Prosthetics and Orthotics Graduate Progam

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Now showing 1 - 10 of 24
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    A Static Evaluation of Transtibial Prosthesis Suspension
    (Georgia Institute of Technology, 2009-04-22) Brooks, Dustin
    Previously, there have been a number of studies comparing different transtibial suspension methods; however, studies using elevated negative pressure (vacuum) as a suspension method are limited. The purpose of this study is to compare three methods of transtibial suspension (vacuum, suction, and knee sleeve) with respect to pistoning. Our hypotheses were: one that vacuum suspension will significantly reduce the amount of pistoning compared to knee sleeve and suction suspensions, and two that a greater magnitude of pistoning would be apparent in individuals with a higher percentage of redundant tissue. Seven subjects with unilateral transtibial amputations were included in this study. A custom made prosthesis was fabricated for each subject that allowed for easy conversion between suspension methods. For each suspension method, radiographic scans of the subject’s limb were produced inside the prosthetic socket using the dual energy X-ray absorptiometry (DEXA) scanner for three conditions. These conditions, designed to simulated dynamic gait, consited of an unweighted, loaded to half body weight, and a 44.5 N distraction. Using a multivariate repeated measures ANOVA along with a Bonferroni post-hoc analysis, statistical significance was shown between both knee sleeve and suction and between knee sleeve and vacuum suspensions with regard to pistoning. Although statistically insignificant, the p value (p=0.063) was very close to the alpha level for significance of 0.05 between suction and vacuum suspensions. In contrast to previous schools of thought this study has also shown that the amount of redundant tissue and pistoning are not strongly correlated.
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    Comparison of Body Composition Measurements in Amputees vs. Non-Amputees
    (Georgia Institute of Technology, 2009-04-15) Larkins, Denise
    Assessing body composition is important to provide information about nutritional status and health risks. Purpose: The purpose of this study was to examine if there is a significant difference in body composition depending on measurement method and if the discrepancy in measurement method is greater for amputees than for non-amputees. Methods: 23 subjects (12 lower limb amputees and 11 non-amputees) were matched based on sex, age, height, weight, ethnicity, and self-reported activity level. Subject’s body composition was assessed through Dual Energy X-Ray Absorptiometry (DEXA) using a Lunar Prodigy whole body scanner (GE Medical Systems, Madison, WI), Bioelectrical Impedance (BIA) using an OMRON (Bannockburn, IL) hand-held body fat analyzer, and the Skinfold Technique with calipers from Cambridge Scientific Industries, Inc. (Cambridge, Maryland). Results: 2-way ANOVA for % body fat by measurement method and percent body fatness showed a main effect for measurement method (p=0.02). Post hoc showed significant difference between BIA & DEXA (p=0.01). There was no interaction effect for measurement method and body fatness (average vs. above average) p=0.77. 2 way ANOVA for % body fat by measurement method and type of individual (amputee vs. non-amputee) showed a main effect for measurement method (p=0.03). Post hoc showed significant difference between BIA & DEXA (p=0.04). There was no interaction effect for measurement method and type of individual (p=0.70). Conclusions: There is a significant difference in body composition depending on measurement method. There is a trend for body composition to differ more by method for subjects with above average % body fat than for subjects with average % body fat. Likewise, there is a trend for body composition to differ more by method for amputees than for non-amputees.
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    Clinical Reliability of a Device for Measuring Forces and Moments in Amputee Gait
    (Georgia Institute of Technology, 2009-04-08) LeGare, Stephanie
    Practitioners find it difficult to measure forces and moments on a prosthesis when an amputee walks. Traditional measures, such as using force platforms, are expensive and inaccessible. Practitioners also question the applicability of lab measurements to everyday activities. The iPecs is a portable device that measures forces and moments on a prosthesis. The device demonstrates reliable data over multiple gait speeds and over two testing days (r > 0.9). The iPecs captures characteristic gait data similar to a force platform; however, variations occur due to different coordinate reference planes and the stiffness of the prosthetic foot. Compared to a force platform, iPecs captures more data in less time and fewer overall steps. Portability of the iPecs allows use in daily activities, outdoors, or in clinic, making it an alternative to traditional methods of measuring kinetic data.
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    An Association Between Translation and Hand Dominance
    (Georgia Institute of Technology, 2009-04-08) Berkman, Traci
    Many tests are available for measuring and evaluating hand function. These tests measure manual dexterity, requiring arm-hand coordination and using the hand as a unit. Translation, a task requiring moving an object from the palm to fingertips, is grossly overlooked in literature and there are no available tests to measure this task in adults. Translation has been studied in adolescents to determine if dysfunction in translation relates to motor delay, but has not been studied in adults or injured populations. The purpose of this study is to determine if translation plays a role in return of full function to an injured dominant hand. The researchers hypothesize that an association exists between switching hand dominance after an injury to the dominant hand and the inability to translate an object. To test the hypothesis two questionnaires were administered to the subjects (verbal and written) to determine hand dominance and three performance tasks were completed: 1) Functional Dexterity Test (FDT), 2) The Minnesota Placing Test, and 3) The Translation Task. Independent t-tests and a chi-square test of independence were used to analyze the data. No significant difference was found between the two groups (Switched Dominance and Did Not Switch Dominance) for the Minnesota Placing Test (p=0.229). Significant Difference was found between groups for the Functional Dexterity Test (p=0.001). The chi-square of independence showed that switching dominance was dependent on the ability to translate. The data suggests that another component, specifically translation is necessary for return of normal hand function in an injured dominant hand.
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    Frontal Plane Characteristics of Multi-Axis Feet: A Test Method for Evaluation and Effect of Shoes on Foot Performance
    (Georgia Institute of Technology, 2008-04-23) Gaw, Stephen
    Introduction: The purpose of this project is to analyze the stiffness properties of multiaxis prosthetic feet in the frontal plane, and analyze the influence on mechanical testing of those feet when a shoe is worn. We hypothesize: (1) Stiffness properties of multiaxis feet in the frontal plane will vary significantly, and the feet will naturally divide into subcategories based on stiffness properties, and (2) Testing with shoes will influence the stiffness properties in the frontal plane of the multiaxis prosthetic foot. Methods: 6 multiaxis prosthetic feet (including dynamic response/multiaxis feet) were tested on an Instron materials testing machine. The feet underwent cyclic loading to simulate midstance phase of gait, and were loaded onto a range of inclines from 0° to 20°. The tests were repeated with a shoe added to the feet. A SACH foot was also tested for comparison purposes. Results: There was significant variability among the feet when tested barefoot. The SACH foot displayed a lower stiffness than 3 of the multiaxis feet at all inclines. Statistical analysis showed there were natural divisions among the feet according to stiffness data. When the feet were tested with a shoe, the stiffness decreased for all feet in all conditions, although the magnitude of the change varied by foot. Natural divisions among feet were also present when tested with a shoe, but the divisions were different than when tested barefoot. Discussion: The results showed that stiffness properties among multiaxis feet did vary, and the feet did divide themselves naturally. When tested with a shoe, stiffness decreased for all feet in all conditions. Limitations of this study include anonymity of feet, variability of shoes, and small aspect of gait cycle.
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    Natural Progression of Non-Synostotic Plagiocephaly
    (Georgia Institute of Technology, 2008-04-23) Spragg, Rebecca
    Background. Despite having a good understanding of the causes and treatment for deformational plagiocephaly, the need for treatment has yet to be determined conclusively. The purpose of this study was to determine the natural progression of non-synostotic plagiocephaly in children between the ages of 18 and 48 months. The study also aimed to determine parent impressions about the current head shape of children with untreated deformational plagiocephaly. Methods. A survey and follow-up scan were completed for twenty-two children diagnosed with deformational plagiocephaly of severity level 3 or higher who declined orthotic treatment. Subjects were between the ages of 18 and 48 months at the time of the study. Cranial vault asymmetry index (CVAI), cephalic ratio (CR), and severity level were compared from the initial diagnosis scan and the current scan. Results. Of the 22 subjects, 17 showed an improvement in CVAI, with an average decrease of 1.6%. CR had an average decrease of 4%. Parents perceived the head shape to have "improved" in 14, "stayed the same" in 6, and were unsure of any change in 4 subjects. Parents were "very satisfied" in 11, "somewhat satisfied" in 6, and "not very" satisfied in 5 subjects. Conclusions. Although there was a decrease in CVAI, it was not large enough to move subjects into a non-treatment severity level. 77% of subjects would still be recommended for orthotic treatment based on their current head shape. Parents are satisfied with the current shape of their children's heads despite any asymmetry that may still be present.