scholarly journals Examining Human Unipedal Quiet Stance: Characterizing Control through Jerk

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Matthew R. Semak ◽  
Jeremiah Schwartz ◽  
Gary Heise
Keyword(s):  
Stochastic Process ◽  
Center Of Pressure ◽  
Force Plate ◽  
Rate Of Change ◽  
Scaling Behavior ◽  
Fluctuation Analysis ◽  
Quiet Stance ◽  
Temporal Scaling ◽  
Eyes Open

We investigated the quality of smoothness during human unipedal quiet stance. Smoothness is quantified by the time rate of change of the accelerations, or jerks, associated with the motion of the foot and can be seen as an indicative of how controlled the balance process is. To become more acquainted with this as a quantity, we wanted to establish whether or not it can be modeled as a (stationary) stochastic process and, if so, explore its temporal scaling behavior. Specifically, our study focused on the jerk concerning the center-of-pressure (COP) for each foot. Data were collected via a force plate for individuals attempting to maintain upright posture using one leg (with eyes open). Positive tests for stochasticity allowed us to treat the time series as a stochastic process and, given this, we took the jerk to be proportional to the increment of the force realizations. Detrended fluctuation analysis was the primary tool used to explore the scaling behavior. Results suggest that both the medial-lateral and anterior-posterior components of the jerk display persistent and antipersistent correlations which can be modeled by fractional Gaussian noise over three different temporal scaling regions. Finally, we discussed certain possible implications of these features such as a jerk-based control over the force on the foot’s COP.

Validation of a Portable Force Plate for Evaluating Postural Sway

2020 ◽  
pp. 003151252094509
Author(s):  
Mark Walsh ◽  
Caroline Church ◽  
Audrey Hoffmeister ◽  
Dean Smith ◽  
Joshua Haworth
Keyword(s):  
Postural Sway ◽  
Center Of Pressure ◽  
Intraclass Correlation ◽  
Force Plate ◽  
Disease Status ◽  
Community Dwelling ◽  
Sport Training ◽  
Eyes Open ◽  
Ground Plate ◽  
Absolute Agreement

Measurements of postural sway are used to assess physiological changes due to therapy or sport training, or to describe group differences based on activity history or disease status. Portable force plates have been widely adopted for this purpose, leading us in this study to validate with linear and nonlinear metrics the posturographic data derived from both a portable plate (Natus) when compared to an in-ground plate (Bertec). Twenty participants stood on each plate for two trials each, with and without a foam perturbation and with and without eyes open on each surface. We calculated measures of path length, range, root mean squares, sample entropy, and correlation dimensions from center of pressure traces on each plate. An intraclass correlation coefficient across trials from each plate in each condition indicated satisfactory overall reliability (ICC consistency), supporting the use of either plate for postural sway research and interventions. Additionally, our results generally supported common validity (ICC absolute agreement), though, the specific degree of similarity differed for each of the tested metrics of postural sway, especially when considering whether or not data was filtered. For situations in which participants cannot visit a laboratory (e.g. performing athletes, community dwelling clinical patients, and virus risk concerns) an in-home portable force plate is a trusted and valuable data collection tool.

scholarly journals Static Balance in Patients with Vestibular Impairments: A Preliminary Study

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Hossein Talebi ◽  
Mohammad Taghi Karimi ◽  
Seyed Hamid Reza Abtahi ◽  
Niloofar Fereshtenejad
Keyword(s):  
Path Length ◽  
Center Of Pressure ◽  
Balance Control ◽  
Force Plate ◽  
Static Balance ◽  
Eyes Closed ◽  
Significant Difference ◽  
Eyes Open ◽  
Age Limits ◽  
The Difference

Aims. Vestibular system is indicated as one of the most important sensors responsible for static and dynamic postural control. In this study, we evaluated static balance in patients with unilateral vestibular impairments.Materials and Methods. We compared static balance control using Kistler force plate platform between 10 patients with unilateral vestibular impairments and 20 normal counterparts in the same sex ratio and age limits (50±7). We evaluated excursion and velocity of center of pressure (COP) and path length in anteroposterior (AP) and mediolateral (ML) planes with eyes open and with eyes closed.Results. There was no significant difference between COP excursions in ML and AP planes between both groups with eyes open and eyes closed (pvalue > 0.05). In contrast, the difference between velocity and path length of COP in the mentioned planes was significant between both groups with eyes open and eyes closed (pvalue < 0.05).Conclusions. The present study showed the static instability and balance of patients with vestibular impairments indicated by the abnormal characteristics of body balance.

scholarly journals Should the Minimal Intervention Principle Be Considered When Investigating Dual-Tasking Effects on Postural Control?

2019 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Felix Wachholz ◽  
Federico Tiribello ◽  
Arunee Promsri ◽  
Peter Federolf
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
Force Plate ◽  
Principal Component ◽  
Mean Velocity ◽  
Dual Tasking ◽  
Minimal Intervention ◽  
Eyes Closed ◽  
Eyes Open ◽  
Postural Movement

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.

scholarly journals Associations Between Bipedal Stance Stability and Locomotor Stability Following a Trip in Unilateral Vestibulopathy

2017 ◽  
Vol 33 (2) ◽  
pp. 112-117 ◽  
Author(s):  
Christopher McCrum ◽  
Katrin Eysel-Gosepath ◽  
Gaspar Epro ◽  
Kenneth Meijer ◽  
Hans H.C.M. Savelberg ◽  
...  
Keyword(s):  
Center Of Pressure ◽  
Force Plate ◽  
Clinical Settings ◽  
Control Mechanisms ◽  
Gait Stability ◽  
Eyes Open ◽  
Unilateral Vestibulopathy ◽  
Base Of Support ◽  
Dynamic Gait ◽  
Pearson Correlations

Posturography is used to assess balance in clinical settings, but its relationship to gait stability is unclear. We assessed if dynamic gait stability is associated with standing balance in 12 patients with unilateral vestibulopathy. Participants were unexpectedly tripped during treadmill walking and the change in the margin of stability (MoSchange) and base of support (BoSchange) relative to nonperturbed walking was calculated for the perturbed and first recovery steps. The center of pressure (COP) path during 30-s stance with eyes open and closed, and the distance between the most anterior point of the COP and the anterior BoS boundary during forward leaning (ADist), were assessed using a force plate. Pearson correlations were conducted between the static and dynamic variables. The perturbation caused a large decrease in the BoS, leading to a decrease in MoS. One of 12 correlations was significant (MoSchange at the perturbed step and ADist; r = −.595, P = .041; nonsignificant correlations: .068 ≤ P ≤ .995). The results suggest that different control mechanisms may be involved in stance and gait stability, as a consistent relationship was not found. Therefore, posturography may be of limited use in predicting stability in dynamic situations.

scholarly journals Effect of ultrasound-guided percutaneous neuromodulation in ankle instability: a case study

2019 ◽  
Vol 02 (02) ◽  
pp. 100-101
Author(s):  
Rodríguez Rosal M. ◽  
Sánchez Sixto A. ◽  
Álvarez Barbosa F. ◽  
Yáñez Álvarez A.
Keyword(s):  
Effect Size ◽  
Center Of Pressure ◽  
Tibial Nerve ◽  
Ankle Instability ◽  
Center Of Mass ◽  
Force Plate ◽  
Chronic Ankle Instability ◽  
Balance Test ◽  
Eyes Closed ◽  
Eyes Open

Abstract Background and Aims Ankle proprioception can be tested in many ways. Some studies have found improvements in individuals with chronic ankle instability after receiving treatment and training proprioceptive acuity and speed. Currently, there is a scarcity of evidence concerning percutaneous neuromodulation. The first findings were reported in the post-surgical stage after total knee arthroplasty and in neural improvements and symptoms in patients with hyperactive bladder. Aim To evaluate the effectiveness of percutaneous neuromodulation on the tibial nerve for the improvement of various proprioception parameters in patients with chronic ankle instability. Material and Methods Five men (age: 24.8 ± 4.9 years; height: 1.78 ± 0.08 m; weight: 86 ± 9.8 kg) with chronic ankle instability, who regularly practiced sports activities participated in the present study. People who had undergone an injury in the previous three months were excluded from the speed. Currently, there is a scarcity of evidence concerning test before and immediately after percutaneous neuromodulation. A single leg balance test was performed with eyes open and closed, maintaining the single-legged position on a force plate during 30 seconds (Accupower; AMTI, Watertown, MA) registering 1000 Hz. The displacement of the center of pressure (DOT) was determined based on the distances of its antero-posterior axes (DOT_AP) and medio-lateral (DOT_ML). Furthermore, the amplitudes of anteroposterior and mediolateral displacement were evaluated (ACPap and ACPml). The posterior tibial nerve was stimulated under ultrasound guidance using a 100 Vpp current, with a pulse width of 250 μs and a repetition frequency of 2 to 10 Hz. The process was performed on three occasions during 30 seconds, with an intensity that was acknowledged by the patient but which did not go beyond a score of 3 in the visual analog scale (VAS). The means and standard deviations were calculated for all variables. The effect size was calculated establishing the confidence interval at 90% and the probability of the change being significant was qualitatively calculated. Results A decrease was found in the ACPap (Pre-test eyes open: 5.42 ± 0.62 and eyes closed: 15.99 ± 0.60; Post-test eyes open 4.05 ± 0.36 and eyes closed 10.33 ± 0.49) after the neuromodulation intervention on the tibial nerve. This was a significant change and a “possible” effect size was found in the closed eyes condition (-0.54; ± 0.72), according to Hopkins. For the remaining variables, no significant differences were observed. Conclusions A decreased displacement of the center of mass was found in the antero-posterior axis after performing the neuromodulation technique on the tibial nerve in patients with chronic ankle instability.

scholarly journals Use of Virtual Reality to Assess Dynamic Posturography and Sensory Organization: Instrument Validation Study (Preprint)

2020 ◽  
Author(s):  
Matthew William Wittstein ◽  
Anthony Crider ◽  
Samantha Mastrocola ◽  
Mariana Guerena Gonzalez
Keyword(s):  
Virtual Reality ◽  
Center Of Pressure ◽  
Force Plate ◽  
Fluctuation Analysis ◽  
Scaling Exponent ◽  
Sensory Organization Test ◽  
Dynamic Posturography ◽  
Sensory Organization ◽  
Intraclass Correlations ◽  
Absolute Agreement

BACKGROUND The Equitest system (Neurocom) is a computerized dynamic posturography device used by health care providers and clinical researchers to safely test an individual’s postural control. While the Equitest system has evaluative and rehabilitative value, it may be limited owing to its cost, lack of portability, and reliance on only sagittal plane movements. Virtual reality (VR) provides an opportunity to reduce these limitations by providing more mobile and cost-effective tools while also observing a wider array of postural characteristics. OBJECTIVE This study aimed to test the plausibility of using VR as a feasible alternative to the Equitest system for conducting a sensory organization test. METHODS A convenience sample of 20 college-aged healthy individuals participated in the study. Participants completed the sensory organization test using the Equitest system as well as using a VR environment while standing atop a force plate (Bertec Inc). The Equitest system measures the equilibrium index. During VR trials, the estimated equilibrium index, 95% ellipse area, path length, and anterior-posterior detrended fluctuation analysis scaling exponent alpha were calculated from center of pressure data. Pearson correlation coefficients were used to assess the relationship between the equilibrium index and center of pressure–derived balance measures. Intraclass correlations for absolute agreement and consistency were calculated to compare the equilibrium index and estimated equilibrium index. RESULTS Intraclass correlations demonstrated moderate consistency and absolute agreement (0.5 &lt; intraclass correlation coefficient &lt; 0.75) between the equilibrium index and estimated equilibrium index from the Equitest and VR sensory organization test (SOT), respectively, in four of six tested conditions. Additionally, weak to moderate correlations between force plate measurements and the equilibrium index were noted in several of the conditions. CONCLUSIONS This research demonstrated the plausibility of using VR as an alternative method to conduct the SOT. Ongoing development and testing of virtual environments are necessary before employing the technology as a replacement to current clinical tests.

Contribution of Vision to Balance in Children Four to Eight Years of Age

2007 ◽  
Vol 116 (9) ◽  
pp. 653-657 ◽  
Author(s):  
Margaretha L. Casselbrant ◽  
Ellen M. Mandel ◽  
Patrick J. Sparto ◽  
Mark S. Redfern ◽  
Joseph M. Furman
Keyword(s):  
Root Mean Square ◽  
Optic Flow ◽  
Center Of Pressure ◽  
Quiet Standing ◽  
Mean Square ◽  
Quiet Stance ◽  
Postural Responses ◽  
Eyes Open ◽  
The Subject ◽  
Anterior Posterior

Objectives: The use of sensory feedback for postural control develops throughout childhood. The aim of this study was to determine how children use cues from anterior-posterior optic flow for balance from 4 to 8 years of age. Methods: One hundred forty-eight children were enrolled. The subjects had yearly otologic and posturographic examinations between the ages of 4 and 8 years. Balance was assessed only if the subject had no evidence of middle ear effusion. The subject stood for 30 seconds with eyes open without optic flow and for 30 seconds while viewing 0.1, 0.25, and 0.4 Hz anterior-posterior optic flow. The center of pressure (COP) was recorded from the force platform. The root-mean-square of the COP during the periods of quiet stance and with optic flow was computed. Results: The root-mean-square COP was significantly larger during the optic flow stimulation as compared with during quiet stance. The subjects had a significant decrease in COP during optic flow from year 5 to year 6 of life (p = 005). Conclusions: A change in the response to optic flow was seen from age 5 to age 6. This change is consistent with transitional changes in postural responses that have been observed during quiet standing.

scholarly journals Static postural control assessment during pregnancy

2015 ◽  
Vol 9 (1) ◽  
Author(s):  
Ana Silvia Moccellin ◽  
Fernanda G. S. A. Nora ◽  
Paula H. L. Costa ◽  
Patricia Driusso
Keyword(s):  
Postural Control ◽  
Pregnant Women ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Force Plate ◽  
Pubic Symphysis ◽  
Eyes Closed ◽  
Increased Risk ◽  
Risk Of Falls ◽  
Eyes Open

The hormonal and anatomic changes during pregnancy affect the musculoskeletal system and may lead to instability of static postural control and increased risk of falls. The aim of this study was to analyze changes in static postural control during the three trimesters of pregnancy, using variables derived from the center of pressure. This is a descriptive study in which posturographic tests were applied in four still standing positions, for three trials, with a combination of different visual conditions (eyes open - EO/eyes closed - EC) and support base configurations on 20 non-pregnant women (C) and 13 pregnant women during the gestational period (G1, G2 and G3). For static postural control assessment, a force plate (Bertec®) was used, and the variables analyzed were statokinesigram area, displacement amplitude, displacement velocity and sway frequency. The results demonstrate that, early in pregnancy, the woman's body seems to already change postural control, probably due to increased mobility of the sacroiliac joint and pubic symphysis caused by hormonal factors, and during the trimesters there is a decrease in postural stability, observed as an increase in the elliptical areas, amplitudes of center of pressure displacement and velocity of center of pressure displacement.

scholarly journals Static postural control assessment during pregnancy

2015 ◽  
Vol 9 (1) ◽  
Author(s):  
Ana Silvia Moccellin ◽  
Fernanda G. S. A. Nora ◽  
Paula H. L. Costa ◽  
Patricia Driusso
Keyword(s):  
Postural Control ◽  
Pregnant Women ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Force Plate ◽  
Pubic Symphysis ◽  
Eyes Closed ◽  
Increased Risk ◽  
Risk Of Falls ◽  
Eyes Open

<p>The hormonal and anatomic changes during pregnancy affect the musculoskeletal system and may lead to instability of static postural control and increased risk of falls. The aim of this study was to analyze changes in static postural control during the three trimesters of pregnancy, using variables derived from the center of pressure. This is a descriptive study in which posturographic tests were applied in four still standing positions, for three trials, with a combination of different visual conditions (eyes open - EO/eyes closed - EC) and support base configurations on 20 non-pregnant women (C) and 13 pregnant women during the gestational period (G1, G2 and G3). For static postural control assessment, a force plate (Bertec®) was used, and the variables analyzed were statokinesigram area, displacement amplitude, displacement velocity and sway frequency. The results demonstrate that, early in pregnancy, the woman's body seems to already change postural control, probably due to increased mobility of the sacroiliac joint and pubic symphysis caused by hormonal factors, and during the trimesters there is a decrease in postural stability, observed as an increase in the elliptical areas, amplitudes of center of pressure displacement and velocity of center of pressure displacement.</p>

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