Rehabilitation interventions for foot drop in neuromuscular disease

"Foot drop" or "Floppy foot drop" is the term commonly used to describe weakness or contracture of the muscles around the ankle joint. It may arise from many neuromuscular diseases

Rehabilitation interventions for foot drop in neuromuscular disease

"Foot drop" or "Floppy foot drop" is the term commonly used to describe weakness or contracture of the muscles around the ankle joint. It may arise from many neuromuscular diseases

Control interfaces for active trunk support

People with Duchenne muscular dystrophy (DMD) lose the ability to move due to severe muscular weakness hindering their activities of daily living (ADL). As a consequence, they have difficulties with remaining independent and have to depend on caregivers. Medication cannot prevent or cure DMD but it can increase the life expectancy of patients. Notwithstanding the increase in life expectancy, people with DMD have a lower Health Related Quality of Life (HRQoL) compared to people without DMD. A possible improvement could be achieved with assistive devices to perform ADL and, as a result, to depend less on caregivers.Symbionics (2.1) has been focusing on developing dynamic trunk and head supportive devices for people with neuromuscular disorders to assist them when performing daily activities. Three sub-projects were defined; they investigated user involvement, passive trunk support and active trunk support. User involvement entailed the interaction between the trunk and arm when accomplishing daily tasks. A passive trunk support was designed and tested in an experimental environment by people without and with an early stage of DMD. As the DMD progresses, more assistance is needed which could possibly be provided by an active trunk support. Thus, an active trunk support (which is the focus of this thesis) concentrates on the actuation and control of a passive trunk support.Operating and controlling an active assistive device requires a control interface. The control interface is responsible for converting the intended movement of the user into a device movement. Several control interfaces have been proposed for the control of assistive devices, the most common ones being a joystick, force sensors and sEMG (surface electromyography). We evaluated their performance by building an experimental user-controllable trunk support.The goal of this dissertation, therefore, is to evaluate control interfaces for active trunk support.To this end, several research questions were formulated and investigated:I. Is there an alternative to the intuitive trunk control interface to steer trunk muscles?Current research on the control of orthotic devices that use sEMG signals as control inputs, focuses mainly on muscles that are directly linked to the movement being performed (intuitive control). However, in some cases, it is hard to detect a proper sEMG signal (e.g., when there is a significant amount of fat) or specifically for EMG from trunk muscles, respiratory muscles are located in the trunk as well and can easily disturb the control signal, which can result in poor control performance. A way to overcome this problem might be the introduction of other, non-intuitive forms of control. We performed an explorative, comparative study on the learning behaviour of two different control interfaces, one with trunk muscle sEMGs (intuitive) and one with leg muscle sEMGs (non-intuitive) that can be potentially used for an active trunk support. Six healthy subjects undertook a 2-D Fitts’ law style task. They were asked to steer a cursor towards targets that were radially distributed symmetrically in five directions. II. Which control interface aids an active trunk support better?A feasibility study evaluated control interface performance with a novel trunk support assistive device (Trunk Drive) for adult men with Duchenne Muscular Dystrophy (DMD) namely, joystick, force on sternum, force on feet and sEMG (electromyography). This was done as a discrete position tracking task. We built a one degree of freedom active trunk support device that was tested on 10 healthy men. An experiment, based on Fitts’ law, was conducted for the evaluation. III. Which assistive admittance controller performs best in a 1-D Fitts’ law task?This study was dedicated to the development and assessment of three different admittance control algorithms for a trunk supporting robot; a law with constant parameters, a law with added feedforward force, and a law with variable parameters. A Fitts’-like experiment with 12 healthy subjects was performed to compare the control laws. IV. Do people with DMD generate satisfactory signals which can potentially drive an active trunk support?In a previous study, we showed that healthy people were able to control an active trunk support using four different control interfaces (based on joystick, force on feet, force on sternum and sEMG). All four control interfaces had different advantages and disadvantages. The aim of this study was to explore which of the four inputs could be detectably used by people with DMD to control an active trunk support. Three subjects with DMD participated in two experiments: an active experiment with an active trunk support assistive device and a static experiment without the active trunk support. The challenge in both experiments was to steer the cursor into a target of a graphical user interface using the signals from the different control interfaces. We concluded that, although the non-intuitive force on feet control is one of the best interfaces for people with DMD to control an active trunk support some DMD patients find it easier to use the EMG from their leg muscles. The joystick is the only usable intuitive control interface but, the function of one hand has to be sacrificed. The decision, as to which control interface works best, must be made per individual.<br/

Motor physical therapy affects muscle collagen type I and decreases gait speed in dystrophin-deficient dogs

Golden Retriever Muscular Dystrophy (GRMD) is a dystrophin-deficient canine model genetically homologous to Duchenne Muscular Dystrophy (DMD) in humans. Muscular fibrosis secondary to cycles of degeneration/regeneration of dystrophic muscle tissue and muscular weakness leads to biomechanical adaptation that impairs the quality of gait. Physical therapy (PT) is one of the supportive therapies available for DMD, however, motor PT approaches have controversial recommendations and there is no consensus regarding the type and intensity of physical therapy. In this study we investigated the effect of physical therapy on gait biomechanics and muscular collagen deposition types I and III in dystrophin-deficient dogs. Two dystrophic dogs (treated dogs-TD) underwent a PT protocol of active walking exercise, 36/week, 40 minutes/day, 12 weeks. Two dystrophic control dogs (CD) maintained their routine of activities of daily living. At t0 (pre) and t1 (post-physical therapy), collagen type I and III were assessed by immunohistochemistry and gait biomechanics were analyzed. Angular displacement of shoulder, elbow, carpal, hip, stifle and tarsal joint and vertical (Fy), mediolateral (Fz) and craniocaudal (Fx) ground reaction forces (GRF) were assessed. Wilcoxon test was used to verify the difference of biomechanical variables between t0 and t1, considering p<.05. Type I collagen of endomysium suffered the influence of PT, as well as gait speed that had decreased from t0 to t1 (p<.000). The PT protocol employed accelerates morphological alterations on dystrophic muscle and promotes a slower velocity of gait. Control dogs which maintained their routine of activities of daily living seem to have found a better balance between movement and preservation of motor functionFAPESP, 06/61561-

Coupling Robot-aided assessment and surface electromyography to evaluate wrist and forearm muscles activity, muscle fatigue and its effect on proprioception

Sensorimotor functions and an intact neural control of muscles are essential for the effective execution of movements during daily living tasks. However, despite the ability of human sensorimotor system to cope with a great diversity of internal and external demands and constraints, these mechanisms can be altered as a consequence of neurological disorders, injuries or just due to excessive effort leading to muscle fatigue. A precise assessment of both motor and sensory impairment is thus needed in order to provide useful cues to monitor the progression of the disease in pathological populations or to prevent injuries in case of workers. In particular, considering muscle fatigue, an objective assessment of its manifestation may be crucial when dealing with subjects with neuromuscular disorders for understanding how specific disease features evolve over time or for testing the efficacy of a potential therapeutic strategy. Indeed, muscle fatigue accounts for a significant portion of the disease burden in populations with neuromuscular diseases but, despite its importance, a standardized, reliable and objective method for fatigue measurement is lacking in clinical practice. The work presented in this thesis investigates a practical solution through the use of a robotic task and parameters extracted by surface electromyography signals. Moreover, a similar approach that combines robot-mediated proprioception test and muscle fatigue assessment has been developed and used in this thesis to objectively investigate the influence of muscle fatigue on position sense. Finally, the effect of posture on muscle activity, from a perspective of injuries prevention, has been examined. Data on adults and children have been collected and quantitative and objective information about muscle activity, muscle fatigue and joint sensitivity were obtained gaining useful insight both in the clinical context and in the prevention of workplace injuries. A novel method to assess muscle fatigue has been proposed together with the definition of an easy readable indicator that can help clinicians in the assessment of the patient. As for the impact of fatigue on the sensorimotor system, results obtained showed a decrease in wrist proprioceptive acuity which led also to a decline in the performance of a simple tracing task. Regarding the adoption of different muscle strategies depending on postures, results showed that muscle activity of forearm muscles was overall similar regardless from the postures

Characterization of Forearm Muscle Activation in Duchenne Muscular Dystrophy via High-Density Electromyography:A Case Study on the Implications for Myoelectric Control

Duchenne muscular dystrophy (DMD) is a genetic disorder that results in progressive muscular degeneration. Although medical advances increased their life expectancy, DMD individuals are still highly dependent on caregivers. Hand/wrist function is central for providing independence, and robotic exoskeletons are good candidates for effectively compensating for deteriorating functionality. Robotic hand exoskeletons require the accurate decoding of motor intention typically via surface electromyography (sEMG). Traditional low-density sEMG was used in the past to explore the muscular activations of individuals with DMD; however, it cannot provide high spatial resolution. This study characterized, for the first time, the forearm high-density (HD) electromyograms of three individuals with DMD while performing seven hand/wrist-related tasks and compared them to eight healthy individuals (all data available online). We looked into the spatial distribution of HD-sEMG patterns by using principal component analysis (PCA) and also assessed the repeatability and the amplitude distributions of muscle activity. Additionally, we used a machine learning approach to assess DMD individuals' potentials for myocontrol. Our analysis showed that although participants with DMD were able to repeat similar HD-sEMG patterns across gestures (similarly to healthy participants), a fewer number of electrodes was activated during their gestures compared to the healthy participants. Additionally, participants with DMD activated their muscles close to maximal contraction level (0.63 ± 0.23), whereas healthy participants had lower normalized activations (0.26 ± 0.2). Lastly, participants with DMD showed on average fewer PCs (3), explaining 90% of the complete gesture space than the healthy (5). However, the ability of the DMD participants to produce repeatable HD-sEMG patterns was unexpectedly comparable to that of healthy participants, and the same holds true for their offline myocontrol performance, disproving our hypothesis and suggesting a clear potential for the myocontrol of wearable exoskeletons. Our findings present evidence for the first time on how DMD leads to progressive alterations in hand/wrist motor control in DMD individuals compared to healthy. The better understanding of these alterations can lead to further developments for the intuitive and robust myoelectric control of active hand exoskeletons for individuals with DMD

Effectiveness of conservative non-pharmacological interventions in people with muscular dystrophies: a systematic review and meta-analysis.

INTRODUCTION: Management of muscular dystrophies (MD) relies on conservative non-pharmacological treatments, but evidence of their effectiveness is limited and inconclusive. OBJECTIVE: To investigate the effectiveness of conservative non-pharmacological interventions for MD physical management. METHODS: This systematic review and meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched Medline, CINHAL, Embase, AMED and Cochrane Central Register of Controlled Trial (inception to August 2022). Effect size (ES) and 95% Confidence Interval (CI) quantified treatment effect. RESULTS: Of 31,285 identified articles, 39 studies (957 participants), mostly at high risk of bias, were included. For children with Duchenne muscular dystrophy (DMD), trunk-oriented strength exercises and usual care were more effective than usual care alone in improving distal upper-limb function, sitting and dynamic reaching balance (ES range: 0.87 to 2.29). For adults with Facioscapulohumeral dystrophy (FSHD), vibratory proprioceptive assistance and neuromuscular electrical stimulation respectively improved maximum voluntary isometric contraction and reduced pain intensity (ES range: 1.58 to 2.33). For adults with FSHD, Limb-girdle muscular dystrophy (LGMD) and Becker muscular dystrophy (BMD), strength-training improved dynamic balance (sit-to-stand ability) and self-perceived physical condition (ES range: 0.83 to 1.00). A multicomponent programme improved perceived exertion rate and gait in adults with Myotonic dystrophy type 1 (DM1) (ES range: 0.92 to 3.83). CONCLUSIONS: Low-quality evidence suggests that strength training, with or without other exercise interventions, may improve perceived exertion, distal upper limb function, static and dynamic balance, gait and well-being in MD. Although more robust and larger studies are needed, current evidence supports the inclusion of strength training in MD treatment, as it was found to be safe