scholarly journals Variability in Postural Control With and Without Balance-Based Torso- Weighting in People With Multiple Sclerosis and Healthy Controls

2014 ◽  
Vol 94 (10) ◽  
pp. 1489-1498 ◽  
Author(s):  
Charlotte M. Hunt ◽  
Gail Widener ◽  
Diane D. Allen

Background People with multiple sclerosis (MS) have diminished postural control, and center of pressure (COP) displacement varies more in this population than in healthy controls. Balance-based torso-weighting (BBTW) can improve clinical balance and mobility in people with MS, and exploration using both linear and nonlinear measures of COP may help determine whether BBTW optimizes movement variability. Objective The aim of this study was to investigate the effects of BBTW on people with MS and healthy controls during quiet standing. Design This was a quasi-experimental study comparing COP variability between groups, between eye closure conditions, and between weighting conditions in the anterior-posterior and medial-lateral directions. Methods Twenty participants with MS and 18 healthy controls stood on a forceplate in 4 conditions: eyes open and closed and with and without BBTW. Linear measures of COP displacement included range and root mean square (RMS). Nonlinear measures included approximate entropy (ApEn) and Lyapunov exponent (LyE). Three-way repeated-measures analyses of variance compared measures across groups and conditions. The association between weighting response and baseline nonlinear variables was examined. When significant associations were found, MS subgroups were created and compared. Results The MS and control groups had significantly different range, RMS, and ApEn values. The eyes-open and eyes-closed conditions had significantly different range and RMS values. Change with weighting correlated with LyE (r=−.70) and ApEn (r=−.59). Two MS subgroups, with low and high baseline LyE values, responded to BBTW in opposite directions, with a significant main effect for weighting condition for the LyE variable in the medial-lateral direction. Limitations The small samples and no identification of impairments related to LyE at baseline were limitations of the study. Conclusions The LyE may help differentiate subgroups who respond differently to BBTW. In both subgroups, LyE values moved toward the average of healthy controls, suggesting that BBTW may help optimize movement variability in people with MS.

Motor Control ◽  
2015 ◽  
Vol 19 (1) ◽  
pp. 10-24 ◽  
Author(s):  
Murielle Grangeon ◽  
Cindy Gauthier ◽  
Cyril Duclos ◽  
Jean-Francois Lemay ◽  
Dany Gagnon

The study aimed to (1) compare postural stability between sitting and standing in healthy individuals and (2) define center-of-pressure (COP) measures during sitting that could also explain standing stability. Fourteen healthy individuals randomly maintained (1) two short-sitting positions with eyes open or closed, with or without hand support, and (2) one standing position with eyes open with both upper limbs resting alongside the body. Thirty-six COP measures based on time and frequency series were computed. Greater COP displacement and velocity along with lower frequency measures were found for almost all directional components during standing compared with both sitting positions. The velocity, 95% confidence ellipse area, and centroidal frequency were found to be correlated between unsupported sitting and standing. Despite evidenced differences between sitting and standing, similarities in postural control were highlighted when sitting stability was the most challenging. These findings support further investigation between dynamic sitting and standing balance.


1999 ◽  
Vol 9 (4) ◽  
pp. 277-286 ◽  
Author(s):  
Mark G. Carpenter ◽  
James S. Frank ◽  
Cathy P. Silcher

One possible factor influencing the control of upright stance is the perceived threat to one's personal safety, i.e. balance confidence. We explored this factor by examining the control of stationary stance when standing on an elevated platform under various conditions of reduced visual and vestibular inputs. Twenty-eight adults (14 male and 14 female, mean age = 23.5 years) participated in the experiment. Postural control was examined by recording the amplitude variability (RMS) and mean power frequency (MPF) of center of pressure excursions (COP) over a 2-minute interval while participants stood in a normal stance on a low (0.19 m) and a high (0.81 m) platform with toes positioned either at or away from the edge of the platform. Vision was manipulated through eyes open and eyes closed trials. Vestibular input was reduced by tilting the head into extension [1]. Anterior-posterior RMS and MPF of COP were significantly influenced by an interaction between surface height and vision. When vision was available, a significant decrease in RMS was observed during quiet standing on a high surface compared to a low surface independent of step restriction. When vision was available MPF increased when subjects were raised from a low to a high surface. The mean position of the COP was significantly influenced by an interaction between height and step restriction. Differences in RMS and MPF responses to height manipulation were observed between genders in eyes closed conditions. Vestibular input influenced postural control at both low and high levels with significant increases in RMS when vestibular input was reduced. The reciprocal changes observed in RMS and MPF suggest modifications to postural control through changes in ankle stiffness. Vision appears to play a role in increasing ankle stiffness when balance confidence is compromised.


2021 ◽  
Vol 4 (1) ◽  
pp. 013-022
Author(s):  
Blanchet Mariève ◽  
Prince François ◽  
Lemay Martin ◽  
Chouinard Sylvain ◽  
Messier Julie

We explored if adolescents with Gilles de la Tourette syndrome (GTS) had functional postural control impairments and how these deficits are linked to a disturbance in the processing and integration of sensory information. We evaluated the displacements of the center of pressure (COP) during maximal leaning in four directions (forward, backward, rightward, leftward) and under three sensory conditions (eyes open, eyes closed, eyes closed standing on foam). GTS adolescents showed deficits in postural stability and in lateral postural adjustments but they had similar maximal COP excursion than the control group. The postural performance of the GTS group was poorer in the eyes open condition (time to phase 1 onset, max-mean COP). Moreover, they displayed a poorer ability to maintain the maximum leaning position under the eyes open condition during mediolateral leaning tasks. By contrast, during forward leaning, they showed larger min-max ranges than control subjects while standing on the foam with the eyes closed. Together, these findings support the idea that GTS produces subclinical postural control deficits. Importantly, our results suggest that postural control disorders in GTS are highly sensitive to voluntary postural leaning tasks which have high demand for multimodal sensory integration.


Author(s):  
Elżbieta Piątek ◽  
Michał Kuczyński ◽  
Bożena Ostrowska

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.


2011 ◽  
Vol 20 (4) ◽  
pp. 442-456 ◽  
Author(s):  
Zohreh Meshkati ◽  
Mehdi Namazizadeh ◽  
Mahyar Salavati ◽  
Masood Mazaheri

Context:Although reliability is a population-specific property, few studies have investigated the measurement error associated with force-platform parameters in athletic populations.Objective:To investigate the skill-related differences between athletes and nonathletes in reliability of center-of-pressure (COP) summary measures under eyes-open (EO) and eyes-closed (EC) conditions.Design:Test–retest reliability study.Setting:COP was recorded during double-leg quiet standing on a Kistler force platform before and after a fatiguing treadmill exercise, with EO and EC.Participants:31 male participants including 15 athletes practiced in karate and 16 nonathletes.Main Outcome Measures:Standard deviation (SD) of amplitude, phase-plane portrait, SD of velocity, mean total velocity, and area were calculated from 30-s COP data. Intraclass correlation coefficient (ICC), standard error of measurement, and coefficient of variation (CV) were used as estimates of reliability and precision.Results:Higher ICCs were found for COP measures in the athlete (compared with the nonathlete) group, postfatigued (compared with prefatigued) condition, and EC (compared with EO) tests. CVs smaller than 15% were obtained for most of the COP measures. SD of velocity in the anteroposterior direction showed the highest reliability in most conditions.Conclusions:Tests with EC and to a lesser extent tests performed in the athlete group and in the postfatigued condition showed better reliability.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7513 ◽  
Author(s):  
Elżbieta Piątek ◽  
Michał Kuczyński ◽  
Bożena Ostrowska

Background It is known that adolescent idiopathic scoliosis (AIS) is often accompanied by balance deficits. This reciprocal relationship must be taken into account when prescribing new therapeutic modalities because these may differently affect postural control, interacting with therapy and influencing its results. Objective The purpose was to compare postural control in girls with AIS while wearing the Chêneau brace (BRA) or performing active self-correction (ASC) with their postural control in a quiet comfortable stance. Methods Nine subjects were evaluated on a force plate in three series of two 20-s quiet standing trials with eyes open or closed; three blocks were randomly arranged: normal quiet stance (QST), quiet stance with BRA, and quiet stance with ASC. On the basis of centre-of-pressure (COP) recordings, the spatial and temporal COP parameters were computed. Results and Discussion Performing ASC was associated with a significant backward excursion of the COP mean position with eyes open and closed (ES = 0.56 and 0.65, respectively; p < 0.05). This excursion was accompanied by an increase in the COP fractal dimension (ES = 1.05 and 0.98; p < 0.05) and frequency (ES = 0.78; p = 0.10 and ES = 1.14; p < 0.05) in the mediolateral (ML) plane. Finally, both therapeutic modalities decreased COP sample entropy with eyes closed in the anteroposterior (AP) plane. Wearing BRA resulted in ES = 1.45 (p < 0.05) while performing ASC in ES = 0.76 (p = 0.13). Conclusion The observed changes in the fractal dimension (complexity) and frequency caused by ASC account for better adaptability of patients to environmental demands and for their adequate resources of available postural strategies in the ML plane. These changes in sway structure were accompanied by a significant (around 25 mm) backward excursion of the mean COP position. However, this improvement was achieved at the cost of lower automaticity, i.e. higher attentional involvement in postural control in the AP plane. Wearing BRA may have an undesirable effect on some aspects of body balance.


2007 ◽  
Vol 50 (2) ◽  
pp. 139-143 ◽  
Author(s):  
Jitka Jančová ◽  
Vlasta Tošnerová

Posture in a still stance has been quantified by changes in the center of pressure (COP), in both anterior-posterior (A/P) and medial-lateral (M/L) directions and measured on a single force platform (Bertec PRO VEC 5.0). The purpose of this study was to estimate the variance in error and the intrasession test-retest reliability, and to determine which measures shall be taken for further measurements, especially with adults age 65 and older. We used two types of approximation for the reliability coefficient. Firstly, we used the equation according to Blahuš (2) and secondly we used the Pearson’s correlation coefficient for test-retest measurements. The findings allow us to say, among other things, that the tests of quiet standing Double Narrow Stance Eyes Open (DNSEO) and Double Narrow Stance Eyes Closed (DNSEC) are parallel, in the sense of parallel testing.


2014 ◽  
Vol 23 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Matthew C. Hoch ◽  
David R. Mullineaux ◽  
Richard D. Andreatta ◽  
Robert A. English ◽  
Jennifer M. Medina-McKeon ◽  
...  

Context:A single talocrural joint-mobilization treatment has improved spatiotemporal measures of postural control but not ankle arthrokinematics in individuals with chronic ankle instability (CAI). However, the effects of multiple treatment sessions on these aspects of function have not been investigated.Objective:To examine the effect of a 2-wk anterior-to-posterior joint-mobilization intervention on instrumented measures of single-limb-stance static postural control and ankle arthrokinematics in adults with CAI.Design:Repeated measures.Setting:Research laboratory.Participants:12 individuals with CAI (6 male, 6 female; age 27.4 ± 4.3 y, height 175.4 ± 9.78 cm, mass 78.4 ± 11.0 kg).Intervention:Subjects received 6 treatments sessions of talocrural grade II joint traction and grade III anterior-to-posterior joint mobilization over 2 wk.Main Outcome Measures:Instrumented measures of single-limb-stance static postural control (eyes open and closed) and anterior and posterior talar displacement and stiffness were assessed 1 wk before the intervention (baseline), before the first treatment (preintervention), 24–48 h after the final treatment (postintervention), and 1 wk later (1-wk follow-up). Postural control was analyzed as center-of-pressure velocity, center-of-pressure range, the mean of time-to-boundary minima, and standard deviation of time-to-boundary minima in the anteroposterior and mediolateral directions for each visual condition.Results:No significant differences were identified in any measures of postural control (P > .08) or ankle arthrokinematics (P > .21).Conclusions:The 2-wk talocrural joint-mobilization intervention did not alter instrumented measures of single-limb-stance postural control or ankle arthrokinematics. Despite the absence of change in these measures, this study continues to clarify the role of talocrural joint mobilization as a rehabilitation strategy for patients with CAI.


2019 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Felix Wachholz ◽  
Federico Tiribello ◽  
Arunee Promsri ◽  
Peter Federolf

Dual-tasking charges the sensorimotor system with performing two tasks simultaneously. Center of pressure (COP) analysis reveals the postural control that is altered during dual-tasking, but may not reveal the underlying neural mechanisms. In the current study, we hypothesized that the minimal intervention principle (MIP) provides a concept by which dual-tasking effects on the organization and prioritization of postural control can be predicted. Postural movements of 23 adolescents (age 12.7 ± 1.3; 8 females) and 15 adults (26.9 ± 2.3) were measured in a bipedal stance with eyes open, eyes closed and eyes open while performing a dual-task using a force plate and 39 reflective markers. COP data was analyzed by calculating the mean velocity, standard deviation and amplitude of displacement. Kinematic data was examined by performing a principal component analysis (PCA) and extracting postural movement components. Two variables were determined to investigate changes in amplitude (aVark) and in control (Nk) of the principal movement components. Results in aVark and in Nk agreed well with the predicted dual-tasking effects. Thus, the current study corroborates the notion that the MIP should be considered when investigating postural control under dual-tasking conditions.


2016 ◽  
Vol 18 (2) ◽  
pp. 59-62 ◽  
Author(s):  
Douglas A. Wajda ◽  
Robert W. Motl ◽  
Jacob J. Sosnoff

Background: Balance impairment and an increased rate of falls are commonly reported in individuals with multiple sclerosis (MS). Force platform–generated center of pressure (COP) metrics have previously been recommended as an outcome measure to quantify balance deficits and distinguish between fallers and nonfallers in MS. Information is limited regarding the preservation of postural control in individuals with MS over extended time frames in the absence of an intervention. This report examines the test-retest reliability and magnitude of change of COP motion during standing balance over 3 months. Methods: Twenty individuals with MS and a history of falling underwent testing on two occasions 3 months apart in the absence of an intervention. On both occasions, participants completed two 30-second trials of three conditions: eyes open, eyes closed, and eyes open with concurrent cognitive challenge (dual task). Measures of COP area, velocity, and temporal structure were calculated and included in the reliability analysis. Results: The COP metrics displayed fair-to-excellent reliability over 3 months without an intervention. Reliability was maintained across the three commonly used balance conditions. Conclusions: These results offer insight into the reliability of COP measures over a 3-month period in MS and can inform the use of COP metrics for future study design (eg, sample size estimates) and balance outcome assessment during randomized controlled trials and fall-prevention studies in individuals with MS.


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