Gait Analysis from Wearable Devices using Image and Signal Processing

We present the results of analyzing gait motion in-person video taken from a commercially available wearable camera embedded in a pair of glasses. The video is analyzed with three different computer vision methods to extract motion vectors from different gait sequences from four individuals for comparison against a manually annotated ground truth dataset. Using a combination of signal processing and computer vision techniques, gait features are extracted to identify the walking pace of the individual wearing the camera and are validated using the ground truth dataset. We perform an additional data collection with both the camera and a body-worn accelerometer to understand the correlation between our vision-based data and a more traditional set of accelerometer data. Our results indicate that the extraction of activity from the video in a controlled setting shows strong promise of being utilized in different activity monitoring applications such as in the eldercare environment, as well as for monitoring chronic healthcare conditions

Feasibility of novel gait training with robotic assistance : dynamic entrainment to mechanical perturbation to the ankle

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 149-156).Rehabilitation of human motor function is an issue of the utmost significance, and the demand for the effective rehabilitation service is even growing with the graying of the population. Robotic technology has provided promising ways to assist recovery of the motor function of upper extremities. In contrast, current robotic therapy for lower extremities has shown inferior efficacy. In this thesis, the source of the limited efficacy of current robotic walking therapy is addressed. Essential mechanical components for robustly stable walking are identified as energy dissipation and proper compensation. Based on these essential components, design criteria of effective robotic walking therapy are suggested as foot-ground interaction and ankle actuation. A novel strategy of robot aided walking therapy reflecting the design criteria is proposed; dynamically entraining human gait with periodic ankle torque from a robot. Experiments with normal subjects and neurologically impaired subjects support the feasibility of the proposed rehabilitation strategy. The gait period of subjects entrain to the periodic mechanical perturbation with a measurable basin of entrainment, and the entrainment always accompanies phase-locking so that the mechanical perturbation assists propulsion. These observations are affected neither by auditory feedback nor by a distractor task for normal subjects, and consistently observed in impaired subjects. A highly simplified one degree of freedom walking model without supra-spinal control or an intrinsic self-sustaining neural oscillator (a rhythmic pattern generator) encapsulated the essence of these observations. This suggests that several prominent limit-cycle features of human walking may stem from peripheral mechanics mediated by simple afferent feedback without significant involvement of supra-spinal control or central pattern generator. The competence of the highly simplified model supports that the proposed entrainment therapy may be effective for a wide range of neurological impairments.by Jooeun Ahn.Ph.D

Design, implementation and control of an overground gait and balance trainer with an active pelvis-hip exoskeleton

Human locomotion is crucial for performing activities of daily living and any disability in gait causes a significant decrease in the quality of life. Gait rehabilitation therapy is imperative to improve adverse effects caused by such disabilities. Gait therapies are known to be more effective when they are intense, repetitive, and allow for active involvement of patients. Robotic devices excel in performing repetitive gait rehabilitation therapies as they can eliminate the physical burden of the therapist, enable safe and versatile training with increased intensity, while allowing quantitative measurements of patient progress. Gait therapies need to be applied to specific joints of patients such that the joints work in a coordinated and repetitious sequence to generate a natural gait pattern. Six determinants of gait pattern have been identified that lead to efficient locomotion and any irregularities in these determinants result in pathological gaits. Three of these six basic gait determinants include movements of the pelvic joint; therefore, an effective gait rehabilitation robot is expected to be capable of controlling the movements of the human pelvis. We present the design, implementation, control, and experimental verification of AssistOn-Gait, a robot-assisted trainer, for restoration and improvement of gait and balance of patients with disabilities affecting their lower extremities. In addition to overground gait and balance training, AssistOn-Gait can deliver pelvis-hip exercises aimed to correct compensatory movements arising from abnormal gait patterns, extending the type of therapies that can be administered using lower extremity exoskeletons. AssistOn-Gait features a modular design, consisting of an impedance controlled, self-aligning pelvis-hip exoskeleton, supported by a motion controlled holonomic mobile platform and a series-elastic body weight support system. The pelvis-hip exoskeleton possesses 7 active degrees of freedom to independently control the rotation of the each hip in the sagittal plane along with the pelvic rotation, the pelvic tilt, lateral pelvic displacement, and the pelvic displacements in the sagittal plane. The series elastic body weight support system can provide dynamic unloading to support a percentage of a patient's weight, while also compensating for the inertial forces caused by the vertical movements of the body. The holonomic mobile base can track the movements of patients on flat surfaces, allowing patients to walk naturally, start/stop motion, vary their speed, sidestep to maintain balance, and turn to change their walking direction. Each of these modules can be used independently or in combination with each other, to provide different configurations for overground and treadmill based training with and without dynamic body weight support. The pelvis-hip exoskeleton of AssistOn-Gait is constructed using two passively backdrivable planar parallel mechanisms connected to the patient with a custom harness, to enable both passive movements and independent active impedance control of the pelvis-hip complex. Furthermore, the exoskeleton is self-aligning; it can automatically adjust the center of rotation of its joint axes, enabling an ideal match between patient's hip rotation axes and the device axes in the sagittal plane. This feature not only guarantees ergonomy and comfort throughout the therapy, but also extends the usable range of motion for the hip joint. Moreover, this feature significantly shortens the setup time required to attach the patient to the exoskeleton. The exoskeleton can also be used to implement virtual constraints to ensure coordination and synchronization between various degrees of freedom of the pelvis-hip complex and to assist patients as-needed for natural gait cycles. The overall kinematics of AssistOn-Gait is redundant, as the exoskeleton module spans all the degrees of freedom covered by the mobile platform. Furthermore, the device features dual layer actuation, since the exoskeleton module is designed for force control with good transparency, while the mobile base is designed for motion control to carry the weight of the patient and the exoskeleton. The kinematically redundant dual layer actuation enables the mobile base of the system to be controlled using workspace centering control strategy without the need for any additional sensors, since the patient movements are readily measured by the exoskeleton module. The workspace centering controller ensures that the workspace limits of the exoskeleton module are not reached, decoupling the dynamics of the mobile base from the dynamics of the exoskeleton. Consequently, AssistOn-Gait possesses virtually unlimited workspace, while featuring the same output impedance and force rendering performance as its exoskeleton module. The mobile platform can also be used to generate virtual fixtures to guide patient movements. The ergonomy and useability of AssistOn-Gait have been tested with several human subject experiments. The experimental results verify that AssistOn-Gait can achieve the desired level of ergonomy and passive backdrivability, as the gait patterns with the device in zero impedance mode are shown not to significantly deviate from the natural gait of the subjects. Furthermore, virtual constraints and force-feedback assistance provided by AssistOn-Gait have been shown to be adequate to ensure repeatability of desired corrective gait patterns

A shoe-integrated sensor system for wireless gait analysis and real-time therapeutic feedback

Thesis (Sc. D.)--Harvard-MIT Division of Health Sciences and Technology, 2004.Includes bibliographical references (p. 307-314).Clinical gait analysis currently involves either an expensive analysis in a motion laboratory, using highly accurate, if cumbersome, kinematic systems, or a qualitative analysis with a physician or physical therapist making visual observations. There is a need for a low cost device that falls in between these two methods, and can provide quantitative and repeatable results. In addition, continuous monitoring of gait would be useful for real-time physical rehabilitation. To free patients from the confines of a motion laboratory, this thesis has resulted in a wireless wearable system capable of measuring many parameters relevant to gait analysis. The extensive sensor suite includes three orthogonal accelerometers, and three orthogonal gyroscopes, four force sensors, two bi-directional bend sensors, two dynamic pressure sensors, as well as electric field height sensors. The "GaitShoe" was built to be worn on any shoes, without interfering with gait, and was designed to collect data unobtrusively, in any environment, and over long periods of time. Subject testing of the GaitShoe was carried out on ten healthy subjects with normal gait and five subjects with Parkinson's disease. The calibrated sensor outputs were analyzed, and compared to results obtained simultaneously from The Massachusetts General Hospital Biomotion Lab; the GaitShoe proved highly capable of detecting heel strike and toe off, as well as estimating orientation and position of the subject. A wide variety of features were developed from the calibrated sensor outputs, for use with standard pattern recognition techniques to classify the gait of the subject. The results of the classification demonstrated the ability of the GaitShoe to identify the subjects with(cont.) Parkinson's disease, as well as individual subjects. Real-time feedback methods were developed to investigate the feasibility of using the continuous monitoring of gait for physical therapy and rehabilitation.by Stacy J. Morris.Sc.D

Biomechanical evaluation of prosthetic feet

An evaluation method was developed which can be used generally for the assessment of any prosthetic feet. The two most common prosthetic feet prescribed to below-knee and above-knee amputees are the Uniaxial and SACH feet. A review of prescription practices shows that in the United Kingdom about 80% of the below-knee and above-knee amputees are fitted with a Uniaxial foot, whereas in the United States about 80% are fitted with the SACH foot. These contradictory prescription practices between the two countries, prompted the project to be concentrated on the evaluation of the SACH and Uniaxial feet. The method developed includes a subjective assessment procedure and a biomechanical evaluation on the function of the two prosthetic feet and their effects on whole body gait kinematics and lower limb kinetics. A review of the methods used in gait analysis is presented in the thesis. This forms a basis for the selection of a suitable gait recording system for the project. A background study of lower limb prosthetics in general and a review of prosthetic ankle/foot assemblies in particular are also presented. The methodology and instrumentation used in the project are given. Altogether, six below-knee and five above-knee amputees were tested. Due to insufficient supply of heel bumper stiffness by the manufacturer for the Uniaxial foot, heel bumpers of varying stiffnesses had to be made in the Bioengineering Unit. The development of the analytical procedure for the three-dimensional analysis is presented. A suite of computer programs was written to facilitate the handling of the large amount of data, details of which are included in the Appendix. Results from the analysis of the tests performed are discussed. Although some apparent differences were observed between the SACH and Uniaxial feet, no conclusion can be drawn as to which is better for the function of the amputee.An evaluation method was developed which can be used generally for the assessment of any prosthetic feet. The two most common prosthetic feet prescribed to below-knee and above-knee amputees are the Uniaxial and SACH feet. A review of prescription practices shows that in the United Kingdom about 80% of the below-knee and above-knee amputees are fitted with a Uniaxial foot, whereas in the United States about 80% are fitted with the SACH foot. These contradictory prescription practices between the two countries, prompted the project to be concentrated on the evaluation of the SACH and Uniaxial feet. The method developed includes a subjective assessment procedure and a biomechanical evaluation on the function of the two prosthetic feet and their effects on whole body gait kinematics and lower limb kinetics. A review of the methods used in gait analysis is presented in the thesis. This forms a basis for the selection of a suitable gait recording system for the project. A background study of lower limb prosthetics in general and a review of prosthetic ankle/foot assemblies in particular are also presented. The methodology and instrumentation used in the project are given. Altogether, six below-knee and five above-knee amputees were tested. Due to insufficient supply of heel bumper stiffness by the manufacturer for the Uniaxial foot, heel bumpers of varying stiffnesses had to be made in the Bioengineering Unit. The development of the analytical procedure for the three-dimensional analysis is presented. A suite of computer programs was written to facilitate the handling of the large amount of data, details of which are included in the Appendix. Results from the analysis of the tests performed are discussed. Although some apparent differences were observed between the SACH and Uniaxial feet, no conclusion can be drawn as to which is better for the function of the amputee

Applications of aerospace technology in biology and medicine

Results of the medically related activities of the NASA Application Team Program at the Research Triangle Institute are reported. A survey of more than 300 major medical device manufacturers has been initiated for the purpose of determining their interest and opinions in regard to participating in the NASA Technology Utilization Program. Design and construction has been commissioned of a permanent exhibit of NASA Biomedical Application Team accomplishments for the aerospace building of the North Carolina Museum of Life and Science at Durham, North Carolina. The team has also initiated an expansion of its activities into the Northeastern United States

Application of surface EMG in diabetic disease

Summary: English The World Health Organization warns that, in 2000, as many as 33 million Europeans suffered from diabetes, approximately 15% will likely develop foot ulcers, and approximately 15% to 20% of these patients will face lower-extremity amputation. In 2004, an estimated 3.4 million people died from consequences of high blood sugar. Diabetic neuropathy is the most common chronic complication associated with diabetes mellitus, affecting 20–50% of diabetic patients 10 years after their diagnosis. Peripheral neuropathy and peripheral arterial disease are the most common and invalidating diabetes’s complications, involved in the pathogenesis of diabetic foot. They account for the leading cause of non-traumatic lower limb amputations. It results from two factors. The first one is a reduced blow of blood in the inferior limbs, caused from the presence of obliterating peripheral arteriopathy disease. The second is the progressive laceration of nervous fibers (neuropathy) that cause a reduction of the sensitivity (also to the pain) and of the ability of movement, and that helps the appearance of lesions. Together with diabetes falls in older adults are a big public health concern and have provided much of the motivation for research into age-related changes in human gait. Tripping during walking is the predominant cause of falls not only in the elderly but also in the neuropathic subjects. Trips can occur during walking on a level ground, but also during crossing visible obstacle, stair ascending and descending. The social and economic weight of the diabetic foot and the tragic consequences that brings with it can be reduced through a prompt diagnosis and treatment from the very beginning. The aim of this thesis, was to evaluate differences in gait parameters, in performing stair ascending and descending task and evaluation of muscle fatigue during treadmill protocol in diabetes subjects with and without complications, in order to provide a further tool for early diagnosis which allows clinicians to change, if is necessary, or only to control, as soon as possible, the follow-up of patients according to their specific characteristics

A synergistic wearable health monitoring system using cellular network technology

Thesis (M.S.) University of Alaska Fairbanks, 2017This thesis presents a synergistic approach to healthcare applications by integrating a wearable health monitoring system into a smart home system. By exploiting synergy within each system and between these two systems, this thesis shows that the efficiency of the health care can be increased while providing the added advantage of utmost user-friendly environment. Initially, a wearable health monitoring prototype system was developed for vital sign data collection and processing. The developed system used biosensor integration to distinguish amongst multiple physical activities and to compare the variations in physiological conditions according to physical activity of the user. Afterward, system learning techniques were established for accomplishing the scalability of the health monitoring system. The resulting system is able to monitor different users without the need for explicitly changing the thresholds for the individual user. The health monitoring was further improved through integration with the smart home system to exploit synergy between various physiological sensors and to reduce false alarms generated by the system. A cellular communication interface was developed for transmitting the collected data to a remote caregiver and also to store the time-stamped data on the online web server. A web interface was developed to allow monitoring user's health and activity data, along with their surrounding environment

The biomechanics of human locomotion

Includes bibliographical references. The thesis on CD-ROM includes Animate, GaitBib, GaitBook and GaitLab, four quick time movies which focus on the functional understanding of human gait. The CD-ROM is available at the Health Sciences Library

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