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Rehabilitation Engineering and Applied Research Lab (REAR Lab)

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Publication Search Results

Now showing 1 - 5 of 5
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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
    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.
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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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    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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    Blood Flow to the Butt
    (Georgia Institute of Technology, 2012-03) Sonenblum, Sharon Eve
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    Biomechanical responses to seated full body tilt and their relationship to clinical application
    (Georgia Institute of Technology, 2009-08-19) Sonenblum, Sharon Eve
    The overall goal of this research is to improve the use of seated tilt to increase function, health and quality of life for people using power wheelchairs. Specifically, the objective of this dissertation is to evaluate the biomechanical responses to seated full body tilt and their relationships to the actual use of tilt-in-space wheelchairs. In the first phase of this study, researchers remotely monitored how 45 fulltime power wheelchair users used their tilt-in-space systems. Participants spent an average of 12.1 hours in their wheelchair each day. They spent more than 2 hours seated at positions greater than 15° and performed tilts of 5° or greater every 27 minutes, but rarely performed tilts past 30°. Two distinct types of tilt behavior were identified: uni-modal (staying at a single position more than 80% of the time) and multi-modal (staying at a single position less than 80% of the time). Participants in the multi-modal group tilted significantly more frequently (4 times per hour) than the uni-modal group, and did not have a single typical position. Participants without sensation were more likely to exhibit uni-modal behavior. In the second phase of this study, researchers used interface pressure measurements and laser Doppler flowmetry to study changes in localized loading and superficial blood flow at the ischial tuberosities across different amounts of tilt. Eleven participants with spinal cord injuries were studied in a laboratory setting. Results showed that biomechanical responses to tilt were highly variable. Pressure reduction at the ischial tuberosity was not present at 15°, but did occur with tilts to 30° and greater, and could be explained by the tilt position and upright pressure. Unlike pressure, blood flow increased with all tilts from an upright position, but did not increase when tilting from 15° to 30°. Only 4 of 11 participants had a considerable increase (≥10%) in blood flow at 30° tilt, whereas 9 participants did during maximum tilt (i.e., 45°-60°). Based on the results of this study, tilting for pressure reliefs as far as the seating system permits is recommended to maximize the potential for significant blood flow increases and pressure relief.