Accuracy, Repeatability, and Reproducibility of a Hand-Held Structured-Light 3D Scanner across Multi-Site Settings in Lower Limb Prosthetics.

The aim of this work was to assess the accuracy, repeatability, and reproducibility of a hand-held, structured-light 3D scanner (EINScan Pro 2X Plus with High Definition Prime Pack, SHINING 3D Tech. Co., Ltd., Hangzhou, China), to support its potential use in multi-site settings on lower limb prosthetics. Four limb models with different shapes were fabricated and scanned with a metrological 3D scanner (EINScan Laser FreeScan 5X, SHINING 3D Tech. Co., Ltd., Hangzhou, China) by a professional operator (OP0). Limb models were then mailed to three sites where two operators (OP1, OP2) scanned them using their own structured-light 3D scanner (same model). OP1 scanned limb models twice (OP1-A, OP1-B). OP0, OP1-A, and OP2 scans were compared for accuracy, OP1-A and OP1-B for repeatability, and OP1-A and OP2 for reproducibility. Among all comparisons, the mean radial error was <0.25 mm, mean angular error was <4°, and root mean square error of the radial distance was <1 mm. Moreover, limits of agreement were <3.5% for perimeters and volumes. By comparing these results with respect to clinically-relevant thresholds and to the literature available on other 3D scanners, we conclude that the EINScan Pro 2X Plus 3D Scanner with High Definition Prime Pack has good accuracy, repeatability, and reproducibility, supporting its use in multi-site settings.

The development of rating scales to evaluate experiential prosthetic foot preference for people with lower limb amputation.

BACKGROUND: Selection of a foot is an important aspect of prosthetic prescription and vital to maximizing mobility and functional goals after lower limb amputation. Development of a standardized approach to soliciting user experiential preferences is needed to improve evaluation and comparison of prosthetic feet. OBJECTIVE: To develop rating scales to assess prosthetic foot preference and to evaluate use of these scales in people with transtibial amputation after trialing different prosthetic feet. DESIGN: Participant-blinded, repeated measures crossover trial. SETTING: Veterans Affairs and Department of Defense Medical Centers, laboratory setting. PARTICIPANTS: Seventy-two male prosthesis users with unilateral transtibial amputation started, and 68 participants completed this study. INTERVENTIONS: Participants trialed three mobility-level appropriate commercial prosthetic feet briefly in the laboratory. MAIN OUTCOME MEASURES: "Activity-specific" rating scales were developed to assess participants' ability with a given prosthetic foot to perform typical mobility activities (eg, walking at different speeds, on inclines, and stairs) and "global" scales to rate overall perceived energy required to walk, satisfaction, and willingness to regularly use the prosthetic foot. Foot preference was determined by comparing the rating scale scores, after laboratory testing. RESULTS: The greatest within-participant differences in scores among feet were observed in the "incline" activity, where 57% ± 6% of participants reported 2+ point differences. There was a significant association (p < .05) between all "activity-specific" rating scores (except standing) and each "global" rating score. CONCLUSIONS: The standardized rating scales developed in this study could be used to assess prosthetic foot preference in both the research and clinical settings to guide prosthetic foot prescription for people with lower limb amputation capable of a range of mobility levels.

Clinician perspectives on postamputation pain assessment and rehabilitation interventions.

OBJECTIVE: The purpose of this study was to explore self-reported Veterans Affairs (VA) amputation clinician perspectives and clinical practices regarding the measurement and treatment for amputation-related pain. STUDY DESIGN: Cross-sectional survey with 73 VA rehabilitation clinicians within the VA Health Care System. RESULTS: The most frequent clinical backgrounds of respondents included physical therapists (36%), prosthetists (32%), and physical medicine and rehabilitation specialist (21%). Forty-one clinicians (56%) reported using pain outcome measures with a preference for average pain intensity numeric rating scale (generic) (97%), average phantom limb pain intensity numeric rating scale (80%), or Patient-Reported Outcomes Measurement Information System pain interference (12%) measures. Clinicians' most frequently recommended interventions were compression garments, desensitization, and physical therapy. Clinicians identified mindset, cognition, and motivation as factors that facilitate a patient's response to treatments. Conversely, clinicians identified poor adherence, lack of belief in interventions, and preference for traditional pain interventions (e.g., medications) as common barriers to improvement. We asked about the frequently used treatment of graded motor imagery. Although graded motor imagery was originally developed with 3 phases (limb laterality, explicit motor imagery, mirror therapy), clinicians reported primarily using explicit motor imagery and mirror therapy. RESULTS: Most clinicians who use standardized pain measures prefer intensity ratings. Clinicians select pain interventions based on the patient's presentation. This work contributes to the understanding of factors influencing clinicians' treatment selection for nondrug interventions. Future work that includes qualitative components could further discern implementation barriers to amputation pain rehabilitation interventions for greater consistency in practice.

Virtual Reality Game Selection for Traumatic Brain Injury Rehabilitation: A Therapist's Wish List for Game Developers.

This project explored the selection process of commercially available virtual reality (VR) games for traumatic brain injury rehabilitation. Occupational therapy practitioners (OTPs) developed a classification framework that they used to evaluate VR games. The classification framework focused on movements required to effectively play the game, cognitive demand, position for game play, ease in menu navigation, and perceived therapeutic applications. OTPs used the ratings to aid in game selection and identified relevant game examples that allowed customizable settings and basic navigation with a game focus on functional activities. The OTPs and the research team identified the need for further work on accessibility and adaptability of game features (e.g., difficulty and limb usage) allowing for more individualization to optimize outcomes of VR-enhanced rehabilitation. The classification framework was useful in evaluating the potential therapeutic benefit of commercially available VR games. However, trial of the game by clinicians prior to use was still warranted.

Veteran Perspectives on Phantom Limb Pain and Non-Drug Interventions.

Background: Phantom limb pain (PLP) commonly occurs post-amputation and can negatively affect the daily functioning of persons with amputation. Best practices for medication and non-drug management remain unclear. Objective: To better understand the PLP experience and patients' familiarity with treatments, phone interviews were conducted at the Minneapolis Veterans Affairs Regional Amputation Center in Veterans with amputations. Methods: Fifty Veteran participants (average age 66, 96% male) with lower limb amputation were recruited for phone-based data collection of patient-reported outcomes (ie, demographics using the Trinity Amputation and Prosthesis Experience Scales-Revised (TAPES-R) and pain experience using the Phantom Phenomena Questionnaire) to characterize the population and a semi-structured interview. Notes taken during interviews were analyzed using the Krueger and Casey constant comparison analysis method. Results: Participants had an average of 15 years since amputation, and 80% reported PLP as identified with the Phantom Phenomena Questionnaire. Investigators identified several core themes from the qualitative interviews including 1) high variability in the experience of PLP, 2) acceptance and resilience, and 3) PLP treatment perceptions. The majority of participants reported trying common non-drug treatments with none endorsed consistently as highly effective. Conclusion: More research is needed to inform identification and implementation of clinical best practices for non-drug interventions for PLP and understand the factors that influence engagement in non-drug interventions. The participants in this study were largely male, so these results may not be generalizable to females.

Footwear limitations in women prosthesis users relate to more than preference.

BACKGROUND: The option to wear desired footwear may be an important part of community reintegration after lower-limb amputation. OBJECTIVES: This study explored outcomes related to footwear, health, and participation in women Veterans with lower-limb amputation. METHODS: A cross-sectional questionnaire was mailed to all women Veterans age 18-82 years with major lower-limb amputation(s) who had received prosthetics services in the US Department of Veterans Affairs (N = 538). The questionnaire assessed Perceived Challenges (including clothing limitations, prosthetic foot limitations [width, height, and shape], and shoe avoidance for safety concerns), type of footwear used and preference, and included subscales from the Patient-Reported Outcome Measurement Information System, Amputee Body Image Scale Prosthetic Limb Users' Survey of Mobility, Community Participation Index, Activities-Specific Balance Confidence Scale, and Prosthesis Evaluation Questionnaire. Bivariate correlations examined relationships between a composite measure of Perceived Challenges and patient-reported outcomes. RESULTS: One hundred questionnaires were returned (18.6% response rate; 3 excluded for limited prosthesis use). The Perceived Challenges score was significantly correlated with scores for the Amputee Body Image Scale-Revised (r = 0.24, p = 0.019), Patient-Reported Outcome Measurement Information System (ability to participate: r = -0.25, p = 0.014), Prosthesis Evaluation Questionnaire (utility: r = -0.32, p = 0.001, appearance: r = -0.48, p < 0.001), Activities-Specific Balance Confidence Scale (r = -0.20, p = 0.046), and Prosthetic Limb Users' Survey of Mobility (r = -0.21, p = 0.036), but not depression or anxiety. CONCLUSIONS: Women who have greater issues with how their prosthesis affects the shoes and clothing they can wear also have poorer body image, reduced functional capabilities, and lower reported participation in activities. Improved prosthetic foot design may help to improve social participation and other important outcomes for women prosthesis users.

Effects of footwear on the gait kinematics of women with unilateral transtibial amputation: an observational case series.

PURPOSE: Prosthesis geometry and behaviour limit the footwear options available to women. Using a commercially available prosthetic foot that permits user-alignment to accommodate shoes with different heel heights, we investigated the effect of footwear on gait kinematics, with and without adjustment for differences in heel-forefoot differential. MATERIALS AND METHODS: Three women with transtibial amputation walked at a self-selected pace, first in an athletic shoe (prosthetist-aligned; baseline condition), then (i) in a flatter shoe without realigning the prosthesis, and (ii) in flat and heeled shoes following user re-alignment. Kinematics in each condition were compared to baseline. RESULTS: Baseline gait patterns were highly variable across participants. Gait was slower in comparison to baseline in all conditions, but movement compensations varied across participants. An increased lower limb extension tendency was evident with the misaligned prosthesis. With user re-alignment to accommodate the shoe there were fewer deviations from baseline, however kinematic differences remained in both the flat and heeled shoes. CONCLUSIONS: The user-alignment feature of the prosthetic foot reduced the effect of a change in footwear on kinematics, and permitted walking in heeled shoes when it might otherwise not be possible. Persistence of some deviations suggests differences in walking task demand remained despite adjustment.Implications for rehabilitationPermitting prosthesis users to don footwear of choice may improve body image, well-being and quality of life following amputation.Prosthetic feet that permit user ankle adjustment can reduce gait deviations associated with a change in footwear heel height, although kinematic adaptations are individual.

Supine arm cycling during the post-flap recovery period for persons with spinal cord injuries: The multi-purpose arm cycle ergometer (M-PACE) safety and pilot testing.

OBJECTIVE: To describe how using a supine arm cycle ergometer can safely reduce deconditioning experienced by patients with spinal cord injury or disorder (SCI/D) during their four to six weeks of complete bed rest after surgery to close a stage 4 pressure injury. DESIGN: This pilot project used a newly designed arm cycle ergometer (known as the M-PACE) that extends over the bed, allowing a patient to lie completely supine while exercising. SETTING: The M-PACE was designed and built at the Minneapolis Veterans Affairs Health Care System (MVAHCS) and pilot tested at the MVAHCS SCI/D Center. PARTICIPANTS: Patients with SCI/D, recovering from flap surgery and deemed appropriate to use the arm cycle ergometer were enrolled in the pilot study (n = 47). OUTCOME MEASURES: A pre-post six-minute arm test (6MAT), a proxy for conditioning, was conducted on a subset (n = 15) of participants before and after the supine cycling exercise training program. Participants' rating of perceived exertion (RPE) scores were collected at cessation of each 6MAT. Participants gave feedback on their perception of using the M-PACE. RESULTS/CONCLUSIONS: The 6MAT RPE was significantly reduced after training with the M-PACE while on bed rest (P = 0.003). Also, significantly more rotations were performed after completing the training program (P = 0.02). Further, study participants who accessed the M-PACE found using it helped offset the tedium of laying supine during flap surgery recovery. The differences in the 6MAT pre- to post measures indicate the M-PACE should be further studied for offsetting the normal deconditioning that occurs with extended bedrest.

Feasibility testing of a novel prosthetic socket sensor system.

PURPOSE: Poorly fitting prosthetic sockets contribute to decreased quality of life, health, and well-being for persons with amputations. Therefore, improved socket fit is a high clinical priority. METHODS: In this study, we describe the design and testing of a novel sensor system that can be incorporated into a prosthetic socket to measure distal end weight bearing in the socket and can alert a prosthesis user if poor socket fit is suspected. We present the results of testing this device with three Veterans who were new prosthesis users and three Veterans who were experienced prosthesis users. RESULTS AND CONCLUSIONS: We collected sensor data during walking trials while participants wore varying numbers of sock plies and qualitative feedback on the design of the socket fit sensor system. For analysis, peak sensor measurements during walking cycles were identified and combined with socket fit data (i.e., a clinician-determined level of "good," "too tight," or "too loose" and the number of sock ply worn each trial). We found consistent relationships between peak sensor measurements and socket fit in our sample. Also, all users expressed an interest in the device, highlighting its potential benefits during early prosthesis training.Implications for RehabilitationEnsuring socket fit is challenging for many prosthesis users.A novel wearable sensor system can be used to identify socket fit issues for some prosthesis users.This type of system could be most helpful for new prosthesis users and those with sensory and cognitive challenges.

Emulating the Effective Ankle Stiffness of Commercial Prosthetic Feet Using a Robotic Prosthetic Foot Emulator.

Prosthetic foot selection for individuals with lower limb amputation relies primarily on clinician judgment. The prosthesis user rarely has an opportunity to provide experiential input into the decision by trying different feet. A prosthetic foot emulator (PFE) is a robotic prosthetic foot that could facilitate prosthesis users' ability to trial feet with different mechanical characteristics. Here, we introduce a procedure by which a robotic PFE is configured to emulate the sagittal plane effective ankle stiffness of a range of commercial prosthetic forefeet. Mechanical testing was used to collect data on five types of commercial prosthetic feet across a range of foot sizes and intended user body weights. Emulated forefoot profiles were parameterized using Bezier curve fitting on ankle torque-angle data. Mechanical testing was repeated with the PFE, across a subset of emulated foot conditions, to assess the accuracy of the emulation. Linear mixed-effects regression and Bland-Altman Limits of Agreement analyses were used to compare emulated and commercial ankle torque-angle data. Effective ankle stiffness of the emulated feet was significantly associated with the corresponding commercial prosthetic feet (p <0.001). On average, the emulated forefeet reproduced the effective ankle stiffness of corresponding commercial feet within 1%. Furthermore, differences were independent of prosthetic foot type, foot size, or user body weight. These findings suggest that commercial prosthetic foot properties can be effectively mimicked by a PFE, which is the important first step toward enabling prosthesis users to quickly trial different feet using a PFE as part of prosthetic foot prescription.

Prosthetic forefoot and heel stiffness across consecutive foot stiffness categories and sizes.

Prosthetic foot stiffness plays a key role in the functional mobility of lower limb prosthesis users. However, limited objective data exists to guide selection of the optimal prosthetic foot stiffness category for a given individual. Clinicians often must rely solely on manufacturer recommendations, which are typically based on the intended user's weight and general activity level. Availability of comparable forefoot and heel stiffness data would allow for a better understanding of differences between different commercial prosthetic feet, and also between feet of different stiffness categories and foot sizes. Therefore, this study compared forefoot and heel linear stiffness properties across manufacturer-designated stiffness categories and foot sizes. Mechanical testing was completed for five types of commercial prosthetic feet across a range of stiffness categories and three foot-sizes. Data were collected for 56 prosthetic feet, in total. Testing at two discrete angles was conducted to isolate loading of the heel and forefoot components, respectively. Each prosthetic foot was loaded for six cycles while force and displacement data were collected. Forefoot and heel measured stiffness were both significantly associated with stiffness category (p = .001). There was no evidence that the relationships between stiffness category and measured stiffness differed by foot size (stiffness category by size interaction p = .80). However, there were inconsistencies between the expected and measured stiffness changes across stiffness categories (i.e., magnitude of stiffness changes varied substantially between consecutive stiffness categories of the same feet). While statistical results support that, on average, measured stiffness is positively correlated with stiffness category, force-displacement data suggest substantial variation in measured stiffness across consecutive categories. Published objective mechanical property data for commercial prosthetic feet would likely therefore be helpful to clinicians during prescription.

Effects of shear force reduction during mechanical testing and day-to-day variation on stiffness of commercial prosthetic feet: a technical note.

BACKGROUND: Mechanical testing is the principal method used to quantify properties of commercial prosthetic feet in a controlled and standardized manner. To test feet in a mechanical testing machine without overconstraining the system, tangential shear forces must be minimized. However, there is scant published information comparing techniques for reducing shear forces during mechanical testing. Furthermore, there are no data on variability in linear stiffness across testing sessions. OBJECTIVES: To compare techniques for reducing shear forces during mechanical testing of prosthetic feet and to evaluate variation in linear stiffness across testing sessions. STUDY DESIGN: Repeated measures. TECHNIQUE: Force-displacement data were collected at two pylon progression angles, one for the forefoot and one for the heel, and compared across three conditions: roller plate (RoPl), low-friction interface on the shoe (SB), and no method for reducing shear forces (NoSB). Data were collected for a range of commercial prosthetic foot models and sizes. Select data were collected over multiple days to assess variation over test sessions. RESULTS: Differences in stiffness between RoPl and SB test conditions ranged from -0.9% to +2.6% across foot models. By contrast, differences between RoPl and no method for reducing shear conditions ranged from -2.9% to +14.6%. Differences in linear stiffness between test sessions ranged from -2.2% to +3.6%. CONCLUSIONS: Methods for reducing shear force in this study demonstrated roughly equivalent effects. Thus, a low-friction interface may be used as a less expensive and less complex method for reducing shear force in prosthetic foot testing. In addition, mechanical testing results were relatively consistent across multiple test sessions, lending confidence to test consistency.

Comparing forefoot and heel stiffnesses across commercial prosthetic feet manufactured for individuals with varying body weights and foot sizes.

BACKGROUND: Despite the effects of prosthetic foot mechanical properties on gait of people with lower limb amputation, scant forefoot and heel stiffness data exist to help guide prosthetic foot prescription. OBJECTIVE: To measure forefoot and heel linear stiffness properties across commonly prescribed commercial prosthetic foot models and to describe variations in stiffness across feet targeted for users with different body weights and foot sizes. STUDY DESIGN: Mechanical testing of five types of commercial prosthetic feet across nine user body weight and foot size combinations. METHODS: Linear forefoot and heel stiffness (force vs. displacement) data were collected for 41 prosthetic feet. Quasistatic testing was conducted at -15 and +20 degrees to isolate loading of the heel and forefoot, respectively. RESULTS: Overall, there was a significant relationship between user body weight and both forefoot and heel stiffness, when adjusted for foot size and type ( P < 0.001). However, there were a substantial number of inconsistencies across foot type within example user body weight and foot sizes combination. Furthermore, the relative order of forefoot stiffness across foot type differed from the relative order of heel stiffness across foot type. CONCLUSIONS: The inconsistencies and differences in relative order of forefoot and heel stiffness across commercial foot type suggest the importance of publishing objective stiffness and other mechanical properties of prosthetic feet. These data can aid clinicians in better matching mechanical properties of prosthetic feet with the functional goals and abilities of prosthesis users.

Strategies for graded motor imagery for clients with phantom limb pain and cognitive impairment.

BACKGROUND: Individuals with amputations often experience phantom limb pain (PLP) that can limit their participation in rehabilitation, prosthesis training, desired activities, and roles. One nonpharmacological rehabilitation intervention for PLP is graded motor imagery (GMI). There are several components to GMI, including right/left discrimination or laterality, motor imagery, sensory retraining, and mirror therapy. Successful implementation of GMI requires a range of cognitive skills, such as attention span, working memory, abstract reasoning, and planning. For individuals with PLP who concurrently display cognitive impairments, GMI protocols can be adapted using strategies derived from clinical practice. OBJECTIVES: The purpose of this technical clinical report was to discuss the application of clinically implemented cognitive compensation techniques to GMI instruction. STUDY DESIGN: Not applicable. METHODS: Clinical expert opinion to explore adaptations for GMI. TECHNIQUE: Graded motor imagery can be an effective tool for pain treatment; however, some clients may need greater clinician support due to existing cognitive difficulties. RESULTS: For clients to be successful, active engagement in learning about and implementing GMI techniques is necessary. CONCLUSIONS: When serving the lifetime amputation care needs of patients with cognitive deficits, we find that targeted learning strategies and accommodations can be helpful when introducing GMI concepts and skill development. Enhanced patient education techniques support client learning.

Effects of women's footwear on the mechanical function of heel-height accommodating prosthetic feet.

The loaded mechanical function of transtibial prostheses that result from the clinical assembly, tuning, and alignment of modular prosthetic components can directly influence an end user's biomechanics and overall mobility. Footwear is known to affect prosthesis mechanical properties, and while the options of footwear are limited for most commercial feet due to their fixed geometry, there exists a selection of commercial prosthetic feet that can accommodate a moderate rise in heel height. These feet are particularly relevant to women prosthesis users who often desire to don footwear spanning a range of heel heights. The aim of this study was to assess the effects of adding women's footwear (flat, trainer, 5.08 cm heel) on the mechanical properties (deformation and energy efficiency) of four models of heel-height accommodating prosthetic feet. Properties were measured through loading-unloading at simulated initial contact, midstance and terminal stance orientations with a universal materials test system, and statistically compared to a barefoot condition. Results suggest that the addition of footwear can alter the level of foot deformation under load, which may be a function of the shoe and alignment. Moreover, while each foot displayed different amounts of energy storage and return, the addition of footwear yielded similar levels of energy efficiency across foot models. Overall, prosthesis users who don shoes of varying heel heights onto adjustable prosthetic feet and their treating clinicians should be aware of the potential changes in mechanical function that could affect the user experience.

Toward improving residual limb climate within prostheses for persons with lower limb loss: a technical note.

BACKGROUND: Individuals with lower limb loss often wear a gel liner and enclosed socket for connecting to a terminal prosthetic device. Historically, a significant limitation to traditional liners and sockets is that they are thermal insulators, thereby trapping heat and moisture within, which can lead to numerous deleterious issues, including loss of suspension and residual limb skin problems, and, in turn, reductions in mobility, function, and overall quality of life. To mitigate these issues, new approaches are therefore needed to enhance the residual limb climate (e.g. breathability and air permeability), allowing the dispersal of heat and moisture from within the liner and socket. METHODS: In this study, a multidisciplinary team sought to establish the feasibility of an innovative prosthetic liner-socket system, designed to improve residual limb climate by capitalizing on passive (i.e. nonpowered) ventilation to reduce temperature/moisture and improve socket comfort for persons with transtibial amputations. Focus group meetings, along with an iterative design approach, were implemented to establish innovative design and development concepts that led to a passively ventilated liner-socket system. CONCLUSIONS: Ex vivo design has supported the feasibility of developing a passively ventilated liner-socket. To build on these successes, future development and human subjects testing are needed to finalize a commercially viable system. Implementing a passively ventilated liner-socket system that improves residual limb health and comfort, without compromising function or mobility of the user, into standard clinical care may encourage a more active lifestyle and enhance the quality of life for individuals after lower limb loss.

A novel ergonomic wheelchair reduces bacterial hand contamination.

OBJECTIVE: To determine whether bacterial contamination of rider's hands is less with a novel ergonomic wheelchair (EW) than a standard wheelchair (SW). EXPERIMENTAL DESIGN: After wheelchair hand rims were disinfected, volunteers wearing nitrile gloves propelled each wheelchair through a standardised "run" in hospital. Post-run cultures were obtained from riders' gloved hands. Bacterial hand counts were compared between runs matched by rider (same rider, different chairs) or time (different riders in each chair, running concurrently), and overall. SETTING: Minneapolis Veterans Affairs Health Care System (MVAHCS), a large tertiary care facility. PARTICIPANTS: Eleven employee volunteers. INTERVENTION: EW, as compared with SW. With SW, co-location of hand rims and tyres potentially exposes the user's hands to tyres, which risks contaminating the user's hands with ground-source bacteria. Our novel ergonomic wheelchair (EW) separates drive wheel and hand rims, potentially reducing hand contamination. MAIN OUTCOME MEASURE: Bacterial hand counts. RESULTS: Post-run bacterial hand counts were over 10-fold lower with the EW than the SW. This was true (i) when the same rider tested both chairs sequentially (n = 8 pairs) (median counts, 40 vs. 1030; p = 0.008), (ii) when different riders tested the two chairs concurrently (n = 9 pairs) (median counts, 40 vs. 660; p = 0.004), and (iii) overall (median counts, 40 [n = 9 runs] vs. 550 [n = 10 runs]; p < 0.001). CONCLUSION: Separation of wheelchair hand rims from tyres significantly reduces bacterial hand contamination. Reduced hand contamination could decrease bacterial infections and dissemination of resistant bacteria, warranting further study.Implications for rehabilitationThe novel design of the ergonomic wheelchair, removing the push rim from proximity to the wheelchair tyre, keeps the hands of wheelchair users cleaner.The re-design of the standard manual wheelchair was implemented initially to improve shoulder ergonomics during manual wheelchair propulsion and has the added benefit of reduction in the transfer of bacteria from floors to hands for manual wheelchair users.Since the ergonomic wheelchair has the potential to decrease rates of bacterial infection in manual wheelchair users, further testing is warranted.

User-centered design and development of a trunk control device for persons with spinal cord injury: A pilot study.

CONTEXT/OBJECTIVE: There are no wheelchair products designed to allow users to dynamically control trunk posture to both significantly improve functional reach and provide pressure relief during forward lean. This pilot study sought to (1) gather stakeholder desires regarding necessary features for a trunk control system and (2) subsequently develop and pilot test a first-generation trunk control prototype. DESIGN: Multi-staged mixed methods study design. SETTING: Minneapolis VA Health Care System, Minneapolis, MN. PARTICIPANTS: Eight people with spinal cord injuries were recruited to participate in a focus group. Five participants returned to discuss, rate, and select a design concepts for prototype development. Two participants returned to test the first-generation trunk control prototype. INTERVENTIONS: The focus group members selected a trunk control device design that uses backpack straps with a single cable as the most desired option. Our design team then manufactured the first-generation prototype at the Minneapolis VA. OUTCOME MEASURES: Bimanual workspace capabilities (n = 1) and pressure map relief changes (n = 2) during supported forward lean were measured. Both participants also provided feedback on the trunk control devices usability. RESULTS: Bimanual workspace (for Participant 1) was increased by 311% in the sagittal plane with use of the trunk control device as compared to without. Pressure relief during a forward lean was increased with an overall dispersion index reduction of 87.6% and 27.7% for Participant 1 and Participant 2 respectfully. CONCLUSION: This pilot study successfully elicited desired features for a trunk control device from stakeholders and successfully developed and tested a first-generation trunk control prototype.

Visualization of user interactions with a pressure mapping mobile application for wheelchair users at risk for pressure injuries.

Pressure injuries for individuals with spinal cord injuries (SCI) are correlated with mortality and are a leading cause for rehospitalizations. The Assisted Weight Shift (AW-Shift©) is a mobile pressure mapping application designed to provide users with a live map view and reminders to perform weight shifts. Novel visualization techniques were used to understand daily distributions of user interaction wit h AW-Shift©. The date and time of system interactions were recorded for six participants with SCI over 7 days (five males/one female, five manual users/one power user, 55.3 ± 17.3 years old, 10.6 ± 6.5 years since injury). Circular frequency plots were created to visualize the time and frequency participants brought the app to the foreground of their phone and received alerts and reminders to complete weight shifts. While some participants used the system regularly throughout the day, others primarily used it before 8am; highlighting the system's importance for regular spot checks and morning wheelchair setup. Participant adherence to weight shift reminders was low suggesting the live pressure map may be more useful. Circular frequency plots can be used by clinicians to more easily review large amounts of patient data. Future work will investigate raw pressure mat data and create a closed-loop weight shift detection algorithm.

Biomechanical characterization of the foot-ground interaction among Service members with unilateral transtibial limb loss performing unconstrained drop-landings: Effects of drop height and added mass.

There exist limited data to guide the development of methodologies for evaluating impact resilience of prosthetic ankle-foot systems, particularly regarding human-device interaction in ecologically valid scenarios. The purpose of this study was to biomechanically characterize foot-ground interactions during drop-landings among Service members with and without unilateral transtibial limb loss. Seven males with, and seven males without, unilateral transtibial limb loss completed six drop-landing conditions consisting of all combinations of three heights (20 cm, 40 cm, 60 cm) and two loads (with and without a 22.2 kg weighted vest). Peak ground reaction forces (GRF), vertical GRF loading rate and impulse, as well as ankle-foot, knee, and hip joint negative (absorption) powers and work were compared across groups (i.e., contralateral side and prosthetic side vs. uninjured controls) by height and load conditions. Loading occurred primarily in the vertical direction, and increased with increasing drop height and/or with added load. Vertical GRFs were overall ~ 15% smaller on the prosthetic side (vs. controls) with similar loading rates across limbs/groups. From the most challenging condition (i.e., 60 cm with 22 kg load), ankle-foot absorption energies on the prosthetic side were 64.6 (7.2) J; corresponding values were 187.4 (8.9) J for the contralateral limb and 161.2 (6.7) J among uninjured controls. Better understanding biomechanical responses to drop-landings in ecological scenarios will help inform future iterations of mechanical testing methodologies for evaluating impact resilience of prosthetic ankle-foot systems (enhancing prescription criteria and return-to-activity considerations) as well as identifying and mitigating risk factors for long-term secondary complications within the contralateral limb (e.g., joint degeneration).