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Rehabilitation Engineering and Applied Research Lab (REAR Lab)

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Now showing 1 - 10 of 25
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    Dataset: Procedure to categorize wheelchair cushion performance using compliant buttock models
    (Georgia Institute of Technology, 2022-09) Sprigle, Stephen ; Deshpande, Yogesh
    Wheelchair cushion prescription often seeks to address tissue integrity in addition to other clinical indicators. Because hundreds of wheelchair cushion models are available, a benefit would result if cushions were classified in a more valid manner to help guide selection by clinicians and users. The objective of this research was to develop an approach to evaluate and classify wheelchair cushion performance with respect to pressure redistribution.
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    Dataset for "Effect of wheels, casters and forks on vibration attenuation and propulsion cost of manual wheelchairs"
    (Georgia Institute of Technology, 2022-08-10) Misch, Jacob ; Liu, Yuanning ; Sprigle, Stephen
    Manual wheelchair users are exposed to whole-body vibrations as a direct result of using their wheelchair. Wheels, tires, and caster forks have been developed to reduce or attenuate the vibration that transmits through the frame and reaches the user. Five of these components with energy-absorbing characteristics were compared to standard pneumatic drive wheels and casters. This study used a robotic wheelchair propulsion system to repeatedly drive an ultra-lightweight wheelchair over four common indoor and outdoor surfaces: linoleum tile, decorative brick, poured concrete sidewalk, and expanded aluminum grates. Data from the propulsion system and a seat-mounted accelerometer were used to evaluate the energetic efficiency and vibration exposure of each configuration. Equivalence test results identified meaningful differences in both propulsion cost and seat vibration. LoopWheels and SoftWheels both increased propulsion costs by 12-16% over the default configuration without reducing vibration at the seat. Frog Legs suspension caster forks increased vibration exposure by 16-97% across all four surfaces. Softroll casters reduced vibration by 11% over metal grates. Wide pneumatic 'mountain' tires showed no difference from the default configuration. All vibration measurements were within acceptable ranges compared to health guidance standards. Out of the component options, softroll casters show the most promising results for ease of efficiency and effectiveness at reducing vibrations through the wheelchair frame and seat cushion. These results suggest some components with built-in suspension systems are ineffective at reducing vibration exposure beyond standard components, and often introduce mechanical inefficiencies that the user would have to overcome with every propulsion stroke.
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    The Design of a Family of Parametric Anatomically-Based Compliant Buttock Models to Evaluate Wheelchair Cushion Performance - Fabrication Package
    (Georgia Institute of Technology, 2022-07) Deshpande, Yogesh ; Sprigle, Stephen
    The evaluation of wheelchair cushion performance is of interest to a variety of stakeholders. Over the years, several buttocks models have been used to evaluate wheelchair cushion performance. These vary in design and purpose, and can be generally classified as either rigid or compliant. To date, published studies using buttock models have been limited to using a single size model. Thus, they were designed to evaluate one size of cushions. A need exists to define a series of models that can be used to evaluate cushions of varying sizes. The objective of this project was to develop a family of compliant buttock models that are based upon the anatomical parameters of persons with varying body sizes. This paper will detail the designs, describe the anatomical basis for the design and provide the rationale for the design decisions. Supplemental material includes greater detail; the full CAD files and model fabrication instructions are available in an open access repository for persons who wish to fabricate the models.
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    Dataset for "Propulsion cost changes of ultra-lightweight manual wheelchairs after one year of simulated use"
    (Georgia Institute of Technology, 2022) Misch, Jacob ; Sprigle, Stephen
    Manual wheelchairs are available with folding or rigid frames to meet the preferences and needs of individual users. Folding styles are commonly regarded as more portable and storable, whereas rigid frames are commonly regarded as more efficient for frequent daily use. To date, there are no studies directly comparing the performances of the frame types. Furthermore, while differences have been reported in the longevity of the frame types, no efforts have been made to relate this durability back to real-world performance of the frames. This study investigated the propulsion efficiencies of 4 folding and 2 rigid ultra-lightweight frames equipped with identical drive tires and casters. A robotic wheelchair tester was used to measure the propulsion costs of each chair over 2 surfaces: concrete and carpet. A motorized carousel was used to drive the chairs 511 km around a circular track to simulate one year of use for each wheelchair. After simulated use, 5 of the 6 wheelchairs showed no decrease in propulsion effort, indicating that the frames were able to withstand the stresses of simulated use without detrimental impact on performance. In the unused 'new' condition, rigid chairs were found to have superior (>5%) performance over folding frames on concrete and carpet, and in the 'worn' condition rigid chairs had superior performance over folding chairs on concrete, but were comparable on the carpeted surface.
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    An Exploratory Analysis of The Role of Adipose Characteristics in Fulltime Wheelchair Users’ Pressure Injury History - Supplementary Data
    (Georgia Institute of Technology, 2021) Sonenblum, Sharon Eve ; Measel, Megan ; Sprigle, Stephen ; Greenhalgh, John ; Cathcart, John McKay
    The goals of this study were 1) to identify the relationship between adipose (subcutaneous and intramuscular) characteristics and pressure injury (PrI) history in wheelchair users, and 2) to identify subject characteristics, including Biomechanical Risk, that are related to adipose characteristics. Data in the supplement is associated with 43 full-time wheelchair users with and without a history of pelvic pressure injuries. Their buttocks were scanned in a seated posture in a FONAR UPRIGHT® MRI. Intramuscular adipose (the relative difference in intensity between adipose and gluteus maximus) and the subcutaneous adipose characteristics (the relative difference in intensity between subcutaneous adipose under and surrounding the ischium) were compared to pressure injury history and subject characteristics. Participants with a history of PrIs had different subcutaneous fat (subQF) characteristics than participants without a history of PrIs. Specifically, they had significantly darker adipose under the ischium than surrounding the ischium than participants without a history of PrIs. On the other hand, only when individuals with complete fat infiltration (n=7) were excluded, did individuals with PrI history have more fat infiltration than those without a PrI history. Presence of spasms and fewer years using a wheelchair were associated with leaner muscle. The results of the study suggest the hypothesis that changes in adipose tissue under the ischial tuberosity (presenting as darker SubQF) are associated with increased biomechanical risk for pressure injury. Further investigation of this hypothesis, as well as the role of intramuscular fat infiltration in PrI development may help our understanding of PrI aetiology. It may also lead to clinically-useful diagnostic techniques that can identify changes in adipose and biomechanical risk to inform early preventative interventions.
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    Friction characteristics of preventative wound dressings under clinically‐relevant conditions dataset
    (Georgia Institute of Technology, 2020-12-15) Sprigle, Stephen ; Caminiti, Riley ; Varenberg, Michael
    Wound dressings can be used prophylactically or during actual treatment. Preventative dressings have become a standard of care to prevent pressure ulcers in patients while in bed. While the mechanism of the preventative benefit has not been completely explained, the friction between the dressing and linen is hypothesized as being a key performance factor. The objective of this project was to quantify the static and kinetic coefficients of friction (COF) of various brands of prophylactic dressings under the stresses experienced in situ, while the dressings are in contact with bed linen materials. The COF of six commercial dressings were calculated using tribometer measurements. The ranges of static COF were 0.333-0.542 and kinetic COF were 0.333-0.513. Four dressings exhibited COF that were consistent with skin-linen values reported in the literature and all dressing COF appear to be lower than the COF of moist skin against linen.
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    Video Demonstrations of Over-Ground AMPS Trials with Intermittent Torque-Controlled Propulsion
    (Georgia Institute of Technology, 2020-10-12) Misch, Jacob P. ; Sprigle, Stephen
    This repository contains videos of the Anatomical Model Propulsion System (AMPS) performing straight and curvilinear maneuvers to characterize the performance of various manual wheelchair configurations. The AMPS was configured with a torque-based motor controller. Different trajectories were deployed for different chairs. The straight maneuver features three 'acceleration phase' pushes followed by four 'steady-state phase' pushes, then the system is allowed to gradually coast to a rest. The slalom maneuver starts with one bilateral push to align the casters straight forward, followed by four alternating unilateral pushes to generate the serpentine-like turning motion. K0004 (high-strength lightweight) chairs were tested over tile and carpet, and were given higher torques than the K0005 (ultra-lightweight) chairs to achieve similar motion. Plots of each of the torque profiles are attached in .png format.
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    Modeling manual wheelchair propulsion cost during straight and curvilinear trajectories dataset
    (Georgia Institute of Technology, 2020-05-11) Misch, Jacob ; Huang, Morris ; Sprigle, Stephen
    Minimizing the effort to propel a manual wheelchair is important to all users in order to optimize the efficiency of maneuvering throughout the day. Assessing the propulsion cost of wheelchairs as a mechanical system is a key aspect of understanding the influences of wheelchair design and configuration. The objective of this study was to model the relationships between inertial and energy-loss parameters to the mechanical propulsion cost across different wheelchair configurations during straight and curvilinear trajectories. Inertial parameters of an occupied wheelchair and energy loss parameters of drive wheels and casters were entered into regression models representing three different maneuvers. A wheelchair-propelling robot was used to measure propulsion cost. General linear models showed strong relationships (R2 > 0.84) between the system-level costs of propulsion and the selected predictor variables representing sources of energy loss and inertial influences. System energy loss parameters were significant predictors in all three maneuvers. Yaw inertia was also a significant predictor during zero-radius turns. The results indicate that simple energy loss measurements can predict system-level performance, and inertial influences are mostly overshadowed by the increased resistive losses caused by added mass, though weight distribution can mitigate some of this added cost. Videos of the test methods used to collect this dataset (wheelchair-propelling robot performing the three maneuvers, coast-down cart test for rolling resistance, and the scrub torque test rig) can be found here:
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    Designing an Ergonomic Infant-to-Toddler Rocker Based on Anthropometric Data
    (Georgia Institute of Technology, 2020-04-27) Ryan, Caitlin Olivia
    Currently ergonomics is not a term frequently associated with infant and toddler products. Many of these products on the market like highchairs, rockers and bouncers aren’t designed using anthropometric data on infants and toddlers. The project focused on gather anthropometric data from children between 0-36 months of age as well as aggregating historic data and utilize the measurements to design an ergonomic rocker that would transition or “grow” with a child from infant to toddler. This takes into account not only the objective size of the infants and toddlers but also designing for the differing use cases for each the infant and the toddler user. The infant users are still developing much of their muscle tone and require a rocker to support their feet in long sitting in a semi-reclined position. While toddlers require a rocker that facilitates upright short sitting as well as independent ingress and egress to accommodate their high activity levels. These disparate needs are not currently being met by similar products on the market leading to a shorted life cycle of the product. Anthropometric data was collected on 55 children and used in tandem with knowledge gained from parent surveys, parent interviews and interacting with children to design a new rocker. The prototype was evaluated by both parents and children to make necessary improvements to the design. The final prototype utilized all the information gathered throughout the entire project resulting in an ergonomic adjustable infant -to-toddler rocker.
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    Using Anthropometric Measurements to Design Ergonomic Infant and Toddler Gear
    (Georgia Institute of Technology, 2019-12-05) Pardue, Emily Louisa
    Infants grow so quickly that gear can have a shockingly short life span. Parents often do a quick calculation before purchases: divide the cost by how many months it will be used. Thus, products that are meant to “grow-with-me” or last for multiple infant stages are extremely desirable. Infant-to-toddler rockers are an example of this type of product. However, the researchers have found that the current infant-to-toddler rocker models on the market could be improved. The goal of this project was to use anthropometric data of children to design an ergonomic infant-to-toddler rocker. Anthropometric data was collected on 58 children in order to properly size a new design for a rocker which lasts from 0 to 36 months old. Researchers also found based on parent interviews, a survey, and child interactions, that the needs of infants are very different from the needs of toddlers. Infants are still developing muscle tone, and it is important for them to be supported in a semi-reclined position. Toddlers are extremely active and need a device which allows them to ingress and egress independently. Concepts were developed, and prototypes built to demonstrate the new concepts. These prototypes were then tested with parents and children to gather feedback and improve designs. The final design is an ergonomic rocker which adjusts in size and recline angle to serve the infants that need to be secure and reclined, as well as the ambulatory toddlers.