scholarly journals QUANTIFICATION OF DIRECTION AND MAGNITUDE OF CYCLICAL POSTURAL SWAY USING ELLIPSES

2001 ◽  
Vol 13 (05) ◽  
pp. 213-217 ◽  
Author(s):  
PATRICK J. SPARTO ◽  
MARK S. REDFERN
Keyword(s):  
Postural Control ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Vestibular Stimulation ◽  
Control Mechanisms ◽  
Pressure Data ◽  
Cardinal Direction ◽  
Periodic Inputs ◽  
Lateral Axis

In this paper we demonstrate a new method to quantify direction and magnitude of sway in response to periodic inputs. The postural sway response was modeled as an ellipse, allowing the determination of angle of heading as well as the resultant magnitude. To demonstrate this methodology, center of pressure data obtained from a subject receiving sinusoidal (0.25 Hz, 1.2 mA peak-to-peak) galvanic vestibular stimulation in both the binaural-bipolar and binaural-monopolar configurations were analyzed. The binaural-bipolar and binaural-monopolar stimuli elicited sway patterns that were oriented at 4° and 97° to the medial-lateral axis, respectively. In addition, the binaural-monopolar stimulus generated twice as much sway as the binaural-bipolar stimulus. We propose that this method can be applied to sway obtained from sinusoidal inputs to the sensory systems controlling balance. Estimation of the direction and magnitude of postural sway will become an important tool for understanding postural control mechanisms for disturbances to balance that do not occur in a cardinal direction.

The effects of stochastic monopolar galvanic vestibular stimulation on human postural sway

2003 ◽  
Vol 12 (2-3) ◽  
pp. 77-85
Author(s):  
Anthony P. Scinicariello ◽  
J. Timothy Inglis ◽  
J.J. Collins
Keyword(s):  
Vestibular System ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Lower Sensitivity ◽  
Input Stimulus ◽  
Vestibular Perception ◽  
Afferent Nerve Endings ◽  
Young Subjects

Galvanic vestibular stimulation (GVS) is a technique in which small currents are delivered transcutaneously to the afferent nerve endings of the vestibular system through electrodes placed over the mastoid bones. The applied current alters the firing rates of the peripheral vestibular afferents, causing a shift in a standing subject's vestibular perception and a corresponding postural sway. Previously, we showed that in subjects who are facing forward, stochastic bipolar binaural GVS leads to coherent stochastic mediolateral postural sway. The goal of this pilot study was to extend that work and to test the hypothesis that in subjects who are facing forward, stochastic monopolar binaural GVS leads to coherent stochastic anteroposterior postural sway. Stochastic monopolar binaural GVS was applied to ten healthy young subjects. Twenty-four trials, each containing a different galvanic input stimulus from among eight different frequency ranges, were conducted on each subject. Postural sway was evaluated through analysis of the center-of-pressure (COP) displacements under each subject's feet. Spectral analysis was performed on the galvanic stimuli and the COP displacement time series to calculate the coherence spectra. Significant coherence was found between the galvanic input signal and the anteroposterior COP displacement in some of the trials (i.e., at least one) in nine of the ten subjects. In general, the coherence values were highest for the mid-range frequencies that were tested, and lowest for the low- and high-range frequencies. However, the coherence values we obtained were lower than those we previously reported for stochastic bipolar binaural GVS and mediolateral sway. These differences may be due to fundamental characteristics of the vestibular system such as lower sensitivity to symmetric changes in afferent firing dynamics, and/or differences between the biomechanics of anteroposterior and mediolateral sway.

scholarly journals Characteristics of Standing Postural Control in Women under Additional Load

2020 ◽  
Vol 17 (2) ◽  
pp. 490
Author(s):  
Bożena Wojciechowska-Maszkowska ◽  
Dorota Borzucka
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Stability Control ◽  
Standing Posture ◽  
Additional Load ◽  
Eyes Open ◽  
Heavy Loads ◽  
Load Conditions

The aim of this study was to evaluate the effect of additional load on postural-stability control in young women. To evaluate postural control in the 34 women in this study (mean age, 20.8 years), we measured postural sway (center of pressure, COP) in a neutral stance (with eyes open) in three trials of 30 s each. Three load conditions were used in the study: 0, 14, and 30 kg. In analysis, we used three COP parameters, variability (linear), mean sway velocity (linear), and entropy (nonlinear). Results suggested that a considerable load on a young woman’s body (approximately 48% of body weight) had significant influence on stability. Specifically, heavy loads triggered random movements, increased the dynamics of postural-stability control, and required more attention to control standing posture. The results of our study indicate that inferior postural control mainly results from insufficient experience in lifting such a load.

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.

Alterations in Gait Initiation Are Present in Those With Posttraumatic Ankle Osteoarthritis: A Pilot Study

2013 ◽  
Vol 29 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Erik A. Wikstrom ◽  
Robert B. Anderson
Keyword(s):  
Motor Control ◽  
Pilot Study ◽  
Postural Control ◽  
Center Of Pressure ◽  
Gait Initiation ◽  
Static Balance ◽  
Control Mechanisms ◽  
Ankle Osteoarthritis ◽  
Sf 36 ◽  
Balance Trials

The purpose of this investigation was to determine if stereotypical patterns of gait initiation are altered in those with posttraumatic ankle osteoarthritis. Ten subjects, five with unilateral ankle osteoarthritis and five uninjured controls, participated. Subjects completed the SF-36 and Ankle Osteoarthritis Scale to quantify self-reported disability as well as 10 dual-limb static stance trials and 10 gait initiation trials with each leg. Center of pressure outcomes were calculated for static balance trials while the peak center of pressure excursions were calculated for each phase of gait initiation. The results indicate greater self-reported disability (P< .05) and worse static postural control (P< .05) in the ankle osteoarthritis group. Nonstereotypical patterns were also observed during the first and third phases of gait initiation in those with ankle osteoarthritis. The results of this pilot study suggest that supraspinal motor control mechanisms may have changed in those with posttraumatic ankle osteoarthritis.

Influences of Arm Proprioception and Degrees of Freedom on Postural Control With Light Touch Feedback

2008 ◽  
Vol 99 (2) ◽  
pp. 595-604 ◽  
Author(s):  
Ely Rabin ◽  
Paul DiZio ◽  
Joel Ventura ◽  
James R. Lackner
Keyword(s):  
Postural Control ◽  
Degrees Of Freedom ◽  
Biceps Brachii ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Tactile Feedback ◽  
Contact Forces ◽  
Light Touch ◽  
Postural Stabilization ◽  
And Control

Lightly touching a stable surface with one fingertip strongly stabilizes standing posture. The three main features of this phenomenon are fingertip contact forces maintained at levels too low to provide mechanical support, attenuation of postural sway relative to conditions without fingertip touch, and center of pressure (CP) lags changes in fingertip shear forces by ∼250 ms. In the experiments presented here, we tested whether accurate arm proprioception and also whether the precision fingertip contact afforded by the arm's many degrees of freedom are necessary for postural stabilization by finger contact. In our first experiment, we perturbed arm proprioception and control with biceps brachii vibration (120-Hz, 2-mm amplitude). This degraded postural control, resulting in greater postural sway amplitudes. In a second study, we immobilized the touching arm with a splint. This prevented precision fingertip contact but had no effect on postural sway amplitude. In both experiments, the correlation and latency of fingertip contact forces to postural sway were unaffected. We conclude that postural control is executed based on information about arm orientation as well as tactile feedback from light touch, although precision fingertip contact is not essential. The consistent correlation and timing of CP movement and fingertip forces across conditions in which postural sway amplitude and fingertip contact are differentially disrupted suggests posture and the fingertip are controlled in parallel with feedback from the fingertip in this task.

Center-of-Pressure Parameters Used in the Assessment of Postural Control

2002 ◽  
Vol 11 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Riann M. Palmieri ◽  
Christopher D. Ingersoll ◽  
Marcus B. Stone ◽  
B. Andrew Krause
Keyword(s):  
Control System ◽  
Postural Control ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Data Sources ◽  
Postural Control System ◽  
Type Data

Objective:To define the numerous center-of-pressure derivatives used in the assessment of postural control and discuss what value each might provide in the assessment of balance.Data Sources:MEDLINE and SPORTDiscus were searched with the termsbalance, postural control, postural sway,andcenter of pressure. The remaining citations were collected from references of similar papers. A total of 67 references were studied.Conclusions:Understanding what is represented by each parameter used to assess postural control is crucial. At the present time the literature has failed to demonstrate how the variables reflect changes made by the postural-control system. Until it can be shown that the center of pressure and its derivatives actually reveal changes in the postural-control system, the value of using these measures to assess deficits in postural control is minimized.

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.

scholarly journals Relation between postural sway magnitude and metabolic energy cost during upright standing on a compliant surface

2015 ◽  
Vol 119 (6) ◽  
pp. 696-703 ◽  
Author(s):  
Han Houdijk ◽  
Starr E. Brown ◽  
Jaap H. van Dieën
Keyword(s):  
Postural Control ◽  
Muscle Activation ◽  
Metabolic Response ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Metabolic Cost ◽  
Optimization Criterion ◽  
Metabolic Energy ◽  
Emg Activity ◽  
Upright Standing

Postural control performance is often described in terms of postural sway magnitude, assuming that lower sway magnitude reflects better performance. However, people do not typically minimize sway magnitude when performing a postural control task. Possibly, other criteria are satisfied when people select the amount of sway they do. Minimal metabolic cost has been suggested as such a criterion. The aim of this study was to experimentally test the relation between sway magnitude and metabolic cost to establish whether metabolic cost could be a potential optimization criterion in postural control. Nineteen healthy subjects engaged in two experiments in which different magnitudes of sway were evoked during upright standing on a foam surface while metabolic energy expenditure, center of pressure (CoP) excursion, and muscle activation were recorded. In one experiment, sway was manipulated by visual feedback of CoP excursion. The other experiment involved verbal instructions of standing still, natural or relaxed. In both experiments, metabolic cost changed with sway magnitude in an asymmetric parabolic fashion, with a minimum around self-selected sway magnitudes and a larger increase at small compared with large sway magnitudes. This metabolic response was paralleled by a change in tonic and phasic EMG activity in the major leg muscles. It is concluded that these results are in line with the notion that metabolic cost can be an optimization criterion used to set postural control and as such could account for the magnitude of naturally occurring postural sway in healthy individuals, although the pathway remains to be elucidated.

scholarly journals Center of pressure-based postural sway differences on parallel and single leg stance in Olympic deaf basketball and volleyball players

2021 ◽  
Vol 17 (6) ◽  
pp. 418-427
Author(s):  
Yücel Makaracı ◽  
Recep Soslu ◽  
Ömer Özer ◽  
Abdullah Uysal
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Force Plate ◽  
Basketball Players ◽  
Male Athletes ◽  
Significant Difference ◽  
Single Leg Stance ◽  
Volleyball Players

In sports such as basketball and volleyball, loss of balance due to the inability to maintain body stability and lack of postural control adversely affect athletic performance. Deaf athletes appear to struggle with balance and postural stability problems. The purpose of this study was to examine postural sway values in parallel and single leg stance of Olympic deaf basketball and volleyball players and reveal differences between the branches. Twenty-three male athletes from the Turkish national deaf basketball (n= 11) and volleyball (n= 12) teams participated in the study. After anthropometric measurements, the subjects completed postural sway (PS) tests in parallel/single leg stances with open eyes and closed eyes on a force plate. PS parameters (sway path, velocity, and area) obtained from the device software were used for the statistical analysis. The Mann-Whitney U-test was used to compare differences in PS parameters between basketball and volleyball players, and the alpha value was accepted as 0.05. Volleyball players had significantly better results in parallel stance and dominant leg PS values than basketball players (P<0.05). There was no significant difference between the groups in nondominant leg PS values (P>0.05). We think that proprioceptive and vestibular system enhancing training practices to be performed with stability exercises will be beneficial in terms of both promoting functional stability and interlimb coordination. Trainers and strength coaches should be aware of differences in the postural control mechanism of deaf athletes.

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