300 research outputs found

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

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    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

    The development of a component to improve the loading safety of bone-anchored prostheses

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    Use of socket prostheses Currently, for individuals with limb loss, the conventional method of attaching a prosthetic limb relies on a socket that fits over the residual limb. However, there are a number of issues concerning the use of a socket (e.g., blisters, irritation, and discomfort) that result in dissatisfaction with socket prostheses, and these lead ultimately a significant decrease in quality of life. Bone-anchored prosthesis Alternatively, the concept of attaching artificial limbs directly to the skeletal system has been developed (bone anchored prostheses), as it alleviates many of the issues surrounding the conventional socket interface.Bone anchored prostheses rely on two critical components: the implant, and the percutaneous abutment or adapter, which forms the connection for the external prosthetic system (Figure 1). To date, an implant that screws into the long bone of the residual limb has been the most common intervention. However, more recently, press-fit implants have been introduced and their use is increasing. Several other devices are currently at various stages of development, particularly in Europe and the United States. Benefits of bone-anchored prostheses Several key studies have demonstrated that bone-anchored prostheses have major clinical benefits when compared to socket prostheses (e.g., quality of life, prosthetic use, body image, hip range of motion, sitting comfort, ease of donning and doffing, osseoperception (proprioception), walking ability) and acceptable safety, in terms of implant stability and infection. Additionally, this method of attachment allows amputees to participate in a wide range of daily activities for a substantially longer duration. Overall, the system has demonstrated a significant enhancement to quality of life. Challenges of direct skeletal attachment However, due to the direct skeletal attachment, serious injury and damage can occur through excessive loading events such as during a fall (e.g., component damage, peri-prosthetic fracture, hip dislocation, and femoral head fracture). These incidents are costly (e.g., replacement of components) and could require further surgical interventions. Currently, these risks are limiting the acceptance of bone-anchored technology and the substantial improvement to quality of life that this treatment offers. An in-depth investigation into these risks highlighted a clear need to re-design and improve the componentry in the system (Figure 2), to improve the overall safety during excessive loading events. Aim and purposes The ultimate aim of this doctoral research is to improve the loading safety of bone-anchored prostheses, to reduce the incidence of injury and damage through the design of load restricting components, enabling individuals fitted with the system to partake in everyday activities, with increased security and self-assurance. The safety component will be designed to release or ‘fail’ external to the limb, in a way that protects the internal bone-implant interface, thus removing the need for restorative surgery and potential damage to the bone. This requires detailed knowledge of the loads typically experienced by the limb and an understanding of potential overload situations that might occur. Hence, a comprehensive review of the loading literature surrounding bone anchored prostheses will be conducted as part of this project, with the potential for additional experimental studies of the loads during normal activities to fill in gaps in the literature. This information will be pivotal in determining the specifications for the properties of the safety component, and the bone-implant system. The project will follow the Stanford Biodesign process for the development of the safety component

    Enhancing Biomechanical Function through Development and Testing of Assistive Devices for Shoulder Impairment and Total Limb Amputation

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    Assistive devices serve as a potential for restoring sensorimotor function to impaired individuals. My research focuses on two assistive devices: a passive shoulder exoskeleton and a muscle-driven endoprosthesis (MDE). Previous passive shoulder exoskeletons have focused on testing during static loading conditions in the shoulder. However, activities of daily living are based on dynamic tasks. My research for passive shoulder exoskeletons analyzes the effect that a continuous passive assistance has on shoulder biomechanics. In my research I showed that passive assistance decreases the muscular activation in muscles responsible for positive shoulder exoskeleton. An MDE has the potential to have accurate and precise control of movement as well as restore a sense of proprioception to the user. Such a transformative and invasive device has never previously been tested. Therefore, my research focused on analyzing fundamental principles of the MDE in an in-vivo rabbit model. The two concepts I tested in my research were the feasibility of implanting an orthopedic device underneath the skin at the distal end of a limb following amputation and the locomotor restorative capabilities of an artificial tendon used for muscle-device connection. In my work I proved the feasibility of implanting fully-footed rigid endoprostheses underneath the skin and isolated the primary factors for a successful surgery and recovery. In addition, my research showed that although artificial tendons have the potential to restore locomotor function, proper in-situ tendon lengths must be achieved for optimal movement. This research informed the design and testing of a fully jointed muscle-driven endoprosthesis prototype

    Ganganalyse bei Patienten mit Oberschenkelamputation

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    This examination analyzes kinematic variability in gait of transfemoral amputees compared to healthy controls and the association between kinematic variability and daily activity. Gait variability was greater during walking in transfemoral amputees compared to healthy controls. Additionally there is a correlation between daily activity and gait variability. Kinematic variability could be a potential marker for quality of gait with diagnostic implications.Diese Arbeit untersucht die Variabilität der Kinematik im Gangbild bei Patienten mit Oberschenkelamputation im Vergleich zu Gesunden sowie den Zusammenhang von kinematischer Variabilität zur Alltagsaktivität. Die Gangvariabilität war bei Patienten im Vergleich zu Gesunden erhöht. Zudem zeigte sich eine Korrelation zwischen Alltagsaktivität und Gangvariabilität. Variabilität der Kinematik kann als Marker für Gangqualität zur Verbesserung der Diagnostik beitragen

    Function and Body Image Levels in Individuals with Transfemoral Amputations Using the C-Leg®

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    Purpose: It was purposed that individuals using the Otto Bock C-Leg®, a microprocessor controlled prosthetic knee joint, may experience an enhanced level of functional independence. Secondly, it was hypothesized that with increased functional abilities and independence from using the C-Leg® comes a positive body image. Methods: Following IRB approval, a purposive sampling method was used to recruit 8 adult volunteers from a regional rehabilitation hospital. Inclusion criteria for participants in this study included individuals who had a transfemoral amputation, were currently using the C-Leg®, were over the age of 18 years, and without cognitive limitations. Subjects were asked to complete a series of three surveys: the Reintegration to Normal Living Index (RNL), the Situational Inventory of Body-Image Dysphoria (SIBID), and the C-Leg® Function & Body Image Survey (CFBIS). Survey questions pertained to personal satisfaction with the C-Leg®, functional independence, role performance, and body image. Results: Response categories of functional role performance and body satisfaction were correlated to test the hypotheses. A Spearman’s rho of -.434 was calculated, showing a fair but not statistically significant relationship. Significant relationships were found between functional role performance and social integration (rs= .743), self-efficacy (rs=.863), personal relationships/sexuality (rs=.711), and psychological distress (rs=-.772). This relationship was supported by responses from the CFBIS indicating that the C-Leg® expands a client’s level of function, self-esteem, and motivation. Conclusions: There was a fair correlation between functional role performance and body satisfaction in individuals using the Otto Bock C-Leg®. Individuals using the C-Leg® were found to exhibit patterns of improvement regarding improved lifestyle, activity performance, motivation, and self-confidence. The most common improvements in activity performance were found with walking, walking up and down stairs, participating in sports (i.e. basketball, hiking, and skating), work/employment activities, and decreased fatigue due to low requirement of energy expenditure. Body image was found to be improved due to the fact that individuals were able to walk with a more natural gait, and also felt more secure in public places because of the stability the C-Leg® offers

    Rehabilitation of lower limb amputees

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    Rehabilitation of amputees represents a complex process during the course of which an amputee receives professional aid and support, so as to adapt to the use of prosthesis, i.e. an artificial supplement for the lost body part. The process aims at achieving an independent performance of the amputee in all areas of everyday life and as high quality of life as possible. The rehabilitation encompasses not only the pre-amputation, postoperative, pre-prosthetic and prosthetic stage, within which an amputee is provided with a prosthetic aiding device, but also the subsequent long-term monitoring and follow-up. The implementation of the rehabilitation process runs in line with the biopsychosocial model and requires a multidisciplinary and an interdisciplinary approach, so as to achieve a successful reintegration of an amputee and allow for a lifestyle resembling the pre-amputation one as much as possible. The article brings the causes and types of amputation, the principles underpinning contemporary amputation surgery, prosthetics and rehabilitation during preoperative, postoperative, pre-prosthetic and prosthetic stages, as well as the stage goals and MOs of their attainment. Principles of evaluation of prosthetic rehabilitation outcomes in limb amputees, which make use of appraisal questionnaires, have been discussed as well

    Motor illusions: What do they reveal about proprioception?

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    Motor illusions: What do they reveal about proprioception?

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    Hard-wired epimysial recordings from normal and reinnervated muscle using a bone-anchored device

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    Background: A combined approach for prosthetic attachment and control using a transcutaneous bone-anchored device and implanted muscle electrodes can improve function for upper-limb amputees. The bone-anchor provides a transcutaneous feed-through for muscle signal recording. This approach can be combined with targeted muscle reinnervation (TMR) to further improve myoelectric control. Methods: A bone-anchored device was implanted trans-tibially in n = 8 sheep with a bipolar recording electrode secured epimysially to the peroneus tertius muscle. TMR was carried out in a single animal: the peroneus tertius was deinnervated and the distal portion of the transected nerve to the peroneus muscle was coapted to a transected nerve branch previously supplying the tibialis anterior muscle. For 12 weeks (TMR) or 19 weeks (standard procedure), epimysial muscle signals were recorded while animals walked at 2 km·h−1. Results: After 19 weeks implantation following standard procedure, epimysial recording signal-to-noise ratio (SNR) was 18.7 dB (± 6.4 dB, 95% CI) with typical recordings falling in the range 10–25 dB. Recoveries in gait and muscle signals were coincident 6 weeks post-TMR; initial muscle activity was identifiable 3 weeks post-TMR though with low signal amplitude and signal-to-noise ratio compared with normal muscle recordings. Conclusions: Following recovery, muscle signals were recorded reliably over 19 weeks following implantation. In this study, targeted reinnervation was successful in parallel with bone-anchor implantation, with recovery identified 6 weeks after surger
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