scholarly journals Keeping still doesn't “make sense”: examining a role for movement variability by stabilizing the arm during a postural control task

2017 ◽  
Vol 117 (2) ◽  
pp. 846-852 ◽  
Author(s):  
Chantelle D. Murnaghan ◽  
Mark G. Carpenter ◽  
Romeo Chua ◽  
J. Timothy Inglis
Keyword(s):  
Postural Control ◽  
Visual Feedback ◽  
Sensory Information ◽  
The Body ◽  
Whole Body ◽  
Movement Variability ◽  
Eyes Closed ◽  
Surrounding Environment ◽  
Angular Displacements ◽  
Postural Task

Small-amplitude, higher frequency oscillations of the body or limb are typically observed when humans attempt to maintain the position of a body or limb in space. Recent investigations have suggested that these involuntary movements of the body during stance could be used as an exploratory means of acquiring sensory information. In the present study, we wanted to determine whether a similar phenomenon would be observed in an upper limb postural task that does not involve whole body postural control. Participants were placed in a supine position with the arm pointing vertically and were asked to maintain the position of the limb in space with and without visual feedback. The wrist was attached to an apparatus that allowed the experimenter to stabilize or “lock” movements of the arm without the participants' awareness. When participants were “locked,” the forces recorded predicted greater accelerations than those observed when the arm was freely moving with and without visual feedback. From unlocked to locked, angular accelerations increased in the eyes-closed condition and when participants were provided visual feedback of arm angular displacements. Irrespective of their origin, small displacements of the limb may be used as an exploratory means of acquiring sensory information from the surrounding environment. NEW & NOTEWORTHY The role of movement variability during a static limb position task is currently unknown. We tested whether variability remains in the absence of sensory-based error with an apparatus that stabilized the limb without the participant's knowledge during a static postural task. Increased forces observed during arm stabilization predicted movements greater than those observed when not externally stabilized. These results suggest movement variability during static postures could facilitate the gathering of sensory information from the surrounding environment.

scholarly journals Maximal stability limits in adolescents with Tourette syndrome

2021 ◽  
Vol 4 (1) ◽  
pp. 013-022
Author(s):  
Blanchet Mariève ◽  
Prince François ◽  
Lemay Martin ◽  
Chouinard Sylvain ◽  
Messier Julie
Keyword(s):  
Postural Control ◽  
Tourette Syndrome ◽  
Center Of Pressure ◽  
Phase 1 ◽  
Sensory Information ◽  
Control Group ◽  
Eyes Closed ◽  
Highly Sensitive ◽  
Eyes Open ◽  
Stability Limits

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.

scholarly journals Whole-Body Vibration Does Not Seem to Affect Postural Control in Healthy Active Older Women

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
P. S. C. Gomes ◽  
M. O. Campos ◽  
L. F. Oliveira ◽  
R. G. T. Mello ◽  
I. A. Fernandes
Keyword(s):  
Postural Control ◽  
Repeated Measures ◽  
Elderly Women ◽  
Whole Body Vibration ◽  
Whole Body ◽  
Body Sway ◽  
Control Group ◽  
Physically Active ◽  
Body Vibration ◽  
Eyes Closed

Objective. This study investigated the acute residual effects induced by different frequencies of whole-body vibration (WBV) on postural control of elderly women. Design. Thirty physically active elderly women (67±5 years) were randomly divided into three groups: two experimental groups (high WBV frequency: 45 Hz and 4 mm amplitude, n=10; low WBV frequency: 30 Hz and 4 mm amplitude, n=10) and one control group (n=10), with no treatment. The participants were first subjected to stabilometry tests and were then guided through three sets of isometric partial squats for 60 s while the WBV stimulation was applied. The control group was subjected to the same conditions but without the WBV stimulation. The participants were again subjected to body balance tests immediately following the end of the intervention period and again at 8, 16, and 24 min. To measure body sway control, three 60 s tests were performed at 10 s intervals for each of the following experimental conditions: (1) eyes opened and (2) eyes closed. The following variables were investigated: the average velocity of the displacement of the centre of pressure in the anterior-posterior and medial-lateral planes as well as in the elliptical area. Results. A 3 (condition) × 5 (test) two-way repeated-measures ANOVA did not identify significant differences in the stabilometric variables, regardless of group, time, or experimental condition. Conclusions. The effect of WBV, regardless of the stimulation frequency, did not have a significant effect immediately after or up to 24 minutes after vibration cessation, on the variables involved in the control of postural stability in physically active elderly women.

scholarly journals Distinct Representations of Body and Head motion are Dynamically Encoded by Purkinje cell Populations in the Macaque Cerebellum

2021 ◽  
Author(s):  
Omid A Zobeiri ◽  
Kathleen E Cullen
Keyword(s):  
Postural Control ◽  
Purkinje Cells ◽  
Body Position ◽  
The Body ◽  
Body Motion ◽  
Whole Body ◽  
Head Motion ◽  
Response Dynamics ◽  
Dynamic Representation ◽  
Self Motion

The ability to accurately control our posture and perceive spatial orientation during self-motion requires knowledge of the motion of both the head and body. However, whereas the vestibular sensors and nuclei directly encode head motion, no sensors directly encode body motion. Instead, the integration of vestibular and neck proprioceptive inputs is necessary to transform vestibular information into the body-centric reference frame required for postural control. The anterior vermis of the cerebellum is thought to play a key role in this transformation, yet how its Purkinje cells integrate these inputs or what information they dynamically encode during self-motion remains unknown. Here we recorded the activity of individual anterior vermis Purkinje cells in alert monkeys during passively applied whole-body, body-under-head, and head-on-body rotations. Most neurons dynamically encoded an intermediate representation of self-motion between head and body motion. Notably, these neurons responded to both vestibular and neck proprioceptive stimulation and showed considerable heterogeneity in their response dynamics. Furthermore, their vestibular responses demonstrated tuning in response to changes in head-on-body position. In contrast, a small remaining percentage of neurons sensitive only to vestibular stimulation unambiguously encoded head-in-space motion across conditions. Using a simple population model, we establish that combining responses from 40 Purkinje cells can explain the responses of their target neurons in deep cerebellar nuclei across all self-motion conditions. We propose that the observed heterogeneity in Purkinje cells underlies the cerebellum's capacity to compute the dynamic representation of body motion required to ensure accurate postural control and perceptual stability in our daily lives.

Vestibular-Neck Interaction and Transformation of Sensory Coordinates

1997 ◽  
Vol 7 (4) ◽  
pp. 347-365
Author(s):  
T. Mergner ◽  
W. Huber ◽  
W. Becker
Keyword(s):  
Postural Control ◽  
Sensory Information ◽  
Physical Space ◽  
The Body ◽  
Support Surface ◽  
Coordinate Transformations ◽  
Motor Tasks ◽  
Postural Stabilization ◽  
Canal Systems ◽  
Self Motion

The article considers findings and concepts on vestibular-proprioceptive interaction for self-motion perception and postural control under the form of simple describing models. It points out that vestibular-neck interaction is only a small fraction of an extended mechanism of coordinate transformations. This links together the different parts of our bodies, so that sensory information arising in one part of the body can be used for perceptual or motor tasks in other parts. Particular emphasis is put on the problems that arise from imperfect signal transduction in the vestibular semicircular canal systems at low stimulus frequencies/velocities. Also, a “down-and-up-channeling” principle is suggested, by which the body support is linked via coordinate transformations to the internal notion of physical space provided by the vestibular system. Furthermore, the following question is addressed: how does the brain use visual input to overcome the vestibular deficiencies, at the risk of visual self-motion illusions? Finally, a conceptual model of postural control is presented in which a proprioceptive feedback that links the body to its support surface is merged with a loop for postural stabilization in space.

Biomechanical, Perceptual, and Cognitive Factors Involved in Maintaining Postural Control While Standing or Walking on Non-Moving and Moving Surfaces: A Literature Review

2010 ◽  
Author(s):  
Kathleen Allen Rodowicz ◽  
Rahmat Muhammad ◽  
Michelle Heller ◽  
Joseph Sala ◽  
Chimba Mkandawire
Keyword(s):  
Postural Control ◽  
Musculoskeletal System ◽  
Muscle Activation ◽  
Balance Control ◽  
Muscle Tone ◽  
Sensory Information ◽  
Transportation Systems ◽  
The Body ◽  
Cognitive Factors ◽  
Moving Surface

Postural control has been defined as “regulating the body’s position in space for the dual purposes of stability and orientation.” How the body achieves postural control depends, in part, on the environment. A person navigating a non-moving surface (e.g. hallway, stairway, or step ladder) will process information and will employ different strategies to maintain postural control than someone who is standing or walking on a moving surface (e.g., forklifts, personal transportation systems, escalators, and moving walkways). In both environments, sensory, cognitive, and motor control systems contribute to postural control. The musculoskeletal system uses muscle activation and joint positioning to control the body’s alignment and muscle tone. The biomechanics of postural control rely on information that the musculoskeletal system receives from sensory systems including the vestibular system, which is generally implicated in behaviors requiring balance control, as well as the somatosensory and visual systems. Furthermore, sensory information from these and other systems can be enhanced by cognitive processes, such as attention. The ability to maintain postural control while standing or walking is critical in preventing falls on both non-moving and moving surfaces. This review focuses on moving surfaces and includes a discussion of the biomechanical, perceptual, and cognitive factors responsible for postural control.

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
Keyword(s):  
Multiple Sclerosis ◽  
Postural Control ◽  
Repeated Measures ◽  
Center Of Pressure ◽  
Quiet Standing ◽  
Healthy Controls ◽  
Movement Variability ◽  
Lateral Direction ◽  
Eyes Closed ◽  
Eyes Open

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.

Additive Effect of Repeated Bouts of Individualized Frequency Whole Body Vibration on Postural Stability in Young Adults

2014 ◽  
Vol 30 (4) ◽  
pp. 529-533 ◽  
Author(s):  
D. Clark Dickin ◽  
Jacqueline E. Heath
Keyword(s):  
Young Adults ◽  
Postural Control ◽  
Postural Stability ◽  
Whole Body Vibration ◽  
Sensory Information ◽  
Muscle Spindles ◽  
Whole Body ◽  
Body Vibration ◽  
Multiple Exposures ◽  
Environment Study

Whole body vibration (WBV) has been shown to improve force and power output as well as flexibility and speed, with improvements suggested to result from reduced electromechanical delays, improved rate of force development, and sensitivity of muscle spindles. Fixed frequency studies on postural control have been somewhat equivocal; however, individualized frequency protocols have shown promising results in other motor tasks. To assess this, 18 healthy young adults experienced three 4-minute WBV sessions with postural control assessed before vibration, after multiple exposures, and during recovery, with altered levels of sensory information available to the participants. Sway velocity, sway path length, and sway area were assessed in each environment. Study findings revealed that stability was impacted following WBV, with more challenging environments eliciting improvements persisting for 20 minutes. When the environment was less challenging, postural stability was impaired; however, the effects dissipated quickly (10-20 min). It was determined that exposure to individualized frequency WBV served to impair postural control when the challenge was low, but resulted in heightened stability when the overall challenge was high and vestibular information was needed for stability.

scholarly journals Correlation between body weight and postural control in healthy individuals using sway meter

2019 ◽  
Vol 16 (2) ◽  
pp. 36-41
Author(s):  
Tharani G ◽  
Vedha Varshini M G ◽  
Senthil Nathan C V ◽  
Mohan Kumar G ◽  
Kamatchi K
Keyword(s):  
Body Weight ◽  
Postural Control ◽  
Body Mass ◽  
Strong Correlation ◽  
Daily Living ◽  
Postural Sway ◽  
The Body ◽  
Healthy Individuals ◽  
Eyes Closed ◽  
Anterior Posterior

BACKGROUND: Postural control is critical for ensuring a safety activity of daily living. Individuals with poor stability are more prone to fall while doing activities of daily living. A certain level of sway is essentially present due to small perturbation within the body during shifting body weight from one to other foot, breathing, etc. The purpose of this study was to analyze the correlation between body mass and postural control in normal, lean and obese individual. AIMS: to analyze the correlation between body mass and postural control in healthy individuals using sway meter. MATERIALS AND METHODS: This is an observational study done with 75 participants. Both male and female healthy individuals between 18-23 years were included in this study. Individuals with any musculoskeletal injuries, neurological conditions, peripheral artery disease and pregnant women were excluded from the study. BMI of each participant was calculated and assigned into three groups. Group A-lean, group B-normal and group C-obese. Postural control was analyzed for each group by using sway meter; level of postural sway was compared between groups A, B C. RESULTS: On comparing mean values of groups A, B and C there was a positive association and strong correlation between body mass index and postural control with eye open and eye closed in anterior, posterior and postural sway towards left between the groups at (P 0.05). However, there was a negative association and weak correlation between BMI and postural control with eye open eye closed in postural sway towards right between the groups at (P 0.05). CONCLUSIONS: This study reveals that there is strong correlation between BMI and postural control. Subjects in eyes closed and eyes opened conditions showed sway in anterior, posterior and left directions but there was less sway towards right side direction.

scholarly journals Human perception of whole body roll-tilt orientation in a hypogravity analog: underestimation and adaptation

2018 ◽  
Vol 120 (6) ◽  
pp. 3110-3121 ◽  
Author(s):  
Raquel C. Galvan-Garza ◽  
Torin K. Clark ◽  
David Sherwood ◽  
Ana Diaz-Artiles ◽  
Marissa Rosenberg ◽  
...  
Keyword(s):  
Perceptual Learning ◽  
Visual Feedback ◽  
Human Perception ◽  
The Body ◽  
Whole Body ◽  
Altered Gravity ◽  
Centripetal Acceleration ◽  
Body Roll ◽  
Visual Vertical ◽  
Roll Tilt

Overestimation of roll tilt in hypergravity (“G-excess” illusion) has been demonstrated, but corresponding sustained hypogravic conditions are impossible to create in ground laboratories. In this article we describe the first systematic experimental evidence that in a hypogravity analog, humans underestimate roll tilt. We studied perception of self-roll tilt in nine subjects, who were supine while spun on a centrifuge to create a hypogravity analog. By varying the centrifuge rotation rate, we modulated the centripetal acceleration (GC) at the subject’s head location (0.5 or 1 GC) along the body axis. We measured orientation perception using a subjective visual vertical task in which subjects aligned an illuminated bar with their perceived centripetal acceleration direction during tilts (±11.5–28.5°). As hypothesized, based on the reduced utricular otolith shearing, subjects initially underestimated roll tilts in the 0.5 GC condition compared with the 1 GC condition (mean perceptual gain change = −0.27, P = 0.01). When visual feedback was given after each trial in 0.5 GC, subjects’ perceptual gain increased in approximately exponential fashion over time (time constant = 16 tilts or 13 min), and after 45 min, the perceptual gain was not significantly different from the 1 GC baseline (mean gain difference between 1 GC initial and 0.5 GC final = 0.16, P = 0.3). Thus humans modified their interpretation of sensory cues to more correctly report orientation during this hypogravity analog. Quantifying the acute orientation perceptual learning in such an altered gravity environment may have implications for human space exploration on the moon or Mars. NEW & NOTEWORTHY Humans systematically overestimate roll tilt in hypergravity. However, human perception of orientation in hypogravity has not been quantified across a range of tilt angles. Using a centrifuge to create a hypogravity centripetal acceleration environment, we found initial underestimation of roll tilt. Providing static visual feedback, perceptual learning reduced underestimation during the hypogravity analog. These altered gravity orientation perceptual errors and adaptation may have implications for astronauts.

scholarly journals From Body Mantle To Internal Core - A Parallel Framework To Organ Systems

2020 ◽  
pp. 1-12
Author(s):  
Yu Edwin Chau-Leung ◽  
Keyword(s):  
Operating Systems ◽  
The Body ◽  
Border Zone ◽  
Whole Body ◽  
The Core ◽  
System A ◽  
Self Organized ◽  
Surrounding Environment ◽  
Organ Systems ◽  
Internal Core

A framework describing a body perspective that can be used under Western Medicine (WM) and Chinese Medicine (CM) in parallel would facilitate a concerted look at the body in both perspectives. The major body systems may be viewed as operating systems, while closely interactive organ clusters forming whole body subsystems sub serve life functions. The whole body is viewed in layers: with the Mantle as border zone, the under-layer Interface as interactional zone, the Core with organ systems, and the Deep biostratum of resources. The mantle acts as a barrier and interface, while the under-layer of fascial, circulatory and neurohumoral elements inter-relate with deeper provisions, supporting and stabilizing activities. The operating systems and life vigor subsystems function up to a surface border-zone to interact effectively and adaptively with the surrounding environment. While current academics consider the dynamic brain tightly integrated with the body as a self-organized system, a clinical framework is lacking. This paper provides a more or less seamless framework between social, physical, biochemical and cellular perspectives, which have formerly been dichotomizing with big gaps. With such a framework, WM workers can expand onto using some parts of the CM perspectives, not losing scientific emphasis of cellular studies, while recognizing that whole body processes in many clinical occasions can explain problems and be handled more effectively. This has implications in diagnosis and understanding pathophysiology. Accordingly, a spectrum of practice modes in medicine presented helps to understand clinical approaches, from lesion to complexity treatment.

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