Identification and Stability Analysis of the Postural Control System During Small Magnitude Perturbations

2008 ◽  
Author(s):  
Bradley S. Davidson ◽  
Michael L. Madigan ◽  
Steve C. Southward ◽  
Maury A. Nussbaum
Keyword(s):  
Control System ◽  
Stability Analysis ◽  
Postural Control ◽  
Postural Sway ◽  
Sensory Information ◽  
Quiet Standing ◽  
Muscle Forces ◽  
Postural Control System ◽  
Small Magnitude ◽  
Age Related

Age-related increases in postural sway during quiet standing are well-documented [1]. These increases could result from age-related degradation of sensory information from the somatosensory [2] and vestibular [3] systems, or may result from inaccurate or imprecise muscle forces resulting from excitation-contraction uncoupling [4].

scholarly journals DYNAMIC PATTERNS OF POSTURAL FLUCTUATIONS DURING QUIET STANDING: A RECURRENCE QUANTIFICATION APPROACH

2011 ◽  
Vol 21 (04) ◽  
pp. 1163-1172 ◽  
Author(s):  
HAMED GHOMASHCHI ◽  
ALI ESTEKI ◽  
ALI MOTIE NASRABADI ◽  
JULIEN CLINTON SPROTT ◽  
FARID BAHRPEYMA
Keyword(s):  
Time Series ◽  
Control System ◽  
Postural Control ◽  
Postural Sway ◽  
Integrated Control ◽  
Quiet Standing ◽  
Group Differences ◽  
Postural Control System ◽  
Recurrence Quantification ◽  
Quantification Analysis

When standing quietly, the human body is continuously moving about an upright posture in an erratic fashion. Conventional posturographic analyses that ignore structure of postural steadiness time series do not fully characterize properties of sway dynamics. Recurrence quantification analysis is a technique that can extract the dynamics of postural fluctuations through several variables. In this study, standing-still-sway dynamics of intact and deteriorated postural control systems were investigated by recurrence quantification of stabilograms. The results indicated that both normal and changed postural fluctuations time series, despite erratic and irregular appearance, contain a hidden structure. Although the two components of postural sway originated from an integrated control system, they exhibit distinct dynamical patterns. More determinism, greater local stability, higher degrees of nonstationarity and more laminar states were observed in fore-aft movements. Our findings reveal that decay of postural control mechanism affects dynamical properties of postural control system (especially along mediolateral direction because of the type of impairment). Determinism, nonstationarity and rigidity of balance program as well as laminar states characteristics were increased due to deterioration of postural control system. These findings imply that these measures not only can be used as the pathologic measures to discriminate between group differences, but also provide new openings to understand the nature of postural sway.

Prolonged Standing Task Affects Adaptability of Postural Control in People With Parkinson’s Disease

2020 ◽  
Vol 35 (1) ◽  
pp. 58-67
Author(s):  
Gabriel Felipe Moretto ◽  
Felipe Balistieri Santinelli ◽  
Tiago Penedo ◽  
Luis Mochizuki ◽  
Natalia Madalena Rinaldi ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Control System ◽  
Postural Control ◽  
The Body ◽  
Quiet Standing ◽  
Body Sway ◽  
Control Group ◽  
Postural Control System ◽  
Prolonged Standing

Background Studies on short-term upright quiet standing tasks have presented contradictory findings about postural control in people with Parkinson’s disease (pwPD). Prolonged trial durations might better depict body sway and discriminate pwPD and controls. Objective The aim of this study was to investigate postural control in pwPD during a prolonged standing task. Methods A total of 26 pwPD and 25 neurologically healthy individuals performed 3 quiet standing trials (60 s) before completing a constrained prolonged standing task for 15 minutes. Motion capture was used to record body sway (Vicon, 100 Hz). To investigate the body sway behavior during the 15 minutes of standing, the analysis was divided into three 5-minute-long phases: early, middle, and late. The following body sway parameters were calculated for the anterior-posterior (AP) and medial-lateral (ML) directions: velocity, root-mean-square, and detrended fluctuations analysis (DFA). The body sway area was also calculated. Two-way ANOVAs (group and phases) and 1-way ANOVA (group) were used to compare these parameters for the prolonged standing and quiet standing, respectively. Results pwPD presented smaller sway area ( P < .001), less complexity (DFA; AP: P < .009; ML: P < .01), and faster velocity (AP: P < .002; ML: P < .001) of body sway compared with the control group during the prolonged standing task. Although the groups swayed similarly (no difference for sway area) during quiet standing, they presented differences in sway area during the prolonged standing task ( P < .001). Conclusions Prolonged standing task reduced adaptability of the postural control system in pwPD. In addition, the prolonged standing task may better analyze the adaptability of the postural control system in pwPD.

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.

scholarly journals Virtual-Reality-Induced Visual Perturbations Impact Postural Control System Behavior

2019 ◽  
Vol 9 (11) ◽  
pp. 113 ◽  
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Christopher M. Hill ◽  
Alana J. Turner ◽  
Shuchisnigdha Deb ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Control System ◽  
Postural Control ◽  
Repeated Measures ◽  
Postural Stability ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Postural Control System ◽  
Postural Responses ◽  
The Impact

Background: Virtual reality (VR) is becoming a widespread tool in rehabilitation, especially for postural stability. However, the impact of using VR in a “moving wall paradigm” (visual perturbation), specifically without and with anticipation of the perturbation, is unknown. Methods: Nineteen healthy subjects performed three trials of static balance testing on a force plate under three different conditions: baseline (no perturbation), unexpected VR perturbation, and expected VR perturbation. The statistical analysis consisted of a 1 × 3 repeated-measures ANOVA to test for differences in the center of pressure (COP) displacement, 95% ellipsoid area, and COP sway velocity. Results: The expected perturbation rendered significantly lower (p < 0.05) COP displacements and 95% ellipsoid area compared to the unexpected condition. A significantly higher (p < 0.05) sway velocity was also observed in the expected condition compared to the unexpected condition. Conclusions: Postural stability was lowered during unexpected visual perturbations compared to both during baseline and during expected visual perturbations, suggesting that conflicting visual feedback induced postural instability due to compensatory postural responses. However, during expected visual perturbations, significantly lowered postural sway displacement and area were achieved by increasing the sway velocity, suggesting the occurrence of postural behavior due to anticipatory postural responses. Finally, the study also concluded that VR could be used to induce different postural responses by providing visual perturbations to the postural control system, which can subsequently be used as an effective and low-cost tool for postural stability training and rehabilitation.

Study of the human postural control system during quiet standing using detrended fluctuation analysis

2009 ◽  
Vol 388 (9) ◽  
pp. 1857-1866 ◽  
Author(s):  
M. Teresa Blázquez ◽  
Marta Anguiano ◽  
Fernando Arias de Saavedra ◽  
Antonio M. Lallena ◽  
Pedro Carpena
Keyword(s):  
Control System ◽  
Postural Control ◽  
Detrended Fluctuation Analysis ◽  
Quiet Standing ◽  
Fluctuation Analysis ◽  
Postural Control System ◽  
Detrended Fluctuation

scholarly journals Physiological complexity and system adaptability: evidence from postural control dynamics of older adults

2010 ◽  
Vol 109 (6) ◽  
pp. 1786-1791 ◽  
Author(s):  
Brad Manor ◽  
Madalena D. Costa ◽  
Kun Hu ◽  
Elizabeth Newton ◽  
Olga Starobinets ◽  
...  
Keyword(s):  
Postural Control ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Quiet Standing ◽  
Multiscale Entropy ◽  
Postural Control System ◽  
Dual Tasking ◽  
Complexity Index ◽  
Pressure Dynamics ◽  
Boston Study

The degree of multiscale complexity in human behavioral regulation, such as that required for postural control, appears to decrease with advanced aging or disease. To help delineate causes and functional consequences of complexity loss, we examined the effects of visual and somatosensory impairment on the complexity of postural sway during quiet standing and its relationship to postural adaptation to cognitive dual tasking. Participants of the MOBILIZE Boston Study were classified into mutually exclusive groups: controls [intact vision and foot somatosensation, n = 299, 76 ± 5 (SD) yr old], visual impairment only (<20/40 vision, n = 81, 77 ± 4 yr old), somatosensory impairment only (inability to perceive 5.07 monofilament on plantar halluxes, n = 48, 80 ± 5 yr old), and combined impairments ( n = 25, 80 ± 4 yr old). Postural sway (i.e., center-of-pressure) dynamics were assessed during quiet standing and cognitive dual tasking, and a complexity index was quantified using multiscale entropy analysis. Postural sway speed and area, which did not correlate with complexity, were also computed. During quiet standing, the complexity index (mean ± SD) was highest in controls (9.5 ± 1.2) and successively lower in the visual (9.1 ± 1.1), somatosensory (8.6 ± 1.6), and combined (7.8 ± 1.3) impairment groups ( P = 0.001). Dual tasking resulted in increased sway speed and area but reduced complexity ( P < 0.01). Lower complexity during quiet standing correlated with greater absolute ( R = −0.34, P = 0.002) and percent ( R = −0.45, P < 0.001) increases in postural sway speed from quiet standing to dual-tasking conditions. Sensory impairments contributed to decreased postural sway complexity, which reflected reduced adaptive capacity of the postural control system. Relatively low baseline complexity may, therefore, indicate control systems that are more vulnerable to cognitive and other stressors.

Postural sway with earth-fixed and body-referenced finger contact in young and older adults

1999 ◽  
Vol 9 (2) ◽  
pp. 103-109
Author(s):  
Reginald L. Reginella ◽  
Mark S. Redfern ◽  
Joseph M. Furman
Keyword(s):  
Older Adults ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Sensory Information ◽  
Body Sway ◽  
Support Surface ◽  
Proprioceptive Information ◽  
Postural Control System ◽  
Fixed Reference ◽  
Older Subjects

Sensory information from lightly touching a reference with the hand is known to influence postural sway in young adults. The primary aim of this study was to compare the influence of finger contact (FC) with an earth-fixed reference to the influence of FC with a body-fixed reference. A second goal of this study was to determine if FC is used differently by older adults compared to younger adults. Using a force plate, center of pressure at the feet was recorded from blindfolded young and older subjects during several conditions. Subjects either did or did not lightly touch a force-sensitive plate that was either earth-fixed or moved forward and backward in synchrony with body sway (that is, sway-referenced). In addition, support surface conditions were also varied, including a fixed floor and a sway-referenced floor using an EquitestTM. Results showed that the type of FC, floor condition, and age each had an effect on postural sway. Touching an earth-fixed plate decreased postural sway as compared to no touching, while touching a sway-referenced plate incresased sway. This influence of FC was enhanced when the floor was sway-referenced. Although older subjects swayed more than young subjects overall, no age-FC interactions occurred, indicating that FC was not utilized differently between the age groups. This study suggests that FC cannot be disregarded as erroneous, especially when proprioceptive information from the legs is distorted. Further, FC is integrated with other sensory information by the postural control system similarly in young and older persons.

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