Effect of Head Orientation on Human Postural Stability Following Unilateral Vestibular Ablation

Effective interpretation of vestibular inputs to postural control requires that orientation of head on body is known. Postural stability might deteriorate when vestibular information and neck information are not properly coupled, as might occur with vestibular pathology. Postural sway was assessed in unilateral vestibulopathic patients before and acutely, 1,4, and 18+ months after unilateral vestibular ablation (UVA) as well as in normal subjects. Postural equilibrium with eyes closed was quantified as scaled pk-pk sway during 20 s trials in which the support surface was modulated proportionally with sway. Subjects were tested with the head upright and facing forward, turned 45∘ right, and 45∘ left. Equilibrium was uninfluenced by head orientation in normal subjects. In contrast, patients after UV A showed both a general reduction in stability and a right/left head orientation-dependent asymmetry. These abnormalities adaptively recovered with time. It is concluded that vestibular inputs to postural control are interpreted within a sensory-motor context of head-on-body orientation.

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The contribution of hearing to normal balance

The Journal of Laryngology & Otology ◽

10.1017/s002221511200179x ◽

2012 ◽

Vol 126 (10) ◽

pp. 984-988 ◽

Cited By ~ 34

Author(s):

R G Kanegaonkar ◽

K Amin ◽

M Clarke

Keyword(s):

Postural Control ◽

Significant Influence ◽

Postural Sway ◽

Normal Subjects ◽

Nintendo Wii ◽

Sensory Inputs ◽

Eyes Closed ◽

Ambient Sound ◽

Eyes Open ◽

Balance Board

AbstractIntroduction:Normal balance relies on three sensory inputs: vision, proprioception and the peripheral vestibular system. This study assessed hearing change and postural control in normal subjects.Materials and methods:Postural control in 20 normal volunteers was assessed using a Nintendo Wii gaming console and balance board. Each subject was tested standing upright for 30 seconds in a clinic room and a soundproof room with their eyes open, eyes closed, whilst standing on and off foam, and with and without ear defenders.Results:There was significantly more postural sway in the following subjects: those standing with their eyes closed vs those with eyes open (normal room, p = 0.0002; soundproof room, p = 0.0164); those standing on foam with eyes open vs those standing normally with eyes open (in both rooms; p < 0.05); those standing with eyes open in a soundproof room vs a normal room (p = 0.0164); and those standing on foam in a soundproof room with eyes open and wearing ear defenders vs those in the same circumstances but without ear defenders.Conclusion:Our results suggest that this method provides a simple, inexpensive tool for assessing static postural control. Whilst it is recognised that visual input and proprioception play a central role in maintaining posture, our findings suggest that ambient sound and hearing may also have a significant influence.

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Dynamic Regulation of Sensorimotor Integration in Human Postural Control

Journal of Neurophysiology ◽

10.1152/jn.00516.2003 ◽

2004 ◽

Vol 91 (1) ◽

pp. 410-423 ◽

Cited By ~ 308

Author(s):

Robert J. Peterka ◽

Patrick J. Loughlin

Keyword(s):

Postural Control ◽

Postural Stability ◽

Sensory Systems ◽

Body Sway ◽

Accurate Information ◽

Support Surface ◽

Proprioceptive Information ◽

Postural Control System ◽

Eyes Closed ◽

Orientation Information

Upright stance in humans is inherently unstable, requiring corrective action based on spatial-orientation information from sensory systems. One might logically predict that environments providing access to accurate orientation information from multiple sensory systems would facilitate postural stability. However, we show that, after a period in which access to accurate sensory information was reduced, the restoration of accurate information disrupted postural stability. In eyes-closed trials, proprioceptive information was altered by rotating the support surface in proportion to body sway (support surface “sway-referencing”). When the support surface returned to a level orientation, most subjects developed a transient 1-Hz body sway oscillation that differed significantly from the low-amplitude body sway typically observed during quiet stance. Additional experiments showed further enhancement of the 1-Hz oscillation when the surface transitioned from a sway-referenced to a reverse sway-referenced motion. Oscillatory behavior declined with repetition of trials, suggesting a learning effect. A simple negative feedback-control model of the postural control system predicted the occurrence of this 1-Hz oscillation in conditions where too much corrective torque is generated in proportion to body sway. Model simulations were used to distinguish between two alternative explanations for the excessive corrective torque generation. Simulation results favor an explanation based on the dynamic reweighting of sensory contributions to postural control rather than a load-compensation mechanism that scales torque in proportion to a fixed combination of sensory-orientation information.

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Time-to-Boundary Function to Study the Development of Upright Stance Control in Children

The Open Biomedical Engineering Journal ◽

10.2174/1874120701711010049 ◽

2017 ◽

Vol 11 (1) ◽

pp. 49-58

Author(s):

Carmen D'Anna ◽

Maurizio Schmid ◽

Andrea Scorza ◽

Salvatore A. Sciuto ◽

Luisa Lopez ◽

...

Keyword(s):

Standard Deviation ◽

Postural Control ◽

Postural Stability ◽

Age Groups ◽

Boundary Function ◽

Mean Value ◽

Upright Stance ◽

Eyes Closed ◽

The Mean ◽

Spatio Temporal

Background: The development of postural control across the primary school time horizon is a complex process, which entails biomechanics modifications, the maturation of cognitive ability and sensorimotor organization, and the emergence of anticipatory behaviour. Postural stability in upright stance has been thus object of a multiplicity of studies to better characterize postural control in this age span, with a variety of methodological approaches. The analysis of the Time-to-Boundary function (TtB), which specifies the spatiotemporal proximity of the Centre of Pressure (CoP) to the stability boundaries in the regulation of posture in upright stance, is among the techniques used to better characterize postural stability in adults, but, as of now, it has not yet been introduced in developmental studies. The aim of this study was thus to apply this technique to evaluate the development of postural control in a sample population of primary school children. Methods: In this cross-sectional study, upright stance trials under eyes open and eyes closed were administered to 107 healthy children, divided into three age groups (41 for Seven Years' Group, Y7; 38 for Nine Years' Group, Y9; 28 for Eleven Years' Group, Y11). CoP data were recorded to calculate the Time-to-Boundary function (TtB), from which four spatio-temporal parameters were extracted: the mean value and the standard deviation of TtB minima (Mmin, Stdmin), and the mean value and the standard deviation of the temporal distance between two successive minima (Mdist, Stddist). Results: With eyes closed, Mmin and Stdmin significantly decreased and Mdist and Stddist increased for the Y7 group, at Y9 Mmin significantly decreased and Stddist increased, while no effect of vision resulted for Y11. Regarding age groups, Mmin was significantly higher for Y9 than Y7, and Stdmin for Y9 was higher than both Y7 and Y11; Mdist and Stddist resulted higher for Y11 than for Y9. Conclusion: From the combined results from the spatio-temporal TtB parameters, it is suggested that, at 9 years, children look more efficient in terms of exploring their limits of stability than at 7, and at 11 the observed TtB behaviour hints at the possibility that, at that age, they have almost completed the maturation of postural control in upright stance, also in terms of integration of the spatio-temporal information.

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Experience on an Elevated Inclined Surface and Postural Control

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/154193120504901410 ◽

2005 ◽

Vol 49 (14) ◽

pp. 1311-1314

Author(s):

Chip Wade ◽

Jerry Davis

Keyword(s):

College Students ◽

Postural Control ◽

Postural Stability ◽

Support Surface ◽

Motion Analysis System ◽

Balance Test ◽

Significant Decrement ◽

Peripheral Area ◽

Analysis System ◽

Inclined Surface

Historically, roofing work has been ranked among the highest of all industries with incidents of fatal and non-fatal falls. The purpose of this study was to investigate the exposure to an elevated inclined surface on postural stability. Twenty males, 10 experienced roofers, and 10 inexperienced college students participated in this study, which consisted of a preliminary balance test, followed by exposure to an elevated inclined surface for ten-minutes of exposure. While subjects walked, a motion analysis system recorded their position on the elevated roofing surface to determine the amount of time a subject spent in each of two areas, central or peripheral. Results suggest that both experienced and inexperienced individuals demonstrated decreased postural stability following exposure to the elevated inclined surface, with experienced individuals demonstrating a lesser decrement. Furthermore, experienced individuals spent a significantly greater portion of time in the peripheral area (extremities of the elevated roofing surface) surface compared to inexperienced individuals. These findings suggest that there is a significant decrement in postural stability due to exposure to an elevated inclined support surface.

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Influence of gender and physical exercise on balance of healthy young adults

Fisioterapia em Movimento ◽

10.1590/0103-5150.027.003.ao10 ◽

2014 ◽

Vol 27 (3) ◽

pp. 399-406 ◽

Cited By ~ 3

Author(s):

Sarina Francescato Torres ◽

Júlia Guimarães Reis ◽

Daniela Cristina Carvalho de Abreu

Keyword(s):

Physical Activity ◽

Energy Expenditure ◽

Postural Control ◽

Postural Sway ◽

Short Form ◽

Quiet Standing ◽

Moderate Activity ◽

Men And Women ◽

Eyes Closed ◽

Sedentary Women

Objective To verify the effects of gender and physical activity on postural sway. Method A cross-sectional study was conducted to analyze upright balance of young men and women between the ages of 20-30, both active and sedentary. Study participants were 60 individuals, who were divided into: active women (n = 15), sedentary women (n = 15), active men (n = 15) and sedentary men (n = 15). The International Physical Activity Questionnaire (IPAQ) short form, was used to evaluate each participant’s level of physical activity. According to the questionnaire, active individuals are those who carry out moderate activity, with an energy expenditure between 3.5 and 6 METs (1 MET: 3.5 ml/kg/min), or vigorous activity, with an energy expenditure above 6 METs, at least three days a week for 20 minutes. To assess control of postural sway, we measured the amplitude and velocity of anteroposterior (AP) and mediolateral (ML) sway in standing position, with their eyes open and closed, with and without foam, on a force platform. Results Comparison between genders revealed that, when compared to sedentary women, sedentary men displayed poorer performance in velocity and amplitude of AP postural control sway with their eyes closed, with and without foam. There were no differences in the amplitude and velocity of ML sway, both with open and closed eyes among groups (p < 0.05). There were no differences when comparing physically active men and women either. Conclusion Sedentary men seem to rely more on vision for maintaining postural control in quiet standing situations with respect to women.

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Characteristics of Standing Postural Control in Women under Additional Load

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17020490 ◽

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.

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Controlling Human Upright Posture: Velocity Information Is More Accurate Than Position or Acceleration

Journal of Neurophysiology ◽

10.1152/jn.00983.2003 ◽

2004 ◽

Vol 92 (4) ◽

pp. 2368-2379 ◽

Cited By ~ 155

Author(s):

John Jeka ◽

Tim Kiemel ◽

Robert Creath ◽

Fay Horak ◽

Robert Peterka

Keyword(s):

Postural Sway ◽

Sensory Information ◽

Accurate Information ◽

Support Surface ◽

Quiet Stance ◽

Eyes Closed ◽

Stance Control ◽

Model Predictions ◽

Velocity Information ◽

Multisensory Information

The problem of how the nervous system fuses sensory information from multiple modalities for upright stance control remains largely unsolved. It is well established that the visual, vestibular, and somatosensory modalities provide position and rate (e.g., velocity, acceleration) information for estimation of body dynamics. However, it is unknown whether any particular property dominates when multisensory information is fused. Our recent stochastic analysis of postural sway during quiet stance suggested that sensory input provides more accurate information about the body's velocity than its position or acceleration. Here we tested this prediction by degrading major sources of velocity information through removal/attenuation of sensory information from vision and proprioception. Experimental measures of postural sway were compared with model predictions to determine whether sway behavior was indicative of a deficit in velocity information rather than position or acceleration information. Subjects stood with eyes closed on a support surface that was 1) fixed, 2) foam, or 3) sway-referenced. Six measures characterizing the stochastic structure of postural sway behaved in a manner consistent with model predictions of degraded velocity information. Results were inconsistent with the effect of degrading only position or acceleration information. These findings support the hypothesis that velocity information is the most accurate form of sensory information used to stabilize posture during quiet stance. Our results are consistent with the assumption that changes in sway behavior resulting from commonly used experimental manipulations (e.g., foam, sway-referencing, eyes closed) are primarily attributed to loss of accurate velocity information.

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Postural Stability in Obese Preoperative Bariatric Patients Using Static and Dynamic Evaluation

Obesity Facts ◽

10.1159/000509163 ◽

2020 ◽

Vol 13 (5) ◽

pp. 499-513

Author(s):

Gabriel M. Pagnotti ◽

Amna Haider ◽

Ariel Yang ◽

Kathryn E. Cottell ◽

Catherine M. Tuppo ◽

...

Keyword(s):

Postural Stability ◽

Postural Sway ◽

Center Of Pressure ◽

Postural Instability ◽

Patient Specific ◽

Morbidly Obese ◽

Tissue Quality ◽

Eyes Closed ◽

Obese Subjects ◽

The Impact

Introduction: Globally, 300 million adults have clinical obesity. Heightened adiposity and inadequate musculature secondary to obesity alter bipedal stance and gait, diminish musculoskeletal tissue quality, and compromise neuromuscular feedback; these physiological changes alter stability and increase injury risk from falls. Studies in the field focus on obese patients across a broad range of body mass indices (BMI >30 kg/m2) but without isolating the most morbidly obese subset (BMI ≥40 kg/m2). We investigated the impact of obesity in perturbing postural stability in morbidly obese subjects elected for bariatric intervention, harboring a higher-spectrum BMI. Subjects and Methods: Traditional force plate measurements and stabilograms are gold standards employed when measuring center of pressure (COP) and postural sway. To quantify the extent of postural instability in subjects with obesity before bariatric surgery, we assessed 17 obese subjects with an average BMI of 40 kg/m2 in contrast to 13 nonobese subjects with an average BMI of 30 kg/m2. COP and postural sway were measured from static and dynamic tasks. Involuntary movements were measured when patients performed static stances, with eyes either opened or closed. Two additional voluntary movements were measured when subjects performed dynamic, upper torso tasks with eyes opened. Results: Mean body weight was 85% (p < 0.001) greater in obese than nonobese subjects. Following static balance assessments, we observed greater sway displacement in the anteroposterior (AP) direction in obese subjects with eyes open (87%, p < 0.002) and eyes closed (76%, p = 0.04) versus nonobese subjects. Obese subjects also exhibited a higher COP velocity in static tests when subjects’ eyes were open (47%, p = 0.04). Dynamic tests demonstrated no differences between groups in sway displacement in either direction; however, COP velocity in the mediolateral (ML) direction was reduced (31%, p < 0.02) in obese subjects while voluntarily swaying in the AP direction, but increased in the same cohort when swaying in the ML direction (40%, p < 0.04). Discussion and Conclusion: Importantly, these data highlight obesity’s contribution towards increased postural instability. Obese subjects exhibited greater COP displacement at higher AP velocities versus nonobese subjects, suggesting that clinically obese individuals show greater instability than nonobese subjects. Identifying factors contributory to instability could encourage patient-specific physical therapies and presurgical measures to mitigate instability and monitor postsurgical balance improvements.

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

Journal of Exercise Rehabilitation ◽

10.12965/jer.2142558.279 ◽

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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The effect of support surface and footwear condition on postural sway and lower limb muscle action of the old people

10.21203/rs.2.10274/v1 ◽

2019 ◽

Author(s):

Meizhen Huang ◽

Kit-lun Yick ◽

Sun-pui Ng ◽

Joanne Yip ◽

Roy Cheung

Keyword(s):

Lower Limb ◽

Postural Stability ◽

Muscle Activation ◽

Postural Sway ◽

The Elderly ◽

The Body ◽

Support Surface ◽

Lower Limb Muscle ◽

Limb Muscle ◽

Age Related

Abstract Background: Diminished somatosensory function and lower plantar cutaneous sensitivity have been identified as a critical age-related change, which is related to postural instability in the older population. Footwear is suggested that can modulate the postural stability by altering the interface between the foot sole and the ground. However, it is unclear whether this footwear effect could also influence lower limb muscle activation for the elderly. This study aimed to investigate the footwear insole texture and supporting surface condition on static postural stability and lower limb muscle activation for healthy older people. Methods: This is a single-session study with repeated measurements. Twenty-three healthy older female stood on the firm (i.e., concrete floor) and foam surfaces with their eyes open in the three footwear conditions, namely barefoot, plain shoes and nodulous insole shoes, for 30 seconds. Static postural sway and muscle activation of biceps femoris (BF), vastus lateralis (VL), tibialis anterior (TA), and lateral gastrocnemius (LG) of the dominant leg were measured during each testing condition. Results: compared to firm surface, standing on the foam could significantly increase the body sway and lower limb muscle activation (p<0.05); compared to barefoot, when standing on the foam, wearing footwear significantly decreased the VL and TA muscle activation and minimize the postural sway in ML and AP direction, while the influence is larger for the nodulous shoes compared to the plain shoes. A positive correlation was observed between the lower limb muscle activation and AP (r=0.327-0.389, p<0.001) and total sway path length (r=0.317-0.427, p<0.001). Conclusions: footwear could improve the postural stability and decease the fall risk comparing to barefoot when the somatosensory input is in disturbance, while the improvement is larger when wearing nodulous insole footwear for the elderly.

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