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Rehabilitation Engineering and Applied Research Lab (REAR Lab)

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Publication Search Results

Now showing 1 - 10 of 46
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    Clinical Application of Pressure Mapping
    (Georgia Institute of Technology, 2007) Sprigle, Stephen ; Davis, Kim ; Georgia Institute of Technology. Center for Assistive Technology and Environmental Access ; Shepherd Center (Atlanta, Ga.)
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    A smartphone application that informs weight shifting behavior to promote tissue health
    (Georgia Institute of Technology, 2015-08-18) Cheng, Philip ; Sprigle, Stephen ; Sonenblum, Sharon E. ; Swarts, Matt ; Industrial Design
    One of the most persistent problems affecting wheelchair users is pressure ulcers. These are ulcers that wheelchair users develop in areas of constant pressure or interruption of blood flow to a localized area. Approximately one- third of patients who suffer from spinal cord injuries develop pressure ulcers, and it is a very expensive consequence for these people. Pressure relief exercises can help, but a high percentage of wheelchair users do not perform them enough. Activity trackers today have the ability to sync with smartphone applications to monitor physical activity. The following study uses weight shifting behavior to help wheelchair users. By studying principles of usability engineering and user interface design, the researcher will design a smartphone application that pairs with a weight shift monitoring system to help promote tissue health. The application will illustrate information for the user to make them aware of their behavior and engage them in pressure relief exercises.
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    Encourage sedentary workers' active seating through product design
    (Georgia Institute of Technology, 2018-07-31) Ni, Chenan ; Sprigle, Stephen ; Budd, James G. ; Sonenblum, Sharon ; Industrial Design
    The purpose of this project is to design a perturbation system for encouraging active sitting. This product would improve the physical environment within which the sedentary workers work and reduce their incidence of musculoskeletal discomfort. Specifically, the sedentary workers would be able to slightly shift postures without being disturbed by the device through an intervention, therefore, encouraging in-seat movement.
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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 ; Georgia Institute of Technology. Rehabilitation Engineering and Applied Research (REAR) Lab
    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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    Design and analysis of an inertial properties measurement device for manual wheelchairs
    (Georgia Institute of Technology, 2010-07-07) Eicholtz, Matthew R. ; Ferri, Aldo A. ; Jayme Caspall ; Michael Leamy ; Sprigle, Stephen ; Mechanical Engineering
    The dynamics of rigid body motion are dependent on the inertial properties of the body - that is, the mass and moment of inertia. For complex systems, it may be necessary to derive these results empirically. Such is the case for manual wheelchairs, which can be modeled as a rigid body frame connected to four wheels. While 3D modeling software is capable of estimating inertial parameters, modeling inaccuracies and ill-defined material properties may introduce significant errors in this estimation technique and necessitate experimental measurements. To that end, this thesis discusses the design of a device called the iMachine that empirically determines the mass, location of the center of mass, and moment of inertia about the vertical (yaw) axis passing through the center of mass of the wheelchair. The iMachine is a spring-loaded rotating platform that freely oscillates about an axis passing through its center due to an initial angular velocity. The mass and location of the center of mass can be determined using a static analysis of a triangular configuration of load cells. An optical encoder records the dynamic angular displacement of the platform, and the natural frequency of free vibration is calculated using several techniques. Finally, the moment of inertia is determined from the natural frequency of the system. In this thesis, test results are presented for the calibration of the load cells and spring rate. In addition, objects with known mass properties were tested and comparisons are made between the analytical and empirical inertia results. In general, the mass measurement of the test object had greater than 99% accuracy. The average relative error for the x and y-coordinates of the center of mass was 0.891% and 1.99%, respectively. For the moment of inertia, a relationship was established between relative error and the ratio of the test object inertia to the inertia of the system. The results suggest that 95% accuracy can be achieved if the test object accounts for at least 25% of the total inertia of the system. Finally, the moment of inertia of a manual wheelchair is determined using the device (I = 1.213 kg-m²), and conclusions are made regarding the reliability and validity of results. The results of this project will feed into energy calculations for the Anatomical Model Propulsion System (AMPS), a wheelchair-propelling robot used to measure the mechanical efficiency of manual wheelchairs.
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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 ; Georgia Institute of Technology. Rehabilitation Engineering and Applied Research (REAR) Lab ; Georgia Institute of Technology. School of Mechanical Engineering
    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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    The Effect of Model Design, Cushion Construction, and Thin Pressure Mats on Pressure Measurement
    (Georgia Institute of Technology, 2007-04-11) Pipkin, Leigh ; School of Applied Physiology ; College of Sciences ; College of Sciences ; School of Biological Sciences
    Wheelchair cushions are designed to protect skin by reducing and distributing pressure. Pressure sensors and buttock models are used in standardized testing of wheelchair cushions. The purpose of this study was to explore how the presence of a thin pressure measurement mat, cushion construction, and buttock model design affect interface pressure (IP), envelopment, and immersion. Aspects reported here are the effect of model design on IP and envelopment and the interaction between model design and cushion construction. Testing was performed with two indenters and seven cushions. Conclusion: Wheelchair cushions deform in response to a loaded indenter. The result is a change in the shape of the indenter-cushion interface, which may not be consistent across loading trials. This is influenced by cushion stiffness and the unloaded shape of the cushion. The data suggests that model design influences the pressure redistribution properties of cushions. Therefore, development of standardized tests should consider the interaction between models and cushions.
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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 ; Georgia Institute of Technology. Rehabilitation Engineering and Applied Research (REAR) Lab
    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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    Using Anthropometric Measurements to Design Ergonomic Infant and Toddler Gear
    (Georgia Institute of Technology, 2019-12-05) Pardue, Emily Louisa ; Sprigle, Stephen ; Bartlett, Chris ; Chininis , Steven ; Industrial Design
    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.
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    Wheelchair in-seat monitoring design considerations
    (Georgia Institute of Technology, 2022-10) Sprigle, Stephen ; Sonenblum, Sharon Eve ; Deshpande, Yogesh ; Jordan, Kathleen ; Georgia Institute of Technology. College of Architecture ; Georgia Institute of Technology. Rehabilitation Engineering and Applied Research Lab ; Georgia Institute of Technology. School of Mechanical Engineering
    Wheelchair in-seat activity trackers are developed to monitor and provide feedback about the pressure redistributing movements of wheelchair users, including weight shifts and other postural shifts that redistribute buttocks pressures. From a design perspective, in-seat activity trackers reflect myriad design decisions that impact performance, function, and usability. Many, if not all, of these decisions involve interconnections across system components, and can have significant impact on tracker operation and user-experience. Technology developers will have to manage many benefits and trade-offs that accompany design of each subsystem. Two documents were created based upon real-world use of in-seat trackers to briefly identify design criteria and constraints that should be considered.