Comparison of four different categories of prosthetic feet during ramp ambulation in unilateral transtibial amputees

2014 ◽  
Vol 39 (5) ◽  
pp. 380-389 ◽  
Author(s):  
Vibhor Agrawal ◽  
Robert S Gailey ◽  
Ignacio A Gaunaurd ◽  
Christopher O’Toole ◽  
Adam Finnieston ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Repeated Measures ◽  
Work Values ◽  
External Work ◽  
Higher Symmetry ◽  
Prosthetic Foot ◽  
Level 3 ◽  
Prosthetic Feet ◽  
Transtibial Amputees ◽  
Level 2

Background:Comparative effectiveness of prosthetic feet during ramp ambulation in unilateral transtibial amputees, who function at different Medicare Functional Classification Levels, has not been published.Objective:To determine differences in symmetry in external work between four categories of prosthetic feet in K-Level-2 and K-Level-3 unilateral transtibial amputees during ramp ascent and descent.Study design:Randomized repeated-measures trial.Methods:Ten subjects completed six testing sessions during which symmetry in external work was calculated using F-scan in-sole sensors. Between testing sessions 1 and 2, subjects received standardized functional prosthetic training. In Sessions 3–6, subjects tested four feet—solid ankle cushion heel, stationary attachment flexible endoskeleton, Talux (categories K1, K2, and K3, respectively), and Proprio-Foot (microprocessor ankle)—using a study socket and had a 10- to 14-day accommodation period with each foot.Results:During ramp descent, K-Level-2 subjects demonstrated higher symmetry in external work values with Talux and Proprio-Foot compared to the solid ankle cushion heel foot. K-Level-3 subjects also had higher symmetry in external work values with the Talux foot than the solid ankle cushion heel foot. Ramp ascent symmetry in external work values were not significantly different between feet.Conclusions:Prosthetic foot category appears to influence symmetry in external work more during decline walking than incline walking. K-Level-2 unilateral transtibial amputees achieve greater symmetry from K3 dynamic response prosthetic feet with J-shaped ankle and microprocessor ankles while descending ramps.Clinical relevanceThe findings suggest that K-Level-2 unilateral transtibial amputees benefit from K3 dynamic response prosthetic feet with J-shaped ankle. These results support the prescription of K3 feet for K-Level-2 amputees who frequently negotiate ramps.

Influence of gait training and prosthetic foot category on external work symmetry during unilateral transtibial amputee gait

2013 ◽  
Vol 37 (5) ◽  
pp. 396-403 ◽  
Author(s):  
Vibhor Agrawal ◽  
Robert Gailey ◽  
Christopher O’Toole ◽  
Ignacio Gaunaurd ◽  
Adam Finnieston
Keyword(s):  
Repeated Measures ◽  
Gait Training ◽  
Third Party ◽  
External Work ◽  
Gait Dynamics ◽  
Prosthetic Foot ◽  
Negative Work ◽  
Level 3 ◽  
Prosthetic Feet ◽  
Level 2

Background:Prosthetic foot prescription guidelines lack scientific evidence and are concurrent with an amputee’s concurrent with an amputee’s Medicare Functional Classification Level (K-Level) and categorization of prosthetic feet.Objective:To evaluate the influence of gait training and four categories of prosthetic feet (K1, K2, K3, and microprocessor ankle/foot) on Symmetry in External Work for K-Level-2 and K-Level-3 unilateral transtibial amputees.Design:Randomized repeated-measures trial.Methods:Five K-Level-2 and five K-Level-3 subjects were tested in their existing prosthesis during Session 1 and again in Session 2, following 2 weeks of standardized gait training. In Sessions 3–6, subjects were tested using a study socket and one of four randomized test feet. There was an accommodation period of 10–14 days with each foot. Symmetry in External Work for positive and negative work was calculated at each session to determine symmetry of gait dynamics between limbs at self-selected walking speeds.Results:K-Level-2 subjects had significantly higher negative work symmetry with the K3 foot, compared to K1/K2 feet. For both subject groups, gait training had a greater impact on positive work symmetry than test feet.Conclusion:Higher work symmetry is possible for K-Level-2 amputees who are trained to take advantage of K3 prosthetic feet designs. There exists a need for an objective determinant for categorizing and prescribing prosthetic feet.Clinical relevanceFindings that gait training can influence symmetry of gait dynamics and that K-Level-2 amputees can achieve greater work symmetry with a K3 foot having a “J-shaped” ankle and heel-to-toe footplate could potentially impact prosthetic care and foot prescription by clinicians and reimbursement guidelines by third-party health-care payers.

Effect of Walking Speed on Angular Stiffness and Roll-Over Shape of the Intact and Prosthetic Feet of Transtibial Amputees

2013 ◽  
Author(s):  
Michelle Roland ◽  
Peter G. Adamczyk ◽  
Michael E. Hahn
Keyword(s):  
Lower Limb ◽  
Stance Phase ◽  
Walking Speed ◽  
Plantar Flexor ◽  
Limb Function ◽  
Prosthetic Foot ◽  
Material Stiffness ◽  
Prosthetic Feet ◽  
Transtibial Amputees ◽  
Lower Limb Function

The calculated roll-over shape and respective radius of intact and prosthetic feet has been shown to be a useful measure of lower limb function during walking [1–2]. Hansen et al [3] reported that the roll-over radius, R, is constant over a range of speeds for the intact foot-ankle system. It may be assumed that the prosthetic foot R would also be constant with increased walking speed. Similarly, the angular stiffness of prosthetic feet is not likely to change with walking speed, as the material stiffness remains unchanged. However, the effective angular stiffness of the intact ankle may increase with the plantar flexor moment during the stance phase of gait, which typically increases in magnitude with walking speed.

Unification of the "Burst" and "Linear" Theories of Periodontal Disease Progression: A Multilevel Manifestation of the Same Phenomenon

2003 ◽  
Vol 82 (3) ◽  
pp. 200-205 ◽  
Author(s):  
M.S. Gilthorpe ◽  
A.T. Zamzuri ◽  
G.S. Griffiths ◽  
I.H. Maddick ◽  
K.A. Eaton ◽  
...  
Keyword(s):  
Periodontal Disease ◽  
Disease Progression ◽  
Repeated Measures ◽  
Regression To The Mean ◽  
Random Coefficient Models ◽  
Linear Change ◽  
New Approach ◽  
Level 3 ◽  
The Mean ◽  
Level 2

Previously, burst and linear theories for periodontal disease progression were proposed based on different but limited statistical methods of analysis. Multilevel modeling provides a new approach, yielding a more comprehensive model. Random coefficient models were used to analyze longitudinal periodontal data consisting of repeated measures (level 1), sites (level 2), teeth (level 3), and subjects (level 4). Large negative and highly significant correlations between random linear and quadratic time coefficients indicated that subjects and teeth with greater-than-average linear change experienced decelerated variation. Conversely, subjects and teeth with less-than-average linear change experienced accelerated variation. Change therefore exhibited a dynamic regression to the mean at the tooth and subject levels. Since no equilibrium was attained throughout the study, changes were cyclical. When considered as a multilevel system, the "linear" and "burst" theories of periodontal disease progression are a manifestation of the same phenomenon: Some sites improve while others progress, in a cyclical manner.

Conducting Three-Level Longitudinal Analyses

2016 ◽  
Vol 37 (1) ◽  
pp. 7-58 ◽  
Author(s):  
James L. Peugh ◽  
Ronald H. Heck
Keyword(s):  
Repeated Measures ◽  
Cluster Sampling ◽  
Longitudinal Analyses ◽  
Cross Sectional ◽  
Data Analyses ◽  
Level Data ◽  
Level 3 ◽  
Level 1 ◽  
Data Analytic ◽  
Level 2

Researchers in the field of early adolescence interested in quantifying the environmental influences on a response variable of interest over time would use cluster sampling (i.e., obtaining repeated measures from students nested within classrooms and/or schools) to obtain the needed sample size. The resulting longitudinal data would be nested at three levels (e.g., repeated measures [Level 1], collected across participants [Level 2], and nested within different schools [Level 3]). A previous publication addressed statistical analysis issues specific to cross-sectional three-level data analytic designs. This article expands upon the previous cross-sectional three-level publication to address topics specific to longitudinal three-level data analyses efforts. Although all analysis examples are demonstrated using SAS, the equivalent SPSS and Mplus syntax scripts, as well as the generated example data and additional supplemental materials, are available online.

The effects of common footwear on stance-phase mechanical properties of the prosthetic foot-shoe system

2017 ◽  
Vol 42 (2) ◽  
pp. 198-207 ◽  
Author(s):  
Matthew J Major ◽  
Joel Scham ◽  
Michael Orendurff
Keyword(s):  
Mechanical Properties ◽  
Repeated Measures ◽  
Clinical Relevance ◽  
Stance Phase ◽  
Mechanical Characteristics ◽  
Mechanical Characterization ◽  
Test Machine ◽  
Mechanical Function ◽  
Prosthetic Foot ◽  
Prosthetic Feet

Background:Prosthetic feet are prescribed based on their mechanical function and user functional level. Subtle changes to the stiffness and hysteresis of heel, midfoot, and forefoot regions can influence the dynamics and economy of gait in prosthesis users. However, the user’s choice of shoes may alter the prosthetic foot-shoe system mechanical characteristics, compromising carefully prescribed and rigorously engineered performance of feet.Objectives:Observe the effects of footwear on the mechanical properties of the prosthetic foot-shoe system including commonly prescribed prosthetic feet.Study design:Repeated-measures, Mechanical characterization.Methods:The stiffness and energy return was measured using a hydraulic-driven materials test machine across combinations of five prosthetic feet and four common shoes as well as a barefoot condition.Results:Heel energy return decreased by an average 4%–9% across feet in all shoes compared to barefoot, with a cushioned trainer displaying the greatest effect. Foot designs that may improve perceived stability by providing low heel stiffness and rapid foot-flat were compromised by the addition of shoes.Conclusion:Shoes altered prosthesis mechanical characteristics in the sagittal and frontal planes, suggesting that shoe type should be controlled or reported in research comparing prostheses. Understanding of how different shoes could alter certain gait-related characteristics of prostheses may aid decisions on footwear made by clinicians and prosthesis users.Clinical relevanceShoes can alter function of the prosthetic foot-shoe system in unexpected and sometimes undesirable ways, often causing similar behavior across setups despite differences in foot design, and prescribing clinicians should carefully consider these effects on prosthesis performance.

POSTURAL STABILITY STRATEGIES IN TRANSTIBIAL AMPUTEES DURING QUIET STANDING IN ALTERED SENSORY CONDITIONS WEARING THREE TYPES OF PROSTHETIC FEET

2020 ◽  
Vol 20 (02) ◽  
pp. 1950071
Author(s):  
NOORANIDA ARIFIN ◽  
NOOR AZUAN ABU OSMAN ◽  
SADEEQ ALI
Keyword(s):  
Postural Stability ◽  
Quiet Standing ◽  
Lateral Direction ◽  
Prosthetic Foot ◽  
Compliant Surface ◽  
Eyes Closed ◽  
Strong Positive Relationship ◽  
Movement Strategy ◽  
Prosthetic Feet ◽  
Transtibial Amputees

Individuals with transtibial amputation exhibit altered movement strategy to sustain stability during quiet standing due to reduced proprioception on the amputated limb. The aim of this study is to determine the movement strategies in anterior–posterior and medial–lateral directions in predicting the overall postural stability. In this crossover study, postural stability of ten transtibial amputees was assessed using computed posturography while wearing different prosthetic foot types: solid ankle cushion heel (SACH), single axis (SA) and energy storage and return (ESAR). Three stability indices were measured during four conditions: standing with eyes opened and closed, standing on compliant surface and standing with tilted head. From the standard multiple regression analysis, 63% to 99% of the OSI score in all sensory conditions were explained from the MLSI score, while 11% to 56% from the APSI score. The Pearson’s [Formula: see text] indicated significant strong positive relationship between OSI and MLSI [Formula: see text]–[Formula: see text] during all sensory conditions. The APSI score was significantly lower than OSI during eyes-closed and head extended conditions for all prosthetic feet [Formula: see text]. Adjustments in postural stability strategies in transtibial amputees mostly occurred in medial–lateral direction regardless of prosthetic feet types and altered sensory conditions.

scholarly journals Evaluation of acceptability of the use of internal and external condoms in couples: a cross-over study

2020 ◽  
Vol 9 (9) ◽  
pp. e846997942
Author(s):  
Tatiana Moreira Afonso ◽  
Taciana Silveira Passos ◽  
Marcos Antonio Almeida-Santos
Keyword(s):  
Repeated Measures ◽  
Analogue Scale ◽  
Ease Of Use ◽  
Wave Type ◽  
Four Dimensions ◽  
Level 3 ◽  
The Mean ◽  
Level 1 ◽  
Level 2 ◽  
Better Than

Objective: To evaluate the acceptability (comfort, ease of use, lubrication, and pleasure) of internal and external condom use in stable couples. Metodology: This randomized cross-over trial included 54 couples (108 adult individuals). Participants were asked to evaluate acceptability measures of both types of condoms using the Visual Analogue Scale.  We developed a three-level hierarchical model [level 1= three repeated measures (wave, type of condom); level 2= individual (gender, age); level 3= couple (sequence of presentation of female versus external condom)]. Results: The "ease of use" dimension represented the biggest difference between the types of condoms for men (Hedges 'g = 0.96; p <0.0001) and women (Hedges' g = 1.62; p <0.0001). Regardless of gender, external condoms performed better (1.61; 95% HPD = 1.41 – 1.81). Men gave lower scores in general (-0.62; 95% HPD = -1.16 − -0.10). Conclusion: The external condom scored better than the internal condom for women and their male partners. The scores tended to improve with the repetitive use of the condom. There is no evidence of the influence of the age of the individuals or the randomly selected sequence of use of condoms with regards to the mean score of the four dimensions.

scholarly journals Symmetry in External Work (SEW): A Novel Method of Quantifying Gait Differences Between Prosthetic Feet

2009 ◽  
Vol 33 (2) ◽  
pp. 148-156 ◽  
Author(s):  
Vibhor Agrawal ◽  
Robert Gailey ◽  
Christopher O'Toole ◽  
Ignacio Gaunaurd ◽  
Tomas Dowell
Keyword(s):  
Low Cost ◽  
Center Of Mass ◽  
External Work ◽  
Prosthetic Limbs ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Body Center ◽  
Prosthetic Feet ◽  
Vertical Ground Reaction Forces ◽  
Transtibial Amputees

Unilateral transtibial amputees (TTAs) show subtle gait variations while using different prosthetic feet. These variations have not been detected consistently with previous experimental measures. We introduce a novel measure called Symmetry in External Work (SEW) for quantifying kinetic gait differences between prosthetic feet. External work is the result of changes in kinetic and potential energy of body center of mass (CoM). SEW is computed by integrating vertical ground reaction forces obtained using F-scan in-sole sensors. Since various prosthetic feet have different designs, we hypothesized that SEW will vary with the type of foot used. This hypothesis was tested with a single unilateral TTA using four prosthetic feet (Proprio, Trias+, Seattle Lite and SACH). The Proprio (mean symmetry 94.5% ± 1.1%) and the Trias+ (92.1% ± 2.5%) feet exhibited higher symmetry between the intact and prosthetic limbs, as compared to the Seattle (67.8% ± 19.3%) and SACH (35.7% ± 11.1%) feet. There was also a good agreement in vertical CoM excursion between the intact foot and prosthetic feet with heel-toe foot plate designs. Results indicate that SEW measure may be a viable method to detect kinetic differences between prosthetic feet and could have clinical applications because of relatively low cost instrumentation and minimal subject intervention.

Variability of kinetic variables during gait in unilateral transtibial amputees

2012 ◽  
Vol 36 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Zdenek Svoboda ◽  
Miroslav Janura ◽  
Lee Cabell ◽  
Milan Elfmark
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Heel Strike ◽  
Force Variability ◽  
Prosthetic Foot ◽  
Prosthetic Limbs ◽  
Prosthetic Feet ◽  
The Stability ◽  
Braking Phase ◽  
Transtibial Amputees

Background: Prosthetic gait increases demands on stability. Some variability measures can be used to investigate the stability of movement for prosthetic feet.Objectives: The purpose of this study was to determine the influence of the prosthetic foot on ground reaction force variability for transtibial amputee gait.Study Design: Comparative analysis.Methods: Eleven male unilateral transtibial amputees participated in this study. Each subject walked at self-selected speed with both conventional (SACH) and energy storing (Sureflex) feet. Time and ground reaction force variables and their coefficients of variation were calculated for each foot type and limb.Results: Mediolateral force variables had high variability for all conditions. The Sureflex had a larger variability than the SACH foot for the braking peak ( p < 0.05), which may have been caused by gait instability after the heel strike. There were significant differences between intact and prosthetic limbs in total loading (force impulses) with the SACH foot ( p < 0.05).Conclusions: The prosthetic foot and alignment issues related to the foot influence GRF variability. During the braking phase the SACH foot is characterized by higher variability in mediolateral direction and Sureflex by higher variability in anterior-posterior direction.Clinical relevanceDifferences in variability in ground reaction force variables can represent a person’s stability. Observing variability can contribute to better understanding of critical events in gait cycle with the use of various prosthetic feet.

Historical text archives and prosopography: the COEL database system

1998 ◽  
Vol 10 (1-3) ◽  
pp. 57-72 ◽  
Author(s):  
K. S. B. Keats-Rohan
Keyword(s):  
Research Tool ◽  
Direct Access ◽  
Specific Situation ◽  
Core Data ◽  
Secondary Sources ◽  
The Core ◽  
Level 3 ◽  
Full Discussion ◽  
Available Information ◽  
Level 2

The COEL database and database software, a combined reference and research tool created by historians for historians, is presented here through Screenshots illustrating the underlying theoretical model and the specific situation to which that has been applied. The key emphases are upon data integrity, and the historian's role in interpreting and manipulating what is often contentious data. From a corpus of sources (Level 1) certain core data are extracted for separate treatment at an interpretive level (Level 3), based upon a master list of the core data (Level 2). The core data are interdependent: each record in Level 2 is of interest in itself; and it either could or should be associated with an(other) record(s) as a specific entity. Sometimes the sources are ambiguous and the association is contentious, necessitating a probabilty-coding approach. The entities created by the association process can then be treated at a commentary level, introducing material external to the database, whether primary or secondary sources. A full discussion of the difficulties is provided within a synthesis of available information on the core data. Direct access to the source texts is only ever a mouse click away. Fully query able, COEL is formidable look-up and research tool for users of all levels, who remain free to exercise an alternative judgement on the associations of the core data. In principle, there is no limit on the type of text or core data that could be handled in such a system.

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