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Control interfaces to actively support the arm function of men with Duchenne Muscular Dystrophy

Authors:
  • ABLE Human Motion

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Adults with DMD can benefit from active arm supports that augment their residual functional capabilities. However, intuitively controlled and fully actuated arm supports are currently not commercially available and adults with DMD are limited to use external robotic arms which contribute to the disuse of their arms. To fill this gap in the field of arm supports, we have developed EMG and force-based control interfaces that have been implemented in two new active arm supports: the A-Arm and the Active A-Gear.We found that both EMG and force-based control interfaces are feasible solutions for the control of active arm support for adults with DMD that have lost their arm function a long time ago. The comparative studies between EMG and force-based control interfaces indicated that, in general, EMG-based control interfaces are better suited for adults with DMD than force-based control interfaces as they are experienced as less fatiguing. Nevertheless, force-based control interfaces with active gravity and joint-stiffness compensation can be a better alternative for those cases in which voluntary forces would still be higher than the intrinsic forces of the arms. This conclusion has an indicative value, as it is based on a low number of subjects. In any case, the decision on the most suited interface will have to be taken based on the specificities of each subject. In conclusion, by developing these new control interfaces and implementing them in new active assistive devices, we made a significant step in improving arm supports for adults with DMD. Hopefully, these novel concepts of arm supports will be the basis for the development of commercially available active arm supports for people with severe muscular weakness. The control and assistive strategies developed in the Flextension A-Gear project may be applicable to other patient groups with muscular weakness.
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... While the life expectancy of people with DMD has increased [4], due to dependency on caregivers, their self-reported quality of life remains poor [5]. Patient groups have expressed a clear desire for technical solutions, in order to achieve a greater degree of independence by using their own limbs for as long as possible [6,7]. ...
... Wearable robotic exoskeletons (WREs) can serve as means to achieve this goal. Such devices can assist in activities of daily living (ADLs) and at the same time enable users to use their own limbs [6], as opposed to external robotic grippers controlled remotely by a joystick and passive splints (Figure 1b) that are often used in DMD [6,7]. Strapped around limbs (see Figure 1c), WREs support and augment the impaired motor function of users. ...
... Wearable robotic exoskeletons (WREs) can serve as means to achieve this goal. Such devices can assist in activities of daily living (ADLs) and at the same time enable users to use their own limbs [6], as opposed to external robotic grippers controlled remotely by a joystick and passive splints (Figure 1b) that are often used in DMD [6,7]. Strapped around limbs (see Figure 1c), WREs support and augment the impaired motor function of users. ...
Article
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Recently, several research projects in the Nether-lands have focused on the development of wearable robotic exoskeletons (WREs) for individuals with Duchenne muscular dystrophy (DMD). Such research on WREs is often treated solely within the disciplines of biomedical and mechanical engineering, overlooking insights from disability studies and philosophy of technology. We argue that mainly two such insights should receive attention: the problematization of the ableism connected to the individual model of disability and the stigmatization by assistive technology. While disability studies have largely rejected the individual model of disability, the engineering sciences seem to still locate disability in an individual's body, not questioning their own problematization of disability. Additionally, philosophy of technology has argued that technologies are not neutral instruments but shape users' actions and perceptions. The design of WREs may convey a message about the understanding of disability, which can be comprehended as a challenge and an opportunity: stigmatization needs to be avoided and positive views on disability can be evoked. This article aims to highlight the benefits of considering these socio-philosophical perspectives by examining the case of WREs for people with DMD and proposing design principles for WREs. These principles may enhance acceptability of WREs, not only by individuals with DMD but also by other users, and help engineers to better place their work in the social context.
... The functionality of the legs is effectively supported using wheelchairs. The Flextension A-Gear project [7], developed passive and active arm supports for individuals with DMD [8]. Currently, the Symbionics 2.1 [9] explored the feasibility of an active support for the trunk and the neck of individuals with DMD. ...
... Physical Function -Despite the high clinical heterogeneity that is present in the progression of individuals with DMD [26], according to Lobo-Prat [8] there is a disease progression pattern (Figure 1.1). The main components of this pattern include the early onset of ambulatory difficulties around the age of 5-6 and the loss of independent ambulation by the age of 12-14 [17]. ...
... If contractures in the lower extremity are not severe, a passive standing device or a power standing wheelchair can be used to enhance mobility [31]. When deformations occur in the spine, due to wheelchair confinement, trunk orthoses or custom-made back rests for wheelchairs are recommended [8]. ...
Thesis
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The hand is a very complex and versatile tool, which allows humans to interact with their immediate environment, engage in daily life activities and socialize. Individuals with Duchenne muscular dystrophy (DMD), experience years of deteriorated hand function, leading to severe dependence on caregivers. Robotic exoskeletons can provide a feasible solution for the active hand support of individuals with DMD. My work describes the development of a hand exoskeleton that meets the specific needs of individuals with DMD, in order to raise their quality of life and social participation and acceptance. To this end, in the Symbionics project we developed the SymbiHand orthosis; an active wearable hand exoskeleton for people with DMD. My role in this project was the characterization of the hand neuro-motor function in DMD and the development and application of robust hand motor intention decoding, for the control of the SymbiHand.
... Additionally, individuals with DMD need robotic devices for daily assistance and for a significant amount of time [81]. In recent years robotic devices to support the arm [82], the trunk [83,84], and the hand [85,86] of people with DMD were developed and tested with promising results. Novel sensors were used [84,85] in integration with novel robotic designs [83,86] to achieve robust interfacing between the user and the robotic device. ...
... Current studies for the use of robotic exoskeletons in DMD are not many and are limited by a small number of participants [82,87]. More extensive longitudinal studies can give further insights into how DMD affects motor control in different individuals with high functional heterogeneity [88]. ...
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Recent advances in the field of neural rehabilitation, facilitated through technological innovation and improved neurophysiological knowledge of impaired motor control, have opened up new research directions. Such advances increase the relevance of existing interventions, as well as al-low novel methodologies and technological synergies. New approaches attempt to partially overcome long-term disability caused by spinal cord injury, using either invasive bridging tech-nologies or non-invasive human-machine interfaces. Muscular dystrophies benefit from electro-myography and novel sensors that shed light on underlying neuromotor mechanisms in people with Duchenne. Novel wearable robotics devices are being tailored to specific patient popula-tions, such as traumatic brain injury, stroke, and amputated individuals. In addition, develop-ments in robot-assisted rehabilitation may enhance motor learning and generate movement repe-titions by decoding the brain activity of patients during therapy. This is further facilitated by ar-tificial intelligence algorithms coupled with faster electronics. The practical impact of integrating such technologies with neural rehabilitation treatment can be substantial. They can potentially empower non-technically trained individuals, namely family members and professional carers, to alter the programming of neural rehabilitation robotic setups, to actively get involved and in-tervene promptly at the point of care. This narrative review considers existing and emerging neu-ral rehabilitation technologies through the perspective of replacing or restoring functions, en-hancing, or improving natural neural output, as well as promoting or recruiting dormant neuro-plasticity. Upon conclusion, we discuss the future directions for neural rehabilitation research, diagnosis and treatment based on the discussed technologies and their major roadblocks. This future may eventually become possible through technological evolution and convergence of mutu-ally beneficial technologies to create hybrid solutions.
... This feasibility of DC control for the real-time myocontrol for a 1-DOF hand exoskeletons was also demonstrated in our previous work (Bos et al., 2019). As it has also become clear by previous research, sEMG may be the most feasible way of controlling assistive devices as the disease progresses (Lobo Prat, 2016). Despite the loss in muscle strength, sEMG is retained in DMD even in late stages of the disease (Lobo-Prat et al., 2017b). ...
Article
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Introduction: Duchenne muscular dystrophy (DMD) is a genetic disorder that induces progressive muscular degeneration. Currently, the increase in DMD individuals' life expectancy is not being matched by an increase in quality of life. The functioning of the hand and wrist is central for performing daily activities and for providing a higher degree of independence. Active exoskeletons can assist this functioning but require the accurate decoding of the users' motor intention. These methods have, however, never been systematically analyzed in the context of DMD. Methods: This case study evaluated direct control (DC) and pattern recognition (PR), combined with an admittance model. This enabled customization of myoelectric controllers to one DMD individual and to a control population of ten healthy participants during a target-reaching task in 1- and 2- degrees of freedom (DOF). We quantified real-time myocontrol performance using target reaching times and compared the differences between the healthy individuals and the DMD individual. Results and Discussion: Our findings suggest that despite the muscle tissue degeneration, the myocontrol performance of the DMD individual was comparable to that of the healthy individuals in both DOFs and with both control approaches. It was also evident that PR control performed better for the 2-DOF tasks for both DMD and healthy participants, while DC performed better for the 1-DOF tasks. The insights gained from this study can lead to further developments for the intuitive multi-DOF myoelectric control of active hand exoskeletons for individuals with DMD.
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Background People with Duchenne muscular dystrophy (DMD) cope with progressive muscular weakness and consequential upper extremity function loss. They benefit from arm supports, or arm exoskeletons, to assist arm function. Especially for severe muscle weakness (DMD ≥ Brooke Scale 4), the design of such arm support is challenging. This study aims to structurally develop functional and technical design requirements of arm supports for people with DMD Brooke Scale 4. Methods An overview of clinical characteristics and a classification of clinically meaningful activities were derived from data from the Dutch Dystrophinopathy Database and available literature. Based on these, functional and technical design requirements of arm supports were developed and matched to the achievable needs of the user. Results First, the clinical characteristics of the target population, such as strength, range of motion, and functional ability, are given. Next, clinically relevant activities of daily living are translated to functional requirements categorised in a ‘must,’ ‘should,’ and ‘could’ category. Last, the technical requirements to realise these functional goals are presented. Conclusions The recommendations following from the functional user needs, technical requirements, and safety considerations can be used to make the development of assistive arm supports for people with DMD Brooke Scale 4 more user-centred.
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This study investigated the degree of upper extremity active range of motion (AROM) provided by an admittance control robot compared to a commercially available passive arm support for individuals with DMD who have limited arm function. The reachable workspace evaluation was used to assess active range of motion provided by both devices. A visual analog scale (VAS) was also used to secure subject‐reported outcome measures. The admittance control robot significantly increased reachable surface area (RSA) scores compared to the passive arm support for the dominant arm (Wilcoxon T=5.00, p=0.022, r2=0.263) and for the non‐dominant arm (paired‐samples t‐test, t(9)=4.66, p=0.001, r2=0.71). The admittance control robot also significantly decreased subject‐reported exertion compared to the passive arm support. This study substantiated the benefits of admittance control for individuals with DMD compared to a commercially available passive arm support. This article is protected by copyright. All rights reserved.
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Background Robotic arm supports aim at improving the quality of life for adults with Duchenne muscular dystrophy (DMD) by augmenting their residual functional abilities. A critical component of robotic arm supports is the control interface, as is it responsible for the human-machine interaction. Our previous studies showed the feasibility of using surface electromyography (sEMG) as a control interface to operate robotic arm supports in adults with DMD (22-24 years-old). However, in the biomedical engineering community there is an often raised skepticism on whether adults with DMD at the last stage of their disease have sEMG signals that can be measured and used for control. Findings In this study sEMG signals from Biceps and Triceps Brachii muscles were measured for the first time in a 37 year-old man with DMD (Brooke 6) that lost his arm function 15 years ago. The sEMG signals were measured during maximal and sub-maximal voluntary isometric contractions and evaluated in terms of signal-to-noise ratio and co-activation ratio. Beyond the profound deterioration of the muscles, we found that sEMG signals from both Biceps and Triceps muscles were measurable in this individual, although with a maximum signal amplitude 100 times lower compared to sEMG from healthy subjects. The participant was able to voluntarily modulate the required level of muscle activation during the sub-maximal voluntary isometric contractions. Despite the low sEMG amplitude and a considerable level of muscle co-activation, simulations of an elbow orthosis using the measured sEMG as driving signal indicated that the sEMG signals of the participant had the potential to provide control of elbow movements. Conclusions To the best of our knowledge this is the first time that sEMG signals from a man with DMD at the last-stage of the disease were measured, analyzed and reported. These findings offer promising perspectives to the use of sEMG as an intuitive and natural control interface for robotic arm supports in adults with DMD until the last stage of the disease. Electronic supplementary material The online version of this article (doi:10.1186/s12984-017-0292-4) contains supplementary material, which is available to authorized users.
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The only book that covers in detail a broad range of cutting-edge topics within motor rehabilitation technology Neural engineering is a discipline that uses engineering techniques to understand, repair, replace, enhance, or treat diseases of neural systems. This book describes state-of-the-art methods within this field, from brain-computer interfaces to spinal and cortical plasticity. Touching on electrode design, signal processing, the neurophysiology of movement, robotics, and much more, this innovative book presents the latest information for readers working in biomedical engineering. Each section of Introduction to Neural Engineering for Motor Rehabilitation begins with an overview of techniques before moving on to provide information on the most recent findings. Topics include: INJURIES OF THE NERVOUS SYSTEM-including diseases and injuries of the central nervous system leading to sensory-motor impairment; peripheral and spinal plasticity after nerve injuries; and motor control modules of human movement in health and disease SIGNAL DETECTION AND CONDITIONING-including progress in peripheral neural interfaces; multi-modal, multi-site neuronal recordings for brain research; methods for non-invasive electroencephalograph detection; wavelet denoising and conditioning of neural recordings FUNCTION REPLACEMENT (Prostheses and Orthosis)-including an introduction to upper limb prosthetics; controlling prostheses using peripheral nerve stimulation invasive interfaces for amputees; and exoskeletal robotics for functional substitution FUNCTION RESTORATION-including methods for movement restoration; advanced user interfaces for upper limb functional electrical stimulation; and selectivity of peripheral neural interfaces REHABILITATION THROUGH NEUROMODULATION-including brain-computer interface applied to motor recovery after brain injury; functional electrical therapy of upper extremities; and robotic assisted neurorehabilitation Introduction to Neural Engineering for Motor Rehabilitation is an important textbook and reference for graduate students and researchers in the fields of biomedical and neural engineering. © 2013 The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.
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Wearble mechatronic systems, capable of tracking human motion and assisting as needed, are being developed with the goal of increasing the quality of life for individuals living with musculoskeletal conditions, such as Duchenne Muscular Dystrophy (DMD). Recently, a control system framework has been developed and implemented for EMG-driven control of wearable mechatronic elbow braces used for musculoskeletal rehabilitation. The intent of this research is to show that the framework can be extended to velocity-based control of wearable mechatronic systems used in non-rehabilitation applications. As a result, the framework was used to develop a control system for the actuation of a wearable assistive exoskeleton designed to assist arm motion of individuals suffering from DMD. EMG and accelerometer data were collected from healthy subjects and used as input to the control system during an elbow motion tracking task. The control system commands the elbow joint velocity of the assistive exoskeleton to replicate the elbow flexion — extension motions completed by the subjects. A root mean square error between the position of the subject and the position of the exoskeleton's elbow joint of 3.45 ± 1.72° and a mean standard deviation between exoskeleton motion trials of 0.68° were found, corresponding to the accuracy and the repeatability of the system, respectively. The experimental results show that the framework is extensible to velocity-based control of wearable motion-assistance systems with an accuracy and repeatability comparable to similar systems.