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Rehabilitation Engineering and Applied Research Lab (REAR Lab)

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Publication Search Results

Now showing 1 - 10 of 22
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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.
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    System design of an activity tracker to encourage behavioral change among those at risk of pressure ulcers
    (Georgia Institute of Technology, 2019-04-24) Obrien, John James
    The Wheelchair In-Seat Activity Tracker (WiSAT) is a sensor-based activity tracker aimed at encouraging in-seat movement among wheelchair users who are at risk of pressure ulcers. Pressure ulcers tend to form in the buttocks or thighs of a wheelchair user due to a lack of pressure redistribution in that part of the body. Pressure ulcers are a serious risk to many wheelchair users due to a plethora of harmful side-effects, such as infection, hospitalization, and long recovery times. However, in-seat movements, such as weight shifts, have been linked with the occurrence of pressure ulcers. WiSAT began as a research tool that enabled researchers to monitor the in-seat activity of wheelchair users during their daily lives through sensor-based reporting, as opposed to relying solely on the self-reporting of research participants. Through the efforts described in this thesis, WiSAT was transformed from a research tool into a consumer product. Specifically, this thesis describes the design, development, and integration of WiSAT’s subsystem through four specific aims: 1. Design and evaluation of a user-interface based upon principles of Health Behavioral Change Theory. 2. Coupling of the Hardware and Smartphone App Subsystems 3. Preparation of the Algorithm Subsystem 4. Integration of the WiSAT Subsystems through Multi-layered Architecture for the WiSAT Smartphone App
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    In-seat activity of wheelchair users measured over multiple epochs dataset
    (Georgia Institute of Technology, 2019-01-18) Sprigle, Stephen ; Sonenblum, Sharon ; Feng, Chen
    Pressure ulcers, by definition, are caused by external forces on the tissues, often in the regions of bony prominences. Wheelchair users are at risk to develop sitting-acquired pressure ulcers, which occur in the regions of the ischial tuberosities, sacrum/coccyx or greater trochanters. As a means to prevent pressure ulcers, instruction on performing pressure reliefs or weight shifts are a part of the rehabilitation process. The objective of this study was to monitor the weight shift activity of full-time wheelchair users with acute spinal cord injury over multiple epochs of time in order to determine consistency or routine within and across epochs. A second objective was to evaluate the accuracy of self-reported pressure relief frequency within each measurement epoch. A wheelchair in-seat activity monitor was used to measure weight shifts and other in-seat movement. The data was classified into multiple in-seat activity metrics using machine learning. Seventeen full-time wheelchair users with spinal cord injury were measured within multiple epochs, each lasting more than 1 week. Across all in-seat activity metrics, no consistent pattern of activity changes emerged. None of the in-seat activity metric changed in any one direction across a majority of subjects. Subjects tended to over-estimate their frequency of performing pressure reliefs. Self-reported pressure relief behaviors are not reliable, and therefore, cannot be used to evaluate preventative behaviors either clinically or within research. This study had the capability of fully investigating in-seat movements of wheelchair users. The results indicated that in-seat movement does not reflect a routine, either in pressure reliefs, weight shifts or other functional in-seat movements. This study has illustrated the complexity of assigning causation of pressure ulcer occurrence to seated behaviors of wheelchair users and identifies the need for improved clinical techniques designed to develop routine behaviors to prevent pressure ulcers.
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    Video: Skeletal Displacement and Shear Strain Example During Head of Bed Elevation
    (Georgia Institute of Technology, 2019) Sonenblum, Sharon E. ; Sprigle, Stephen
    This realtime MRI video demonstrates the caudal displacement of the spine relative to the skin when the head of the bed is elevated 30 degrees. Friction with the sheets keeps the skin from slipping. This video is a great teaching tool to demonstrate internal shear strain in the adipose near the sacrum and coccyx, and it serves as a nice counterpart to the published article: Sprigle, S. and S. Sonenblum, Visualizing Tissue Strain Under the Sacrum and Coccyx in Different Supine Postures: A Case Series. Adv Skin Wound Care, 2019, in which static measurements of skeletal displacement are reported.
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    Video Demonstrations of Component- and Systems-Level Test Methods for Wheelchair Propulsion Characterization
    (Georgia Institute of Technology, 2018-11) Huang, Morris ; Misch, Jacob ; Sprigle, Stephen
    The five videos included in this repository demonstrate the fundamental test methods used to characterize performance of various wheelchair components. The Anatomical Model Propulsion System (AMPS) was designed to emulate the weight distribution and force application of a human wheelchair user. Three canonical maneuvers were identified to quantify the effects of rolling resistance, drive wheel scrub, and caster swivel. The ‘AMPS straight.mp4’ file shows the straight maneuver. ‘AMPS left FW turn.mp4’ demonstrates a fixed-wheel turn, where one wheel is locked and scrubbing against the floor as the chair drives the other wheel. The ‘AMPS CCW.mp4’ shows an alternating zero-radius maneuver designed to cause caster swivel by driving the wheels in opposing directions. Also included in this directory are videos representing the standalone coast-down and scrub torque component tests. ‘Caster Wheel Coast-down Test Video.m4v’ shows the coast-down cart loaded with weights and instrumented with accelerometers to log the deceleration of the cart. This test measures the force of rolling resistance acting on the cart. The final video, ‘scrub test demo.mp4’, shows the test rig used to measure scrub torque. A ZwickRoell materials testing machine pulls the steel cable attached to a pulley system, which rotates the load arm and effectively scrubs the tile or carpet swatch against the fixed wheel. These videos were taken in 2017 to use as demonstrations for future researchers and collaborators. More information can be found in Morris Huang’s dissertation located at
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    Encourage sedentary workers' active seating through product design
    (Georgia Institute of Technology, 2018-07-31) Ni, Chenan
    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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    User specific assistive technology: Hand mounted switch control platform design
    (Georgia Institute of Technology, 2018-04-27) Yuan, Xiuxiu
    The purpose of this project is to design a platform for user specific assistive technology. This platform would allow occupational therapists to design and deliver highly customizable hand mounted switch controls for persons with severe disabilities using rapid prototyping tools. Specifically, occupational therapists would be able to adjust a pre-designed model through an intuitive user interface therefore change the design to meet users’ unique needs. The study first conducted literature review about assistive technology and rapid prototyping, then used participatory approach and human centered design methodology, engaged three occupational therapists to design and develop the platform through workshops and interviews. The aims of this project including designing the switch device, platform user interface and system packaging, and evaluating the designs with the occupational therapists. Findings, limitations and future work were discussed in the end.
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    Buttock tissue response to loading in men with SCI dataset
    (Georgia Institute of Technology, 2018-01-26) Sonenblum, Sharon Eve ; Sprigle, Stephen
    Objective/Background: Despite the fact that most people with a spinal cord injury who use a wheelchair for mobility are considered at-risk for pressure ulcer (PrU) development, there still exists a spectrum of risk amongst this group. Efforts to differentiate risk level would benefit from clinical tools that can measure or predict the buttocks response to loading. Therefore, the goal of this study was to identify how tissue compliance and blood flow were impacted by clinically-measurable risk factors in young men with SCI. Methods: Blood flow at the ischial tuberosity was measured using laser Doppler flowmetry while the seated buttock was unloaded, and loaded at lower (40-60 mmHg) and high (>200 mmHg) loads. Tissue compliance of the buttock was measured using the Myotonometer while subject were lifted in a Guldmann Net. Results: Across 28 participants, blood flow was significantly reduced at high loads, while no consistent, significant changes were found at lower loads. At 40-60 mmHg, blood flow decreased in participants with a pressure ulcer history and lower BMI, but stayed the same or increased in most other participants. The buttock displaced an average of 9.3 mm (2.7 mm) at 4.2 N, which represented 82% (7%) of maximum displacement. BMI was related to the amount of buttock tissue displacement while smoking status explained some of the variation in the percent of max displacement. Conclusion: Wide variability in tissue compliance and blood flow responses across a relatively homogeneous population indicate that differences in biomechanical risk may provide an explanation for the spectrum of PrU risk among persons with SCI.
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    Assistive Technology Outcomes Measure (ATOM) v2.0
    (Georgia Institute of Technology, 2018) Sprigle, Stephen ; Harris, Frances
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    Development of component and system level test methods to characterize manual wheelchair propulsion cost
    (Georgia Institute of Technology, 2017-11-10) Huang, Morris
    The current approach to manual wheelchair design lacks a sound and objective connection to metrics for wheelchair performance. The objective of this research was three-fold: 1) to characterize the inertial and resistive properties of different wheelchair components and configurations, 2) to characterize the systems-level wheelchair propulsion cost, and 3) to model wheelchair propulsion cost as a function of measured component and configuration properties. Scientific tools developed include 1) a series of instruments and methodologies to evaluate the rotational inertia, rolling resistance, and scrub torque of wheelchair casters and drive wheels on various surface types, and 2) a wheelchair-propelling robot capable of measuring propulsion cost across a collection of maneuvers representative of everyday wheelchair mobility. This suite of tools were used to demonstrate the variance manifested in the resistive properties of 8 casters and 4 drive wheels, and the impact/tradeoffs of these components (as well as mass and weight distribution) on system-level wheelchair propulsion cost. Coupling these findings with a theoretical framework describing wheelchair dynamics resulted in two empirical models linking system propulsion cost to component resistive properties. The outcomes of this research empower clinicians and users to make more informed wheelchair selections, as well as offer manufacturers a basis by which to optimize their wheelchair designs.