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Tuesday, June 25, 2019 – Speaker Sessions

Keynote Speaker: Dr. Ed Lemaire, PhD; Professor, Physical Medicine and Rehabilitation, University of Ottawa; Affiliate Investigator, Clinical Epidemiology Program, Ottawa Hospital Research Institute

Title: Wearable and Wear-nothing Approaches for Assistive Technology Assessment

Abstract: Wearable technology has evolved to provide accessible and cost effective opportunities to measure human movement and generate quantitative information to assist clinical decision-making. This presentation will examine a variety of technologies and outcome analysis approaches that can provide useful and immediate information to the healthcare provider. Examples include inertial measurement units and machine learning to evaluate movement quality and fall risk, augmented reality technology for real-time posture analysis, and markerless tracking for moving beyond discrete biomechanical analysis to continuous movement assessment. By combining these technologies, assistive technology providers can work in a new era where data processing is replaced by real-time reporting and immediate evidence-based practice is in their hands.

 

Open Paper: Dr. Krista Best, Université Laval

Title: Development of a Mobility Device Training Catalogue: Online Resources for Training in the Use of Mobility Devices for People with Physical Disabilities

Abstract:

Background: More than 1.4 million Canadians report using a mobility device (MD) to facilitate independent mobility and social participation. However, provision alone does not guarantee safe or effective use. Given that individuals obtain MDs from various sources (e.g., clinician prescription, direct from vendors, recycling programs), individuals receive little to no training.

Objectives: 1) To identify existing online educational resources for training individuals and their caregivers on how to use MDs; and 2) create a downloadable and printable Mobility Device Training Catalogue.

Method: A systematic Google search was conducted to locate educational resources that provided instruction or training to support knowledge or skill development for MD use. Search strategies and keywords related to MDs (i.e., manual wheelchair, power wheelchair, scooter, cane, crutches, walker) were used to conduct a ‘typical’ search (in French and English). Relevant websites were assessed for inclusion and exclusion criteria to simulate the point where the ‘typical’ person may stop their search. Technical quality was assessed by 2 authors using JAMA criteria, which was considered in the selection of resources to be included in the Mobility Device Training Catalogue.

Results: A total of 350 resources were identified, including 34 for wheeled MD and 316 for walking aids. Technical quality ranged from 3.4-5.0 out of 6.0. A total of 116 resources (58 French and 58 English were included in a Mobility Device Training Catalogue (www.cdpp.ca).

Conclusions: The technical quality of online MD training resources was variable. Findings from this study contributed to the creation of a Mobility Device Training Catalogue that can be used by individuals who use MDs, caregivers and clinicians. Details about resource quality may help to inform resource developers about the information that should be included when developing new resources.

 

Open Paper: Dr. Arezoo Eshraghi, West Park Healthcare Centre

Title: Clinical Aspects of Additive Manufacturing Application in Prosthetics and Orthotics: Current and Upcoming Overviews

Abstract: Computer-aided design/computer-aided manufacturing (CAD/CAM) has been used for prosthetics and orthotics manufacturing for decades. Three-dimensional (3D) printing is an additive manufacturing (AM) process with growing usage, offering improved accuracy and reduced labour for the manufacturing of prosthetics and orthotics, in particular the socket component. Additionally, advanced hand-held scanner systems import limb impressions into a digital model, thus eliminating the conventional plaster casting process. The success of the end product hinges on the accuracy of the imported model and the modifications produced with CAD software. Practitioners have mixed feelings regarding use of AM as their primary manufacturing tool, since the CAD process is still abstract and not intuitive enough, necessitating a large learning curve. Nonetheless, practitioners and patients may benefit from the elimination of messy plaster cast mold taking, a potential faster turnaround time, indefinite record of molds, and instant replication of sockets. 3D printing materials are becoming stronger and more durable, therefore an entire prosthetic limb may soon be 3D printed. However, the end product is not yet as clinically successful as one would anticipate. The disadvantages primarily lie in the forefront of the process: the ductile and tactile feedback conventionally obtained during hands-on casting is paramount for the success of producing an accurate socket interface, and is an essential missing link in the scanning process. Another major hurdle for the practitioner is the rectification process of the animated CAD object that necessitates a large learning curve with poor outcome predictability. This work aims to provide an overview of the current state of 3D printing systems and procedures for prosthetics and orthotics, with a focus on the clinical aspects. We will also present case studies of 3D printed components for prosthetics, accomplished or ongoing, at West Park Healthcare Centre.

 

Panel: Dr. Alison William, Dr. Matt Ratto, Dr. Jan Andrysek, Sandra Ramdial, Gordon Ruder

Title: Ethics of Additive Manufacturing in Prosthetic & Orthotic Care

Abstract: Appropriate Assistive Technology is known to enable persons with disabilities to live dignified, independent and healthy lives. However, inappropriate prescription and/or provision of devices has been reported to waste health care dollars and result in delays in achieving expected improvements in an individual’s symptoms/health.

For these reasons it is of importance to seek avenues to increase access to appropriate devices while mitigating the risks associated with an inappropriate treatment models.

The World Health Organization estimates that only 1 in 10 persons who require assistive products, including prosthetics and orthotics, have access to them, owing to a range of barriers including high cost, lack of availability, insufficient policies, and a limited of supply of trained personnel to deliver services.

Additive manufacturing processes (including 3D printing) hold great potential for application in prosthetics/orthotics which may remove barriers to accessing services, reduce cost and help to optimize resources. However, the proliferation of technology in additive manufacture brings with it the risk that complex clinical systems will be over simplified resulting in a reduced quality of care and ultimately may compromise the potential outcome for individual users.

The objective of this session is for an expert panel to discuss the opportunities and risks associated with additive manufacturing as it relates to prosthetic/orthotic care and highlight the ethical responsibilities of individuals providing devices using digital technologies.

 

 

Wednesday, June 26, 2019 – Speaker Sessions

Invited Speaker: Dr. Michael Payne, MSc, MD, FRCP(C); Associate Professor, Western University

Title: The Impact of Cognition of Prosthetic Outcomes

Abstract: Most major lower extremity amputations are performed due to one or both of diabetes and peripheral vascular disease.  These dysvascular medical conditions are frequently (56% of people admitted to a rehabilitation program) associated with some degree of cognitive impairment.  Typically, these cognitive impairments present as deficits in memory, attention, and visuospatial perception, all of which are important for achieving success with prosthetic rehabilitation.

Cognitive impairment related to traumatic brain injury associated with traumatic upper extremity amputation has not been studied extensively, although likely diminishes outcomes in rehabilitation-intensive protocols such as following targeted muscle reinnervation.

Both cognitive and prosthetic performance have various clinical measures that can be useful to evaluate for a given patient.  Dual-task testing is a method of measuring performance of two independent tasks, performed concurrently, that may challenge the cognitive capacity of the individual.  When the cognitive capacity is exceeded, performance may suffer in one or both tasks.  Among people with amputations, both gait and cognitive responses deteriorate when performed together, although gait appears to be more commonly prioritized over the cognitive task.

Ambulation with a prosthesis is a cognitively demanding task for many patients, especially in pursuing the goal of reintegration to the community.  The dual-task costs of cognitive and gait tasks do not change over time, suggesting that cognitive rehabilitation is an important component of prosthetic training in addition to the physical use of a prosthesis.

 

Invited Speaker: Dr. Matthew Major, PhD; Assistant Professor, Northwestern University, Feinberg School of Medicine; Research Health Scientist, Jesse Brown VA Medical Center

Title: Personalized Rehabilitation: Mapping the Links between Prosthetic Device Parameters, Motor Capacity, and Clinical Outcomes for Optimizing Interventions

Abstract: The selection of prosthetic device parameters to restore function of persons with lower-limb loss can be framed as an optimization problem to maximize a given performance outcome. The choice of particular outcomes, such as locomotor stability, comfort, or metabolic cost, is a shared decision amongst the rehabilitation team and patient, and depends on a patient’s functional capacity and motivation. Historically, the selection of prosthesis parameters to match components with patients has been constrained to those fixed mechanical properties of commercial devices. Classical comparative studies have suggested an effect of commercial prosthesis design on clinically-relevant outcomes, but these studies lack reliability and the results are often inconsistent. However, recent parametric studies have begun to systematically probe the influence of prosthesis parameters (i.e., mechanical function) on performance outcomes through the use of novel methodologies and experimental prosthetic technology. Results from these parametric studies generate maps defining the relationships between select parameters (e.g., stiffness, damping, roll-over geometry) and a desired outcome. Moreover, these maps can be expanded into a multidimensional landscape when considering factors of patient motor capacity (e.g., muscle strength, sensory feedback) as an additional covariate. Through these correlate maps, parameter values can be identified which maximize a given performance outcome, thereby providing an objective framework to optimize prosthesis designs. Importantly, by accounting for person-specific variables pertaining to motor performance, this framework can yield predictions of performance outcomes for individual patients. This review will discuss: 1) a selection of novel experimental techniques being implemented to populate these correlate maps, and 2) how an iterative optimization approach can deliver personalized lower-limb loss rehabilitation interventions when integrating targeted physical therapies that encourage self-organization with the prosthesis.

 

Invited Speaker: Dr. Stefania Fatone, PhD, BPO(Hons); Professor, Northwestern University, Feinberg School of Medicine

Title: Development and Dissemination of the Northwestern University Flexible Sub-Ischial Socket Technique

Abstract: Current standard-of-care Ischial Containment sockets for transfemoral amputees fit intimately with the ischium, limiting hip motion and contributing to socket discomfort. Hence, we developed a technique to fabricate and fit a sub-ischial socket aimed at improving socket comfort without compromising function. Both the Northwestern University Flexible Sub-Ischial Vacuum (NU-FlexSIV) Socket and the Northwestern University Flexible Sub-Ischial Suction (NU-FlexSIS) Socket have lower proximal trim lines that do not impinge on the pelvis and include compliant materials in their fabrication to improve user comfort. Since the socket we developed is a technique and not a product, dissemination has relied on being able to successfully communicate and teach the technique to other prosthetists. To facilitate teaching of our technique we developed a simplified approach to casting, rectifying and fitting the sub-ischial socket supported by documentation in the form of a socket work form, mold reduction algorithm and rectification mapping. This presentation will describe development of our socket technique and our experiences disseminating the technique to prosthetists via mechanisms that include hands on workshops, online webinars, conference presentations and peer-reviewed publications. We anticipated that dissemination of the sub-ischial socket technique might be challenging given that removal of the proximal brim challenges conventional understanding of the biomechanics of transfemoral sockets wherein “locking onto the pelvis” is believed to stabilize the socket in the coronal plane. While we encountered some initial skepticism regarding the potential success of the technique it did not last long. Since launching the technique in 2015, we have experienced ongoing demand nationally and internationally for hands-on workshops and invitations to present at conferences with increasing anecdotal evidence of clinical implementation. To date over 200 prosthetists have taken our hands-on workshop, we’ve published 8 peer-reviewed articles and given nearly 60 presentations at conferences, including 18 invited and keynote lectures on the development and research related to this sub-ischial socket technique.

 

Open Paper: Quinn Boser, University of Alberta

Title: Characterizing the Eye Gaze Behaviour of Body-Powered Prosthesis Users

Abstract:

Background: Despite availability of technically advanced myoelectric upper limb prostheses, traditional body-powered devices remain prevalent among prosthesis users. Moreover, it is estimated that over 20% of persons with upper limb loss choose not to use any type of prosthesis. The need to visually monitor the prosthesis is often cited as a limitation of these devices. Quantitative assessment of visual attention to the hand or terminal device has been investigated with myoelectric prosthesis users. However, the eye gaze behaviour of body-powered prosthesis users remains undocumented.
Methods: In this study quantitative methods were used to characterize the eye gaze behaviour of five transradial body-powered prosthesis users. A combination of motion capture and eye-tracking technologies was used to track the participants’ visual attention relative to movement of their terminal device during completion of two functional upper limb tasks. Both tasks consisted of reach-grasp-transport-release object interactions. Results were compared to normative eye gaze behaviour.
Results: Body-powered prosthesis users fixated on their prosthesis and task relevant objects for a similar percentage of reach-grasp actions to able-bodied individuals. However, because their movements were slower and grasp phases were especially prolonged, they tended to spend more time fixating on objects prior to picking them up. After picking up an object to move it, the prosthesis users continued to fixate on their terminal device for longer than normative (up to 50% of transport phase).

Discussion: This study is the first to quantitatively characterize the eye gaze behaviour of upper limb body-powered prosthesis users and demonstrate their increased reliance on visual attention. These results will be valuable for future comparison with myoelectric prosthesis users and new prosthesis technologies.

 

Invited Speaker: Dr. Jan Andrysek, PhD, PEng; Senior Scientist, Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital

Title: Using Biofeedback Systems to Improve Gait of Lower-Limb Prosthetic Users

Abstract: Biofeedback, the practice of providing direct, real-time biological information, can aid the rehabilitation of individuals with musculoskeletal disorders including amputations, and accelerate and optimize recovery of aspects of physical function and movement. A major benefit of biofeedback systems is the ability to provide feedback to reinforce personalized physiotherapy goals and good walking pattern habits. In this talk, I will provide an overview of the state of biofeedback systems within rehabilitation of lower-limb prosthesis users, and present our original research aimed at advancing the use of wearable haptic-based biofeedback systems for gait training.

 

Invited Speaker: Dr. Robert Gregg, PhD; Eugene McDermott Professor, University of Texas at Dallas

Title: On the Design and Control of Partial-Assist Powered Orthoses for Broad Patient Populations

Abstract: The majority of assistive exoskeletons (i.e., powered orthoses) are designed to rigidly track time-based kinematic patterns using highly geared actuators, which prevents users from moving their joints freely without help from the exoskeleton. This class of exoskeletons is appropriate for individuals with spinal cord injury, but many patient populations present with weakened volitional control of their lower extremities (e.g., stroke or musculoskeletal disorders) and only require partial assistance to regain mobility. This clinical need motivates novel design and control methods for powered orthoses that are more compatible with human interaction. In order to assist or augment volitional human motion, orthotic joints must be backdrivable and the control strategy must be invariant to the user’s activity. This talk will present the design philosophy behind two generations of backdrivable powered orthoses, which utilize torque-dense motors with low-ratio transmissions. A trajectory-free control framework shapes the kinetic and potential energies of the human body rather than prescribing joint kinematics. Preliminary human subject experiments demonstrate the user-cooperative and task-invariant nature of this design and control approach. The talk will conclude with a discussion of future work including connections to powered prostheses for agile amputee locomotion.

 

Open Paper: Nicolas Fromme, Empa

Title: Assessment of a Soft, Passive Tremor Suppression Orthosis

Abstract:

Background: Tremor is the most common movement disorder with a high prevalence in the upper limb. The mechanical suppression of the involuntary movement is an alternative and additional treatment to medication or surgery. Here we present a wearable, passive and soft orthosis for task specific activation for tremor suppression.

Methods: A new concept of a textile based passive wrist orthosis was designed with an integrated air-filled structure, which can be inflated or deflated for a certain activity of daily living. The air-filled structure, which is placed on the dorsal side of the wrist, gets bended and compressed by movements when inflated. By the constraint in volume of the orthoses, the air in the structure compresses and creates a counterforce. We evaluated the effect of a passive soft orthosis suppressing involuntary movements in the wrist of tremor-affected patients during activities of daily living. We tracked the movements of the study participants with the activated (inflated) and deactivated (deflated) orthosis to assess the tremor suppression of the device calculating the acceleration power spectral densities. Further, we evaluated the tremor in active and inactive mode by the clinically established WHIGET Tremor Rating Scale.

Results: We demonstrated that the soft orthosis reduces tremor power of the first harmonics for certain activities significantly. This tremor power reduction contributed to a significant reduction of the WHIGET score. Further, the participants perceived a tremor-reducing effect of the orthosis in the wrist.

Discussion/Conclusion: The developed orthosis is a lightweight and unobtrusive assistive technology, which suppresses involuntary movements and is accepted by the wearer. This air structure technology could also be applied for other movement disorders like spasticity or even integrated into future exoskeletons for variable stiffness in the system.

 

Open Paper: Michael Rosenberg, University of Washington

Title: Muscle Coordination Differs between Non-Steady-State and Steady-State Walking with Ankle Exoskeletons

Abstract:

Introduction: Altering muscle coordination using ankle exoskeletons (exos) is a goal in locomotor rehabilitation and performance. However, exos are typically studied during steady-state (SS) gait, despite non-steady-state (nSS) gait comprising a large portion of daily locomotion (Orendurff et al. 2008, JRRD.). Understanding the impacts of exo stiffness on muscle coordination may inform exo design to enhance performance and all-day rehabilitation. We investigated the ability of SS muscle synergies – a common representation of motor control – to model nSS muscle activity during walking with ankle exos.

Methods: We collected electromyography (EMG) data from seven leg muscles bilaterally in three healthy adults (2/1 F/M; Age=24.0±3.6yrs; Mass=62.6±11.9kg) walking overground with bilateral passive ankle exos at a self-selected SS speed and accelerating (nSS) from quiet standing to SS. Participants walked in four exo stiffness conditions for four SS and 12 nSS passes per exo condition. We computed four-synergy solutions (Clark et al. 2010, J Neurophys.) unilaterally for SS and nSS gait in each condition. We computed total Variance Accounted For for nSS EMG data using nSS (tVAFnSS) and SS (tVAFSS) synergy weights. We compared tVAFnSS and tVAFSS over the first three strides of nSS gait.

Results: Reconstructions using SS synergy weights (tVAFSS) accounted for 76±1% of the variance in the nSS EMG data, 18±3 percentage points lower than using nSS weights (tVAFnSS, 92±1%). While tVAFnSS was insensitive to exo stiffness, tVAFSS deviated less from tVAFnSS as exo stiffness increased (slope=-0.02%*deg/Nm).

Discussion: Effective modulation of muscle coordination using lower-limb exos during nSS gait initiation may benefit from specific evaluation of nSS EMG and merits further investigation. As exo stiffness increased, nSS and SS muscle coordination became more-similar, suggesting that stiffness may influence how soon after gait initiation muscle coordination converges to SS.