaliados com o teste t de student para amostras emparelhadas. Não se observaram alterações significativas em nenhum dos parâmetros. No entanto, no Grupo A os valores pré e pós-UWT do comprimentos da passada, e do SIPFz e SIIFz nos membros torácicos demonstraram uma forte correlação positiva, o que também se verificou nos valores do comprimento da passada, velocidade média, SIPFz dos membros pélvicos e SIPCA dos membros torácicos no Grupo B. No Grupo B, observou-se uma diminuição geral no SIPFz dos membros pélvicos. Em ambos grupos, o valor médio de SIPCA aumentou nos membros torácicos e diminuiu nos pélvicos. O valor médio do comprimento da passada aumentou em 6 cães, e manteve-se inalterado em 2. A correlação exponencial entre o comprimento da passada e a altura do garrote apresentou um valor de R = 0.78. Após UWT, 1 dos 9 participantes passou a ser considerado não claudicante. Investigação adicional é necessária para determinar os efeitos a curto prazo da UWT nos parâmetros temporo-espaciais e pressão ao solo em cães com claudicação de origem ortopédica.N/

3D video based detection of early lameness in dairy cattle

Lameness is a major issue in dairy cattle and its early and automated detection offers animal welfare benefits together with potentially high commercial savings for farmers. Current advancements in automated detection have not achieved a sensitive measure for classifying early lameness; it remains to be a key challenge to be solved. The state-of-the-art also lacks behind on other aspects e.g. robust feature detection from a cow's body and the identification of the lame leg/side. This multidisciplinary research addresses the above issues by proposing an overhead, non-intrusive and covert 3-Dimensional (3D) video setup. This facilitates an automated process in order to record freely walking Holstein dairy cows at a commercial farm scale, in an unconstrained environment.The 3D data of the cow's body have been used to automatically track key regions such as the hook bones and the spine using a curvedness feature descriptor which operates at a high detection accuracy (100% for the spine, >97% for the hooks). From these tracked regions, two locomotion traits have been developed. First, motivated by a novel biomechanical approach, a proxy for the animal's gait asymmetry is introduced. This dynamic proxy is derived from the height variations in the hip joint (hooks) during walking, and extrapolated into right/left vertical leg motion signals. This proxy is evidently affected by minor lameness and directly contributes in identifying the lame leg. Second, back posture, which is analysed using two cubic-fit curvatures (X-Z plane and X-Y plane) from the spine region. The X-Z plane curvature is used to assess the spine's arch as an early lameness trait, while the X-Y plane curvature provides a novel definition for localising the lame side. Objective variables were extracted from both traits to be trained using a linear Support Vector Machine (SVM) classifier. Validation is made against ground truth data manually scored using a 1–5 locomotion scoring (LS) system, which consist of two datasets, 23 sessions and 60 sessions of walking cows. A threshold has been identified between LS 1 and 2 (and above). This boundary is important as it represents the earliest point in time at which a cow is considered lame, and its early detection could improve intervention outcome, thereby minimising losses and reducing animal suffering. The threshold achieved an accuracy of 95.7% with a 100% sensitivity (detecting lame cows), and 75% specificity (detecting non-lame cows) on dataset 1 and an accuracy of 88.3% with an 88% sensitivity and 92% specificity on dataset 2. Thereby outperforming the state-of-the-art at a stricter lameness boundary. The 3D video based multi-trait detection strives towards providing a comprehensive locomotion assessment on dairy farms. This contributes to the detection of developing lameness trends using regular monitoring which will improve the lack of robustness of existing methods and reduce reliance on expensive equipment and/or expertise in the dairy industry

Analysis of 3D human gait reconstructed with a depth camera and mirrors

L'évaluation de la démarche humaine est l'une des composantes essentielles dans les soins de santé. Les systèmes à base de marqueurs avec plusieurs caméras sont largement utilisés pour faire cette analyse. Cependant, ces systèmes nécessitent généralement des équipements spécifiques à prix élevé et/ou des moyens de calcul intensif. Afin de réduire le coût de ces dispositifs, nous nous concentrons sur un système d'analyse de la marche qui utilise une seule caméra de profondeur. Le principe de notre travail est similaire aux systèmes multi-caméras, mais l'ensemble de caméras est remplacé par un seul capteur de profondeur et des miroirs. Chaque miroir dans notre configuration joue le rôle d'une caméra qui capture la scène sous un point de vue différent. Puisque nous n'utilisons qu'une seule caméra, il est ainsi possible d'éviter l'étape de synchronisation et également de réduire le coût de l'appareillage. Notre thèse peut être divisée en deux sections: reconstruction 3D et analyse de la marche. Le résultat de la première section est utilisé comme entrée de la seconde. Notre système pour la reconstruction 3D est constitué d'une caméra de profondeur et deux miroirs. Deux types de capteurs de profondeur, qui se distinguent sur la base du mécanisme d'estimation de profondeur, ont été utilisés dans nos travaux. Avec la technique de lumière structurée (SL) intégrée dans le capteur Kinect 1, nous effectuons la reconstruction 3D à partir des principes de l'optique géométrique. Pour augmenter le niveau des détails du modèle reconstruit en 3D, la Kinect 2 qui estime la profondeur par temps de vol (ToF), est ensuite utilisée pour l'acquisition d'images. Cependant, en raison de réflections multiples sur les miroirs, il se produit une distorsion de la profondeur dans notre système. Nous proposons donc une approche simple pour réduire cette distorsion avant d'appliquer les techniques d'optique géométrique pour reconstruire un nuage de points de l'objet 3D. Pour l'analyse de la démarche, nous proposons diverses alternatives centrées sur la normalité de la marche et la mesure de sa symétrie. Cela devrait être utile lors de traitements cliniques pour évaluer, par exemple, la récupération du patient après une intervention chirurgicale. Ces méthodes se composent d'approches avec ou sans modèle qui ont des inconvénients et avantages différents. Dans cette thèse, nous présentons 3 méthodes qui traitent directement les nuages de points reconstruits dans la section précédente. La première utilise la corrélation croisée des demi-corps gauche et droit pour évaluer la symétrie de la démarche, tandis que les deux autres methodes utilisent des autoencodeurs issus de l'apprentissage profond pour mesurer la normalité de la démarche.The problem of assessing human gaits has received a great attention in the literature since gait analysis is one of key components in healthcare. Marker-based and multi-camera systems are widely employed to deal with this problem. However, such systems usually require specific equipments with high price and/or high computational cost. In order to reduce the cost of devices, we focus on a system of gait analysis which employs only one depth sensor. The principle of our work is similar to multi-camera systems, but the collection of cameras is replaced by one depth sensor and mirrors. Each mirror in our setup plays the role of a camera which captures the scene at a different viewpoint. Since we use only one camera, the step of synchronization can thus be avoided and the cost of devices is also reduced. Our studies can be separated into two categories: 3D reconstruction and gait analysis. The result of the former category is used as the input of the latter one. Our system for 3D reconstruction is built with a depth camera and two mirrors. Two types of depth sensor, which are distinguished based on the scheme of depth estimation, have been employed in our works. With the structured light (SL) technique integrated into the Kinect 1, we perform the 3D reconstruction based on geometrical optics. In order to increase the level of details of the 3D reconstructed model, the Kinect 2 with time-of-flight (ToF) depth measurement is used for image acquisition instead of the previous generation. However, due to multiple reflections on the mirrors, depth distortion occurs in our setup. We thus propose a simple approach for reducing such distortion before applying geometrical optics to reconstruct a point cloud of the 3D object. For the task of gait analysis, we propose various alternative approaches focusing on the problem of gait normality/symmetry measurement. They are expected to be useful for clinical treatments such as monitoring patient's recovery after surgery. These methods consist of model-free and model-based approaches that have different cons and pros. In this dissertation, we present 3 methods that directly process point clouds reconstructed from the previous work. The first one uses cross-correlation of left and right half-bodies to assess gait symmetry while the other ones employ deep auto-encoders to measure gait normality

Development of a global gait symmetry score using biomechanical parameters

The clinical implications of an asymmetric gait pattern led to a growing interest in restoring gait symmetry in clinical populations. This entails the accurate and reliable assessment of overall gait symmetry. Given the limitations of pre-existing symmetry indices, the aim of this thesis was to develop and test a new global index for gait symmetry that comprised information from the lower limbs, trunk and pelvis, throughout the entire gait cycle. To achieve this goal, four studies were conducted. In the first study, a global symmetry index, based on the bilateral differences in 3D joint angles, was developed and tested by comparing the scores obtained by healthy individuals in three walking conditions, in which different levels of asymmetry were induced artificially. The second and third studies analysed the inter-session agreement and reliability of this and other global indices, also in a healthy group. Based on the obtained results, the first index was refined by replacing the joint angles with the joint linear positions. The final study tested the ability of this new index to detect the presence of higher levels of asymmetry in a group of patients with an expected asymmetric gait pattern. These studies showed that while symmetry indices based on joint angles can detect acute changes in symmetry within the same session, their poor inter-session repeatability prevents their application to assess differences in symmetry over time and among individuals. On the other hand, the final index proposed in this thesis has good inter-session agreement and reliability, and is sensitive to the increased level of asymmetry typically found in patients with an asymmetric gait pattern. These findings suggest that this index may be a useful tool to assess gait symmetry in a clinical context.As implicações clínicas de um padrão de marcha assimétrico levaram ao crescente interesse na recuperação da simetria da marcha em populações clínicas. Isto requer uma avaliação precisa e fiável da simetria da marcha na sua globalidade. Dadas as limitações dos índices de simetria pré-existentes, o objectivo desta Tese foi desenvolver e testar um novo índice global de simetria da marcha que abrangesse informação dos membros inferiores, do tronco e da pélvis, ao longo do ciclo completo da marcha. Para alcançar este objectivo, foram realizados quatro estudos. No primeiro, este índice, desenvolvido com base nas diferenças bilaterais de ângulos articulares em 3D, foi testado através da comparação dos resultados obtidos por indivíduos saudáveis em três condições de marcha, nas quais diferentes níveis de assimetria foram induzidos artificialmente. Os segundo e terceiro estudos analisaram a concordância e fiabilidade inter-sessão deste e de outros índices globais, também num grupo saudável. Com base nos resultados obtidos, o primeiro índice foi aperfeiçoado, substituindo os ângulos inter-segmentares pelas posições lineares das articulações. O estudo final testou a capacidade deste novo índice detectar a presença de níveis de assimetria superiores num grupo de indivíduos, cujo padrão de marcha é expectavelmente assimétrico. Estes estudos mostraram que, enquanto os índices baseados em ângulos articulares conseguem detectar alterações agudas na simetria dentro da mesma sessão, a sua baixa repetibilidade entre sessões desaconselha a sua aplicação para avaliar diferenças na simetria ao longo do tempo e entre indivíduos. Por outro lado, o índice proposto nesta Tese apresenta uma boa concordância e fiabilidade inter-sessão, e é sensível ao nível de assimetria tipicamente encontrado em sujeitos com um padrão de marcha assimétrico. Estas conclusões sugerem que este índice poderá ser uma ferramenta útil para a avaliação da simetria da marcha em contexto clínico

Effects of Physical Exertion and Alignment Alterations on Trans-Tibial Amputee Gait, and Concurrent Validity of Prosthesis-Integrated Measurement of Gait Kinetics

This study investigated the effects of slight changes in the alignment of the artificial limb of trans-tibial amputees on the walking pattern on the level of forces and moments, particularly when physical exertion levels increase. Two alignment conditions were assessed in ten trans-tibial amputees while walking with low and with strong levels of exertion. Two separate data collection methods were utilized simultaneously: a conventional motion analysis, and continuous recordings from prosthesis-integrated force sensors. While the former was used to compare bilateral leg symmetry across conditions, the latter allowed analyzing unilateral step variability within subjects. This paper presents both analyses in separate chapters. A third chapter addresses the question of concurrent validity of the utilized integrated-sensor-based gait data collection method. Findings indicate that increased physical exertion and prosthesis ankle plantar-flexion angle was related to decreases in step length symmetry, maximal knee flexion angle, knee moment, and dorsi-flexion moment, but had no significant effect on an overall gait symmetry index. It was also shown, that effects were different among participants, with only three of them showing a significant change in parameters measured by the integrated sensor system. Integrated sensor measurements namely of axial force and joint moments were found to be closely correlated to conventional measurements, while pertaining to slightly different biomechanical quantities. The detected effects of alignment perturbations and physical exertion were small in magnitude and inconsistent between participants of our sample population. The concept of a range of acceptable prosthesis alignments, within which no optimization is feasible, is supported. However, amputee gait pattern and responses to alignment perturbations seem to change with the level of exertion. This suggests a consideration of real life conditions for the individual optimization of prosthetic alignment. Provided the systematic limitations of the integrated sensor measurements are carefully considered, it appears possible to use this method for the assessment of individual effects of alignment changes

An investigation into the efficacy of kinematics and kinetics method for stride-characteristic measurements of horses trotting on a treadmill

The aim of this study was to investigate the validity of stride characteristic measurements taken from the sternum by means of an Optical Motion Capture System (OMCS) and an Inertia Measurement Unit (IMU), in comparison with OMCS hoof markers. Measurements were taken from sound horses of a range of breeds, trotting at self-selected speeds on a treadmill (OMCS N=15; IMU N=4). Hoof marker trajectories were compared in terms of dorsoventral position (pZ), craniocaudal velocity (vX) and dorsoventral velocity (vZ). Contra-laterally coupled limbs were compared at beginning and end of stance according to vX. A Girth Marker (GM) placed over the sternum was used to identify beginning and end of stance of each diagonal using dorsoventral acceleration (aZ) and dorsoventral velocity (vZ) respectively. These were compared with hoof marker vX. GM aZ and vZ were then validated against the same measurements taken by an IMU measuring at the same time from the same location. No significant difference (p < 0.05) was found by ANOVA between hoof marker trajectories pZ, vX or vZ at beginning or end of stance. No significant difference was found by t-test or ICC between contralaterally coupled limbs at beginning or end of stance. GM aZ and vZ could be used to identify beginning and end of stance for each diagonal without significant difference from hoof vX timings according to t-test and ICC. OMCS GM and IMU did not differ in terms of velocity (peak or trough timing or amplitude, or absolute difference: peak minus trough), or acceleration peak timing, trough timing or trough amplitude according to t-test or ICC. However, OMCS GM and IMU differed significantly in terms of acceleration peak amplitude (p = .01, ICC = 0.46) and absolute difference (p = .04, ICC = 0.66). The sternum can be used as a site to collect data providing accurate information on beginning or end of stance of horses with no advanced placement of contralaterally coupled limbs, whilst trotting at self selected speeds on a treadmill. Temporal acceleration data, and temporal or amplitudal velocity data are sufficient to identify beginning and end of stance from the sternum using an IMU. Amplitudal acceleration data from an IMU should be further investigated before assumed valid under these conditions