Optimal locations and computational frameworks of FSR and IMU sensors for measuring gait abnormalities

Neuromuscular diseases cause abnormal joint movements and drastically alter gait patterns in patients. The analysis of abnormal gait patterns can provide clinicians with an in-depth insight into implementing appropriate rehabilitation therapies. Wearable sensors are used to measure the gait patterns of neuromuscular patients due to their non-invasive and cost-efficient characteristics. FSR and IMU sensors are the most popular and efficient options. When assessing abnormal gait patterns, it is important to determine the optimal locations of FSRs and IMUs on the human body, along with their computational framework. The gait abnormalities of different types and the gait analysis systems based on IMUs and FSRs have therefore been investigated. After studying a variety of research articles, the optimal locations of the FSR and IMU sensors were determined by analysing the main pressure points under the feet and prime anatomical locations on the human body. A total of seven locations (the big toe, heel, first, third, and fifth metatarsals, as well as two close to the medial arch) can be used to measure gate cycles for normal and flat feet. It has been found that IMU sensors can be placed in four standard anatomical locations (the feet, shank, thigh, and pelvis). A section on computational analysis is included to illustrate how data from the FSR and IMU sensors are processed. Sensor data is typically sampled at 100 Hz, and wireless systems use a range of microcontrollers to capture and transmit the signals. The findings reported in this article are expected to help develop efficient and cost-effective gait analysis systems by using an optimal number of FSRs and IMUs

Gait stability and balance strategies of both acquired and congenital lower limb prosthetic users in response to perturbations

Incorrect date on title page. Year of award is 2021.Falls are a health care problem for lower limb prosthetic users. The study of gait stability in lower limb prosthetic users facilitates improved insight and knowledge in different adaptation strategies of the human body in order to walk as functionally as possible with a prosthesis. The aim of this thesis was to determine how prosthetic users cope with unbalanced situations during walking and how these coping strategies may differ from able-bodied individuals. Improved understanding of such mechanisms may help reduce fall incidence. A number of prosthetic factors were considered including the use of a prosthetic foot incorporating an ankle joint, compared to a conventional prosthetic foot. Additionally, the effect of different alignments and the aetiology of the amputation or absence (congenital vs acquired amputation) was also considered. The study was conducted using an advanced dual-belt instrumented treadmill (CAREN). The protocol of perturbations in the study was adopted from a previous work by a group of researchers in University of Strathclyde (Roeles et al., 2018). Interventions used were anteroposterior (AP) perturbations by means of sudden changes in the walking speed to mimic a slip that can be faced in real-life situations. Main Outcome Measurements measured were AP and ML margins of stability (MoS) Hof et al. (2005). Step length, width and time were also measured to investigate the coping strategy following perturbation. Prosthetic users were less stable than able-bodied individuals. The involvement of the prosthetic side to recover stability was limited therefore, during rehabilitation stability training tasks for the intact side may help the prosthetic users enhance their overall stability and may reduce the fall incidence rate. Energy storing and return prosthetic feet may provide a sufficient level of stability compared to the feet which incorporate a moving ankle mechanism. The Ossur Pro-Flex foot demonstrated enhanced stability in the AP direction. Alignment changes from the optimal alignment may impose extra challenge to the stability. A short prosthesis was found to be the most challenging alignment change in response to perturbation. The prosthetic user with congenital related limb anomaly was found to be more stable than the prosthetic users with other lower limb loss. The outcomes of this study are novel and have potential to improve the understanding of how prosthetic users (acquired and congenital) react in when stability is compromised and the variables which may affect this further (foot design and alignment). It is envisaged that greater understanding of different adaptation strategies of the human body may help influence future prosthetic treatment, prescription, alignment and potentially component design.Falls are a health care problem for lower limb prosthetic users. The study of gait stability in lower limb prosthetic users facilitates improved insight and knowledge in different adaptation strategies of the human body in order to walk as functionally as possible with a prosthesis. The aim of this thesis was to determine how prosthetic users cope with unbalanced situations during walking and how these coping strategies may differ from able-bodied individuals. Improved understanding of such mechanisms may help reduce fall incidence. A number of prosthetic factors were considered including the use of a prosthetic foot incorporating an ankle joint, compared to a conventional prosthetic foot. Additionally, the effect of different alignments and the aetiology of the amputation or absence (congenital vs acquired amputation) was also considered. The study was conducted using an advanced dual-belt instrumented treadmill (CAREN). The protocol of perturbations in the study was adopted from a previous work by a group of researchers in University of Strathclyde (Roeles et al., 2018). Interventions used were anteroposterior (AP) perturbations by means of sudden changes in the walking speed to mimic a slip that can be faced in real-life situations. Main Outcome Measurements measured were AP and ML margins of stability (MoS) Hof et al. (2005). Step length, width and time were also measured to investigate the coping strategy following perturbation. Prosthetic users were less stable than able-bodied individuals. The involvement of the prosthetic side to recover stability was limited therefore, during rehabilitation stability training tasks for the intact side may help the prosthetic users enhance their overall stability and may reduce the fall incidence rate. Energy storing and return prosthetic feet may provide a sufficient level of stability compared to the feet which incorporate a moving ankle mechanism. The Ossur Pro-Flex foot demonstrated enhanced stability in the AP direction. Alignment changes from the optimal alignment may impose extra challenge to the stability. A short prosthesis was found to be the most challenging alignment change in response to perturbation. The prosthetic user with congenital related limb anomaly was found to be more stable than the prosthetic users with other lower limb loss. The outcomes of this study are novel and have potential to improve the understanding of how prosthetic users (acquired and congenital) react in when stability is compromised and the variables which may affect this further (foot design and alignment). It is envisaged that greater understanding of different adaptation strategies of the human body may help influence future prosthetic treatment, prescription, alignment and potentially component design

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

Design of a vibrotactile stimulus paradigm for a biofeedback device to improve gait rehabilitation of lower limb amputees

Dissertação de mestrado integrado em Biomedical Engineering (specialization in Biomaterials Rehabilitation and Biomechanics)A lower limb amputation not only affects locomotion, but also the amputee's somatosensory system, body perception, and mental health and, naturally, the fear of falling is more pronounced. Consequently, the patient is faced with the challenge of developing motor strategies that allow him to carry out daily activities since the use of the prosthesis does not fully compensate for the deficiencies acquired by a prosthetic gait, such as, for instance, asymmetry and variation in the duration of the gait events. Faced with the absence of effective treatments that restore locomotor functionality, the BioWalk project presents a rehabilitation solution: a biofeedback system that assists amputees during gait training sessions. This system consists in applying a vibrotactile stimulus on the skin of the affected leg. This stimulus can be activated at different moments of the prosthetic gait, allowing the patient to have a better perception and awareness of his body and locomotion to be able to detect any abnormal motor behaviours during the rehabilitation sessions and, in the future, to establish an adequate and healthy gait pattern. Consequently, there is a need to analyse muscular and kinematic data of the gait of amputees to detect which events are critical in prosthetic gait, which muscles are activated or most required in gait, how the centre of mass behaves in the gait of an amputee, among other parameters. Thus, in this dissertation, the main goal is to investigate and propose the best way (i.e., paradigm) to apply a vibrotactile stimulus to be used in a biofeedback device during rehabilitation sessions.Uma amputação do membro inferior não afeta apenas a locomoção, mas também o sistema somatosensorial do amputado, a sua perceção corporal, a sua saúde mental e, naturalmente, o medo de cair encontra-se mais acentuado. Consequentemente, o paciente é confrontado com o desafio de desenvolver estratégias motoras que lhe permitam a realização de atividades diárias dado que o uso da prótese não compensa totalmente as deficiências adquiridas por uma marcha protética, como por exemplo, a assimetria e a variação na duração dos eventos de marcha. Perante a ausência de tratamentos eficazes que restaurem a funcionalidade locomotora, o projeto BioWalk apresenta uma solução de reabilitação: um sistema de biofeedback que auxilie a pessoa amputada durante sessões de treino de marcha. Este sistema consiste na aplicação de um estímulo vibrotátil sobre a pele da perna afetada. Este estímulo pode ser ativado em diversos momentos da marcha protética permitindo ao paciente uma melhor percetibilidade e consciência sobre o seu corpo e locomoção para que seja capaz de detetar algum comportamento motor anormal durante as sessões de reabilitação e para, futuramente, estabelecer um padrão de marcha adequado e saudável. Consequentemente, surge a necessidade de analisar dados musculares e cinemáticos da marcha de amputados de forma a detetar quais os eventos críticos na marcha protética, quais são os músculos ativados ou os que são mais requeridos na marcha, como se comporta o centro de massa na marcha de um amputado, entre outros parâmetros. Assim, nesta dissertação, o objetivo é propor um paradigma de estímulos vibrotáteis para serem usados num dispositivo de biofeedback durante sessões de reabilitação

Analysis of Human Gait Cycle with Body Equilibrium based on leg Orientation

Gait analysis identifies the posture during movement in order to provide the correct actions for a normal gait. A person\u27s gait may differ from others and can be recognized by specific patterns. Healthy individuals exhibit normal gait patterns, while lower limb amputees exhibit abnormal gait patterns. To better understand the pitfalls of gait, it is imperative to develop systems capable of capturing the gait patterns of healthy individuals. The main objective of this research was to introduce a new concept in gait analysis by computing the static and dynamic equilibrium in a real-world environment. A relationship was also presented among the parameters stated as static \& dynamic equilibrium, speed, and body states. A sensing unit was installed on the designed metal-based leg mounting assembly on the lateral side of the leg. An algorithm was proposed based on two variables: the position of the leg in space and the angle of the knee joint measured by an IMU sensor and a rotary encoder. It was acceptable to satisfy the static conditions when the body was in a fixed position and orientation, whether lying down or standing. While walking and running, the orientation is determined by the position and knee angle variables, which fulfill the dynamic condition. High speed reveals a rapid change in orientation, while slow speed reveals a slow change in orientation. The proposed encoder-based feedback system successfully determined the flexion at 47$^\circ$, extension at 153$^\circ$, and all seven gait cycle phases were recognized within this range of motion. Body equilibrium facilitates individuals when they are at risk of falling or slipping

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

最小限のウェアラブルセンサーを用いたマルチモーダルな定量的歩行評価

Tohoku University林部充弘課

Studies on gait control using a portable pneumatically powered ankle-foot orthosis (PPAFO) during human walking

A powered ankle-foot orthosis (AFO) can be very useful for people with neuromuscular injury. Control of powered AFOs will be more efficient to provide assistance to individuals with lower limb muscle impairments if we can identify different gait events during walking. A walking or gait cycle can be divided into multiple phases and sub-phases by proper gait event detection, and these phases/sub-phases are associated with one of the three main functional tasks during the gait cycle: loading response, forward propulsion, and limb advancement. The gait cycle of one limb can also be characterized by examining the limb’s behavior over one stride, which can be quantified as 0% to 100% of a gait cycle (GC). One easy approach to identify gait events is by checking whether sensor signals go above/below a predetermined threshold. By estimation of a walker’s instantaneous state, as represented by a specific percentage of the gait cycle (from states 0 to 100, which correlate with 0% to 100% GC), we can efficiently detect the various gait events more accurately. Our Human Dynamics and Controls Laboratory previously developed the portable pneumatically powered ankle-foot orthosis (PPAFO), which was capable of providing torque in both plantarflexion and dorsiflexion directions at the ankle. There were three types of sensor attached with the PPAFO (two force sensitive resistors and an angle sensor). In this dissertation, three aspects of effective control strategies for the PPAFO have been proposed. In the first study, two improved and reliable state estimators (Modified Fractional Time (MFT) and Artificial Neural Network (ANN)) were proposed for identifying when the limb with the PPAFO was at a certain percentage of the gait cycle. A correct estimation of percentage of gait cycle will assist with detecting specific gait events more accurately. The performance of new estimators was compared to a previously developed Fractional Time state estimation technique. To control a powered AFO using these estimators, however, detection of proper actuation timing is necessary. In the second study, a supervised learning algorithm to classify the appropriate start timing for plantarflexor actuation was proposed. Proper actuation timing has only been addressed in the literature in terms of functional efficiency or metabolic cost during walking. In this study, we will explore identifying the plantarflexor actuation timing in terms of biomechanics outcomes of human walking using a machine learning based algorithm. The third study investigated the recognition of different gait modes encountered during walking. The actuation scheme plays a significant role in walking on level ground, stair descent or stair ascent modes. The wrong actuation scheme for a given mode can cause falls or trips. A gait mode recognition technique was developed for detecting these different modes by attaching an inertial measurement unit and using a classifier based on artificial neural networks. This new algorithm improves upon the current one step delay limitation found as a drawback of a previously developed technique. Overall, this dissertation focused on addressing some important issues related to control of powered AFO that ultimately will help to assist people wearing the device in daily life situations during walking. The proposed approaches and algorithms introduced in this dissertation showed very promising results that proved that these methods can successfully improve the control system of powered AFOs

Wearable Movement Sensors for Rehabilitation: From Technology to Clinical Practice

This Special Issue shows a range of potential opportunities for the application of wearable movement sensors in motor rehabilitation. However, the papers surely do not cover the whole field of physical behavior monitoring in motor rehabilitation. Most studies in this Special Issue focused on the technical validation of wearable sensors and the development of algorithms. Clinical validation studies, studies applying wearable sensors for the monitoring of physical behavior in daily life conditions, and papers about the implementation of wearable sensors in motor rehabilitation are under-represented in this Special Issue. Studies investigating the usability and feasibility of wearable movement sensors in clinical populations were lacking. We encourage researchers to investigate the usability, acceptance, feasibility, reliability, and clinical validity of wearable sensors in clinical populations to facilitate the application of wearable movement sensors in motor rehabilitation

A Review on Accelerometry-Based Gait Analysis and Emerging Clinical Applications

Gait analysis continues to be an important technique for many clinical applications to diagnose and monitor certain diseases. Many mental and physical abnormalities cause measurable differences in a person's gait. Gait analysis has applications in sport, computer games, physical rehabilitation, clinical assessment, surveillance, human recognition, modelling, and many other fields. There are established methods using various sensors for gait analysis, of which, accelerometers are one of the most often employed. Accelerometer sensors are generally more user friendly and less invasive. In this paper, we review research regarding accelerometer sensors used for gait analysis with particular focus on clinical applications. We provide a brief introduction to accelerometer theory followed by other popular sensing technologies. The commonly used gait phases and parameters are enumerated. The details of extracting the papers for review are provided. We also review several gait analysis software. Then, we provide an extensive report of accelerometry based gait analysis systems and applications with additional emphasis on trunk accelerometry. We conclude this review with future research directions