scholarly journals Hypothetical control of postural sway

2021 ◽  
Vol 18 (176) ◽  
Author(s):  
Madhur Mangalam ◽  
Damian G. Kelty-Stephen
Keyword(s):  
Postural Control ◽  
Postural Sway ◽  
Relative Strength ◽  
Quiet Standing ◽  
Task Constraints ◽  
Pdf Analysis ◽  
Inertial Control ◽  
Non Gaussian ◽  
Engagement And Disengagement ◽  
Linear Decay

Quiet standing exhibits strongly intermittent variability that has inspired at least two interpretations. First, variability can be intermittent through the alternating engagement and disengagement of complementary control processes at distinct scales. A second and perhaps deeper way to interpret this intermittency is through the possibility that postural control depends on cascade-like interactions across many timescales at once, suggesting specific non-Gaussian distributional properties at different timescales. Multiscale probability density function (PDF) analysis shows that quiet standing on a stable surface exhibits a crossover from low, increasing non-Gaussianity (consistent with exponential distributions) at shorter timescales, reflecting inertial control, towards higher non-Gaussianity. Feedback-based control at medium to longer timescales yields a linear decrease that is characteristic of cascade dynamics. Destabilizing quiet standing with an unstable surface or closed eyes serves to attenuate inertial control and to elicit more of the feedback-based control over progressively shorter timescales. The result was to strengthen the appearance of the linear decay indicating cascade dynamics. Finally, both linear and nonlinear indices of postural sway also govern the relative strength of crossover or of linear decay, suggesting that tempering of non-Gaussianity across log-timescale is a function of both extrinsic constraints and endogenous postural control. These results provide new evidence that cascading interactions across longer timescales supporting postural corrections can even recruit shorter timescale processes with novel task constraints that can destabilize posture.

scholarly journals Hypothetical control of postural sway

2020 ◽  
Author(s):  
Madhur Mangalam ◽  
Damian G. Kelty-Stephen
Keyword(s):  
Closed Loop ◽  
Postural Sway ◽  
Surface Condition ◽  
Quiet Standing ◽  
Task Constraints ◽  
Loop Control ◽  
Control Processes ◽  
Stable Surface ◽  
Pdf Analysis ◽  
Non Gaussian

AbstractQuiet standing exhibits strongly intermittent variability reflecting a richly interactive foundation. This intermittency can be understood in various ways. First, variability can be intermittent through the engagement and disengagement of complementary control processes at distinct scales. A second and perhaps a deeper way to understand this intermittency is through the possibility that closed-loop control depends on the cascade-like interactions across many timescales at once. These diverse control processes suggest specific non-Gaussian distributional properties at different timescales. Multiscale probability density (PDF) analysis shows that quiet standing on a stable surface exhibits a crossover between low non-Gaussianity (consistent with exponential distributions) at shorter timescales reflecting openloop control, increasing towards higher non-Gaussianity and subsequently decreasing (consistent with cascade-driven Lévy-like distributions) at longer scales. Destabilizing quiet standing elicits non-Gaussianity that begins high and decreases across timescales (consistent with cascade-driven Lévy-like distribution), reflecting closed-loop postural corrections at more of the shorter timescales. Finally, indices of postural sway govern the appearance or disappearance of crossovers, suggesting that tempering of non-Gaussianity across log-timescale in stable-surface condition is mostly a function of endogenous postural control. These results provide new evidence that cascading interactions across longer-timescales supporting postural corrections can even recruit shorter-timescale processes with novel task constraints.

scholarly journals Postural constraints recruit shorter-timescale processes into the non-Gaussian cascade processes

2020 ◽  
Author(s):  
Mariusz P. Furmanek ◽  
Madhur Mangalam ◽  
Damian G. Kelty-Stephen ◽  
Grzegorz Juras
Keyword(s):  
Postural Sway ◽  
Linear Perspective ◽  
Healthy Human ◽  
Control Processes ◽  
Pdf Analysis ◽  
Cascade Structure ◽  
Cascade Processes ◽  
Non Gaussian ◽  
Long Timescales ◽  
Engagement And Disengagement

AbstractHealthy human postural sway exhibits strong intermittency, reflecting a richly interactive foundation of postural control. From a linear perspective, intermittent fluctuations might be interpreted as engagement and disengagement of complementary control processes at distinct timescales or from a nonlinear perspective, as cascade-like interactions across many timescales at once. The diverse control processes entailed by cascade-like multiplicative dynamics suggest specific non-Gaussian distributional properties at different timescales. Multiscale probability density function (PDF) analysis showed that when standing quietly while balancing a sand-filled tube with the two arms elicited non-Gaussianity profiles showing a negative-quadratic crossover between short and long timescales. A more stringent task of balancing a water-filled tube elicited simpler monotonic decreases in non-Gaussianity, that is, a positive-quadratic cancellation of the negative-quadratic crossover. Multiple known indices of postural sway governed the appearance or disappearance of the crossover. Finally, both tasks elicited lognormal distributions over progressively larger timescales. These results provide the first evidence that more stringent postural constraints recruit shorter-timescale processes into the non-Gaussian cascade processes, that indices of postural sway moderate this recruitment, and that more stringent postural constraints show stronger statistical hallmarks of cascade structure.

scholarly journals Influence of gender and physical exercise on balance of healthy young adults

2014 ◽  
Vol 27 (3) ◽  
pp. 399-406 ◽  
Author(s):  
Sarina Francescato Torres ◽  
Júlia Guimarães Reis ◽  
Daniela Cristina Carvalho de Abreu
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Postural Control ◽  
Postural Sway ◽  
Short Form ◽  
Quiet Standing ◽  
Moderate Activity ◽  
Men And Women ◽  
Eyes Closed ◽  
Sedentary Women

Objective To verify the effects of gender and physical activity on postural sway. Method A cross-sectional study was conducted to analyze upright balance of young men and women between the ages of 20-30, both active and sedentary. Study participants were 60 individuals, who were divided into: active women (n = 15), sedentary women (n = 15), active men (n = 15) and sedentary men (n = 15). The International Physical Activity Questionnaire (IPAQ) short form, was used to evaluate each participant’s level of physical activity. According to the questionnaire, active individuals are those who carry out moderate activity, with an energy expenditure between 3.5 and 6 METs (1 MET: 3.5 ml/kg/min), or vigorous activity, with an energy expenditure above 6 METs, at least three days a week for 20 minutes. To assess control of postural sway, we measured the amplitude and velocity of anteroposterior (AP) and mediolateral (ML) sway in standing position, with their eyes open and closed, with and without foam, on a force platform. Results Comparison between genders revealed that, when compared to sedentary women, sedentary men displayed poorer performance in velocity and amplitude of AP postural control sway with their eyes closed, with and without foam. There were no differences in the amplitude and velocity of ML sway, both with open and closed eyes among groups (p < 0.05). There were no differences when comparing physically active men and women either. Conclusion Sedentary men seem to rely more on vision for maintaining postural control in quiet standing situations with respect to women.

scholarly journals The Effects of Active Self-Correction on Postural Control in Girls with Adolescent Idiopathic Scoliosis: The Role of an Additional Mental Task

2020 ◽  
Vol 17 (5) ◽  
pp. 1640 ◽  
Author(s):  
Elżbieta Piątek ◽  
Michał Kuczyński ◽  
Bożena Ostrowska
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Postural Control ◽  
Repeated Measures ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Force Plate ◽  
Stroop Test ◽  
Quiet Standing ◽  
Mental Task

Due to balance deficits that accompany adolescent idiopathic scoliosis (AIS), the potential interaction between activities of daily living and active self-correction movements (ASC) on postural control deserves particular attention. Our purpose was to assess the effects of ASC movements with or without a secondary mental task on postural control in twenty-five girls with AIS. It is a quasi-experimental within-subject design with repeated measures ANOVA. They were measured in four 20-s quiet standing trials on a force plate: no task, ASC, Stroop test, and both. Based on the center-of-pressure (COP) recordings, the COP parameters were computed. The ASC alone had no effect on any of the postural sway measures. Stroop test alone decreased COP speed and increased COP entropy. Performing the ASC movements and Stroop test together increased the COP speed and decreased COP entropy as compared to the baseline data. In conclusion, our results indicate that AIS did not interfere with postural control. The effects of the Stroop test accounted for good capacity of subjects with AIS to take advantage of distracting attentional resources from the posture. However, performing both tasks together exhibited some deficits in postural control, which may suggest the need for therapeutic consultation while engaging in more demanding activities.

IDENTIFICATION OF DYNAMIC PATTERNS OF BODY SWAY DURING QUIET STANDING: IS IT A NONLINEAR PROCESS?

2010 ◽  
Vol 20 (04) ◽  
pp. 1269-1278 ◽  
Author(s):  
HAMED GHOMASHCHI ◽  
ALI ESTEKI ◽  
JULIEN CLINTON SPROTT ◽  
ALI MOTIE NASRABADI
Keyword(s):  
Time Series ◽  
Postural Control ◽  
Correlation Dimension ◽  
Postural Sway ◽  
Convincing Evidence ◽  
Temporal Organization ◽  
Quiet Standing ◽  
Body Sway ◽  
Linear Measure ◽  
Control Mechanisms

During quiet standing, the human body continuously moves about an upright posture in an erratic fashion. Many researchers characterize postural fluctuations as a stochastic process while some others suggest chaotic dynamics for postural sway. In this study, first we examined these assumptions using principles of chaos theory in normal healthy and in patients with deteriorated postural control mechanisms. Next, we compared the ability of a nonlinear dynamics quantifier correlation dimension to that of a linear measure standard deviation to describe variability of healthy and deteriorated postural control mechanisms during quiet standing. Our findings did not provide convincing evidence for existence of low dimensional chaos within normal and abnormal sway dynamics but support the notion that postural fluctuations time series are distinguishable from these generated by a random process. The results indicated that although linear variability measures discriminated well between groups, they did not provide any information about the structure of postural fluctuations. Calculated correlation dimension as a complexity measure which describes spatio temporal organization of time series may be useful in this regard.

Impact of Attentional Loading and Task Constraints on Postural Control of Healthy Older Adults

2020 ◽  
Vol 2 (2) ◽  
pp. 12-25
Author(s):  
Eryk Przysucha ◽  
Brontë A. Vollebregt ◽  
Carlos Zerpa
Keyword(s):  
Older Adults ◽  
Postural Control ◽  
Cognitive Task ◽  
Quiet Standing ◽  
Support Surface ◽  
Task Constraints ◽  
Healthy Older Adults ◽  
Practical Standpoint ◽  
Support Surfaces ◽  
Attentional Tasks

Postural control is attention demanding, and it may be jeopardized when a secondary cognitive task is involved, particularly for older adults. The magnitude of this interference depends on different individual (perceptuo-motor status), task (single vs. dual tasking), and environmental constraints (support surface). The purpose of this research was to examine if older adults may be affected by various types of secondary cognitive tasks, while maintaining quiet standing on different support surfaces. In line with conceptual models, the results indicated that postural control of older adults was compromised when they were required to dual-task, especially when the support surface was challenging. This was a robust finding across all the measures of COP. In regards to the degree to which different attentional tasks affected postural control, the results remained equivocal. From a practical standpoint, the results indicated that older adults should exhibit caution when simultaneously performing a balance and a cognitive task involved particularly when the surface is unsteady.

scholarly journals The effect of age, sex and a firm-textured surface on postural control

2021 ◽  
Author(s):  
Francesco Palazzo ◽  
Alessandra Nardi ◽  
Niloofar Lamouchideli ◽  
Alfio Caronti ◽  
Anas Alashram ◽  
...  
Keyword(s):  
Postural Control ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Sensory System ◽  
The Body ◽  
Quiet Standing ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Experimental Conditions ◽  
Eyes Open

AbstractIn previous studies, the influence of plantar sensation has been examined using various textured surfaces with different stiffness materials to assess static balance. This study investigated the effects of a Firm Textured Surface (FTS) along with age and sex-related influences on postural control under different visual conditions. Forty subjects (20 elderly, 10 males, mean age 68.30, 10 females, mean age 68.00, and 20 young people, 10 males, mean age 25.45, 10 females, mean age 27.30) participated in this study maintained a quiet standing on FTS, foam and firm surfaces with eyes open and closed. The center of pressure displacement (CoPDISP), CoP velocity (CoPVEL), and sway velocity of the CoP in anteroposterior (AP) and mediolateral (ML) direction (VA/P and VM/L) were measured. FTS was associated with lower postural sway measures in both the groups with eyes open and closed. However, the foam surface showed the worst results in all postural parameters under all experimental conditions. Separate four-way ANOVAs were applied to each dependent variable. The main effects of surface (p < 0.0001), vision (p < 0.0001) and age (p < 0.0001 for CoPDISP, CoPVEL and VA/P; p = 0.0003 for VM/L) were significant in each of the four fitted models. Sex was never significant, either as a main effect or an interaction with other experimental factors. Eyes open were able to reduce the negative effects of the foam surfaces but without vision the proprioceptive sensory system cues of the body state become more important for maintaining balance. A good stimulation with rigid texture should be considered as relief to reduce the physiological-related decline of afferent information with age.

scholarly journals Multifractality distinguishes reactive from proactive cascades in postural control

2020 ◽  
Author(s):  
Damian G. Kelty-Stephen ◽  
Mariusz P. Furmanek ◽  
Madhur Mangalam
Keyword(s):  
Postural Control ◽  
Orthogonal Polynomials ◽  
Center Of Pressure ◽  
Equilibrium Points ◽  
Control Process ◽  
Task Demands ◽  
Scale Invariant ◽  
Task Constraints ◽  
Cascade Processes ◽  
Non Gaussian

AbstractIntermittency is a flexible control process entailing context-sensitive engagement with task constraints. The present work aims to situate the intermittency of dexterous behavior explicitly in multifractal modeling for non-Gaussian cascade processes. Multiscale probability density function (PDF) analysis of the center of pressure (CoP) fluctuations during quiet upright standing yields non-Gaussianity parameters lambda exhibiting task-sensitive curvilinear relationships with timescale. The present reanalysis aims for a finer-grained accounting of how non-Gaussian cascade processes might align with known, separable postural processes. It uses parallel decomposition of non-Gaussianity lambda-vs.-timescale and CoP. Orthogonal polynomials decompose lambda curvilinearity, and rambling-trembling analysis decomposes CoP into relatively more intentional rambling (displacement to new equilibrium points) and less intentional trembling sway (deviations around new equilibrium points). Modeling orthogonal polynomials of non-Gaussianity’s lambda-vs.-timescale relationship allows us to differentiate linear from quadratic decay, each of which indicates scale-invariant and scale-dependent cascades, respectively. We tested whether scale-dependent and scale-invariant cascades serve different roles, that is, responding to destabilizing task demands and supporting the proactive movement to a new equilibrium point, respectively. We also tested whether these cascades appear more clearly in rambling rather than trembling sway. More generally, we test whether multifractal nonlinear correlations supports this capacity of postural control to this two-step differentiation: both into rambling vs. trembling, then into scale-dependent vs. scale-invariant cascades within rambling sway. The results supported these hypotheses. Thus, the present work aligns specific aspects of task setting with aspects of cascade dynamics and confirms multifractal foundations of the organism-task relationship.

scholarly journals Stiffness Control of Balance During Quiet Standing and Dual Task in Older Adults: The MOBILIZE Boston Study

2010 ◽  
Vol 104 (6) ◽  
pp. 3510-3517 ◽  
Author(s):  
Hyun Gu Kang ◽  
Lewis A. Lipsitz
Keyword(s):  
Older Adults ◽  
Postural Control ◽  
Dual Task ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Muscle Tone ◽  
Community Dwelling ◽  
Quiet Standing ◽  
Study Cohort ◽  
Boston Study

Distractions affect postural control, but this mechanism is not well understood. Diversion of resources during cognitive stress may lead to decreased motor drive and postural muscle tone. This may appear as decreased postural stiffness and increased postural sway amplitude. We hypothesized that dual tasking leads to decreased stiffness and increased sway amplitude. Postural sway (center of pressure; COP) data were used from 724 participants aged 77.9 ± 5.3 yr, a representative sample of community-dwelling older adults, the MOBILIZE Boston Study cohort. Subjects stood barefoot with eyes open for 30 s per trial on a force plate. Five trials were performed each with and without a serial subtractions-by-3 task. Sway data were fit to a damped oscillator inverted pendulum model. Amplitudes (COP and center of mass), mechanical stiffness, and damping of the sway behavior were determined. Sway amplitudes and damping increased with the dual task ( P < 0.001); stiffness decreased only mediolaterally ( P < 0.001). Those with difficulty doing the dual task exhibited larger sway and less damping mediolaterally ( P ≤ 0.001) and an increased stiffness with dual task anteroposteriorly (interaction P = 0.004). Dual task could still independently explain increases in sway ( P < 0.001) after accounting for stiffness changes. Thus the hypothesis was supported only in mediolateral sway. The simple model helped to explain the dual task related increase of sway only mediolaterally. It also elucidated the differential influence of cognitive function on the mechanics of anteroposterior and mediolateral sway behaviors. Dual task may divert the resources necessary for mediolateral postural control, thus leading to falls.

scholarly journals Relation between the Sensory and Anthropometric Variables in the Quiet Standing Postural Control: Is the Inverted Pendulum Important for the Static Balance Control?

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Angélica C. Alonso ◽  
Luis Mochizuki ◽  
Natália Mariana Silva Luna ◽  
Sérgio Ayama ◽  
Alexandra Carolina Canonica ◽  
...  
Keyword(s):  
Body Composition ◽  
Postural Control ◽  
Bone Mineral ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Balance Control ◽  
The Body ◽  
Limb Length ◽  
Quiet Standing ◽  
Mineral Density

The aim of this study was to evaluate the relation between the sensory and anthropometric variables in the quiet standing.Methods. One hundred individuals (50 men, 50 women; 20–40 years old) participated in this study. For all participants, the body composition (fat tissue, lean mass, bone mineral content, and bone mineral density) and body mass, height, trunk-head length, lower limb length, and upper limb length were measured. The center of pressure was measured during the quiet standing posture, the eyes opened and closed with a force platform. Correlation and regression analysis were run to analyze the relation among body composition, anthropometric data, and postural sway.Results. The correlation analysis showed low relation between postural sway and anthropometric variables. The multiple linear regression analyses showed that the height explained 12% of the mediolateral displacement and 11% of the center of pressure area. The length of the trunk head explained 6% of displacement in the anteroposterior postural sway. During eyes closed condition, the support basis and height explained 18% of mediolateral postural sway.Conclusion. The postural control depends on body composition and dimension. This relation is mediated by the sensory information. The height was the anthropometric variable that most influenced the postural sway.

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