ReLiPh: rehabilitation for lower limb with phantom pain

O membro fantasma ou sensação fantasma, ao longo dos anos, têm se destacado por ser originada de diferentes causas. Pesquisas e estudos mostram que, após uma amputação, na maioria dos casos, experienciam a sensação de membro fantasma e em muitos desses casos dolorosos. A presente tese baseia-se em uma pequena parte deste amplo tópico. Baseada na terapia de espelho usada na reabilitação e tratamento da dor fantasma. Ao longo do projeto, nós estudamos quais são os componentes mais relevantes para a reorganização/reestruturação, a fim de eliminar os sintomas negativos e futuros distúrbios/perturbações. Associada na relação do cérebro com o corpo, ou seja, as imagens formadas pelo cérebro em relação ao corpo físico desempenhando um papel crucial na relação do membro fantasma e da dor no membro fantasma, bem como no processo de cura e tratamento através de exercícios e no relacionamento da imagem que o cérebro tem do corpo físico. Esta dissertação tem como objetivo na construção de uma nova abordagem tecnológica, baseando-se nos princípios e critérios utilizados na terapia de espelho. A metodologia assenta na criação de um ambiente de realidade virtual controlado por um dispositivo que captura a atividade muscular em tempo real. Implementado num jogo baseado em movimentos/exercícios simples e naturais, sem uso de força ou esforço. Os elevados resultados verificados e testados, em indivíduos saudáveis e em um estudo de caso, na redução da dor fantasma, gerando um interesse e motivação, além de um melhor senso de presença e foco durante o seu uso. Concluindo, o projeto abre novas direções futuras de como novas abordagens tecnológicas podem ser usados nas pesquisas médicas na área do membro e na dor fantasma, em ambientes controlados e contextualizados. Melhorando a eficácia e eficiência, garantindo uma maior flexibilidade nos diferentes casos de amputação.The phantom limb or phantom sensation, over the years, has stood out being originated from different causes. Research and studies show that after an amputation, in most cases, they experience the sensation of a phantom limb and in many of those painful feelings. This thesis is based on a small part of this wide topic. Based on the mirror therapy used in rehabilitation and treatment for phantom pain. Throughout the project, we study what are the most relevant components to reorganization/restructuring in order to eliminate negative symptoms and future disturbances. Moreover it is established in the relationship of the brain with the body, that the images formed by the brain in relation to the physical body play a crucial role in the relationship with the phantom limb and phantom limb pain, as well as in the process of healing and treatment throughout exercises and the relationship of the image that the brain has to the physical body. This dissertation aims to build a new technological approach, based on the principles and criteria used in mirror therapy. The methodology is based on the creation of a virtual reality environment controlled by a device which captures the muscle activity in real time. Implemented in a game based on natural and simple effortless exercises without the use of strength. The high results verified and tested, in healthy subjects and in a case study, to reduce phantom pain, generating an interest and motivation, as well as a better sense of presence and focus during its use. In conclusion, the project opens up new future directions of how new technological approaches can be used in medical research in the field of phantom limbs and in phantom pain, in a controlled and contextualized environments and/or movements. Improving effectiveness and efficiency ensuring greater flexibility in different cases of amputation

Phantom Limb Pain: Implications for Treatment When the Mechanisms Are Unknown

During the Civil War, American physician Silas Weir Mitchell was the first to coin the “phantom” to the sensations individuals experienced in their nonintact limb following limb amputation. Even though physicians have been aware of phantom sensations, and similarly phantom limb pain, for over a century, the mechanism for the pain is not well understood. Because the mechanisms are not well understood, my thesis provides a bioethical framework for clinicians in order to treat phantom limb pain. The thesis begins with an introduction to the history of phantom limb pain and the current theories available to explain the phenomenon. It then looks at the treatments available for phantom limb pain and focuses specifically on mirror therapy. Mirror therapy is a noninvasive, physical therapy practice available for phantom limb pain. Through the framework provided, my thesis argues that mirror therapy should be the first treatment presented to patients experiencing phantom limb pain. It concludes with my own theory of why phantom limb could exist, and further directions of where research and treatment should be focused on phantom limb pain

HoloPHAM: An Augmented Reality Training System For Upper Limb Myoelectric Prosthesis Users

From hook-shaped prosthetic devices to myoelectric prostheses with increased functional capabilities such as the Modular Prosthetic Limb (MPL), upper limb prostheses have come a long way. However, user acceptance rate does not show a similar increasing trend. Functional use training is incorporated into occupational therapy for myoelectric prosthesis users to bridge this gap. Advancements in technology for virtual and augmented reality enable the application of immersive virtual environments in prosthesis user training. Such training systems have been shown to result in higher user performance and participation in training exercises. The work presented here introduces the application of augmented reality (AR) in myoelectric prosthesis user training. This was done through the development of HoloPHAM, an AR training tool designed to mimic a real-world training protocol called Prosthetic Hand Assessment Measure (PHAM). This AR system was built for use with the Microsoft HoloLens, thus requiring a motion tracking system that could enable the user to move around freely in a room. The Bluetooth Orientation Tracking System (BOTS) was developed as an inertial measurement unit (IMU)-based wireless motion tracking system for this purpose. Performance of BOTS as a motion tracker was evaluated by comparison with the Microsoft Kinect sensor. Results showed that BOTS out-performed the Kinect sensor as a motion tracking system for our intended application in HoloPHAM. BOTS and the Myo armband were combined to form a human-machine interface (HMI) to control the virtual arm of HoloPHAM, enabling virtual object manipulation. This HMI along with the virtual PHAM set-up makes HoloPHAM a portable AR training environment that can be applied for prosthesis user training or evaluation of new myoelectric control strategies

Manipulation of visual biofeedback during gait with a time delayed adaptive Virtual Mirror Box.

A mirror placed in the mid-sagittal plane of the body has been used to reduce phantom limb pain and improve movement function in medical conditions characterised by asymmetrical movement control. The mirrored illusion of unimpaired limb movement during gait might enhance the effect, but a physical mirror is only capable of showing parallel movement of limbs in real time typically while sitting. We aimed to overcome the limitations of physical mirrors by developing and evaluating a Virtual Mirror Box which delays the mirrored image of limbs during gait to ensure temporal congruency with the impaired physical limb

On the use of Phantom Motor Execution for the treatment of Phantom Limb Pain

Phantom limb pain (PLP) is a common complaint among amputees and despite having been studiedfor centuries, it remains a mysterious object of debate among researcher. To date, a vast number ofways to treat PLP has been proposed in the literature, however none of them has proven to beuniversally effective, thus creating uncertainty on how to operate clinically. The uncertainty is largelyattributable to the scarcity of well conducted randomized controlled trials (RCTs) to prove the efficacyof PLP treatments.Phantom Motor Execution (PME) -exertion of voluntary phantom limb movements – aims at restoringthe control over the phantom limb and the exercise of such control has been hypothesized to reverseneural changes implicated in PLP. Preliminary evidence supporting this hypothesis has been providedby clinical investigations on upper limb amputees. The main purpose of this Licentiate thesis was toenable a RCT on the use of PME for the treatment of PLP in order to provide robust and unbiasedevidence for clinical practice. However, the implementation and kick-off of this clinical investigationrequired to complete few preparatory steps. For example, most amputees and PLP patients have lowerlimb amputation, thus PME needed to be adapted and validated for this population. Further, the RCTprotocol needed to be carefully planned and made openly accessible, as per guidelines for conductingand publishing clinical RCT. Finally, a secondary aim of this thesis emerged with the need of providinglong term relief from PLP to patient. Preliminary evidence seemed to indicate that in order to maintainpain relief, periodic rehearsal of the phantom motor skills acquired through PME is necessary. Thisraised the question of whether it is beneficial and possible to translate the technology from clinic tohome use, question that was explored employing both quantitative and qualitative methods fromengineering, medical anthropology, and user interface design.The work conducted within this thesis resulted in the extension of PME to lower limb patients byproposal and validation of a new and more user-friendly recording configuration to record EMG signals.The use of PME was then shown to be efficacious in relieving PLP with a case study on a patient. Theprotocol for the RCT was then designed and published. These two first steps permitted theestablishment of the RCT, which is currently ongoing and expected to close in March 2021. With regardto the secondary aim of this thesis, the work conducted enabled PME to be used by the patients in thecomfort of their home, while it also allowed investigate the benefits and challenges generally faced(not only by PME) in the transition from the clinic to home and its effects on treatment adherence. Thework conducted is presented in the three appended publications.Future work includes the presentation of the results of the RCT. Further, having a way to modulate PLPis an incredibly useful tool to study the neural basis of PLP. By capitalizing on this tool, we are currentlyconducting brain imaging studies using fMRI and electroencephalography that are the main focus ofthe work that lies ahead

Cortical representation of illusory body perception in healthy persons and amputees: implications for the understanding and treatment of phantom limb pain

A disturbed body perception is characteristic for various neurological and mental disorders and becomes particularly evident in phantom phenomena after limb amputation. Body illusions, such as mirror visual feedback (MVF) illusions, have been shown to be efficient in treating chronic pain and to be further related to a reversal of cortical reorganization. The present thesis aimed at identifying the neural circuitry of illusory body perception in healthy subjects and unilateral upper-limb amputees using functional magnetic resonance imaging. Study 1 investigated the perceived mirror illusion capacity and the neural correlates of a novel MVF-device (the mirror glasses) in comparison to the well-established mirror box in healthy persons. Study 2 investigated the neural circuitry of stimulus-evoked non-painful phantom phenomena in unilateral upper-limb amputees. During mirror illusions, movements of the affected limb are visually recreated by movements of the contralateral limb. The visual recreation of the affected limb seems to be linked to a recruitment of the primary sensorimotor representation of the affected limb. In contrast to the mirror box, the mirror glasses limit the user’s view to the visual reflection of the moving hand as opposed to seeing both hands moving in synchrony. It has been proposed that seeing the actually moving limb in addition to the mirror reflection might have a distracting effect. Study 1 evaluated the utility of mirror glasses based on a comparison to the mirror box and tested the hypothesis that increased interhemispheric communication between motor hand representations might drive the activation in the non-mirrored limb representation. Mirror illusion capacity and brain circuitry were measured in a within-subject design during both MVF-conditions with 20 healthy subjects in counterbalanced order. The self-reported mirror illusion capacity and brain activation patterns did not significantly differ between both mirror tasks. The representation of the non-mirrored hand was recruited in both mirror tasks. A significant increase in interhemispheric connectivity between the hand areas, however, was only found in the mirror glasses condition, suggesting divergent mechanisms for the recruitment of the non-mirrored hand representation between both mirror tasks. Most amputees still perceive their amputated limb (phantom limb awareness). Phantom phenomena comprise a variety of non-painful and painful sensations allocated to the amputated limb. Some amputees experience non-painful phantom phenomena when the residual limb or other parts of the body are stimulated (evoked phantom sensations). The neural correlates of non-painful phantom phenomena remain unknown. Study 2 aimed to identify the neural circuitry of evoked nonpainful phantom sensations. Twelve upper-limb amputees who reliably perceived non-painful phantom sensations upon stimulation of distal body parts and 12 yoked controls (matched for sex and age) were investigated. Amputees were stimulated at a body site eliciting phantom sensation with a stimulus related on- and offset and a control site without illusory perception. Controls were stimulated at matched body sites. A conjunction analysis showed specificity of the left ventral premotor and inferior frontal cortices (BA44/45) for the perception of referred sensations. Generalized psychophysiological interaction analyses revealed a widespread network showing significant positive intra-parietal and fronto-parietal connectivity. Our study indicates a high convergence between the neural correlates of nonpainful phantom sensations and (other) body illusions. Both studies of the present thesis offer new insights into the understanding the neuronal basis of illusory body perception. Such illusory body perceptions are frequent in chronic pain and targeting these distortions of body perception has been shown to be fruitful for relieving pain and disability

Doctor of Philosophy

dissertationHands are so central to the human experience, yet we often take for granted the capacity to maneuver objects, to form a gesture, or to caress a loved-one’s hand. The effects of hand amputation can be severe, including functional disabilities, chronic phantom pain, and a profound sense of loss which can lead to depression and anxiety. In previous studies, peripheral-nerve interfaces, such as the Utah Slanted Electrode Array (USEA), have shown potential for restoring a sense of touch and prosthesis movement control. This dissertation represents a substantial step forward in the use of the USEAs for clinical careâ€"ultimately providing human amputees with widespread hand sensation that is functionally useful and psychologically meaningful. In completion of this ultimate objective, we report on three major advances. First, we performed the first dual-USEA implantations in human amputees; placing one USEA in the residual median nerve and another USEA in the residual ulnar nerve. Chapter 2 of this dissertation shows that USEAs provided full-hand sensory coverage, and that movement of the implant site to the upper arm in the second subject, proximal to nerve branch-points to extrinsic hand muscles, enabled activation of both proprioceptive sensory percepts and cutaneous percepts. Second, in Chapter 3, we report on successful use of USEA-evoked sensory percepts for functional discrimination tasks. We provide a comprehensive report of functional discrimination among USEA-evoked sensory percepts from three human subjects, including discrimination among multiple proprioceptive or cutaneous sensory percepts with different hand locations, sensory qualities, and/or intensities. Finally, in Chapter 4, we report on the psychological value of multiple degree of freedom prosthesis control, multisensor prosthesis sensation, and closed-loop control. This chapter represents the first report of prosthesis embodiment during closed-loop and open-loop prosthesis control by an amputee, as well as the most sophisticated closed-loop prosthesis control reported in literature to-date, including 5-degree-of-freedom motor control and sensory feedback from 4 hand locations. Ultimately, we expect that USEA-evoked hand sensations may be used as part of a take-home prosthesis system which will provide users with both advanced functional capabilities and a meaningful sense of embodiment and limb restoration

Bodily resonance: Exploring the effects of virtual embodiment on pain modulation and the fostering of empathy toward pain sufferers

Globally, around 20% of people suffer from chronic pain, an illness that cannot be cured and has been linked to numerous physical and mental conditions. According to the BioPsychoSocial model of pain, chronic pain presents patients with biological, psychological, and social challenges and difficulties. Immersive virtual reality (VR) has shown great promise in helping people manage acute and chronic pain, and facilitating empathy of vulnerable populations. Therefore, the first research trajectory of this dissertation targets chronic pain patients’ biological and psychological sufferings to provide VR analgesia, and the second research trajectory targets healthy people to build empathy and reduce patients’ social stigma. Researchers have taken the attention distraction approach to study how acute pain patients can manage their condition in VR, while the virtual embodiment approach has mostly been studied with healthy people exposed to pain stimulus. My first research trajectory aimed to understand how embodied characteristics affect users’ sense of embodiment and pain. Three studies have been carried out with healthy people under heat pain, complex regional pain syndrome patients, and phantom limb pain patients. My findings indicate that for all three studies, when users see a healthy or intact virtual body or body parts, they experience significant reductions in their self-reported pain ratings. Additionally, I found that the appearance of a virtual body has a significant impact on pain, whereas the virtual body’s motions do not. Despite the prevalence of chronic pain, public awareness of it is remarkably low, and pain patients commonly experience social stigma. Thus, having an embodied perspective of chronic pain patients is critical to understand their social stigma. Although there is a growing interest in using embodied VR to foster empathy towards gender or racial bias, few studies have focused on people with chronic pain. My second trajectory explored how researchers can foster empathy towards pain patients in embodied VR. To conclude, this dissertation uncovers the role of VR embodiment and dissects embodied characteristics in pain modulation and empathy generation. Finally, I summarized a novel conceptual design framework for embodied VR applications with design recommendations and future research directions