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14:00   Rehabilitation Chair: Gabrielle Tuijthof 14:00 15 mins Elbow joint loads during eight simulated activities of daily living: effect of post-operative instruction Roos GA Duijn, Daniëlle Meijering, Riemer JK Vegter, Friederike Albers, Alexander L Boerboom, Denise Eygendaal, Sjoerd K Bulstra, Michel PJ Bekerom, Claudine CJ Lamouth, Martin Stevens, Reslin Schelhaas, Alessio Murgia Abstract: Background: Survival rates of elbow prostheses following total elbow arthroplasty (TEA) are low compared to hip and knee prostheses. Overloading of the elbow joint is hypothesized to be one of the failure mechanisms following total elbow arthroplasty. However, it is unclear whether the current post-operative loading instruction of “not lifting more than 1kg” would lead to lower elbow loads. The aim of this study is to investigate the elbow joint loads, expressed as joint moments, in three directions (flexion-extension (FE), pronation-supination (PS), varus-valgus (VV)) during eight simulated activities of daily living (ADLs). In addition, the effect of the current post-operative instruction is examined. Our hypothesis is that instruction will not lead to a significant decrease in elbow joint load. Methods: Nine healthy participants (49.8±14.7years) performed eight ADL tasks in an uninstructed and an instructed condition. Elbow joint angles and elbow joint moments were calculated using inverse dynamical and musculoskeletal modeling software (OpenSim, Stanford University, CA). Wilcoxon signed-rank test was used to investigate the influence of the instruction on peak joint moment during the eight ADL tasks. Results: The results show no significant effect of the instruction on elbow joint moment in FE-direction and PS-direction (all p>0.05). The most demanding ADLs were rising from a chair (-14±6.7Nm FE, -3.7±1.7Nm PS), followed by opening a door (7.7±1.9Nm FE, 2.9±1.9Nm PS). The slide task shows the lowest elbow moments (4.1±0.8Nm FE, 0.6±1.3Nm PS). Conclusion: The results of this study show that the current post-operative instruction is not sufficient to decrease the elbow joint loading, i.e., joint moments, in the selected ADLs. This finding raises the question whether people can accurately predict which changes in movement will lead to lower moments in the elbow. The outcomes provide a first step in formulating a more evidence-based and specific post-operative instruction for patients following TEA. However, to formulate evidence-based recommendations, joint contact forces, in both healthy adults and patients following TEA need to be investigated in future research. 14:15 15 mins Hyper-realistic multisensory robotic neurorehabilitation Laura Marchal-Crespo Abstract: The possibility of using robotic devices and virtual reality to support neurorehabilitation is promising since robots can support high-intensity training in a motivating virtual environment. However, recent meta-analyses concluded that traditional robotic training yields inferior outcomes to conventional therapy, especially in activities of daily living (ADL). This is not surprising, since current rehabilitation robots only assist to perform rather artificial movements that are abstractly visualized on 2D screens while somatic (tactile and proprioceptive) feedback is underutilized. Screens lack depth cues that might result in non-physiological movements and increase cognitive load. The absence of somatosensory information from the interaction with virtual objects might also limit the transfer of the gained skill into ADL. Head-mounted displays (HMDs) might provide a more naturalistic movement visualization as they preserve eye-hand coordination by showing an avatar −with immersive VR (IVR)− or the real body −with augmented reality (AR) [1]. Providing somatosensory information through robotic haptic rendering might also enhance motor learning and transfer [2]. We run two experiments to evaluate: 1) The impact of different visualization technologies −namely IVR HMD, AR HMD, and a 2D screen− on movement quality, cognitive load, motivation, and usability on 20 old adults (> 59 y.o.) and four neurologic patients who performed a reaching task in 3D space and a parallel cognitive; and 2) The effect of haptic rendering and assistance (arm weight support) from an upper limb exoskeleton on motor learning and skill transfer of a dynamic task (i.e., inverting a pendulum) on 40 healthy participants. Old participants and patients performed straighter, shorter, and smoother movements when visualizing their movements with both HMDs compared to the screen. No differences were found in cognitive load or motivation between the different visualizations. Importantly, participants rated the IVR as highly usable. In the second experiment, we found that training with haptic rendering enhanced motor learning and skill transfer, while weight support hampered learning. Taking together, incorporating HMDs and haptic rendering into motor training offers a more naturalistic movement training that enhances movement quality, motor learning, and skill transfer. However, further work is needed to provide robotic assistance without hampering motor learning. [1] N. Wenk et al. “Effect of immersive visualization technologies on cognitive load, motivation, usability, and embodiment.” Virtual Reality, 2021. [2] Ö. Özen, et al. “Haptic rendering modulates task performance, physical effort and movement strategy during robot-assisted training.” Proc. IEEE RAS EMBS Int. Conf. Biomed. Robot. Biomechatronics 2020, pp.1223–1228. 14:30 15 mins Smart hip implants Helene Noordhuis, Claudine Lamoth, Paul Jutte, Charissa Roossien Abstract: Patients suffering from worn or damaged hip joints often rely upon implants to uphold their economic, social, and functional independence. In most cases of hip failure an implant has proven to be a reliable solution. However, despite the innovations in implant technology, failure of the implant is still causing major issues. The lifespan of the average hip implant is 15 to 20 years. Because of the limited durability and the longer expected lifetime of younger patients, patients below 50 do not receive implants unless there is no other choice. These patients often endure years of chronic pain and become dependent on society. Common reasons for hip implant failure are aseptic loosening, which is caused by the inflammatory tissue response to wear particles; infection, which is caused by biofilm formation; and bone cement failure, which is caused by blunt force or repetitive motions. Treating infections and loosening of the implant can only be done by removing the implant. Revision surgeries can result in traumatic conditions, a high mortality rate and high healthcare costs. This puts a strain on both the patient and the hospital. The cause and moment of failure of the implant are hard to determine because of the limited information available. It can be difficult to determine the state of the implant and the surrounding tissue while inside a patient’s body. By monitoring the hip implant and the body’s reactions during daily life activities, more information could be gathered about the state of the implant over time. Therefore, a new project was developed which aims to design the next generation of smart implants for the musculoskeletal system. In the coming years, first an overview of the state-of-the-art developments in the implant field will be created. Afterwards a sensor system for the hip implant, including pressure- and ph-sensors, will be designed and validated. Validation will be done using in-vitro- and cadaveric studies. The integration of smart, biocompatible and sensing implants in the musculoskeletal system will open radically new avenues for the future, i.e., real-time risk assessment of potential complications associated with these hip implants. 14:45 15 mins Design requirements for upper extremity support for home use in people with severely impaired arm function in Duchenne Muscular Dystrophy Suzanne Filius, Jaap Harlaar, Herman van der Kooij, Mariska Janssen Abstract: Optimizing orthotics to real user needs is a challenge in our field. A variety of upper extremity supports is available for people with severe muscle weakness, such as Duchenne Muscular Dystrophy (DMD). Unfortunately, the rate of disuse of these products is high due to multiple reasons, among which mismatch between the specific user needs and design requirements. Moreover, in the more advanced disease stages (>Brooke scale 3), there seem no suitable wearable arm support (i.e. motorized) available. This paper aims to 1) provide clinical guidance to match the technology to the patient needs, and within this framework 2) formulate functional and technical design requirements for the development of an active exoskeleton for people with DMD Brooke 4. A clinical meaningful classification was developed based on available literature over the past 1.5 years and data from the Dutch Dystrophinopathy Database (DDD) was reused. The DDD is the Dutch national register for Duchenne and Becker muscular dystrophy, in which natural history data is collected. On a functional level the muscle force/torque, active and passive range of motion, reachable workspace, and performance of upper limb (PUL) scores of boys and men with DMD Brooke scale 4 were described. With this, technical design requirements were formulated to restore arm function to achievable levels, aligned with the needs of the user. The results present the clinical characteristics of DMD patients with Brooke scale 4. Showing that their range of motion is limited to what they can reach with elbow and wrist movements. As a results of increased muscle stiffness, their joint impedance around the elbow and shoulder is elevated. The muscle strength of their arm muscles varies between 3-25 N (i.e. 0.8-9 Nm of torque). Intuitive force-based support with active weight and joint impedance compensation is expected to best match their needs. Both the shoulder and elbow should be supported and there are important safety considerations that are specific to this population. This paper can be used to make the prescription and further development of arm supports more user-centered. It is important to closely match target population to design requirements in order to prevent non-use. An active arm support with weight and joint impedance compensation is expected to best match the needs of boys and men with DMD Brooke Scale 4. In addition, (and beyond our scheme) it is important to consider the (personal and environmental) barriers that could result in non-use. We would like to thank the Duchenne Centre Netherlands (DCN) for providing us with access to the Dutch Dystrophinopathy Database (DDD). This work is part of research program Wearable Robotics (P16-05) funded by Dutch Research Council (NWO), Duchenne Parent Project, Spieren voor Spieren, Festo, Yumen Bionics, Baat Medical and the FSHD society. 15:00 15 mins Comparing four compensation strategies for an active elbow support, an exploratory pilot study in healthy subjects Suzanne Filius, Mariska Janssen, Herman van der Kooij, Jaap Harlaar Abstract: There is a need for active arm supports in people with progressive muscle weakness such as Duchenne Muscular Dystrophy (DMD) to support functional arm movements during daily activities to enhance their independence, social participation and their quality of live. The best technical strategy to support functional arm movements remains challenging. This study serves as exploratory pilot study in the development of a motorized arm support for daily use in boys and men with DMD (Brooke Scale >3). This study aims to develop 4 different high level control strategies (e.g. modelled-based, hybrid-based, measured-based, and personalized-based) and compares the compensation efficacy and preferences in an active elbow support in healthy subjects. The study is performed in 12 healthy male participants and exists out of 2 sessions: 1) measurement of the passive interaction forces around the elbow joint in horizontal and vertical plane (relaxation task), 2) comparison of the four compensation strategies in vertical plane (position task). The passive interaction forces where measured with a force-torque sensor at the sleeve interface and the compensation support was provided by a motor at the elbow joint with a compensation gain of 80%. The modelled-based strategy makes use of a gravitational kinematic model, using an estimation of mass and center of mass (COM) of the forearm and hand. The measured-based strategy makes use of all passive forces measured in session 1 in the vertical plane. The hybrid-based strategy makes use of a combination of the kinematic model and the measured passive forces in the horizontal plane. Personalized-based makes use of a model of both gravity and joint impedance fit to the measured passive forces in vertical plane. The compensation efficacy was determined by the area under the curve (AUC) of the surface electromyography (sEMG) of the m. biceps brachii and long head of m. triceps muscles, and the tracking error during the target position tracking task. Out of the 12 (aged 24 to 35 years), 4 preferred the modelled-based, 4 preferred measured-based, 3 preferred personalized-based and 1 the hybrid-based compensation strategy. The root mean square (RMS) values of the torque-angle profiles of the modelled-based and hybrid-based were 13% and 20% higher compared to both the measured-based and personalized-based compensation strategy. On average the EMG AUC of the biceps muscle was 34% lower in the modelled-based and 21% lower for the hybrid-based compared to the measured-based. In the triceps muscles and tracking error no significant differences are expected. The discrepancy between the measured-based and modelled-based is expected to be the result of the horizontal plane passive forces (e.g. elbow joint impedance) and errors in the parameter estimation. This difference is expected to be larger in DMD due to elevated muscle stiffness and deviating anthropometry. The effect on the compensation efficacy (performance and muscle activity) in healthy subjects is only small but is expected to be larger in DMD. This will be investigated in the future. This work is part of Wearable Robotics program (P16-05), (partly) funded by the Dutch Research Council (NWO), The Netherlands. 15:15 15 mins Heroes, an exergame for stroke patients to train stepping responses at home Aurora Ruiz-Rodríguez, Lotte Hagedoorn, Vivian Weerdesteyn, Hermie Hermens, Edwin van Asseldonk Abstract: Stroke survivors have problems with balance, causing an increased risk of falling. To train balance in rehabilitation, stepping recovery is practised by perturbing the patients. Even though traditional therapies are necessary, literature indicates that playing video games during therapy sessions can increase the motivation to do therapy. Serious videogames, such as exergames, that train voluntary stepping can be found, but it remains a challenge to train recovery steps in a home environment. In this paper, we proposed the design of a serious videogame to train stepping responses of stroke patients in a home environment, using recent findings of action observation and motor imagery. We followed an iterative user-centred methodology to design the HEROES exergame. It consists of 4 main stages, Empathize, Define, Ideate and Prototype. The design characteristics of the HEROES exergame emerged from the User-Centered design process, and are validated in every stage. During this process, stroke patients, physiotherapists, game designers and experts in human movement were involved. First, during the Empathize stage, we conducted a contextual study to understand the population and the problem to solve, interviews were conducted with physiotherapists and stroke patients. Then, using the contextual study results, we define the video game's logistical, technical, therapeutical and conceptual aspects. Next, we followed participatory design sessions where the stakeholders were involved to ideate game concepts of the therapeutic video game. Finally, we design a low-fidelity prototype producing an inexpensive version of the product. The design of the HEROES exergame complies with the stroke accessibility guidelines, providing clear instructions and feedback. The therapeutic goal is achieved by the progression of the level design. The patient is able to train paretic and non-paretic legs in a safe set-up.

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