Gait abnormalities following slipped capital femoral epiphysis treated with in situ fixation

Publication date: March 2019

Source: Gait & Posture, Volume 69

Author(s): Brice Henry, Christine Detrembleur, Philippe Mahaudens, Sophie Boulet, Pierre-Louis Docquier

Abstract

Background

Slipped capital femoral epiphysis (SCFE) is a common disorder in adolescent for which no consensus exists regarding management. The aim of the present study was to analyze gait modifications following SCFE treated with in situ fixation (ISF) and to relate it to radiologic stage. Research question. To verify if gait biomechanics are impaired in patients with SCFE and to try to determine a degree of slippage from which gait modifications would appear.

Methods

We evaluated 16 patients treated by ISF for SCFE with slippage ranging from 11° to 61°. Gait variables were compared to normal population according to age and walking speed and were normalized in Z-scores.

Results

Spatiotemporal parameters, mechanical and energetic variables were inferior to |1.5| Z-scores and considered as normal. Kinematics showed increase of pelvic tilt and hip adduction. Kinetic variables showed modifications with increased hip extension moment. There was also a strong increase in power of hip extensor. Hip extension moment and power of hip extensors were significantly correlated to radiologic stage. Analysis of ROC curves showed a cut-off value of slippage about 25°–30° affecting kinematics of pelvis and hip and kinetic variables.

Conclusion

The gait variables were close to normal values. Main modifications were observed in kinematic and kinetic data with a significant increase in extension moment and power generated at the operated hip. This could participate to long-term joint degradation observed in SCFE, even in mild slips. The clinical message is to control regularly SCFE with initial slippage greater than >25–30° to allow for early diagnosis of premature hip osteoarthritis.

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Movement Variability emerges in Gait as Adaptation to Task Constraints in Dynamic Environments

Publication date: Available online 4 February 2019

Source: Gait & Posture

Author(s): Carla Caballero, Keith Davids, Ben Heller, Jonathan Wheat, Francisco J. Moreno

Abstract

Background

Motor variability has been related to motor control playing a functional role in human adaptive behaviours. However, the direction of the relationship between variability and motor control can be unclear. The specific relations that exist between task constraints and movement (re)organization could explain some of this controversy.

Research question

This study sought to understand whether manipulation of task constraints result in changes in the magnitude or structure of motor system variability observed in a basic walking task. We also investigated the relationship between performance in achieving task goals and the structure of motor variability.

Methods

Twenty volunteers walked around a circular track with binary combinations of 3 task constraints, providing 8 conditions. The manipulated task constraints were: 1) track width; 2) surface stiffness; and 3), walking direction. Performance was analysed using standard deviation (SD) of sacral displacement and its mean velocity (MV). Fuzzy Entropy (FE) and Detrended Fluctuation Analysis (DFA) were used to assess the kinematic variability structure.

Results

Individuals showed lower SD and MV walking on the narrower track. These changes were also followed by higher DFA values, indicating a more auto-correlated structure of variability. The foam surface was also associated with an increase in amplitude, velocity and irregularity (FE) of movement.

Significance

Results of this study describe how specific task constraints, such as the width of the walking track and the surface stiffness, shape emergent movement coordination patterns as participants search for functional information from the environment to regulate performance behaviors. Changes in variability structure could reveal the search for adaptive strategies during walking. Smaller movement fluctuations and higher velocity in gait patterns are related to greater irregularity and lower autocorrelation in the kinematic variability structure, demonstrating that a specific relationship emerges between system variability and movement performance, which is driven by task constraints.

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Gait abnormalities following slipped capital femoral epiphysis treated with in situ fixation

Publication date: March 2019

Source: Gait & Posture, Volume 69

Author(s): Brice Henry, Christine Detrembleur, Philippe Mahaudens, Sophie Boulet, Pierre-Louis Docquier

Abstract

Background

Slipped capital femoral epiphysis (SCFE) is a common disorder in adolescent for which no consensus exists regarding management. The aim of the present study was to analyze gait modifications following SCFE treated with in situ fixation (ISF) and to relate it to radiologic stage. Research question. To verify if gait biomechanics are impaired in patients with SCFE and to try to determine a degree of slippage from which gait modifications would appear.

Methods

We evaluated 16 patients treated by ISF for SCFE with slippage ranging from 11° to 61°. Gait variables were compared to normal population according to age and walking speed and were normalized in Z-scores.

Results

Spatiotemporal parameters, mechanical and energetic variables were inferior to |1.5| Z-scores and considered as normal. Kinematics showed increase of pelvic tilt and hip adduction. Kinetic variables showed modifications with increased hip extension moment. There was also a strong increase in power of hip extensor. Hip extension moment and power of hip extensors were significantly correlated to radiologic stage. Analysis of ROC curves showed a cut-off value of slippage about 25°–30° affecting kinematics of pelvis and hip and kinetic variables.

Conclusion

The gait variables were close to normal values. Main modifications were observed in kinematic and kinetic data with a significant increase in extension moment and power generated at the operated hip. This could participate to long-term joint degradation observed in SCFE, even in mild slips. The clinical message is to control regularly SCFE with initial slippage greater than >25–30° to allow for early diagnosis of premature hip osteoarthritis.

from #Audiology via ola Kala on Inoreader http://bit.ly/2DQRaQ9
via IFTTT

Movement Variability emerges in Gait as Adaptation to Task Constraints in Dynamic Environments

Publication date: Available online 4 February 2019

Source: Gait & Posture

Author(s): Carla Caballero, Keith Davids, Ben Heller, Jonathan Wheat, Francisco J. Moreno

Abstract

Background

Motor variability has been related to motor control playing a functional role in human adaptive behaviours. However, the direction of the relationship between variability and motor control can be unclear. The specific relations that exist between task constraints and movement (re)organization could explain some of this controversy.

Research question

This study sought to understand whether manipulation of task constraints result in changes in the magnitude or structure of motor system variability observed in a basic walking task. We also investigated the relationship between performance in achieving task goals and the structure of motor variability.

Methods

Twenty volunteers walked around a circular track with binary combinations of 3 task constraints, providing 8 conditions. The manipulated task constraints were: 1) track width; 2) surface stiffness; and 3), walking direction. Performance was analysed using standard deviation (SD) of sacral displacement and its mean velocity (MV). Fuzzy Entropy (FE) and Detrended Fluctuation Analysis (DFA) were used to assess the kinematic variability structure.

Results

Individuals showed lower SD and MV walking on the narrower track. These changes were also followed by higher DFA values, indicating a more auto-correlated structure of variability. The foam surface was also associated with an increase in amplitude, velocity and irregularity (FE) of movement.

Significance

Results of this study describe how specific task constraints, such as the width of the walking track and the surface stiffness, shape emergent movement coordination patterns as participants search for functional information from the environment to regulate performance behaviors. Changes in variability structure could reveal the search for adaptive strategies during walking. Smaller movement fluctuations and higher velocity in gait patterns are related to greater irregularity and lower autocorrelation in the kinematic variability structure, demonstrating that a specific relationship emerges between system variability and movement performance, which is driven by task constraints.

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Characterizing the Health-Related Quality of Life Burden of Overactive Bladder Using Disease-Specific Patient-Reported Outcome Measures: A Systematic Literature Review

Abstract

Introduction

The objective was to identify the most commonly used patient-reported outcome (PRO) instruments for overactive bladder (OAB), determine which are the most useful for measuring burden in OAB and characterize the findings of recent studies that have employed PRO instruments to assess OAB symptoms and the effects of treatment.

Methods

A systematic search of OAB literature published between January 2006 and November 2017 using Medline/PubMed and EMBASE databases.

Results

Of 3425 abstracts and 500 full-text articles reviewed, 58 studies (both clinical trials and observational studies) were included in the review. The most commonly used PRO instruments were the OAB Questionnaire (OAB-q; 64%), followed by the King's Health Questionnaire (KHQ; 31%) and the Patient Perception of Bladder Condition (PCBC; 21%). Synthesis of data from studies using the OAB-q showed that OAB treatment with antimuscarinics, mirabegron and onabotulinumtoxinA all improve health-related quality of life (HRQoL) and symptoms beyond the benefits observed with placebo. The OAB-q could detect dose–response relationships in some studies and demonstrated there were no significant differences across therapies from different drug classes.

Conclusion

The HRQoL burden of OAB and response to treatment can be reliably measured by PRO instruments, and the OAB-q is the most commonly used instrument in OAB, particularly in clinical trials of OAB interventions. These data will be useful to provide benchmarks of burden levels for PRO scores obtained among those on contemporary therapies for comparison with outcomes from patients managed with emerging treatments.

Funding

Astellas Pharma Global Development, Inc.

http://bit.ly/2UEtVhM

Introduction to Special Issue on Primate Hybridization and Hybrid Zones

http://bit.ly/2MSqgdW

Scalable algorithms for locally low-rank matrix modeling

Abstract

We consider the problem of modeling data matrices with locally low-rank (LLR) structure, a generalization of the popular low-rank structure widely used in a variety of real-world application domains ranging from medical imaging to recommendation systems. While LLR modeling has been found to be promising in real-world application domains, limited progress has been made on the design of scalable algorithms for such structures. In this paper, we consider a convex relaxation of LLR structure and propose an efficient algorithm based on dual projected gradient descent (D-PGD) for computing the proximal operator. While the original problem is non-smooth, so that primal (sub)gradient algorithms will be slow, we show that the proposed D-PGD algorithm has geometrical convergence rate. We present several practical ways to further speed up the computations, including acceleration and approximate SVD computations. With experiments on both synthetic and real data from MRI (magnetic resonance imaging) denoising, we illustrate the superior performance of the proposed D-PGD algorithm compared to several baselines.

http://bit.ly/2t5izaX