Technology Acceptance and User-Centred Design of Assistive Exoskeletons for Older Adults: A Commentary

Background and purpose Refinement of robotic exoskeletons for overground walking is progressing rapidly. We describe clinicians' experiences, evaluations, and training strategies using robotic exoskeletons in spinal cord injury rehabilitation and wellness settings and describe clinicians' perceptions of exoskeleton benefits and risks and developments that would enhance utility. Methods We convened focus groups at 4 spinal cord injury model system centers. A court reporter took verbatim notes and provided a transcript. Research staff used a thematic coding approach to summarize discussions. Results Thirty clinicians participated in focus groups. They reported using exoskeletons primarily in outpatient and wellness settings; 1 center used exoskeletons during inpatient rehabilitation. A typical episode of outpatient exoskeleton therapy comprises 20 to 30 sessions and at least 2 staff members are involved in each session. Treatment focuses on standing, stepping, and gait training; therapists measure progress with standardized assessments. Beyond improved gait, participants attributed physiological, psychological, and social benefits to exoskeleton use. Potential risks included falls, skin irritation, and disappointed expectations. Participants identified enhancements that would be of value including greater durability and adjustability, lighter weight, 1-hand controls, ability to navigate stairs and uneven surfaces, and ability to balance without upper extremity support. Discussion and conclusions Each spinal cord injury model system center had shared and distinct practices in terms of how it integrates robotic exoskeletons into physical therapy services. There is currently little evidence to guide integration of exoskeletons into rehabilitation therapy services and a pressing need to generate evidence to guide practice and to inform patients' expectations as more devices enter the market.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A231).

/pdf/experience-of-robotic-exoskeleton-use-at-four-spinal-cord-7un5rcg8ew.pdf

Experience of Robotic Exoskeleton Use at Four Spinal Cord Injury Model Systems Centers.

ObjectiveTo explore user-centered design methods currently implemented during development of lower limb wearable robots and how they are utilized during different stages of product development.Back...

/pdf/assessing-the-involvement-of-users-during-development-of-8ersvyo2nj.pdf

Assessing the Involvement of Users During Development of Lower Limb Wearable Robotic Exoskeletons: A Survey Study.

The growing interest of the industry production in wearable robots for assistance and rehabilitation purposes opens the challenge for developing intuitive and natural control strategies. Myoelectric control, or myo-control, which consists in decoding the human motor intent from muscular activity and its mapping into control outputs, represents a natural way to establish an intimate human-machine connection. In this field, model based myo-control schemes (e.g., EMG-driven neuromusculoskeletal models, NMS) represent a valid solution for estimating the moments of the human joints. However, a model optimization is needed to adjust the model's parameters to a specific subject and most of the optimization approaches presented in literature consider complex NMS models that are unsuitable for being used in a control paradigm since they suffer from long-lasting setup and optimization phases. In this work we present a minimal NMS model for predicting the elbow and shoulder torques and we compare two optimization approaches: a linear optimization method (LO) and a non-linear method based on a genetic algorithm (GA). The LO optimizes only one parameter per muscle, whereas the GA-based approach performs a deep customization of the muscle model, adjusting 12 parameters per muscle. EMG and force data have been collected from 7 healthy subjects performing a set of exercises with an arm exoskeleton. Although both optimization methods substantially improved the performance of the raw model, the findings of the study suggest that the LO might be beneficial with respect to GA as the latter is much more computationally heavy and leads to minimal improvements with respect to the former. From the comparison between the two considered joints, it emerged also that the more accurate the NMS model is, the more effective a complex optimization procedure could be. Overall, the two optimized NMS models were able to predict the shoulder and elbow moments with a low error, thus demonstrating the potentiality for being used in an admittance-based myo-control scheme. Thanks to the low computational cost and to the short setup phase required for wearing and calibrating the system, obtained results are promising for being introduced in industrial or rehabilitation real time scenarios.

/pdf/a-linear-approach-to-optimize-an-emg-driven-164fq8d9xk.pdf

A Linear Approach to Optimize an EMG-Driven Neuromusculoskeletal Model for Movement Intention Detection in Myo-Control: A Case Study on Shoulder and Elbow Joints.

Systematic Reviews of Clinical Benefits of Exoskeleton Use for Gait and Mobility in Neurologic Disorders: A Tertiary Study

Objectives: Exoskeletons are electromechanical devices that are worn by a human operator to increase their physical performance. Several exoskeletons have been developed to restore functional movements, such as walking, for those with paralysis due to neurological impairment. However, existing exoskeletons have limitations with respect to affordability, size, weight, speed, and efficiency, which may reduce their functional application. Therefore, the aim of this scoping review is to collect and narratively synthesize the perspectives of users of exoskeleton technology. Methods: A systematic literature search was conducted across several healthcare related online databases. Results: A total of 4,619 articles were identified, of which 51 were selected for full review. Only three studies were identified that met the inclusion criteria. Of these, one showed an incongruence between users’ expectations and experiences of device use; another reported perspectives on potential rather than actual device use, ranking design features in order of perceived importance; and the other reported ratings of ease of device use in training. Conclusions: The heterogeneity of studies included within this review, leave the authors unable to suggest consensus as to user perspectives of exoskeleton technology. However, it is apparent that users are able to suggest priorities for exoskeleton design and that users’ perspectives of exoskeleton technology might change in response to experience of use. The authors, therefore, suggest that exoskeleton design should be an iterative process, whereby user perspectives are sought, incorporated and refined by tangible experience, to ensure that devices developed are acceptable to and usable by the populations they seek to re-enable.

/pdf/what-are-user-perspectives-of-exoskeleton-technology-a-598ib97ghc.pdf

Deborah Hill

Papers

What are user perspectives of exoskeleton technology? a literature review.