Virtual reality tool for balance training

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Eletrónica Médica)Em todo o mundo, 15 milhões de pessoas sofrem um acidente vascular cerebral (AVC) por ano. Destas, 66% sobrevivem e metade delas ficam com incapacidade permanente de equilíbrio, limitando a sua independência motora e qualidade de vida. Estes pacientes podem recuperar o seu equilíbrio e independência motora através do fenómeno da neuroplasticidade, alcançado com intervenções de reabilitação. Asferramentas de realidade virtual (RV) podem ser utilizadas como complemento àsterapias físicas convencionais, promovendo treinos de alta repetição com estratégias de aprendizagem otimizadas. Assim, os ambientes virtuais podem ser personalizados de acordo com as necessidades iminentes dos pacientes, maximizando a reorganização do cérebro e plasticidade, aumentando a eficácia e acelerando a recuperação do equilíbrio. Não obstante, existe uma falta de ferramentas de RV neste campo, as quais não apresentam uma visão centrada no utilizador. Esta dissertação tem como objetivo conceber, desenvolver e validar uma ferramenta totalmente imersiva baseada em RV, seguindo uma visão centrada no utilizador. A ferramenta de RV desenvolvida inclui quatro desafios virtuais baseados em atividades do dia-a-dia (ADDs), compreendendo um total de nove tarefas motoras. A ferramenta de RV fornece estímulos visuais, sonoros e hápticos, através de óculos de RV, auscultadores incorporados, e comandos vibratórios. Paralelamente, foi realizado um estudo sobre as ADDs mais realizadas e apreciadas, com recurso a um questionário, provando que os desafios virtuais concebidos estão de acordo com a preferência da maioria das pessoas. A partir de uma validação preliminar com sujeitos saudáveis, verificou-se que a ferramenta de RV melhorou significativamente o deslocamento do centro de massa (CDM) na direção mediolateral (ML) e a velocidade mínima do CDM na direção anteroposterior (AP), durante a marcha. Além disso, o deslocamento do CDM e a velocidade máxima e mínima do CDM, nas direções AP e ML, embora não significativas, exibiram melhorias noutras tarefas motoras. Os testes clínicos também revelaram uma melhoria após o treino RV. A avaliação da experiência do utilizador provou a elevada aceitabilidade, valor e utilidade da ferramenta de RV. O trabalho futuro envolve a melhoria da ferramenta com mais e personalizados desafios virtuais e a validação do sistema com doentes durante treinos mais longos.Worldwide, 15 million people suffer a stroke each year. Of these, 66 % survive and half of them are left with permanent balance disabilities, limiting their motor independence and compromising their quality of life. The patients can recover their balance function and regain their motor independence through neuroplasticity phenomenon, achieved by rehabilitation intervention. Virtual reality (VR) tools may be used as a complement to physical therapies to promote high-repetitive training with optimised learning strategies. Thus, virtual environments can be customised according to the patient’s imminent needs, maximising brain reorganisation, allowing to increase the effectiveness and accelerate balance recovery. Nonetheless, there is a lack of VR tools in this field, and no user-centered design is available. This dissertation aims to design, develop, and validate a fully immersive VR-based tool, following a user-centered design. The developed VR tool includes four virtual challenges based on activities of daily living (ADLs), comprising a total of nine motor tasks. The VR-based tool provides visual, sonorous, and haptic stimuli, through a Head-Mounted Display (HMD), built-in headphones, and vibrotactile controllers. In parallel, a study about the most performed and appreciated ADLs was carried out, using a questionnaire, proving that the developed virtual challenges are in accordance with most peoples’ preferences. From a preliminary validation with healthy subjects, the VR tool significantly improved the user’s center of mass (COM) displacement in the mediolateral (ML) direction, and the minimum COM velocity in the anteroposterior (AP) direction when walking. Moreover, COM displacement and the maximum and minimum COM velocity on both AP and ML directions, although not significantly, also showed improvements in many other tasks. Furthermore, clinical tests revealed improvements after VR training. The user experience evaluation proved the high acceptability, value, and usefulness of the VR-based tool. Future work towards enhancing the VR-based tool with more and customised virtual challenges and extending the VR tool validation with end-users throughout a longer training period

Beneficial effects of whole-body vibration exercise for brain disorders in experimental studies with animal models:A systematic review

Brain disorders have been a health challenge and is increasing over the years. Early diagnosis and interventions are considered essential strategies to treat patients at risk of brain disease. Physical exercise has shown to be beneficial for patients with brain diseases. A type of exercise intervention known as whole-body vibration (WBV) exercise gained increasing interest. During WBV, mechanical vibrations, produced by a vibrating platform are transmitted, to the body. The purpose of the current review was to summarize the effects of WBV exercise on brain function and behavior in experimental studies with animal models. Searches were performed in EMBASE, PubMed, Scopus and Web of Science including publications from 1960 to July 2021, using the keywords "whole body vibration" AND (animal or mice or mouse or rat or rodent). From 1284 hits, 20 papers were selected. Rats were the main animal model used (75%) followed by mice (20%) and porcine model (5%), 16 studies used males species and 4 females. The risk of bias, accessed with the SYRCLE Risk of Bias tool, indicated that none of the studies fulfilled all methodological criteria, resulting in possible bias. Despite heterogeneity, the results suggest beneficial effects of WBV exercise on brain functioning, mainly related to motor performance, coordination, behavioral control, neuronal plasticity and synapse function. In conclusion, the findings observed in animal studies justifies continued clinical research regarding the effectiveness and potential of WBV for the treatment of various types of brain disorders such as trauma, developmental disorders, neurogenetic diseases and other neurological diseases

Body sensor networks: smart monitoring solutions after reconstructive surgery

Advances in reconstructive surgery are providing treatment options in the face of major trauma and cancer. Body Sensor Networks (BSN) have the potential to offer smart solutions to a range of clinical challenges. The aim of this thesis was to review the current state of the art devices, then develop and apply bespoke technologies developed by the Hamlyn Centre BSN engineering team supported by the EPSRC ESPRIT programme to deliver post-operative monitoring options for patients undergoing reconstructive surgery. A wireless optical sensor was developed to provide a continuous monitoring solution for free tissue transplants (free flaps). By recording backscattered light from 2 different source wavelengths, we were able to estimate the oxygenation of the superficial microvasculature. In a custom-made upper limb pressure cuff model, forearm deoxygenation measured by our sensor and gold standard equipment showed strong correlations, with incremental reductions in response to increased cuff inflation durations. Such a device might allow early detection of flap failure, optimising the likelihood of flap salvage. An ear-worn activity recognition sensor was utilised to provide a platform capable of facilitating objective assessment of functional mobility. This work evolved from an initial feasibility study in a knee replacement cohort, to a larger clinical trial designed to establish a novel mobility score in patients recovering from open tibial fractures (OTF). The Hamlyn Mobility Score (HMS) assesses mobility over 3 activities of daily living: walking, stair climbing, and standing from a chair. Sensor-derived parameters including variation in both temporal and force aspects of gait were validated to measure differences in performance in line with fracture severity, which also matched questionnaire-based assessments. Monitoring the OTF cohort over 12 months with the HMS allowed functional recovery to be profiled in great detail. Further, a novel finding of continued improvements in walking quality after a plateau in walking quantity was demonstrated objectively. The methods described in this thesis provide an opportunity to revamp the recovery paradigm through continuous, objective patient monitoring along with self-directed, personalised rehabilitation strategies, which has the potential to improve both the quality and cost-effectiveness of reconstructive surgery services.Open Acces

System Identification of Bipedal Locomotion in Robots and Humans

The ability to perform a healthy walking gait can be altered in numerous cases due to gait disorder related pathologies. The latter could lead to partial or complete mobility loss, which affects the patients’ quality of life. Wearable exoskeletons and active prosthetics have been considered as a key component to remedy this mobility loss. The control of such devices knows numerous challenges that are yet to be addressed. As opposed to fixed trajectories control, real-time adaptive reference generation control is likely to provide the wearer with more intent control over the powered device. We propose a novel gait pattern generator for the control of such devices, taking advantage of the inter-joint coordination in the human gait. Our proposed method puts the user in the control loop as it maps the motion of healthy limbs to that of the affected one. To design such control strategy, it is critical to understand the dynamics behind bipedal walking. We begin by studying the simple compass gait walker. We examine the well-known Virtual Constraints method of controlling bipedal robots in the image of the compass gait. In addition, we provide both the mechanical and control design of an affordable research platform for bipedal dynamic walking. We then extend the concept of virtual constraints to human locomotion, where we investigate the accuracy of predicting lower limb joints angular position and velocity from the motion of the other limbs. Data from nine healthy subjects performing specific locomotion tasks were collected and are made available online. A successful prediction of the hip, knee, and ankle joints was achieved in different scenarios. It was also found that the motion of the cane alone has sufficient information to help predict good trajectories for the lower limb in stairs ascent. Better estimates were obtained using additional information from arm joints. We also explored the prediction of knee and ankle trajectories from the motion of the hip joints

Fitness standards for the Maritime and Coastguard Agency and the Oil and Gas Industry

The studies presented in this thesis were conducted to develop two minimum fitness standards, one for the Maritime and Coastguard Agency and the second for the Oil and Gas Industry. This provided the opportunity to compare across the essential tasks and resultant standards. The following stages were used for both the Maritime and Coastguard Agency and Oil and Gas Industry: a. Review the tasks requiring a significant physical fitness component (Task Analysis); b. Determine the importance of the physically demanding tasks and identify those which are critical for success and safe work (Task Assessment); c. Establish the method of best practice (Technique) for undertaking the essential tasks; d. Establish and agree the minimum performance standard for the essential tasks (Task Performance) when performed using the method of best practice; e. Assess the physical and physiological demands of these tasks (Task Quantification); f. Design and validate a simple-to-administer minimum fitness standard. The essential tasks and fitness requirements of the Maritime and Coastguard Agency fell into three groups, these were: Group 1 (All Operations): achieve a maximum aerobic score of at least 31 mL.kg-¹.min-¹ based on the aerobic demand of 21.8 mL.kg-¹.min-¹ required to carry a stretcher at the head-end 200 m at a speed of 3.2 km.h-¹; continuously lift a 3 kg sledge hammer 10 times above shoulder height, based on hammering a stake into the ground; pull a rope, with a resistance of 35 kg, and maintain this load for 15 s based on manning a main rescue-line; carry a 19 kg hand-held load 200 m in 3 min 45 s allow 3 min 45 s rest, then carry a 25.5 kg hand held load, 200 m in 3 min 45 s, based on the ability to carry a stretcher (89 kg) as part of a four person team. Group 2 (Rope Technicians) should complete all the tasks as Group 1, plus pass all the technical competencies currently in place for Rope Technicians. Group 3 (Mud Technicians) as Group 1, plus achieve a predicted maximum aerobic score of at least 39 mL.kg- ¹.min-¹ based on the aerobic demand of 27.4 mL.kg-¹.min-¹ required to pull a stretcher across the mud at 0.8 km.h-¹, (this equates to covering 200 m in 15 minutes), prior to performing a simulated mud rescue. The essential tasks and the minimum fitness requirements of the Oil and Gas Industry were: Stair and Ladder-Climbing, achieve a predicted maximum aerobic score of at least 31 mL.kg-¹.min-¹ based on the aerobic demand of 23.4 mL.kg- ¹.min-¹ required to climb a flight of stairs at a rate of 80 steps.min-¹ and 23.6 mL.kg- ¹.min-¹ to climb a ladder at 24 rungs.min-¹; Manual Handling, based on the requirement to climb a flight of stairs at a rate of 80 steps.min-¹ for a minute carrying a load of 10 kg, 20 kg or 25 kg; Valve Turning, based on the requirement to continuously turn a medium size valve (25.4 cm diameter) set at a torque of 8.3 N.m, for 5 min; Emergency Response Team, achieve a predicted maximum aerobic score of at least 41 mL.kg-¹.min ¹, based on the aerobic demand of 30.7 mL.kg-¹.min-¹ required to pull a trailer/foam monitor at a speed of 5 km.h-¹. If trailer/foam monitors are not used achieve a predicted maximum aerobic score of at least 39 mL.kg-¹.min-¹ based on the aerobic demand of 28.9 mL.kg-¹.min-¹ required to climb a ladder at 34.5 rungs.min-¹. Stretcher carry 89 kg either in a two or four person lift (dependant on the facility), rope haul the heaviest anticipated load (10 kg first aid kit) up 10 m gantry, roll out a 23 m fire hose. There were no time constraints recommended for hauling kit and rolling out a hose. For those essential tasks that could not be assessed by a direct task measurement or a direct task simulation, a Predictive selection test was recommended and validated. Prediction intervals were used to take into account the inherent error between the predictive tests and the direct measurements, to determine “Pass”, “Borderline” and “Fail” categories. As a result of this work a modular approach was adopted in which individuals only undertake those test applicable to their job, with a combination of direct task measurements, direct task simulations, and Predictive selection tests recommended. It is suggested that, where possible, the use of a direct task measurement or simulation should either be progressive e.g. stretcher-carrying, or performed after a Predictive selection test, in order to reduce the risk of injury when the individuals proceed to undertake the direct task measurement or simulation e.g. manual handling. This approach has meant that consideration is given to the health and safety of the individuals undertaking the fitness standard whilst maintaining a high level of face validity.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Yale-New Haven Magazine, Fall 1998

https://elischolar.library.yale.edu/ynhh_magazine/1069/thumbnail.jp

Evaluation of a novel approach to promoting post-ischemic recovery of upper extremity function in the rat

Following stroke, impairments in arm function are common motor deficits in survivors, affecting thousands of people each year. A useful technique used in clinical rehabilitation of patients with arm impairments is to force use of the impaired arm through constraint of the unaffected (or less affected) one. The success of this ‗constraint induced movement therapy‘ (CIMT) is believed to be due to neuroplastic changes that take place on a cellular level in surviving brain tissue, however, little is understood about the mechanisms involved. Appropriate animal models are necessary to study how rehabilitation affects neuroplasticity. Previous literature has described several models of forced use following stroke in rats which have resulted in varying success. Animal stress and lack of behavioural pressure may have contributed to the inconsistency of prior forced use models. The purpose of the research presented in this thesis was to optimize a surgical model of post-ischemic upper extremity impairment, determine whether it would be possible to force use of the impaired forelimb using a novel appetitively motivated protocol, and then to investigate the effects of this novel model on markers of neuroplasticity. First, the endothelin-1 (ET-1) model of focal unilateral ischemia was optimized by attempting a previously unpublished protocol of injections along the motor cortex and to the striatum. Male Sprague Dawley rats were subjected to ET-1 or sham surgery. Ensuing forelimb functional deficits were measured using a battery of behavioural tests, which were compared to intact sham surgical control performance. The stroke model resulted in reliable and reproducible lesions to forelimb motor regions of the brain, and deficits that lasted up to the end of the 21 day study period in some tests. Next, this ET-1 stroke surgery was used to evaluate a novel form of forced use rehabilitation in which rats engaged the impaired limb to move voluntarily in commercial pet activity balls. Animals were subjected to ET-1 or sham surgery, and then received either rehabilitation or a control treatment. Behavioural tests revealed that animals receiving rehabilitation recovered to sham levels of performance sooner than animals receiving the control treatment. Stroke, but not rehabilitation, affected the proportion of cells expressing brain derived neurotrophic factor (BDNF) and the presence of doublecortin-positive neuroblasts, but had no effect on the expression of the growth inhibiting protein NOGOA. Finally, the novel forced use model was developed further to more closely resemble clinical CIMT with the addition of a task-specific reaching component. Animals were subjected to either ET-1 followed by rehabilitation, ET-1 followed by a control treatment, or sham surgery. Again, behavioural tests revealed that animals that had undergone ET-1 surgery had significant deficits that recovered sooner in the group that received rehabilitation. Rehabilitation did not affect the proportion of BDNF-expressing cells, but did appear to cause a shift in the cellular origin of the BDNF that was present. Further, rehabilitation resulted in more doublecortin-positive cells in the damaged hemisphere. This novel approach to rehabilitation represents a useful model of forced use therapy which results in accelerated functional recovery following ischemic injury. The mechanisms underlying this effect may be related to changes in BDNF expression and increased generation or survival of new born cells

Neuroprosthetic rehabilitation and translational mechanism after severe spinal cord injury

Traumatic SCIs have long-term health, economic and social consequences, stressing the urgency to develop interventions to improve recovery after such injuries. Today, the only proven effective interventions to enhance recovery after SCI are activity-based rehabilitation therapies, such as locomotor training. However, locomotor training shows no or very limited efficacy to improve function after a severe SCI that induces paralysis of the limbs. To mimic the outcome of severe but incomplete SCI in rodents, we developed a model of double opposite-side lateral hemisections termed staggered hemisection in adult rats. This model induced permanent paralysis below the level of injury but leaves an intervening gap of intact neural tissue that provides a substrate for recovery. We showed that this SCI leads to degradation of motor functions, which correlates with the formation of aberrant neuronal connections below the lesion. Robotic devices with a rehabilitative purpose should act as propulsive or postural neuroprosthesis allowing training under natural conditions. Our versatile robotic interface provides multidirectional bodyweight support during overground locomotion in rats. We next evaluated the effects of robot-assisted gait training enabled by electrochemical stimulation of spinal circuits to restore locomotion after staggered hemisection SCI. We found that after two months of daily training, paralyzed rats recovered the ability to initiate, sustain and adjust bipedal locomotion while supported in the robot under electrochemical stimulation. This recovery correlated with ubiquitous reorganization of corticospinal, brainstem, and intraspinal fibers. We next evaluated whether this treatment was capable of restoring supraspinal control of locomotion after a clinically relevant SCI. Rats received a severe contusion of the spinal cord that spared less than 10% of intact tissue. Robot-assisted rehabilitation restored weight-bearing locomotion in all the trained rats when stimulated electrochemicallay and in a subset of rats in the absence of any enabling factors which paralelled with the reorganization of axonal projections of reticulospinal fibers below the contusion. Virus-mediated silencing of reticulospinal neurons projecting to lumbar segments demonstrated that these inputs were necessary to initiate and sustain walking after training. When delaying the onset of training by two months, in the chronic stage, all the rats regained voluntary locomotor movements but the extent of the recovery was reduced compared to rats trained early after SCI. The results provide a strong rationale to evaluate the impact of neuroprosthetic training to improve motor functions in human patients with incomplete SCI. Translation of treatment paradigms developed in rodent models into effective clinical applications remains a major challenge in biomedical research. Here, we studied recovery of motor functions in more than 400 quadriplegic patients who presented various degree of spinal cord damage laterality. We found that recovery increases with the asymmetry of early motor deficits. We conclude that emergence of spinal cord decussating corticospinal fibers and bilateral motor cortex projections during mammalian evolution supports greater recovery after lateralized SCI primates compared to rodents. Novel experimental models and dedicated therapeutic strategies are necessary to take advantage of this powerful neuronal substrate for recovery after SCI

Make Someone\u27s Life Better

2012 annual report of Governors State University College of Health and Human Services.https://opus.govst.edu/chhs_annual_reports/1006/thumbnail.jp