Human-Centered Design of a Novel Soft Exosuit for Post-Stroke Gait Rehabilitation

Human-Centered Design of a Novel Soft Exosuit for Post-Stroke Gait Rehabilitation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Human-Centered Design of a Novel Soft Exosuit for Post-Stroke Gait Rehabilitation Chandramouli Krishnan, Olugbenga P. Adeeko, Edward Peter Washabaugh, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3891566/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 24 Apr, 2024 Read the published version in Journal of NeuroEngineering and Rehabilitation → Version 1 posted 7 You are reading this latest preprint version Abstract Background Stroke remains a major cause of long-term adult disability in the United States, necessitating effective rehabilitation strategies for post-stroke gait impairments. Despite advancements in post-stroke care, existing rehabilitation often falls short, prompting the development of devices like robots and exoskeletons. However, these technologies often lack crucial input from end-users, such as clinicians, patients, and caregivers, hindering their clinical utility. Employing a human-centered design approach can enhance the design process and address user-specific needs. Objective To establish a proof-of-concept of the human-centered design approach by refining the NewGait® exosuit device for post-stroke gait rehabilitation. Methods Using iterative design sprints, the research focused on understanding the perspectives of clinicians, stroke survivors, and caregivers. Two design sprints were conducted, including empathy interviews at the beginning of the design sprint to integrate end-users’ insights. After each design sprint, the NewGait device underwent refinements based on emerging issues and recommendations. The final prototype underwent mechanical testing for durability and a system usability evaluation, comparing it with the original NewGait device and a commercial product, Theratogs®. Results Affinity mapping from the design sprints identified crucial categories for stakeholder adoption, including fit for females, ease of donning and doffing, and usability during barefoot walking. To address these issues, a system redesign was implemented within weeks, incorporating features like a loop-backed neoprene, a novel closure mechanism for the shoulder harness, and a hook-and-loop design for the waist belt. Additional improvements included reconstructing anchors with rigid hook materials and replacing latex elastic bands with non-latex silicone-based bands for enhanced durability. Further, changes to the dorsiflexion anchor were made to allow for barefoot walking. Mechanical testing revealed a remarkable 10-fold increase in durability, enduring 500,000 cycles without degradation. Usability testing indicated superior performance of the stroke-specific NewGait device, scoring 84.3 on the system usability scale compared to 62.7 for the original NewGait device and 46.9 for Theratogs. Conclusion This study successfully establishes the proof-of-concept for a human-centered design approach using design sprints to rapidly develop a stroke-specific gait rehabilitation system. Future research should focus on evaluating the clinical efficacy and effectiveness of the NewGait device for post-stroke rehabilitation. hemiparesis CVA hemiplegia end-user feedback mechanical testing MTS walking empathy interview exoskeleton rehab Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 BACKGROUND Stroke is the leading cause of long-term adult disability worldwide ( 1 ). By 2030, nearly 4% of the US population is expected to have had a stroke, leading to an estimated cost burden of ~ $ 184 billion ( 2 ). While some level of spontaneous biological recovery can occur after a stroke, this process is often incomplete, leaving most stroke survivors with persistent gait impairments, which can lead to walking disabilities, falls, and reduced health-related quality of life ( 3 , 4 ). As a result, clinicians emphasize the restoration of gait and balance as a central goal of stroke rehabilitation. Numerous innovative therapeutic approaches, such as body weight supported treadmill training and robotic therapy, have emerged to address this challenge ( 5 , 6 ). However, the outcomes of these interventions have frequently fallen short of expectations, in part due to their high costs and modest benefits, limiting their clinical translation ( 7 , 8 ). Recognizing the pressing need for effective, efficient, and low-cost technologies for gait rehabilitation after stroke, researchers and engineers have explored various wearable solutions. Conventional ankle-foot orthoses (AFOs) offer simplicity and affordability, but they may inadvertently result in disuse atrophy and reduced gait efficiency by limiting Achilles tendon excursion and propulsive forces during walking ( 9 , 10 ). Moreover, they primarily target the ankle joint, overlooking the essential roles of the hip, knee, and trunk in gait and balance ( 11 ). While devices like TheraTogs ( 12 ) and TheraSuit ( 13 ) aim to address multiple joint areas, their primary focus on the pediatric market ( 14 ) raises challenges when adapting to the adult stroke population. TripleFlex ( 15 ), a more recent development, targets foot drop and leg-lift deficiencies by putting energy into flexing each joint during the swing phase of gait, thereby offering potential improvements, particularly for adults with neurological conditions like stroke. Nonetheless, the scarcity of comprehensive studies assessing these devices' efficacy and effectiveness leaves substantial uncertainties regarding the clinical utility and useability of these devices for stroke rehabilitation. A recurring issue in the field is that many of these devices have been conceived without adequate input from the individuals who matter most in the rehabilitation process—stroke survivors, their caregivers, and the clinicians providing care. This omission has led to devices that often do not fully align with the actual needs and preferences of these end-users ( 16 – 18 ). As a result, the utilization of these devices remains limited, and questions linger about how well they address the needs and desires of clinicians and patients, further hindering their clinical utility and usability. Addressing these challenges necessitates a shift in the approach to device development strategies. Integrating the principles of human-centered design can significantly enhance the development process and result in more inclusive, tailored, and empowering solutions ( 19 , 20 ). Human-centered design emphasizes understanding people's needs, motivations, and concerns while engaging stakeholders from the outset and adopting a systems approach to generalize individual interests to collective solutions ( 21 ). It allows for more effective and efficient design by engaging with users early in the development process, yielding valuable insights while working with prototypes and sketches, rather than fully built products, which can prevent the misallocation of resources ( 22 ). In this study, we employ a novel device design framework based on human-centered design strategies, known as "design sprints" ( 23 ), to comprehensively grasp user needs and expectations in order to refine a low-cost, passive exosuit device called NewGait device for stroke rehabilitation ( 24 – 26 ). The NewGait device (see Fig. 1 ), originally developed as a sports and performance enhancement device called SpeedMaker®, features lightweight elastic bands, leg straps, a shoulder harness, a waist belt, and movable anchor points for connecting the bands, rendering it highly modular. These elastic bands work in concert with muscle and tendon groups to assist or resist motion. While the clinical efficacy of the NewGait device has not been extensively documented, many clinicians have used it to treat gait and balance issues in individuals with stroke and have anecdotally reported noteworthy clinical improvements. However, feedback from clinicians and patients revealed the need for refinement, particularly for stroke-specific populations, as the original device was not intended for this population. Therefore, the purpose of this study was to use human-centered design approaches to tailor the NewGait device to the unique requirements of stroke rehabilitation. We hope that by prioritizing the input and feedback of stroke survivors, caregivers, and clinicians, we will be able to ultimately enhance its clinical usability and effectiveness in improving the lives of those affected by this debilitating condition. METHODS Study Overview The development process of the stroke-specific NewGait device involved two iterations of design sprints. Design sprint #1 also included user interviews (i.e., empathy interviews) in the understand phase to gain insights from stroke patients and incorporate their perspectives into the development process ( 27 ). After each design sprint, the NewGait device technical team made necessary adjustments to improve the prototype to address key issues and recommendations that emerged from the design sprint. Once the product development was complete, benchtop mechanical testing was conducted to evaluate the durability of the NewGait device. Additionally, a system usability evaluation was performed to compare the usability of the newer prototype with both the older version of the NewGait device and a competitor's device (TheraTogs). These evaluations provided valuable data on product durability, as well as usability in comparison with existing solutions. Design Sprints Design sprints attempt to compress the human-centered design process into a compact schedule of several hours ( 28 ). A traditional design sprint, as initially formulated by Google Ventures, lasts five days, with each day dedicated to one of the five stages: Understand , Sketch , Decide , Prototype , and Test . The process encourages teams to fail faster, meaning that shortcomings in a product or process are brought to light early in the design process before significant time and money have been invested. Ideally, the participants in a sprint bring varied perspectives on the problem, for example, clinicians, patients, caregivers, designers and/or programmers. Empathy interviews, a cornerstone of human-centered design, are used to help understand the needs of target users. All study activities were approved by the University of Michigan IRBMED as exempt; participants provided verbal agreement and offered $ 50 for their participation. Empathy Interviews The primary goal for empathy interviews was to engage clinicians with expertise in providing physical or occupational therapy and stroke survivors to learn more about the selection, adoption, and utilization of mobility aids. Specifically, interviews focused on the benefits of mobility aids, preferences around single use devices or a multi-functional device, features that make a mobility device acceptable, and strategies to facilitate the selection, adoption, and utilization of a mobility aid. Results of the empathy interviews helped to determine the constraints of the design sprints and where input would be most useful, which was particularly important given the NewGait device is an existing product. Results of interviews also informed the Journey Maps produced at the end of design sprint #2. All interviews were moderated by an expert in design sprints (MB) and expert in rehabilitation (CK); all interviews were audio-recorded and professionally transcribed. Overview of Design Sprints Because the NewGait device is a pre-existing product being marketed to a different target audience than originally intended ( 24 ), the design sprint process was modified (see Fig. 2 ). Each design sprint was conducted over a duration of one day, encompassing a total of seven hours. The Decide and Prototype steps were executed externally to the design sprints. Design Sprint #1 In design sprint #1, we followed the traditional Understand process, using notes taken by participants during Expert Talks to identify important themes. Expert Talks allow each of the participants to explain their unique perspective on the design problem ( 28 ). Although each conversation takes only 5–10 minutes, the questions the facilitators ask (MB and CZK) are designed to give the participant an opportunity to discuss their knowledge, feelings and experiences. During these conversations, the other participants take note of ideas that surprise, intrigue, or resonate with them. Participants share the notes that they took from those conversations with the entire group. As themes in these notes reveal themselves, the notes are grouped and labeled to allow the patterns of the group’s thinking to emerge. These notes form the raw material for the subsequent Affinity Mapping step. Affinity maps are used to visualize information from brainstorming sessions, resulting in themes that emerged from discussion. After discussing these themes in the group, a single theme is given priority ( Define a Sprint Question ) to focus the work of the rest of the session. With this theme in mind, participants used the NewGait device and (as a modified Sketch ) gave feedback on their experience. We then identified the themes present in this user feedback, deciding on what the participants felt were the most pressing issues. Six participants were involved in design sprint #1: NewGait developer (OPA), three rehabilitation researchers who are rehabilitation engineers, and two stroke survivors. The sprint was led by an expert in user-centered design (MB) and human-centered research (CZK). A postdoctoral fellow assisted stroke survivor participants with note taking. Between Design Sprints After design sprint #1, the NewGait team reviewed the Affinity Maps of feedback based on end users trying the NewGait device and decided ( Decide phase) what to incorporate into a new prototype ( Prototype phase) device, which was used in Sprint #2. Whereas these steps often co-occur during a single design sprint, due to the technical knowledge needed to make appropriate adjustments to the device, the NewGait team evaluated and adopted what they felt were appropriate modifications to the device based on the user input from design sprint #1. Design Sprint #2 In design sprint #2, we used the Understand phase to construct a Journey Map of the donning and doffing process for the device. As the users then tested ( Test phase) the new prototype device, their feedback was plotted against the Journey Map to visualize pain points in the process worth addressing. Eleven participants were involved in design sprint #2: NewGait developer (OPA), two rehabilitation researchers who are rehabilitation engineers, two physical therapists and one prosthetist who were experienced users of the NewGait device, and three stroke survivors and two caregivers. The sprint was led by the same expert in user-centered design (MB) as for design sprint #1. A postdoctoral fellow assisted stroke survivor participants with note taking. Post-Sprint Feedback and Durability Testing Upon the culmination of the two design sprints, we implemented design modifications to the NewGait device. We then administered System Usability Scale surveys (SUS) to patients and physical therapists to assess the usability of the original device, the new prototype, and a competitive device (Theratogs®, Telluride, Colorado). The System Usability Scale (SUS) ( 29 ) is a reliable and popular measure of a user’s perception of the usability of a device, software, or system. It is a 10-item questionnaire with five response options from Strongly agree to Strongly disagree. The final score is converted to a scale, ranging between 0-100, where a higher score indicates greater usability. The final scores can also be converted into a percentile score to better interpret the usability of the system. The interpretation of the scores of the SUS surveys are provided in Fig. 3 . Durability (i.e., fatigue) testing was performed to ensure that the new prototype could withstand repeated loading that would be expected while using the device. Fatigue testing was performed on the interfaces between the straps, anchor points, and elastic bands, which we identified as the likely failure points. We tested elastic bands made of two materials of similar stiffness: latex-based, as has been used with previous iterations of the NewGait device, and silicone-based, which are known to be more durable. These device components were loaded into a hydraulic tensile testing machine (Instron 8521, Canton, MA, USA). Briefly, a hook-and-loop neoprene strap was fastened to a wooden block that was clamped down to the base of the tensile testing machine. An anchor point was attached to the strap and the elastic band was connected between the anchor point and the actuator of the tensile testing machine. The cross-head of the machine was adjusted so that the band was not in slack when the actuator was fully extended. Care was taken to ensure proper alignment of the sample with the actuator. The machine was configured so that the components would undergo 10 cm of deformation in accordance with a sine wave (frequency = 1.75 Hz). The 10 cm of deformation was based on band excursions obtained from biomechanical data of stroke survivors. Note that although the silicone tubing had a longer interface with the clips, the active elastic portion of each band was the same length. The characteristics of the loading (i.e., force, deformation, and rate) were recorded using on-board instrumentation. The sample was repeatedly loaded until either the sample failed (e.g., breaking of the elastic band or degradation of the hook and loop fastening), or the machine reached 500,000 loading cycles (equivalent of 3000 steps/day for 6 months, as anticipated for clinical or in-home use). RESULTS Participants Participants in empathy interviews included four stroke survivors, two occupational therapists, and two physical therapists. One interview included both stroke survivor and their physical therapist. Fourteen unique adults participated in the design sprints: Six adults participated in design sprint #1, and eleven adults participated in design sprint #2 (Fig. 4 ). Participants were eligible to participate if they belonged to one of the following cohorts: stroke survivor, caregiver of a stroke survivor ( e.g. , spouse), clinician, or engineer. All participants provided verbal consent to participation and the study was determined to be exempt from ongoing Institutional Review Board oversight by the University of Michigan IRBMED. Empathy Interviews Interviews highlighted the common patient frustrations using aids that are heavy or uncomfortable, leading to their eventual abandonment. For both clinicians and stroke survivors, the ease of understanding how to use an aid and actually use it, such as donning or doffing as independently as possible, were critical in adoption and utilization. Features like being light weight and easy to put on one-handed, offering support and stability were noted as particularly important. The visual appearance of an aid while wearing could also be relevant, particularly for initial adoption. High costs were generally prohibitive for most users in purchasing aids out of pocket. Design Sprint #1 – Affinity Mapping Affinity mapping in design sprints is a tool for organizing complex sets of data into meaningful categories, enabling a user-centered approach to design by highlighting user needs and preferences. This method helps teams move from a broad range of ideas to focused, actionable insights. During Experts Talk, each participant took notes on themes they heard during the talks. Next, participants placed these notes onto a board and arranged them into common themes through discussion. See Fig. 5 for Affinity Mapping themes. The Design Sprint Question In reviewing the themes that resulted from the Affinity Mapping process, the participants felt that “Adoption” was the most important theme to investigate further. As a group they drafted the Sprint Question on which to focus the remaining session: How might we enhance the NewGait device to improve adoption by stroke survivors ? With the Sprint Question in mind, the two stroke survivor participants got to try out the NewGait device for themselves. The stroke survivors were fitted for the device and then moved naturally around the space. The participants ambulated on level ground, completed transitional movements such as sit to stand transfers, and ascended and descended a staircase, while other sprint participants took note of their feedback. Once the stroke survivors had the opportunity to use the NewGait device in a variety of configurations and have their feedback recorded, the group took that feedback and grouped the notes by themes (see Fig. 6 ). After discussing the relative importance of the themes which emerged, the group agreed that “Donning & Doffing” and “Fit for Females” were the two most important issues to be addressed further. Between Design Sprints Substantial modifications were identified and implemented between the first and second design sprints. This process was guided by a focus on enhancements addressing issues highlighted during the affinity mapping phase of the initial sprint. In the context of the donning and doffing area, significant alterations were made across the entire system. The most notable change involved the transition to loop-backed neoprene for the primary components of the system, facilitating enhanced adhesion of any hook component to the device. The shoulder harness was reengineered, featuring a novel closure and attachment mechanism to the waist belt. This revision entailed replacing the traditional buckle system with a hook and loop design, thereby simplifying adjustment and donning processes. Additionally, the material of the shoulder harness keeper was upgraded to a more robust plastic, capable of resisting deformation under the stress exerted by elastic bands. The waist belt also underwent extensive redesign. The closure mechanism was transformed from a pullback strap to a straightforward hook and loop system. The anchors connected to the waist belt were reconstructed using rigid hook materials, enhancing their mobility around the waist belt and leg straps. This modification also facilitates lateral adjustments of the connection point between the shoulder harness and waist belt, accommodating users with varying breast sizes and shapes. Collectively, these design alterations have resulted in a product with reduced stitching, potentially increasing durability. The new design is less cumbersome and offers improved discretion when worn under clothing. These advancements collectively herald a design that not only meets functional requirements but also accommodates a wider range of body types, all while maintaining discretion and comfort when worn beneath clothing. Design Sprint #2 At the start of design sprint #2, the NewGait team (OPA and two therapists) modeled the new prototype device. As a group, the participants helped break down the donning and doffing process into the component steps. Each of the three stroke survivors was matched up with a clinician with experience using the NewGait device who helped fit the refined prototype based on their specific needs. Other design sprint participants took note of their feedback as they moved around with the device, organizing the feedback into positive (+), negative (-), questions (?) and new ideas (!). This feedback was then matched with the Donning and Doffing Journey Maps (see Figs. 7 and 8 ; see Supplemental Materials for individual journey maps) to match each user’s emotional response to the different steps. Post-Sprint Design Changes, Feedback, and Durability Testing Subsequent to the second design sprint, the team implemented modifications concerning the elastic band material driven from design sprint # 1, and attachment points of the elastic bands to the shoe/foot area, driven by feedback from design sprint # 2 to allow for barefoot walking and enhanced plantarflexion assistance. We replaced the latex-based elastic bands with silicone-based (latex-free) elastic bands, as the silicone-based elastic bands may be a more durable option for the NewGait device training. While silicone is a more expensive material, changing the bands to silicone could permit cost savings for patients and clinicians, as they would have to purchase fewer bands for routine treatment. Latex is also known to degrade more than silicone due to environmental factors ( 30 ). Silicone also has the added benefit of being hypoallergenic, as latex allergies are common ( 31 ). For barefoot walking, the modification entailed the development of a dorsal attachment piece to aid in dorsiflexion. This was achieved using an elastic material featuring a d-ring, designed to comfortably fit over the user's foot without the need for shoes. For enhanced plantarflexion assistance, we developed two new straps to be used inside and outside a user’s shoe. The first strap was engineered to be secured inside the shoe, beneath the sole. This strap included a small loop protruding 1–2 inches past the heel, aligning with the Achilles tendon. The second strap introduced a strap assembly that wraps around the shoe, equipped with a loop near the heel for carabiner attachment, thus aiding in plantarflexion. Results of the SUS revealed that Theratogs® scored an average of 46.9, the original NewGait device achieved 62.7, and the new stroke-specific NewGait device obtained a score of 84.3 in the usability assessments. A SUS score above 84.1 would be considered best imaginable and equivalent to a 96 percentile. Durability testing of the updated NewGait device was performed over days/weeks. The updated hook and loop neoprene straps and accompanying anchor points withstood testing and did not show any signs of deterioration with repeated loading. The elastic bands proved to be the weak point of the system. Latex-based bands were unable to withstand the number of cycles that would be required for routine use of the device and failed after 26,727 cycles. Inspection of the sample indicated that failure occurred at the interface between the elastic tubing and the clip, and partial fractures could be seen along the length of the band (Fig. 9 B). Silicone-based elastic bands proved to be much more durable and remained intact after 500,000 cycles with just a small tear near the interface of the elastic tubing and the clip (Fig. 9 C). DISCUSSION In this study, we developed a refined version of the NewGait device for post-stroke rehabilitation through iterative design sprints, involving essential stakeholders patients, caregivers, and clinicians. To our knowledge, this is the first exosuit device that was developed using a human-centered design approach that involved iterative design sprints for post-stroke gait rehabilitation. This iterative methodology was pivotal in developing a product that is both user-friendly and clinically adoptable, reflecting the core values of human-centered research. Through this process, we gathered critical feedback on the pros and cons of the existing NewGait device and the refined prototype, which played a significant role in refining the product's usability and enhancing the overall user experience. The implementation of this structured approach resulted in effective stakeholder participation and the development of a superior product (improved usability, comfort, modularity, and durability). The changes made to the design through design sprints were markedly more efficient compared to a non-structured approach. These design sprints, characterized by concentrated collaboration with diverse stakeholders within a structured environment, significantly accelerated the design process. The result was not only a faster development timeline but also a more refined product achieved through an efficient and systematic methodology. The new design boasts improved modularity and flexibility, expanding its application scope. Separately, enhancements in the design have also led to increased durability and cost-effectiveness because the newer prototype requires less stitching and calls for fewer product stock keeping units. The design's comfort level was also enhanced, which is anticipated to improve user compliance. These features are especially relevant in achieving our overall goal of creating a more accessible, low-cost post-stroke gait rehabilitation device. The overall improvements in the device are expected to promote greater independence and well-being for users, thereby widening its global impact and applicability. Strengths and Limitations A particular strength of our approach to this work was the engagement of all study team members with diverse backgrounds and experience in interpreting feedback gathered in all phases of this study. In doing this work, it is important to avoid two pitfalls. The first is the inevitable desire for overvaluing positive feedback and undervaluing negative feedback. Because we were invested in the success of our efforts to modify the device to meet the needs of stroke survivors, the risk of this bias influencing our interpretation of feedback is higher than it may be with quantitative measures. The second pitfall is the tendency of groups to fall into “group think” and seek agreement over disagreement. We mitigated these risks by gathering a diverse group of experts, encouraging and reinforcing the autonomy of roles and positions (e.g., engineers, developers, human-centered design experts, and end-users), encouraging dissent (e.g., asking team members to critique process and decisions in ways that are constructive), and taking turns when presenting counter arguments. While we made significant progress in improving on the device, there remain important concerns to address in future iterations, such as enabling greater ease in donning and doffing with one hand and greater comfort wearing underneath typical clothing, which were identified as important features driving adoption. Another limitation is that we currently do not know if the human-centered approach used in the study actually improved clinical adoption, as the new device is not in the market. Further, the clinical effectiveness of the device is yet to be tested for post-stroke rehabilitation (currently in progress), although anecdotal experience from clinicians and emerging research from other patient populations indicate that the NewGait device effectively addresses gait and balance issues ( 24 – 26 ). CONCLUSIONS In summary, we developed a low-cost, stroke-specific, gait and balance rehabilitation system using a novel human-centered design approach that involved empathy interviews and design sprints to collectively brainstorm ideas and incorporate end-user feedback in the device development process. We also performed a benchtop validation testing to establish product durability and system usability evaluation to evaluate whether device usability was improved with the human-centered design. The findings of this study indicate that this iterative approach resulted in a stroke-specific NewGait device that met user needs effectively while offering enhanced durability and usability compared to previous versions and competitive devices. Future research is needed to evaluate the short-term biomechanical adaptations and long-term clinical effectiveness of the NewGait device in a broad group of stroke population. Abbreviations AFO ankle-foot orthoses SUS System Usability Scale Declarations Ethics approval and consent to participate All participants provided verbal consent to participation and the study was determined to be exempt from ongoing Institutional Review Board oversight by the University of Michigan IRBMED. Consent for publication Not applicable Availability of data and materials The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Competing Interests OPA is the inventor of the NewGait device and CEO/Founder of the company that developed and sells the product. No other conflicts exist. Funding This work was supported by the Eunice Kennedy Shiver National Institute of Child Health and Human Development / National Institutes of Health (R41-HD111289). MB’s effort on this project was supported by funding from the Michigan Institute for Clinical & Health Research (NIH UM1-TR004404). Authors' contributions The authors confirm contribution to the paper as follows: Study conception and design: CZK, CK, OPA, EPW; Data Collection: TEA, MB, CK, CZK, EPW, AP, OPA; Analysis and interpretation of data: CK, OPA, MB, EPW, CZK; Major contributors in writing the manuscript and preparing figures: CK, CZK, EPW, OPA, TEA, MB; All authors reviewed the results, approved the final version of the manuscript, and agreed to be personally accountable for their own contributions and to ensure that any questions related to the accuracy or integrity of any part of the work (even concerning matters in which they were not personally involved) should be appropriately investigated, resolved, and the resolution documented in the literature. Acknowledgments We are grateful to Kimberly Spranger and Lynn Vanwelsenaers, for their assistance as expert clinicians. Lynn Vanwelsenaers was also responsible for fabricating prototypes. References Boehme AK, Esenwa C, Elkind MS. Stroke Risk Factors, Genetics, and Prevention. Circ Res. 2017;120(3):472–95. Ovbiagele B, Goldstein LB, Higashida RT, Howard VJ, Johnston SC, Khavjou OA, et al. Forecasting the future of stroke in the United States: a policy statement from the American Heart Association and American Stroke Association. Stroke. 2013;44(8):2361–75. Krakauer JW, Carmichael ST. Broken movement: the neurobiology of motor recovery after stroke. MIT Press; 2022. Winstein CJ, Stein J, Arena R, Bates B, Cherney LR, Cramer SC, et al. Guidelines for Adult Stroke Rehabilitation and Recovery: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2016;47(6):e98–e169. Marchal-Crespo L, Reinkensmeyer DJ. Review of control strategies for robotic movement training after neurologic injury. J Neuroeng Rehabil. 2009;6:20. Sloot LH, Baker LM, Bae J, Porciuncula F, Clement BF, Siviy C, et al. Effects of a soft robotic exosuit on the quality and speed of overground walking depends on walking ability after stroke. J Neuroeng Rehabil. 2023;20(1):113. Lee M, Rittenhouse M, Abdullah HA. Design issues for therapeutic robot systems: results from a survey of physiotherapists. J Intell Rob Syst. 2005;42:239–52. Lu EC, Wang RH, Hebert D, Boger J, Galea MP, Mihailidis A. The development of an upper limb stroke rehabilitation robot: identification of clinical practices and design requirements through a survey of therapists. Disabil Rehabil Assist Technol. 2011;6(5):420–31. Hesse S, Werner C, Matthias K, Stephen K, Berteanu M. Non-velocity-related effects of a rigid double-stopped ankle-foot orthosis on gait and lower limb muscle activity of hemiparetic subjects with an equinovarus deformity. Stroke. 1999;30(9):1855–61. Yamamoto M, Shimatani K, Hasegawa M, Kurita Y. Effects of Varying Plantarflexion Stiffness of Ankle-Foot Orthosis on Achilles Tendon and Propulsion Force During Gait. IEEE Trans Neural Syst Rehabil Eng. 2020;28(10):2194–202. Chen G. Induced acceleration contributions to locomotion dynamics are not physically well defined. Gait Posture. 2006;23(1):37–44. Maguire C, Sieben JM, Frank M, Romkes J. Hip abductor control in walking following stroke -- the immediate effect of canes, taping and TheraTogs on gait. Clin Rehabil. 2010;24(1):37–45. Martins E, Cordovil R, Oliveira R, Pinho J, Diniz A, Vaz JR. The Immediate Effects of a Dynamic Orthosis on Gait Patterns in Children With Unilateral Spastic Cerebral Palsy: A Kinematic Analysis. Front Pediatr. 2019;7:42. Belizon-Bravo N, Romero-Galisteo RP, Cano-Bravo F, Gonzalez-Medina G, Pinero-Pinto E, Luque-Moreno C. Effects of Dynamic Suit Orthoses on the Spatio-Temporal Gait Parameters in Children with Cerebral Palsy: A Systematic Review. Child (Basel). 2021;8(11). AxioBionics. TripleFlex 2023 [Available from: https://www.axiobionics.com/tripleflex/ . Alqahtani S, Joseph J, Dicianno B, Layton NA, Toro ML, Ferretti E, et al. Stakeholder perspectives on research and development priorities for mobility assistive-technology: a literature review. Disabil Rehabil Assist Technol. 2021;16(4):362–76. Wolff J, Parker C, Borisoff J, Mortenson WB, Mattie J. A survey of stakeholder perspectives on exoskeleton technology. J Neuroeng Rehabil. 2014;11:169. Manz S, Valette R, Damonte F, Avanci Gaudio L, Gonzalez-Vargas J, Sartori M, et al. A review of user needs to drive the development of lower limb prostheses. J Neuroeng Rehabil. 2022;19(1):119. Still B, Crane K. Fundamentals of user-centered design: A practical approach. CRC press; 2017. Fidopiastis CM, Rizzo AA, Rolland JP. User-centered virtual environment design for virtual rehabilitation. J Neuroeng Rehabil. 2010;7:11. Melles M, Albayrak A, Goossens R. Innovating health care: key characteristics of human-centered design. Int J Qual Health Care. 2021;33(Supplement1):37–44. Holeman I, Kane D. Human-centered design for global health equity. Inf Technol Dev. 2019;26(3):477–505. Banfield R, Lombardo CT, Wax T. Design sprint: A practical guidebook for building great digital products. O'Reilly Media, Inc.; 2015. Tooman K. Trial of the NewGaitTM to Alter Running Mechanics in a High School Athlete: A Case Report. Orthop Phys Therapy Pract. 2022;34(4):233–7. Tooman KM, Weiler J, Larson CA. Trial of NewGait™ to Improve Gait and Sit-to-Stand Mechanics in an Older Adult Following Total Joint Replacements: A Case Report. JOSPT Cases. 2023;3(1):43–52. Ustinova KI, Langenderfer JE. Feasibility of using the NewGait assistive device for correcting gait deviations in individuals with various neurological disorders: Case study. Physiother Res Int. 2023:e2055. Farao J, Malila B, Conrad N, Mutsvangwa T, Rangaka MX, Douglas TS. A user-centred design framework for mHealth. PLoS ONE. 2020;15(8):e0237910. Knapp J, Zeratsky J, Kowitz B, Sprint. How to solve big problems and test new ideas in just five days. Simon and Schuster; 2016. Brooke J. Sus: a quick and dirty’usability. Usability evaluation in industry. 1996;189(3):189–94. Rose K, Steinbuchel A. Biodegradation of natural rubber and related compounds: recent insights into a hardly understood catabolic capability of microorganisms. Appl Environ Microbiol. 2005;71(6):2803–12. Wu M, McIntosh J, Liu J. Current prevalence rate of latex allergy: Why it remains a problem? J Occup Health. 2016;58(2):138–44. Sauro J. 5 Ways in Interpret a SUS Score: Measuring U; 2018 [Available from: https://measuringu.com/interpret-sus-score/ . Additional Declarations Competing interest reported. OPA is the inventor of the NewGait device and CEO/Founder of the company that developed and sells the product. No other conflicts exist. Supplementary Files SupplementalMaterials.docx Cite Share Download PDF Status: Published Journal Publication published 24 Apr, 2024 Read the published version in Journal of NeuroEngineering and Rehabilitation → Version 1 posted Editorial decision: Revision requested 26 Feb, 2024 Reviews received at journal 29 Jan, 2024 Reviewers agreed at journal 29 Jan, 2024 Reviewers invited by journal 27 Jan, 2024 Editor assigned by journal 24 Jan, 2024 Submission checks completed at journal 24 Jan, 2024 First submitted to journal 23 Jan, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3891566","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":269083720,"identity":"3619da6d-d7a0-43e1-a7fc-653e2ac701d5","order_by":0,"name":"Chandramouli Krishnan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAnklEQVRIiWNgGAWjYHACxgMJFQwMbAw8DCCSOHAg4QzJWhjbQBSxWnTbewwOPJx3OJqP/ewBhg9lhwlrMTtzxuBA4rbDuW08eQmMM84Ro+VGDlSLBI8BM28b0VrmQLX8JV5LA1QLI1FazhwrOJBwLB3olxyDgz3n0onQcrx548MfNda589vPGD74UWZNWAsKOECi+lEwCkbBKBgFuAAAtJE+soDogtYAAAAASUVORK5CYII=","orcid":"","institution":"University of Michigan","correspondingAuthor":true,"prefix":"","firstName":"Chandramouli","middleName":"","lastName":"Krishnan","suffix":""},{"id":269083721,"identity":"8a62ccba-5638-4d7c-b264-a11d06b0ce64","order_by":1,"name":"Olugbenga P. Adeeko","email":"","orcid":"","institution":"Elite Athlete Products, Inc","correspondingAuthor":false,"prefix":"","firstName":"Olugbenga","middleName":"P.","lastName":"Adeeko","suffix":""},{"id":269083722,"identity":"2c1fcca5-d999-4e68-9562-d48e52309d17","order_by":2,"name":"Edward Peter Washabaugh","email":"","orcid":"","institution":"Wayne State University","correspondingAuthor":false,"prefix":"","firstName":"Edward","middleName":"Peter","lastName":"Washabaugh","suffix":""},{"id":269083723,"identity":"49f9ae60-b9d0-4f67-a72f-45fbf91e0dd1","order_by":3,"name":"Thomas E Augenstein","email":"","orcid":"","institution":"University of Michigan","correspondingAuthor":false,"prefix":"","firstName":"Thomas","middleName":"E","lastName":"Augenstein","suffix":""},{"id":269083724,"identity":"a2a45678-c5c5-41a7-88ba-81cd363ba1ff","order_by":4,"name":"Maureen Brudzinski","email":"","orcid":"","institution":"University of Michigan","correspondingAuthor":false,"prefix":"","firstName":"Maureen","middleName":"","lastName":"Brudzinski","suffix":""},{"id":269083725,"identity":"00cda234-a1f8-4466-bd04-e86c3f08ddc9","order_by":5,"name":"Alyssa Portelli","email":"","orcid":"","institution":"University of Michigan","correspondingAuthor":false,"prefix":"","firstName":"Alyssa","middleName":"","lastName":"Portelli","suffix":""},{"id":269083726,"identity":"c0157295-f068-4f59-aee0-1ca209e35319","order_by":6,"name":"Claire Zabelle Kalpakjian","email":"","orcid":"","institution":"University of Michigan","correspondingAuthor":false,"prefix":"","firstName":"Claire","middleName":"Zabelle","lastName":"Kalpakjian","suffix":""}],"badges":[],"createdAt":"2024-01-23 16:14:46","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3891566/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3891566/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12984-024-01356-3","type":"published","date":"2024-04-24T23:27:34+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":50182844,"identity":"0b0dc4d2-bb8a-41e0-8fd8-778cb5fa7c20","added_by":"auto","created_at":"2024-01-25 19:03:10","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2604428,"visible":true,"origin":"","legend":"\u003cp\u003eThe NewGait® device\u003c/p\u003e","description":"","filename":"figure113.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/48b1d93bb11b300403a57532.png"},{"id":50182531,"identity":"e4b692b5-36a5-4394-8d88-c76eaf549f78","added_by":"auto","created_at":"2024-01-25 18:55:10","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":324506,"visible":true,"origin":"","legend":"\u003cp\u003eA schematic of the design sprint overview\u003c/p\u003e","description":"","filename":"figure210.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/e6016a8016027dd144eae830.png"},{"id":50182533,"identity":"2d776892-f1bc-4ae1-b9c1-45cd9ffe52d0","added_by":"auto","created_at":"2024-01-25 18:55:10","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":823165,"visible":true,"origin":"","legend":"\u003cp\u003ePercentiles, grades, and adjectives to describe raw SUS. (adapted from Sauro, J) (32)\u003c/p\u003e","description":"","filename":"figure38.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/6d7571cfdf773e757a12a296.png"},{"id":50183186,"identity":"798194bc-0e8f-408b-8189-f2191dc69300","added_by":"auto","created_at":"2024-01-25 19:11:10","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":526737,"visible":true,"origin":"","legend":"\u003cp\u003eDemographic information of design sprint study participants. (Left) Basic demographic information for all participants. (Right) Cohort-specific demographic information\u003c/p\u003e","description":"","filename":"figure45.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/d9733c21516d9e9e91d31fa5.png"},{"id":50182532,"identity":"87a578d9-c305-4b5d-bae4-6b5e2a7b669c","added_by":"auto","created_at":"2024-01-25 18:55:10","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1060651,"visible":true,"origin":"","legend":"\u003cp\u003eA schematic of affinity mapping themes\u003c/p\u003e","description":"","filename":"figure53.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/856790dce622ca4ac78f22e6.png"},{"id":50183185,"identity":"394041e6-008c-4b4a-b41d-2858f94d2fa5","added_by":"auto","created_at":"2024-01-25 19:11:10","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1038209,"visible":true,"origin":"","legend":"\u003cp\u003eA schematic of the primary themes that emerged from the design sprints\u003c/p\u003e","description":"","filename":"figure62.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/1ae5d8fd4b67ec5e17ebbbc2.png"},{"id":50182540,"identity":"a7f4d804-7dfa-4472-8ab4-14ff67a95826","added_by":"auto","created_at":"2024-01-25 18:55:10","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":401451,"visible":true,"origin":"","legend":"\u003cp\u003eA schematic of the device donning journey map from design sprint #1 and #2\u003c/p\u003e","description":"","filename":"figure72.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/033a658d41ca1c3573a5e252.png"},{"id":50182841,"identity":"7ba4fbe2-6a3b-4566-a011-8ea7b472897a","added_by":"auto","created_at":"2024-01-25 19:03:10","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":293070,"visible":true,"origin":"","legend":"\u003cp\u003eA schematic of the device doffing journey map from design sprint #1 and #2\u003c/p\u003e","description":"","filename":"figure82.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/752e9442fd79c17fcf50854f.png"},{"id":50182535,"identity":"fcc27c4a-e11e-4ad4-b82b-703b0436a0bd","added_by":"auto","created_at":"2024-01-25 18:55:10","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":690076,"visible":true,"origin":"","legend":"\u003cp\u003eDurability testing. (A) Schematic of the system used for durability testing of the NewGait prototype design. (B) Representative schematic indicating the failure zones on the latex elastic band after total failure (26,727 cycles). (C) Representative schematic indicating the condition of the silicone elastic band after completing 500,000 cycles of loading.\u003c/p\u003e","description":"","filename":"figure92.png","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/b69ea5df09b055a21777fad4.png"},{"id":51069951,"identity":"eb1474ed-9cde-48d9-b979-ba96fcfbcf83","added_by":"auto","created_at":"2024-02-13 16:01:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2192256,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/7e7bf449-5821-48af-b1e3-b76811b6c404.pdf"},{"id":50182842,"identity":"84cf79d3-709a-437e-b693-81941529ef7e","added_by":"auto","created_at":"2024-01-25 19:03:10","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1127868,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalMaterials.docx","url":"https://assets-eu.researchsquare.com/files/rs-3891566/v1/b858e2cd78d9db3569639c7c.docx"}],"financialInterests":"Competing interest reported. OPA is the inventor of the NewGait device and CEO/Founder of the company that developed and sells the product. No other conflicts exist.","formattedTitle":"Human-Centered Design of a Novel Soft Exosuit for Post-Stroke Gait Rehabilitation","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eStroke is the leading cause of long-term adult disability worldwide (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). By 2030, nearly 4% of the US population is expected to have had a stroke, leading to an estimated cost burden of ~\u003cspan\u003e$\u003c/span\u003e184\u0026nbsp;billion (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). While some level of spontaneous biological recovery can occur after a stroke, this process is often incomplete, leaving most stroke survivors with persistent gait impairments, which can lead to walking disabilities, falls, and reduced health-related quality of life (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). As a result, clinicians emphasize the restoration of gait and balance as a central goal of stroke rehabilitation.\u003c/p\u003e \u003cp\u003eNumerous innovative therapeutic approaches, such as body weight supported treadmill training and robotic therapy, have emerged to address this challenge (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). However, the outcomes of these interventions have frequently fallen short of expectations, in part due to their high costs and modest benefits, limiting their clinical translation (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). Recognizing the pressing need for effective, efficient, and low-cost technologies for gait rehabilitation after stroke, researchers and engineers have explored various wearable solutions. Conventional ankle-foot orthoses (AFOs) offer simplicity and affordability, but they may inadvertently result in disuse atrophy and reduced gait efficiency by limiting Achilles tendon excursion and propulsive forces during walking (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Moreover, they primarily target the ankle joint, overlooking the essential roles of the hip, knee, and trunk in gait and balance (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). While devices like TheraTogs (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e) and TheraSuit (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e) aim to address multiple joint areas, their primary focus on the pediatric market (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e) raises challenges when adapting to the adult stroke population. TripleFlex (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e), a more recent development, targets foot drop and leg-lift deficiencies by putting energy into flexing each joint during the swing phase of gait, thereby offering potential improvements, particularly for adults with neurological conditions like stroke. Nonetheless, the scarcity of comprehensive studies assessing these devices' efficacy and effectiveness leaves substantial uncertainties regarding the clinical utility and useability of these devices for stroke rehabilitation.\u003c/p\u003e \u003cp\u003eA recurring issue in the field is that many of these devices have been conceived without adequate input from the individuals who matter most in the rehabilitation process\u0026mdash;stroke survivors, their caregivers, and the clinicians providing care. This omission has led to devices that often do not fully align with the actual needs and preferences of these end-users (\u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). As a result, the utilization of these devices remains limited, and questions linger about how well they address the needs and desires of clinicians and patients, further hindering their clinical utility and usability.\u003c/p\u003e \u003cp\u003eAddressing these challenges necessitates a shift in the approach to device development strategies. Integrating the principles of human-centered design can significantly enhance the development process and result in more inclusive, tailored, and empowering solutions (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). Human-centered design emphasizes understanding people's needs, motivations, and concerns while engaging stakeholders from the outset and adopting a systems approach to generalize individual interests to collective solutions (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). It allows for more effective and efficient design by engaging with users early in the development process, yielding valuable insights while working with prototypes and sketches, rather than fully built products, which can prevent the misallocation of resources (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this study, we employ a novel device design framework based on human-centered design strategies, known as \"design sprints\" (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e), to comprehensively grasp user needs and expectations in order to refine a low-cost, passive exosuit device called NewGait device for stroke rehabilitation (\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). The NewGait device (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), originally developed as a sports and performance enhancement device called SpeedMaker\u0026reg;, features lightweight elastic bands, leg straps, a shoulder harness, a waist belt, and movable anchor points for connecting the bands, rendering it highly modular. These elastic bands work in concert with muscle and tendon groups to assist or resist motion. While the clinical efficacy of the NewGait device has not been extensively documented, many clinicians have used it to treat gait and balance issues in individuals with stroke and have anecdotally reported noteworthy clinical improvements. However, feedback from clinicians and patients revealed the need for refinement, particularly for stroke-specific populations, as the original device was not intended for this population. Therefore, the purpose of this study was to use human-centered design approaches to tailor the NewGait device to the unique requirements of stroke rehabilitation. We hope that by prioritizing the input and feedback of stroke survivors, caregivers, and clinicians, we will be able to ultimately enhance its clinical usability and effectiveness in improving the lives of those affected by this debilitating condition.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Overview\u003c/h2\u003e \u003cp\u003eThe development process of the stroke-specific NewGait device involved two iterations of design sprints. Design sprint #1 also included user interviews (i.e., empathy interviews) in the understand phase to gain insights from stroke patients and incorporate their perspectives into the development process (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e). After each design sprint, the NewGait device technical team made necessary adjustments to improve the prototype to address key issues and recommendations that emerged from the design sprint. Once the product development was complete, benchtop mechanical testing was conducted to evaluate the durability of the NewGait device. Additionally, a system usability evaluation was performed to compare the usability of the newer prototype with both the older version of the NewGait device and a competitor's device (TheraTogs). These evaluations provided valuable data on product durability, as well as usability in comparison with existing solutions.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eDesign Sprints\u003c/h2\u003e \u003cp\u003e \u003cem\u003eDesign sprints\u003c/em\u003e attempt to compress the human-centered design process into a compact schedule of several hours (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). A traditional design sprint, as initially formulated by Google Ventures, lasts five days, with each day dedicated to one of the five stages: \u003cem\u003eUnderstand\u003c/em\u003e, \u003cem\u003eSketch\u003c/em\u003e, \u003cem\u003eDecide\u003c/em\u003e, \u003cem\u003ePrototype\u003c/em\u003e, and \u003cem\u003eTest\u003c/em\u003e. The process encourages teams to fail faster, meaning that shortcomings in a product or process are brought to light early in the design process before significant time and money have been invested. Ideally, the participants in a sprint bring varied perspectives on the problem, for example, clinicians, patients, caregivers, designers and/or programmers. Empathy interviews, a cornerstone of human-centered design, are used to help understand the needs of target users. All study activities were approved by the University of Michigan IRBMED as exempt; participants provided verbal agreement and offered \u003cspan\u003e$\u003c/span\u003e50 for their participation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eEmpathy Interviews\u003c/h2\u003e \u003cp\u003eThe primary goal for empathy interviews was to engage clinicians with expertise in providing physical or occupational therapy and stroke survivors to learn more about the selection, adoption, and utilization of mobility aids. Specifically, interviews focused on the benefits of mobility aids, preferences around single use devices or a multi-functional device, features that make a mobility device acceptable, and strategies to facilitate the selection, adoption, and utilization of a mobility aid. Results of the empathy interviews helped to determine the constraints of the design sprints and where input would be most useful, which was particularly important given the NewGait device is an existing product. Results of interviews also informed the Journey Maps produced at the end of design sprint #2. All interviews were moderated by an expert in design sprints (MB) and expert in rehabilitation (CK); all interviews were audio-recorded and professionally transcribed.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eOverview of Design Sprints\u003c/h2\u003e \u003cp\u003eBecause the NewGait device is a pre-existing product being marketed to a different target audience than originally intended (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e), the design sprint process was modified (see Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Each design sprint was conducted over a duration of one day, encompassing a total of seven hours. The \u003cem\u003eDecide\u003c/em\u003e and \u003cem\u003ePrototype\u003c/em\u003e steps were executed externally to the design sprints.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eDesign Sprint #1\u003c/h2\u003e \u003cp\u003eIn design sprint #1, we followed the traditional \u003cem\u003eUnderstand\u003c/em\u003e process, using notes taken by participants during \u003cem\u003eExpert Talks\u003c/em\u003e to identify important themes. \u003cem\u003eExpert Talks\u003c/em\u003e allow each of the participants to explain their unique perspective on the design problem (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). Although each conversation takes only 5\u0026ndash;10 minutes, the questions the facilitators ask (MB and CZK) are designed to give the participant an opportunity to discuss their knowledge, feelings and experiences. During these conversations, the other participants take note of ideas that surprise, intrigue, or resonate with them. Participants share the notes that they took from those conversations with the entire group. As themes in these notes reveal themselves, the notes are grouped and labeled to allow the patterns of the group\u0026rsquo;s thinking to emerge. These notes form the raw material for the subsequent \u003cem\u003eAffinity Mapping\u003c/em\u003e step. Affinity maps are used to visualize information from brainstorming sessions, resulting in themes that emerged from discussion.\u003c/p\u003e \u003cp\u003eAfter discussing these themes in the group, a single theme is given priority (\u003cem\u003eDefine a Sprint Question\u003c/em\u003e) to focus the work of the rest of the session. With this theme in mind, participants used the NewGait device and (as a modified \u003cem\u003eSketch\u003c/em\u003e) gave feedback on their experience. We then identified the themes present in this user feedback, deciding on what the participants felt were the most pressing issues. Six participants were involved in design sprint #1: NewGait developer (OPA), three rehabilitation researchers who are rehabilitation engineers, and two stroke survivors. The sprint was led by an expert in user-centered design (MB) and human-centered research (CZK). A postdoctoral fellow assisted stroke survivor participants with note taking.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eBetween Design Sprints\u003c/h2\u003e \u003cp\u003eAfter design sprint #1, the NewGait team reviewed the Affinity Maps of feedback based on end users trying the NewGait device and decided (\u003cem\u003eDecide\u003c/em\u003e phase) what to incorporate into a new prototype (\u003cem\u003ePrototype\u003c/em\u003e phase) device, which was used in Sprint #2. Whereas these steps often co-occur during a single design sprint, due to the technical knowledge needed to make appropriate adjustments to the device, the NewGait team evaluated and adopted what they felt were appropriate modifications to the device based on the user input from design sprint #1.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eDesign Sprint #2\u003c/h2\u003e \u003cp\u003eIn design sprint #2, we used the \u003cem\u003eUnderstand\u003c/em\u003e phase to construct a Journey Map of the donning and doffing process for the device. As the users then tested (\u003cem\u003eTest\u003c/em\u003e phase) the new prototype device, their feedback was plotted against the Journey Map to visualize pain points in the process worth addressing. Eleven participants were involved in design sprint #2: NewGait developer (OPA), two rehabilitation researchers who are rehabilitation engineers, two physical therapists and one prosthetist who were experienced users of the NewGait device, and three stroke survivors and two caregivers. The sprint was led by the same expert in user-centered design (MB) as for design sprint #1. A postdoctoral fellow assisted stroke survivor participants with note taking.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003ePost-Sprint Feedback and Durability Testing\u003c/h2\u003e \u003cp\u003eUpon the culmination of the two design sprints, we implemented design modifications to the NewGait device. We then administered System Usability Scale surveys (SUS) to patients and physical therapists to assess the usability of the original device, the new prototype, and a competitive device (Theratogs\u0026reg;, Telluride, Colorado). The System Usability Scale (SUS) (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e) is a reliable and popular measure of a user\u0026rsquo;s perception of the usability of a device, software, or system. It is a 10-item questionnaire with five response options from Strongly agree to Strongly disagree. The final score is converted to a scale, ranging between 0-100, where a higher score indicates greater usability. The final scores can also be converted into a percentile score to better interpret the usability of the system. The interpretation of the scores of the SUS surveys are provided in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eDurability (i.e., fatigue) testing was performed to ensure that the new prototype could withstand repeated loading that would be expected while using the device. Fatigue testing was performed on the interfaces between the straps, anchor points, and elastic bands, which we identified as the likely failure points. We tested elastic bands made of two materials of similar stiffness: latex-based, as has been used with previous iterations of the NewGait device, and silicone-based, which are known to be more durable. These device components were loaded into a hydraulic tensile testing machine (Instron 8521, Canton, MA, USA). Briefly, a hook-and-loop neoprene strap was fastened to a wooden block that was clamped down to the base of the tensile testing machine. An anchor point was attached to the strap and the elastic band was connected between the anchor point and the actuator of the tensile testing machine. The cross-head of the machine was adjusted so that the band was not in slack when the actuator was fully extended. Care was taken to ensure proper alignment of the sample with the actuator. The machine was configured so that the components would undergo 10 cm of deformation in accordance with a sine wave (frequency\u0026thinsp;=\u0026thinsp;1.75 Hz). The 10 cm of deformation was based on band excursions obtained from biomechanical data of stroke survivors. Note that although the silicone tubing had a longer interface with the clips, the active elastic portion of each band was the same length. The characteristics of the loading (i.e., force, deformation, and rate) were recorded using on-board instrumentation. The sample was repeatedly loaded until either the sample failed (e.g., breaking of the elastic band or degradation of the hook and loop fastening), or the machine reached 500,000 loading cycles (equivalent of 3000 steps/day for 6 months, as anticipated for clinical or in-home use).\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eParticipants\u003c/h2\u003e \u003cp\u003e Participants in empathy interviews included four stroke survivors, two occupational therapists, and two physical therapists. One interview included both stroke survivor and their physical therapist. Fourteen unique adults participated in the design sprints: Six adults participated in design sprint #1, and eleven adults participated in design sprint #2 (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Participants were eligible to participate if they belonged to one of the following cohorts: stroke survivor, caregiver of a stroke survivor (\u003cem\u003ee.g.\u003c/em\u003e, spouse), clinician, or engineer. All participants provided verbal consent to participation and the study was determined to be exempt from ongoing Institutional Review Board oversight by the University of Michigan IRBMED.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eEmpathy Interviews\u003c/h2\u003e \u003cp\u003eInterviews highlighted the common patient frustrations using aids that are heavy or uncomfortable, leading to their eventual abandonment. For both clinicians and stroke survivors, the ease of understanding how to use an aid and actually use it, such as donning or doffing as independently as possible, were critical in adoption and utilization. Features like being light weight and easy to put on one-handed, offering support and stability were noted as particularly important. The visual appearance of an aid while wearing could also be relevant, particularly for initial adoption. High costs were generally prohibitive for most users in purchasing aids out of pocket.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eDesign Sprint #1 \u0026ndash; Affinity Mapping\u003c/h2\u003e \u003cp\u003eAffinity mapping in design sprints is a tool for organizing complex sets of data into meaningful categories, enabling a user-centered approach to design by highlighting user needs and preferences. This method helps teams move from a broad range of ideas to focused, actionable insights. During Experts Talk, each participant took notes on themes they heard during the talks. Next, participants placed these notes onto a board and arranged them into common themes through discussion. See Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e for Affinity Mapping themes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eThe Design Sprint Question\u003c/h2\u003e \u003cp\u003eIn reviewing the themes that resulted from the Affinity Mapping process, the participants felt that \u0026ldquo;Adoption\u0026rdquo; was the most important theme to investigate further. As a group they drafted the Sprint Question on which to focus the remaining session: \u003cem\u003eHow might we enhance the NewGait device to improve adoption by stroke survivors\u003c/em\u003e? With the Sprint Question in mind, the two stroke survivor participants got to try out the NewGait device for themselves. The stroke survivors were fitted for the device and then moved naturally around the space. The participants ambulated on level ground, completed transitional movements such as sit to stand transfers, and ascended and descended a staircase, while other sprint participants took note of their feedback.\u003c/p\u003e \u003cp\u003eOnce the stroke survivors had the opportunity to use the NewGait device in a variety of configurations and have their feedback recorded, the group took that feedback and grouped the notes by themes (see Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). After discussing the relative importance of the themes which emerged, the group agreed that \u0026ldquo;Donning \u0026amp; Doffing\u0026rdquo; and \u0026ldquo;Fit for Females\u0026rdquo; were the two most important issues to be addressed further.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eBetween Design Sprints\u003c/h2\u003e \u003cp\u003eSubstantial modifications were identified and implemented between the first and second design sprints. This process was guided by a focus on enhancements addressing issues highlighted during the affinity mapping phase of the initial sprint. In the context of the donning and doffing area, significant alterations were made across the entire system. The most notable change involved the transition to loop-backed neoprene for the primary components of the system, facilitating enhanced adhesion of any hook component to the device. The shoulder harness was reengineered, featuring a novel closure and attachment mechanism to the waist belt. This revision entailed replacing the traditional buckle system with a hook and loop design, thereby simplifying adjustment and donning processes. Additionally, the material of the shoulder harness keeper was upgraded to a more robust plastic, capable of resisting deformation under the stress exerted by elastic bands.\u003c/p\u003e \u003cp\u003eThe waist belt also underwent extensive redesign. The closure mechanism was transformed from a pullback strap to a straightforward hook and loop system. The anchors connected to the waist belt were reconstructed using rigid hook materials, enhancing their mobility around the waist belt and leg straps. This modification also facilitates lateral adjustments of the connection point between the shoulder harness and waist belt, accommodating users with varying breast sizes and shapes.\u003c/p\u003e \u003cp\u003eCollectively, these design alterations have resulted in a product with reduced stitching, potentially increasing durability. The new design is less cumbersome and offers improved discretion when worn under clothing. These advancements collectively herald a design that not only meets functional requirements but also accommodates a wider range of body types, all while maintaining discretion and comfort when worn beneath clothing.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eDesign Sprint #2\u003c/h2\u003e \u003cp\u003eAt the start of design sprint #2, the NewGait team (OPA and two therapists) modeled the new prototype device. As a group, the participants helped break down the donning and doffing process into the component steps. Each of the three stroke survivors was matched up with a clinician with experience using the NewGait device who helped fit the refined prototype based on their specific needs. Other design sprint participants took note of their feedback as they moved around with the device, organizing the feedback into positive (+), negative (-), questions (?) and new ideas (!). This feedback was then matched with the Donning and Doffing Journey Maps (see Figs.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e7\u003c/span\u003e and \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e8\u003c/span\u003e; see Supplemental Materials for individual journey maps) to match each user\u0026rsquo;s emotional response to the different steps.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003ePost-Sprint Design Changes, Feedback, and Durability Testing\u003c/h2\u003e \u003cp\u003eSubsequent to the second design sprint, the team implemented modifications concerning the elastic band material driven from design sprint # 1, and attachment points of the elastic bands to the shoe/foot area, driven by feedback from design sprint # 2 to allow for barefoot walking and enhanced plantarflexion assistance. We replaced the latex-based elastic bands with silicone-based (latex-free) elastic bands, as the silicone-based elastic bands may be a more durable option for the NewGait device training. While silicone is a more expensive material, changing the bands to silicone could permit cost savings for patients and clinicians, as they would have to purchase fewer bands for routine treatment. Latex is also known to degrade more than silicone due to environmental factors (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). Silicone also has the added benefit of being hypoallergenic, as latex allergies are common (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFor barefoot walking, the modification entailed the development of a dorsal attachment piece to aid in dorsiflexion. This was achieved using an elastic material featuring a d-ring, designed to comfortably fit over the user's foot without the need for shoes. For enhanced plantarflexion assistance, we developed two new straps to be used inside and outside a user\u0026rsquo;s shoe. The first strap was engineered to be secured inside the shoe, beneath the sole. This strap included a small loop protruding 1\u0026ndash;2 inches past the heel, aligning with the Achilles tendon. The second strap introduced a strap assembly that wraps around the shoe, equipped with a loop near the heel for carabiner attachment, thus aiding in plantarflexion.\u003c/p\u003e \u003cp\u003eResults of the SUS revealed that Theratogs\u0026reg; scored an average of 46.9, the original NewGait device achieved 62.7, and the new stroke-specific NewGait device obtained a score of 84.3 in the usability assessments. A SUS score above 84.1 would be considered best imaginable and equivalent to a 96 percentile.\u003c/p\u003e \u003cp\u003eDurability testing of the updated NewGait device was performed over days/weeks. The updated hook and loop neoprene straps and accompanying anchor points withstood testing and did not show any signs of deterioration with repeated loading. The elastic bands proved to be the weak point of the system. Latex-based bands were unable to withstand the number of cycles that would be required for routine use of the device and failed after 26,727 cycles. Inspection of the sample indicated that failure occurred at the interface between the elastic tubing and the clip, and partial fractures could be seen along the length of the band (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003eB). Silicone-based elastic bands proved to be much more durable and remained intact after 500,000 cycles with just a small tear near the interface of the elastic tubing and the clip (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003eC).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eIn this study, we developed a refined version of the NewGait device for post-stroke rehabilitation through iterative design sprints, involving essential stakeholders patients, caregivers, and clinicians. To our knowledge, this is the first exosuit device that was developed using a human-centered design approach that involved iterative design sprints for post-stroke gait rehabilitation. This iterative methodology was pivotal in developing a product that is both user-friendly and clinically adoptable, reflecting the core values of human-centered research. Through this process, we gathered critical feedback on the pros and cons of the existing NewGait device and the refined prototype, which played a significant role in refining the product's usability and enhancing the overall user experience. The implementation of this structured approach resulted in effective stakeholder participation and the development of a superior product (improved usability, comfort, modularity, and durability).\u003c/p\u003e \u003cp\u003eThe changes made to the design through design sprints were markedly more efficient compared to a non-structured approach. These design sprints, characterized by concentrated collaboration with diverse stakeholders within a structured environment, significantly accelerated the design process. The result was not only a faster development timeline but also a more refined product achieved through an efficient and systematic methodology.\u003c/p\u003e \u003cp\u003eThe new design boasts improved modularity and flexibility, expanding its application scope. Separately, enhancements in the design have also led to increased durability and cost-effectiveness because the newer prototype requires less stitching and calls for fewer product stock keeping units. The design's comfort level was also enhanced, which is anticipated to improve user compliance. These features are especially relevant in achieving our overall goal of creating a more accessible, low-cost post-stroke gait rehabilitation device. The overall improvements in the device are expected to promote greater independence and well-being for users, thereby widening its global impact and applicability.\u003c/p\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eStrengths and Limitations\u003c/h2\u003e \u003cp\u003eA particular strength of our approach to this work was the engagement of all study team members with diverse backgrounds and experience in interpreting feedback gathered in all phases of this study. In doing this work, it is important to avoid two pitfalls. The first is the inevitable desire for overvaluing positive feedback and undervaluing negative feedback. Because we were invested in the success of our efforts to modify the device to meet the needs of stroke survivors, the risk of this bias influencing our interpretation of feedback is higher than it may be with quantitative measures. The second pitfall is the tendency of groups to fall into \u0026ldquo;group think\u0026rdquo; and seek agreement over disagreement. We mitigated these risks by gathering a diverse group of experts, encouraging and reinforcing the autonomy of roles and positions (e.g., engineers, developers, human-centered design experts, and end-users), encouraging dissent (e.g., asking team members to critique process and decisions in ways that are constructive), and taking turns when presenting counter arguments. While we made significant progress in improving on the device, there remain important concerns to address in future iterations, such as enabling greater ease in donning and doffing with one hand and greater comfort wearing underneath typical clothing, which were identified as important features driving adoption. Another limitation is that we currently do not know if the human-centered approach used in the study actually improved clinical adoption, as the new device is not in the market. Further, the clinical effectiveness of the device is yet to be tested for post-stroke rehabilitation (currently in progress), although anecdotal experience from clinicians and emerging research from other patient populations indicate that the NewGait device effectively addresses gait and balance issues (\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"CONCLUSIONS","content":"\u003cp\u003eIn summary, we developed a low-cost, stroke-specific, gait and balance rehabilitation system using a novel human-centered design approach that involved empathy interviews and design sprints to collectively brainstorm ideas and incorporate end-user feedback in the device development process. We also performed a benchtop validation testing to establish product durability and system usability evaluation to evaluate whether device usability was improved with the human-centered design. The findings of this study indicate that this iterative approach resulted in a stroke-specific NewGait device that met user needs effectively while offering enhanced durability and usability compared to previous versions and competitive devices. Future research is needed to evaluate the short-term biomechanical adaptations and long-term clinical effectiveness of the NewGait device in a broad group of stroke population.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eAFO\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eankle-foot orthoses\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSUS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSystem Usability Scale\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll participants provided verbal consent to participation and the study was determined to be exempt from ongoing Institutional Review Board oversight by the University of Michigan IRBMED.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOPA is the inventor of the NewGait device and CEO/Founder of the company that developed and sells the product. No other conflicts exist.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Eunice Kennedy Shiver National Institute of Child Health and Human Development / National Institutes of Health (R41-HD111289). MB\u0026rsquo;s effort on this project was supported by funding from the Michigan Institute for Clinical \u0026amp; Health Research (NIH UM1-TR004404).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors confirm contribution to the paper as follows: Study conception and design: CZK, CK, OPA, EPW; Data Collection: TEA, MB, CK, CZK, EPW, AP, OPA; Analysis and interpretation of data: CK, OPA, MB, EPW, CZK; Major contributors in writing the manuscript and preparing figures: CK, CZK, EPW, OPA, TEA, MB; All authors reviewed the results, approved the final version of the manuscript, and agreed to be personally accountable for their own contributions and to ensure that any questions related to the accuracy or integrity of any part of the work (even concerning matters in which they were not personally involved) should be appropriately investigated, resolved, and the resolution documented in the literature.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe are grateful to Kimberly Spranger and Lynn Vanwelsenaers, for their assistance as expert clinicians. Lynn Vanwelsenaers was also responsible for fabricating prototypes.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBoehme AK, Esenwa C, Elkind MS. Stroke Risk Factors, Genetics, and Prevention. Circ Res. 2017;120(3):472\u0026ndash;95.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOvbiagele B, Goldstein LB, Higashida RT, Howard VJ, Johnston SC, Khavjou OA, et al. Forecasting the future of stroke in the United States: a policy statement from the American Heart Association and American Stroke Association. Stroke. 2013;44(8):2361\u0026ndash;75.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrakauer JW, Carmichael ST. Broken movement: the neurobiology of motor recovery after stroke. MIT Press; 2022.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWinstein CJ, Stein J, Arena R, Bates B, Cherney LR, Cramer SC, et al. Guidelines for Adult Stroke Rehabilitation and Recovery: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2016;47(6):e98\u0026ndash;e169.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarchal-Crespo L, Reinkensmeyer DJ. Review of control strategies for robotic movement training after neurologic injury. J Neuroeng Rehabil. 2009;6:20.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSloot LH, Baker LM, Bae J, Porciuncula F, Clement BF, Siviy C, et al. Effects of a soft robotic exosuit on the quality and speed of overground walking depends on walking ability after stroke. J Neuroeng Rehabil. 2023;20(1):113.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee M, Rittenhouse M, Abdullah HA. Design issues for therapeutic robot systems: results from a survey of physiotherapists. J Intell Rob Syst. 2005;42:239\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLu EC, Wang RH, Hebert D, Boger J, Galea MP, Mihailidis A. The development of an upper limb stroke rehabilitation robot: identification of clinical practices and design requirements through a survey of therapists. Disabil Rehabil Assist Technol. 2011;6(5):420\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHesse S, Werner C, Matthias K, Stephen K, Berteanu M. Non-velocity-related effects of a rigid double-stopped ankle-foot orthosis on gait and lower limb muscle activity of hemiparetic subjects with an equinovarus deformity. Stroke. 1999;30(9):1855\u0026ndash;61.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamamoto M, Shimatani K, Hasegawa M, Kurita Y. Effects of Varying Plantarflexion Stiffness of Ankle-Foot Orthosis on Achilles Tendon and Propulsion Force During Gait. IEEE Trans Neural Syst Rehabil Eng. 2020;28(10):2194\u0026ndash;202.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen G. Induced acceleration contributions to locomotion dynamics are not physically well defined. Gait Posture. 2006;23(1):37\u0026ndash;44.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaguire C, Sieben JM, Frank M, Romkes J. Hip abductor control in walking following stroke -- the immediate effect of canes, taping and TheraTogs on gait. Clin Rehabil. 2010;24(1):37\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMartins E, Cordovil R, Oliveira R, Pinho J, Diniz A, Vaz JR. The Immediate Effects of a Dynamic Orthosis on Gait Patterns in Children With Unilateral Spastic Cerebral Palsy: A Kinematic Analysis. Front Pediatr. 2019;7:42.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBelizon-Bravo N, Romero-Galisteo RP, Cano-Bravo F, Gonzalez-Medina G, Pinero-Pinto E, Luque-Moreno C. Effects of Dynamic Suit Orthoses on the Spatio-Temporal Gait Parameters in Children with Cerebral Palsy: A Systematic Review. Child (Basel). 2021;8(11).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAxioBionics. TripleFlex 2023 [Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.axiobionics.com/tripleflex/\u003c/span\u003e\u003cspan address=\"https://www.axiobionics.com/tripleflex/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlqahtani S, Joseph J, Dicianno B, Layton NA, Toro ML, Ferretti E, et al. Stakeholder perspectives on research and development priorities for mobility assistive-technology: a literature review. Disabil Rehabil Assist Technol. 2021;16(4):362\u0026ndash;76.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWolff J, Parker C, Borisoff J, Mortenson WB, Mattie J. A survey of stakeholder perspectives on exoskeleton technology. J Neuroeng Rehabil. 2014;11:169.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eManz S, Valette R, Damonte F, Avanci Gaudio L, Gonzalez-Vargas J, Sartori M, et al. A review of user needs to drive the development of lower limb prostheses. J Neuroeng Rehabil. 2022;19(1):119.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStill B, Crane K. Fundamentals of user-centered design: A practical approach. CRC press; 2017.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFidopiastis CM, Rizzo AA, Rolland JP. User-centered virtual environment design for virtual rehabilitation. J Neuroeng Rehabil. 2010;7:11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMelles M, Albayrak A, Goossens R. Innovating health care: key characteristics of human-centered design. Int J Qual Health Care. 2021;33(Supplement1):37\u0026ndash;44.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHoleman I, Kane D. Human-centered design for global health equity. Inf Technol Dev. 2019;26(3):477\u0026ndash;505.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBanfield R, Lombardo CT, Wax T. Design sprint: A practical guidebook for building great digital products. O'Reilly Media, Inc.; 2015.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTooman K. Trial of the NewGaitTM to Alter Running Mechanics in a High School Athlete: A Case Report. Orthop Phys Therapy Pract. 2022;34(4):233\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTooman KM, Weiler J, Larson CA. Trial of NewGait\u0026trade; to Improve Gait and Sit-to-Stand Mechanics in an Older Adult Following Total Joint Replacements: A Case Report. JOSPT Cases. 2023;3(1):43\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUstinova KI, Langenderfer JE. Feasibility of using the NewGait assistive device for correcting gait deviations in individuals with various neurological disorders: Case study. Physiother Res Int. 2023:e2055.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFarao J, Malila B, Conrad N, Mutsvangwa T, Rangaka MX, Douglas TS. A user-centred design framework for mHealth. PLoS ONE. 2020;15(8):e0237910.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKnapp J, Zeratsky J, Kowitz B, Sprint. How to solve big problems and test new ideas in just five days. Simon and Schuster; 2016.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrooke J. Sus: a quick and dirty\u0026rsquo;usability. Usability evaluation in industry. 1996;189(3):189\u0026ndash;94.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRose K, Steinbuchel A. Biodegradation of natural rubber and related compounds: recent insights into a hardly understood catabolic capability of microorganisms. Appl Environ Microbiol. 2005;71(6):2803\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu M, McIntosh J, Liu J. Current prevalence rate of latex allergy: Why it remains a problem? J Occup Health. 2016;58(2):138\u0026ndash;44.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSauro J. 5 Ways in Interpret a SUS Score: Measuring U; 2018 [Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://measuringu.com/interpret-sus-score/\u003c/span\u003e\u003cspan address=\"https://measuringu.com/interpret-sus-score/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-neuroengineering-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jner","sideBox":"Learn more about [Journal of NeuroEngineering and Rehabilitation](http://jneuroengrehab.biomedcentral.com/)","snPcode":"12984","submissionUrl":"https://submission.nature.com/new-submission/12984/3","title":"Journal of NeuroEngineering and Rehabilitation","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"hemiparesis, CVA, hemiplegia, end-user feedback, mechanical testing, MTS, walking, empathy interview, exoskeleton, rehab","lastPublishedDoi":"10.21203/rs.3.rs-3891566/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3891566/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eStroke remains a major cause of long-term adult disability in the United States, necessitating effective rehabilitation strategies for post-stroke gait impairments. Despite advancements in post-stroke care, existing rehabilitation often falls short, prompting the development of devices like robots and exoskeletons. However, these technologies often lack crucial input from end-users, such as clinicians, patients, and caregivers, hindering their clinical utility. Employing a human-centered design approach can enhance the design process and address user-specific needs.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo establish a proof-of-concept of the human-centered design approach by refining the NewGait\u0026reg; exosuit device for post-stroke gait rehabilitation.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eUsing iterative design sprints, the research focused on understanding the perspectives of clinicians, stroke survivors, and caregivers. Two design sprints were conducted, including empathy interviews at the beginning of the design sprint to integrate end-users\u0026rsquo; insights. After each design sprint, the NewGait device underwent refinements based on emerging issues and recommendations. The final prototype underwent mechanical testing for durability and a system usability evaluation, comparing it with the original NewGait device and a commercial product, Theratogs\u0026reg;.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAffinity mapping from the design sprints identified crucial categories for stakeholder adoption, including fit for females, ease of donning and doffing, and usability during barefoot walking. To address these issues, a system redesign was implemented within weeks, incorporating features like a loop-backed neoprene, a novel closure mechanism for the shoulder harness, and a hook-and-loop design for the waist belt. Additional improvements included reconstructing anchors with rigid hook materials and replacing latex elastic bands with non-latex silicone-based bands for enhanced durability. Further, changes to the dorsiflexion anchor were made to allow for barefoot walking. Mechanical testing revealed a remarkable 10-fold increase in durability, enduring 500,000 cycles without degradation. Usability testing indicated superior performance of the stroke-specific NewGait device, scoring 84.3 on the system usability scale compared to 62.7 for the original NewGait device and 46.9 for Theratogs.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis study successfully establishes the proof-of-concept for a human-centered design approach using design sprints to rapidly develop a stroke-specific gait rehabilitation system. Future research should focus on evaluating the clinical efficacy and effectiveness of the NewGait device for post-stroke rehabilitation.\u003c/p\u003e","manuscriptTitle":"Human-Centered Design of a Novel Soft Exosuit for Post-Stroke Gait Rehabilitation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-25 18:55:05","doi":"10.21203/rs.3.rs-3891566/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-02-26T17:35:25+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-01-29T15:51:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"65571988-46f6-413b-8937-a38f3d34fe7b_SNPRID","date":"2024-01-29T09:28:23+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-01-27T17:53:04+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-01-24T05:35:27+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-01-24T05:35:26+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of NeuroEngineering and Rehabilitation","date":"2024-01-23T16:07:08+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-neuroengineering-and-rehabilitation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jner","sideBox":"Learn more about [Journal of NeuroEngineering and Rehabilitation](http://jneuroengrehab.biomedcentral.com/)","snPcode":"12984","submissionUrl":"https://submission.nature.com/new-submission/12984/3","title":"Journal of NeuroEngineering and Rehabilitation","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"819a437e-2738-4659-932f-aa74eb82cb85","owner":[],"postedDate":"January 25th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-05-01T23:27:34+00:00","versionOfRecord":{"articleIdentity":"rs-3891566","link":"https://doi.org/10.1186/s12984-024-01356-3","journal":{"identity":"journal-of-neuroengineering-and-rehabilitation","isVorOnly":false,"title":"Journal of NeuroEngineering and Rehabilitation"},"publishedOn":"2024-04-24 23:27:34","publishedOnDateReadable":"April 24th, 2024"},"versionCreatedAt":"2024-01-25 18:55:05","video":"","vorDoi":"10.1186/s12984-024-01356-3","vorDoiUrl":"https://doi.org/10.1186/s12984-024-01356-3","workflowStages":[]},"version":"v1","identity":"rs-3891566","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3891566","identity":"rs-3891566","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}