Cluster Analysis of Center-of-Pressure Measures

Baig, Shabana; Dansereau, Richard M.; Chan, Alvin C.; Remaud, Anthony; Beznoska, Martin

doi:10.11159/ijecs.2012.002

Cited by 7 publications

(11 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For example, the rate of change in normalized shear wave speed increased significantly when subjects closed their eyes while standing. Similarly, we observed increases in the velocity of the COP, which is considered one of the most informative summary metrics of standing balance performance (Baig et al, ; Raymakers et al, ). These results suggest that shear wave tensiometers may have sufficient sensitivity to delineate changes in standing balance due to altered sensory conditions that arise due to aging (Acuña, Francis, Franz, & Thelen, ; Hortobágyi et al, ; Peterson & Martin, ) or pathological conditions.…”

Section: Discussionsupporting

confidence: 73%

“…We then centered the mean COP at zero in the ML and AP directions (Duarte & Freitas, ). We summarized the fluctuations of the COP using four conventional metrics: (a) the mean radial displacement of the COP from center, (b) the standard deviation of COP AP , (c) the mean velocity of the COP AP trajectory, and (d) the range of the COP AP (Baig, Dansereau, Chan, Remaud, & Bilodeau, ; Duarte et al, ; Raymakers, Samson, & Verhaar, ; Schubert, Kirchner, Schmidtbleicher, & Haas, ).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Achilles tendon shear wave speed tracks the dynamic modulation of standing balance

et al. 2019

View full text Add to dashboard Cite

Standing balance performance is often characterized by sway, as measured via fluctuations of the center of pressure (COP) under the feet. For example, COP metrics can effectively delineate changes in balance under altered sensory conditions. However, COP is a global metric of whole‐body dynamics and thus does not necessarily lend insight into the underlying musculotendon control. We have previously shown that shear wave tensiometers can track wave speeds in tendon as a surrogate measure of the load transmitted by the muscle‐tendon unit. The purpose of this study was to investigate whether shear wave metrics have sufficient sensitivity to track subtle variations in Achilles tendon loading that correspond with postural sway. Sixteen healthy young adults (26 ± 5 years) stood for 10 s with their eyes open and closed. We simultaneously recorded COP under the feet and shear wave speed in the right Achilles tendon. We found that Achilles tendon shear wave speed closely tracked (r > 0.95) dynamic fluctuations of the COP in the anteroposterior direction. Achilles tendon wave speed fluctuations significantly increased during standing with eyes closed, mirroring increases in COP fluctuations. These results demonstrate that tendon wave speed can track the subtle variations in Achilles tendon loading that modulate COP in standing. Hence, shear wave tensiometry exhibits the sensitivity to investigate the muscular control of quiet standing, and may also be useful for investigating other fine motor and force steadiness tasks.

show abstract

Section: Discussionsupporting

confidence: 73%

Section: Methodsmentioning

confidence: 99%

Achilles tendon shear wave speed tracks the dynamic modulation of standing balance

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Moreover, the delineated area and average speed of sway showed higher correlations with clinical measures in pwMS, and the difference between the two vision conditions showed significant correlations only for these two balance outcomes; these results are consistent with the significant vision*group interaction obtained in the ANCOVA analysis. We consider that these differences could be associated to technical characteristics evaluated by these parameters, as their generation involves different methods and measures in the force platform, and previous studies suggest a better performance of outcomes involving area and velocity measurements [35,36]. Our results indicate that the delineated area and the average speed of sway may have the best performance in the assessment of pwMS.…”

Section: Discussionmentioning

confidence: 75%

Visual Feedback and Postural Control in Multiple Sclerosis

Inojosa

Schriefer

Trentzsch

et al. 2020

JCM

View full text Add to dashboard Cite

As people with multiple sclerosis (pwMS) manifest heterogeneous demyelinating lesions that could affect somatosensory or vestibular ways, visual stimulus as feedback could be especially relevant to achieve postural control. This has clinical importance for the development of preventive measures and rehabilitation therapies in order to avoid falls and accidents in this group. In our study, we objectively evaluated the influence of visual feedback on the stabilization of balance in pwMS versus healthy controls (HC) and its potential utility in clinical evaluation. Static posturography tests were performed in 99 pwMS and 30 HC. Subjects stood on a force platform with open and closed eyes. During this procedure, three balance parameters were obtained for both vision conditions: average sway, average speed, and average speed of sway. Neurostatus-Expanded Disease Disability Score (EDSS) and Multiple Sclerosis Functional Composite (MSFC) were performed in parallel as well. A two-way mixed repeated measures ANCOVA, controlling for sex and age, was performed to evaluate the effect of vision, MS diagnosis, and the interaction of both in static posturography parameters. The difference between both closed and open eyes conditions was calculated for each parameter and further analyzed according to MS-relevant clinical variables. The magnitude of the vision effect differed between pwMS and HC as a significant interaction between the vision and the MS diagnosis in the delineated area (p < 0.001) and average speed of sway (p = 0.001) was seen. These parameters had a greater increase in pwMS than in HC after closing eyes. For the average sway, a significant main effect of vision was present (p = 0.047). Additionally, the differences obtained between open and closed eyes conditions assessed with the delineated area and average speed of sway were moderately correlated to the assessed clinical tests EDSS (r = 0.405 and r = 0.329, respectively) and the MSFC (r = −0.385 and r = −0.259, respectively). In our study, pwMS were more dependent of visual feedback than HC to maintain postural control. This easy and short evaluation by static posturography could support the development of targeted preventive measures and interventions in pwMS.

show abstract

“…We use a 95% confidence ellipsoid (CE) to verify the applicability of a 3-D confidence ellipsoid [42][43][44]. The 95% confidence ellipsoid (with 0.95 probability [45,46]) volume is the volume of an ellipsoid that is expected to bound 95 % of the measured data, i.e., the set of points is obtained by plotting three accelerations against each other. The confidence ellipsoid volume is given by the equation:…”

Section: Discussionmentioning

confidence: 99%

Assessment of Postural Instability in Patients With a Neurological Disorder Using a Tri-Axial Accelerometer

et al. 2015

View full text Add to dashboard Cite

Abstract. Current techniques for quantifying human postural stability during quiet standing have several limitations. The main problem is that only two movement variables are evaluated, though a better description of complex three-dimensional (3-D) movements can be provided with the use of three variables. A single tri-axial accelerometer placed on the trunk was used to measure 3-D data. We are able to evaluate 3-D movements using a method based on the volume of confidence ellipsoid (VE) of the set of points obtained by plotting three accelerations against each other. Our method was used to identify and evaluate pathological balance control. In this study, measurements were made of patients with progressive cerebellar ataxia, and also control measurements of healthy subjects, and a statistical analysis was performed. The results show that the VEs of the neurological disorder patients are significantly larger than the VEs of the healthy subjects. It can be seen that the quantitative method based on VE is very sensitive for identifying changes in stability, and that it is able to distinguish between neurological disorder patients and healthy subjects.

show abstract

Cluster Analysis of Center-of-Pressure Measures

Abstract: Abstract− Postural stability analysis is useful in a variety of applications, such as assessing the risk of falls for older adults or investigating neuromuscular disorders. Variations in the center -of-pressure (COP)

Cited by 7 publications

References 33 publications

Achilles tendon shear wave speed tracks the dynamic modulation of standing balance

Achilles tendon shear wave speed tracks the dynamic modulation of standing balance

Visual Feedback and Postural Control in Multiple Sclerosis

Assessment of Postural Instability in Patients With a Neurological Disorder Using a Tri-Axial Accelerometer

Contact Info

Product

Resources

About