Visual cue training to improve walking and turning after stroke:a study protocol for a multi-centre, single blind randomised pilot trial

Visual information comprises one of the most salient sources of information used to control walking and the dependence on vision to maintain dynamic stability increases following a stroke. We hypothesize, therefore, that rehabilitation efforts incorporating visual cues may be effective in triggering recovery and adaptability of gait following stroke. This feasibility trial aims to estimate probable recruitment rate, effect size, treatment adherence and response to gait training with visual cues in contrast to conventional overground walking practice following stroke.Methods/design: A 3-arm, parallel group, multi-centre, single blind, randomised control feasibility trial will compare overground visual cue training (O-VCT), treadmill visual cue training (T-VCT), and usual care (UC). Participants (n = 60) will be randomly assigned to one of three treatments by a central randomisation centre using computer generated tables to allocate treatment groups. The research assessor will remain blind to allocation. Treatment, delivered by physiotherapists, will be twice weekly for 8 weeks at participating outpatient hospital sites for the O-VCT or UC and in a University setting for T-VCT participants.Individuals with gait impairment due to stroke, with restricted community ambulation (gait spee

fNIRS response during walking — Artefact or cortical activity? A systematic review

This systematic review aims to (i) evaluate functional near infrared spectroscopy (fNIRS) walking study design in young adults, older adults and people with Parkinson’s disease (PD); (ii) examine signal processing techniques to reduce artefacts and physiological noise in fNIRS data; and (iii) provide evidence-based recommendations for fNIRS walking study design and signal analysis techniques. An electronic search was undertaken. The search request detailed the measurement technique, cohort and walking task. Thirty-one of an initial yield of 73 studies satisfied the criteria. Protocols and methods for removing artefacts and noise varied. Differences in fNIRS signals between studies were found in rest vs. walking, speed of walking, usual vs. complex walking and easy vs. difficult tasks. In conclusion, there are considerable technical and methodological challenges in conducting fNIRS studies during walking which can introduce inconsistencies in study findings. We provide recommendations for the construction of robust methodologies and suggest signal processing techniques implementing a theoretical framework accounting for the physiology of haemodynamic responses

Wheelchair Training Program for New Manual Wheelchair Users

Manual wheelchairs are commonly used for everyday mobility among people with lower limb impairments, including persons with spinal cord injury (SCI). Manual wheelchair users often experience pain and chronic overuse injuries in their upper extremities, limiting their mobility and their ability to complete daily activities. The repetitive trauma of propelling a wheelchair may be a contributing factor to upper extremity pain and injury. The anatomy of the upper extremities is not designed for the number of repetitions and the amount of force involved in everyday wheelchair propulsion. Research has been conducted to identify recommendations for decreasing the number of repetitions and the amount of force involved with manual wheelchair propulsion; however, training on how to use a wheelchair, specifically propulsion training, is often not implemented during rehabilitation. Important steps in identifying strategies for teaching wheelchair propulsion and skills include exploring devices for training, understanding health care professional and wheelchair user perspectives of wheelchair training, and training based on motor learning approaches. Therefore, the overall goal of this project was to further explore methodology for training of new manual wheelchair users. To this end, we conducted three studies (Chapters 2-4). In study 1 (Chapter 2), we tested a wheelchair dynamometer roller system, the WheelMill System (WMS), on its use in simulating different surfaces (i.e., overground and ramps) and assessing propulsion variables that can be used for training new wheelchair users. We identified that the WMS has the ability to accurately simulate flat overground movement; however, the accuracy of the WMS was poor in simulation of ramps. Modifications to the software model and the addition of visual feedback may improve the accuracy of the simulation of ramps. The WMS was accurate in the quantification of biomechanical propulsion variables. In study 2 (Chapter 3), we identified perspectives of health care professionals and manual wheelchair users to assist in prioritizing the focus of wheelchair skills training of new manual wheelchair users. During focus groups, health care professionals and manual wheelchair users discussed if and how wheelchair propulsion biomechanics were taught and important skills that should be included in training. Results indicate that propulsion biomechanics were introduced but not addressed in detail. Important training components discussed include propulsion techniques, transfers in an out of the wheelchair, providing maintenance to the wheelchair, and navigating barriers such as curbs, ramps, and rough terrain. Health care professionals and manual wheelchair users identified many of the same skills as important but ranked them in a different order. In study 3 (Chapter 4), we piloted a wheelchair training program implementing aspects of motor learning for new manual wheelchair users and measured the impact of this program on wheelchair propulsion biomechanics and overall wheelchair skills. Post-training wheelchair biomechanics changed, as well as propulsion performance overground. Wheelchair skills did not change significantly post-training. Wheelchair training has the potential for change; however, there are many challenges associated with implementing training programs for new manual wheelchair users. Together, these results contribute knowledge to evidence-based approaches to teaching new manual wheelchair users with SCI how to efficiently and effectively use their wheelchairs. Specifically, we obtained information about technology for simulating and assessing manual wheelchair propulsion, perspectives of stakeholders with regard to the manual wheelchair training process, and methodology for training new manual wheelchair users

Development and Cross-Validation of a Cadence-Based Metabolic Equation for Walking

The ACSM Metabolic Equation is a widely recognized equation for predicting metabolic intensity from walking speed. However, an equation that uses an observable metric (i.e., cadence [steps/min]), accounts for individual characteristics, and is validated across walking conditions may enable more accessible and accurate predictions of walking intensity. PURPOSE: To develop metabolic equations that predict metabolic intensity (oxygen consumption; mL/kg/min) from cadence using a large treadmill walking dataset (Study One) and cross-validate these equations during overground unconstrained and cadence-constrained walking conditions (Study Two). METHODS: In Study One, 193 adults (21-81 years) completed treadmill walking bouts while oxygen consumption was measured with indirect calorimetry (converted to metabolic equivalents [METs]; 1 MET=3.5 mL/kg/min=1 kcal/kg/min). Directly-observed step counts divided by bout duration produced cadence. The least squares regression of the cadence-intensity relationship produced a simple equation and a full equation was developed using best subsets regression (additional possible predictors of leg length, body mass, BMI, percent body fat, sex, and age). Predictive accuracy and bias of each cadence-based metabolic equation and the ACSM Metabolic Equation was evaluated through k-fold cross-validation. In Study Two, these three metabolic equations were applied to data collected from 20 young adults during overground walking at self-selected paces (unconstrained) and with foot-strikes entrained to music tempos (cadence-constrained). RESULTS: In Study One, the simple equation predicted walking intensity within 0.5 METs, on average, and approximately no bias (CONCLUSIONS: The simple equation performed comparably to the full equation (which accounted for individual characteristics) and appreciably better than the ACSM Metabolic Equation. The simple cadence-based metabolic equation is an improved, user-friendly tool for predicting and prescribing walking intensity with reasonable accuracy (within ~0.5 METs; 45 kcals/hr for the average American)

FATIGUE-RELATED ASYMMETRY AND INSTABILITY DURING A 3200-M TIME-TRIAL PERFORMANCE IN HEALTHY RUNNERS

The purpose of this study was to examine fatigue effects on symmetry and stability during a maximal effort running time-trial m). Recreational runners had continuous recordings of 3D trunk acceleration parameters (spatio-temporal, RMS vector ratio, step symmetry, and stride regularity) during the lT. Statistical analysis was carried out using generalised estimating equations (GEE) to investigate longitudinal changes (laps two to eight) compared to baseline (lap one), while statistically adjusting for running speed. Runners had significantly longer contact times (4m lap onwards), higher mediolateral root mean square (RMS) ratio (3d lap onwards), lower vertical symmetry and vertical RMS ratio (final lap). Coaches could use these results to recognize, minimize, and delay fatigue related onset of asymmetries and instabilities possibly through training strategies

Training functional mobility using a dynamic virtual reality obstacle course

Falling poses a significant risk of injury for older adults, thus decreasing quality of life. Major risk factors for falling include decrements in gait and balance, and adverse patient-reported health and well-being. Virtual Reality (VR) can be a cost-effective, resource-efficient, and highly engaging training tool, and previous research has utilized VR to reduce fall-risk factors in a variety of populations with aging and pathology. However, there are barriers to implementing VR as a training tool to improve functional mobility in older adults that include the manner in which healthy older adults perform in VR relative to younger adults, the effect of extended duration training, and the relation of fall-risk clinical metrics to performance in VR. The purpose of this dissertation is threefold: (1) to compare performance between older and younger adults in VR and in real-world gait and balance tests as a result of a single bout of VR training; (2) to compare performance in VR and gait and balance within younger adults as a result of extended training duration; and (3) to evaluate clinical tests as prerequisite measures for performance within the VR environment. Thirty-five healthy adults participated in this study and were placed into either the older adult training group (n=8; 67.0±4.4yrs), younger training (n=13; 22.1±2.5yrs), or younger control (n=13; 21.7±1.0yrs). All participants completed an online patient-reported survey of balance confidence and health and well-being, as well as a pre-test of clinical assessments and walking and balance tests. The training groups then completed 15 trials of a VR obstacle course, while the controls walked overground for 15 minutes. The VR obstacle course included a series of gait and dynamic balance tasks, such as stepping on irregularly placed virtual stepping stones and walking a virtual balance beam. All participants repeated the walking and balance tests at post-test. The younger training group also completed 3 weeks of training in the same VR obstacle course and a second post-test. Analyses of variance were completed to determine the extent to which participants improved within VR and the walking and balance tests both as a result of a single bout of training, and for the younger adults – three weeks of extended training. Multiple regressions were run to determine the extent to which patient-reports and clinical assessments may predict performance within VR. The results reported in Manuscript I show that although younger adults completed the VR course quicker, their learning rate was not different from older adults; and as a result of extended training, younger adults continued to improve their time to complete the course. For gait and balance tests, age related differences were observed. Both groups showed better performance on some post-tests, indicating that VR training may have had a positive effect on neuromotor control. The results reported in Manuscript II suggest the RAND-1 pain subscale and simple reaction time (SRT) may predict time to complete the VR course, and SRT and BBS Q14 may additionally predict obstacle contact. These data suggest a VR obstacle course may be effective in improving gait and balance in both younger and older adults. It is recommended that future work enroll older adults in the extended training portion of the study and to increase the VR obstacle course difficulty when benchmarks are met

Human Gait Based Relative Foot Sensing for Personal Navigation

Human gait dynamics were studied to aid the design of a robust personal navigation and tracking system for First Responders traversing a variety of GPS-denied environments. IMU packages comprised of accelerometers, gyroscopes, and magnetometer are positioned on each ankle. Difficulties in eliminating drift over time make inertial systems inaccurate. A novel concept for measuring relative foot distance via a network of RF Phase Modulation sensors is introduced to augment the accuracy of inertial systems. The relative foot sensor should be capable of accurately measuring distances between each node, allowing for the geometric derivation of a drift-free heading and distance. A simulation to design and verify the algorithms was developed for five subjects in different gait modes using gait data from a VICON motion capture system as input. These algorithms were used to predict the distance traveled up to 75 feet, with resulting errors on the order of one percent

Design, implementation and validation of an exoskeletal robot for locomotion studies in rodents

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 214-226).Growing interest in robotic treatment of patients with neurological injury motivates the development of therapeutic robots for basic research into recovery. Though humans are the ultimate beneficiaries, basic research frequently involves rodent models of neurological injury, which motivates robotic devices that can interact with rats or mice. Currently, available apparatus for locomotion studies of rodents is built upon treadmills, which simplify the design and implementation but also restrict the scope of possible experiments. This is largely due to the treadmill's single-dimensional movement and the lack of accommodation for natural or voluntary movement of the animal. In order to open up new possibilities for locomotion studies in rodents, this work introduces newly developed apparatus for locomotion research in rodents. The key concept is to allow maximal freedom of voluntary movement of the animal while providing forceful interaction when necessary. Advantages and challenges of the proposed machine over other existing designs are discussed. Design and implementation issues are presented and discussed, emphasizing their impact on free, voluntary, movement of the animal. A live-animal experiment was conducted to verify the design principles. Unconstrained natural movement of the animal was compared with movement with the overground robot attached. The compact, overground design and backdrivable implementation of this robot allow novel experiments that involve open-space, free (or interactive) locomotion of the animal.by Yun Seong Song.Ph.D

A comparison of measured and modelled energetics, estimated from global positioning systems (GPS) velocity

Introduction:Traditionally in laboratory settings, indirect calorimetry and blood lactate B[La] analysis provide a criterion measure of bioenergetics, although it is not feasible within a multitude of competitive sports. Mathematical modelling provides a solution to estimate metabolic power during competitive sport, whereby a sprint running model was proposed, using global positioning systems (GPS) velocity data and the known energy cost of the equivalent slope running. Now a novel mechanical approach has been presented as an alternative model to estimate metabolic power from GPS velocity data and principles of the work-energy theorem. The purpose of this study was to compare metabolic power as produced from the sprint running model, the mechanical model and indirect calorimetry. Methods:Thirteen participants performed a maximal effort 400 m- and a repeated 40 m- sprint and sub-maximal continuous running and repeated 20 m shuttle running test. The tests were completed across two testing sessions a week apart. In all tests, through exercise and recovery periods, V̇ O2 was measured by single breath analysis and B[La] was sampled during the recovery. The sum of V̇ O2 and B[La] determined the energy cost. GPS velocity data collected throughout each test was processed through the sprint running and mechanical models to estimate energy cost. Results:Indirect calorimetry determined significantly greater values of overall metabolic power than sprint running (P < 0.001) and mechanical (P < 0.001) models across all exercise tests, and the mechanical model estimated larger overall metabolic power values than the sprint running model. Conclusion:This study urges sports scientists to understand the constructs of modelling bioenergetics and the inherent limitations of modelled energetics before implementing them within professional practice. Modelled bioenergetics may provide an estimation of the aerobic energy demand of overground running during exercise but is unable to account for the increased metabolic supply post-exercise

Smart Technology for Telerehabilitation: A Smart Device Inertial-sensing Method for Gait Analysis

The aim of this work was to develop and validate an iPod Touch (4th generation) as a potential ambulatory monitoring system for clinical and non-clinical gait analysis. This thesis comprises four interrelated studies, the first overviews the current available literature on wearable accelerometry-based technology (AT) able to assess mobility-related functional activities in subjects with neurological conditions in home and community settings. The second study focuses on the detection of time-accurate and robust gait features from a single inertial measurement unit (IMU) on the lower back, establishing a reference framework in the process. The third study presents a simple step length algorithm for straight-line walking and the fourth and final study addresses the accuracy of an iPod’s inertial-sensing capabilities, more specifically, the validity of an inertial-sensing method (integrated in an iPod) to obtain time-accurate vertical lower trunk displacement measures. The systematic review revealed that present research primarily focuses on the development of accurate methods able to identify and distinguish different functional activities. While these are important aims, much of the conducted work remains in laboratory environments, with relatively little research moving from the “bench to the bedside.” This review only identified a few studies that explored AT’s potential outside of laboratory settings, indicating that clinical and real-world research significantly lags behind its engineering counterpart. In addition, AT methods are largely based on machine-learning algorithms that rely on a feature selection process. However, extracted features depend on the signal output being measured, which is seldom described. It is, therefore, difficult to determine the accuracy of AT methods without characterizing gait signals first. Furthermore, much variability exists among approaches (including the numbers of body-fixed sensors and sensor locations) to obtain useful data to analyze human movement. From an end-user’s perspective, reducing the amount of sensors to one instrument that is attached to a single location on the body would greatly simplify the design and use of the system. With this in mind, the accuracy of formerly identified or gait events from a single IMU attached to the lower trunk was explored. The study’s analysis of the trunk’s vertical and anterior-posterior acceleration pattern (and of their integrands) demonstrates, that a combination of both signals may provide more nuanced information regarding a person’s gait cycle, ultimately permitting more clinically relevant gait features to be extracted. Going one step further, a modified step length algorithm based on a pendulum model of the swing leg was proposed. By incorporating the trunk’s anterior-posterior displacement, more accurate predictions of mean step length can be made in healthy subjects at self-selected walking speeds. Experimental results indicate that the proposed algorithm estimates step length with errors less than 3% (mean error of 0.80 ± 2.01cm). The performance of this algorithm, however, still needs to be verified for those suffering from gait disturbances. Having established a referential framework for the extraction of temporal gait parameters as well as an algorithm for step length estimations from one instrument attached to the lower trunk, the fourth and final study explored the inertial-sensing capabilities of an iPod Touch. With the help of Dr. Ian Sheret and Oxford Brookes’ spin-off company ‘Wildknowledge’, a smart application for the iPod Touch was developed. The study results demonstrate that the proposed inertial-sensing method can reliably derive lower trunk vertical displacement (intraclass correlations ranging from .80 to .96) with similar agreement measurement levels to those gathered by a conventional inertial sensor (small systematic error of 2.2mm and a typical error of 3mm). By incorporating the aforementioned methods, an iPod Touch can potentially serve as a novel ambulatory monitor system capable of assessing gait in clinical and non-clinical environments