Postural stability during task performance on elevated and/or inclined surfaces

2003 ◽  
Vol 3 (2) ◽  
pp. 83-97 ◽  
Author(s):  
Amit Bhattacharya ◽  
Paul Succop ◽  
Laurel Kincl ◽  
Ming Lun Lu ◽  
Angshuman Bagchee

The purpose of this study was to subjectively and objectively evaluate the postural stability of forty industrial workers while performing simulated industrial tasks on inclined and elevated surfaces under various combinations of environmental lighting and noise distraction conditions. The results suggest the following ordering for the effects of risk factors on objective measure of postural balance: (1) environmental lighting, (2) elevation of standing surface, (3) gender, (4) inclination of standing surface, (5) age. The task performed would be ranked highest had the data been analyzed across the three tasks. The postural sway length significantly increased with increasing elevations and inclination angles for the stationary and bending tasks implying body's perceived risk of fall deployed increase in postural muscle contraction. This compensatory mechanism indicated by increased sway length actually did reduce postural sway amplitudes with increasing elevation but for increasing inclination the postural sway amplitudes increased. While the objective measure of postural sway increased with the increasing combination of elevation and inclination, the subjective measure of stability did not show a significant two way interaction, implying that the participants were not able to perceive the combined risk to postural imbalance, causing potential inability to deploy appropriate postural muscle corrective actions.

1998 ◽  
Vol 1 (2) ◽  
pp. 81-93 ◽  
Author(s):  
Shiowyi Chiou ◽  
Amit Bhattacharya ◽  
Chwan-Fu Lai ◽  
Paul A. Succop

The objective of this study was to evaluate workers' ability to detect changes in postural balance using a short questionnaire -- the perceived sense of postural sway and instability (PSPSI) scale. Ratings of perceived sense of postural sway and instability for four simulated tasks were obtained from fifty-two healthy industrial workers and compared with objective measurements determined by a strain gauge type force platform. The simulated tasks were performed under various experimental conditions that may influence postural stability. It was found that subjects were able to perceive the changes in postural sway and instability due to the modification in peripheral vision, environmental lighting, workload, and surface firmness, as reflected by their PSPSI ratings. Results from this study indicate that the PSPSI scale is a promising tool, which provides a simple and valid method to evaluate the potential for loss of balance in the workplace.


Author(s):  
L. Kind ◽  
A. Bhattacharya ◽  
P. Succop

For the construction industry, especially the roofing industry, slips/trips and falls have the highest incident rate leading to an injury and fatality. This study investigated the eye movement and postural sway patterns of industrial workers (n=48) with various work experience (months of work experience on inclined surfaces), fatigue conditions (none, half and full), visual cues (none, H cue), tasks (stationary, reach) and surface inclinations (0°, 14°, 26°). Eye movement variables of length and area of movement as well as fixation data and postural sway variables of area and length were significantly affected (p<0.05) by incline, cue, task and work experience. The effect of the eye movement variables on the postural balance was limited and further study is necessary. The use of visual cues is an effective means of increasing postural stability and could be used in occupational situations where no vertical or horizontal cues are naturally available.


2003 ◽  
Vol 3 (4) ◽  
pp. 251-259
Author(s):  
Laurel Kincl ◽  
Amit Bhattacharya ◽  
Paul Succop ◽  
Angshuman Bagchee

Maintenance of upright balance involves interplay between sensory (somatosensory, vestibular and visual) inputs and neuro-motor outputs. Visual spatial perception (VSP) of vertical and horizontal orientation plays a significant role in the maintenance of upright balance. For this experiment, a custom designed computer program randomly generated 42 images of horizontal and vertical lines at various angles for 60 industrial workers (39 ± 9.8 years). Half of the workers had more than three years of experience working on inclined and/or elevated surfaces. The main effects investigated included within subject factors of standing surface inclination (0°, 14° and 26°), job experience (number of months), and postural workload (0%, 50% or 100%). The VSP outcome measure was the count of correct responses to the angles presented. The inclination did not have a significant effect on VSP, but the parameter estimates indicated less correct responses on the inclined surfaces. The postural workload significantly affected the VSP, indicating that with increased workload, less correct responses were given. Finally, job experience was found to improve VSP response scores. In summary, these results indicate that job experience increases accurate VSP, while workloads and inclined work surfaces decrease accurate VSP responses.


2020 ◽  
Vol 29 (2) ◽  
pp. 174-178
Author(s):  
Kelly M. Meiners ◽  
Janice K. Loudon

Purpose/Background: Various methods are available for assessment of static and dynamic postural stability. The primary purpose of this study was to investigate the relationship between dynamic postural stability as measured by the Star Excursion Balance Test (SEBT) and static postural sway assessment as measured by the TechnoBody™ Pro-Kin in female soccer players. A secondary purpose was to determine side-to-side symmetry in this cohort. Methods: A total of 18 female soccer players completed testing on the SEBT and Technobody™ Pro-Kin balance device. Outcome measures were anterior, posterior medial, and posterior lateral reaches from the SEBT and center of pressure in the x- and y-axes as well as SD of movement in the forward/backward and medial/lateral directions from the force plate on left and right legs. Bivariate correlations were determined between the 8 measures. In addition, paired Wilcoxon signed-rank tests were performed to determine similarity between limb scores. Results: All measures on both the SEBT and postural sway assessment were significantly correlated when comparing dominant with nondominant lower-extremities with the exception of SD of movement in both x- and y-axes. When correlating results of the SEBT with postural sway assessment, a significant correlation was found between the SEBT right lower-extremity posterior lateral reach (r = .567, P < .05) and summed SEBT (r = .486, P < .05) and the center of pressure in the y-axis. A significant correlation was also found on the left lower-extremity, with SD of forward/backward movement and SEBT posterior medial reach (r = −.511, P < .05). Conclusions: Dynamic postural tests and static postural tests provide different information to the overall assessment of balance in female soccer players. Relationship between variables differed based on the subject’s lower-extremity dominance.


Author(s):  
Cole Woods ◽  
Vishesh Vikas

Abstract The balance of inverted pendulum on inclined surfaces is the precursor to their control in unstructured environments. Researchers have devised control algorithms with feedback from contact (encoders - placed at the pendulum joint) and non-contact (gyroscopes, tilt) sensors. We present feedback control of Inverted Pendulum Cart (IPC) on variable inclines using non-contact sensors and a modified error function. The system is in the state of equilibrium when it is not accelerating and not falling over (rotational equilibrium). This is achieved when the pendulum is aligned along the gravity vector. The control feedback is obtained from non-contact sensors comprising of a pair of accelerometers placed on the inverted pendulum and one on the cart. The proposed modified error function is composed of the dynamic (non-gravity) acceleration of the pendulum and the velocity of the cart. We prove that the system is in equilibrium when the modified error is zero. We present algorithm to calculate the dynamic acceleration and angle of the pendulum, and incline angle using accelerometer readings. Here, the cart velocity and acceleration are assumed to be proportional to the motor angular velocity and acceleration. Thereafter, we perform simulation using noisy sensors to illustrate the balance of IPC on surfaces with unknown inclination angles using PID feedback controller with saturated motor torque, including valley profile that resembles a downhill, flat and uphill combination. The successful control of the system using the proposed modified error function and accelerometer feedback argues for future design of controllers for unstructured and unknown environments using all-accelerometer feedback.


Author(s):  
Satoshi Matsuno ◽  
Takuya Yoshiike ◽  
Atsushi Yoshimura ◽  
Sachiyo Morita ◽  
Yusuke Fujii ◽  
...  

Although standing plantar perception training (SPPT) may improve standing postural stability, the underlying neural mechanisms remain unclear. The authors investigated the relationship between regional cortical responses to SPPT using a balance pad and training outcomes in 32 older participants (mean ± SD:72.2 ± 6.0, range:60–87). Regional cortical activity was measured in the bilateral supplementary motor area, primary sensorimotor area, and parietal association area using near-infrared spectroscopy. Postural sway changes were compared before and after SPPT. Changes in two-point plantar discrimination and regional cortical activity during SPPT, associated with standing postural stability improvements, were examined using multiple regression and indicated improved standing postural stability after SPPT (p < .0001). Changes in right parietal association area activity were associated with standing postural stability improvements while barefoot. Overall, the results suggest that right parietal association area activation during SPPT plays a crucial role in regulating standing postural stability and may help develop strategies to prevent older adults from falling.


Author(s):  
Bożena Wojciechowska-Maszkowska ◽  
Dorota Borzucka

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.


2019 ◽  
Vol 48 (Supplement_4) ◽  
pp. iv18-iv27 ◽  
Author(s):  
Kitima Rongsawad ◽  
Laddawon Worawan ◽  
Karnsiree Jirarojprapa ◽  
Sararat Kaewkham ◽  
Sarawut Khattiwong

Abstract Introduction Static postural stability is the ability to maintain the posture with minimum sway. Increasing postural sway during standing in different sensory conditions is associated with aging due to decline in sensory and motor functions. Sway area measured by using sway meter is usually simple method for assessing postural stability in elderly subjects. Like many biological measurements, sway area has an intrinsic variability that affects their test-retest reliability and responsiveness of postural stability assessment. The minimal detectable change (MDC) is ability to detect smallest change beyond measurement error that reflects a reliable change. Therefore, the MDC value could provide information of clinical relevance on postural stability. The aims of this study were to determine test-retest reliability and MDC of sway area obtained from sway meter in elderly subjects. Methods Twelve healthy elderly subjects aged 60 years and above were participated in this study. The test and retest repeatability of postural sway measurements were performed twice with a 1-hour interval. For each subject was assess postural sway using Lord’s sway meter during standing on 4 sensory conditions for 30 seconds of each condition. The test-retest reliability of sway area was calculated using intraclass correlation coefficient. The MDC for each sway area was calculated to quantify clinical relevance. Results The test-retest reliability of sway area revealed good to excellent reliability ranged from 0.85 to 0.94. Standard error of measurement (SEM) and MDC ranged from 75 to 205 mm2 and 209 to 568 mm2, respectively. Discussion and Conclusion Our findings reveal that sway area in different sensory conditions could be used in assessment of postural stability in elderly subjects. SEM and MDC of sway area increased when subjects were asked to close their eyes and on foam surface. The sway meter is a reliable tool for assessing postural stability in clinical setting.


2017 ◽  
Vol 1 (S1) ◽  
pp. 26-26
Author(s):  
Haylie Miller ◽  
Nicoleta Bugnariu ◽  
Priscila Caçola ◽  
Rita Patterson

OBJECTIVES/SPECIFIC AIMS: Individuals with autism spectrum disorder (ASD) and developmental coordination disorder (DCD) share overlap in their motor symptom profile and underlying neurology (Sumner, Leonard, & Hill, 2016, JADD). DSM-5 guidelines allow these 2 disorders to be independent or co-occurring (APA, 2013), but common clinical practice does not include systematic assessment to determine the presence or absence of co-occurring DCD in children with ASD, or vice versa. Furthermore, in many cases DCD is managed in a nonspecific manner, with schools making accommodations for a child’s motor challenges without formally assigning a diagnosis of DCD. Thus, somewhat subjective, qualitative judgments are made by clinicians to classify children as DCD, ASD, or ASD+DCD in the absence of a reliable, valid, quantitative measure to distinguish between these profiles. As a first step toward developing such a measure, researchers must tease apart the nuanced differences in the motor symptoms of these 2 developmental disorders using methods that are scalable to clinical and educational settings. These methods must also be developed with consideration for logistical variables such as cost, clinical utility of data output, and ease-of-use if they are to be transferrable to physicians, school nurses, and other community health workers outside of academic laboratory settings. To that end, we conducted 2 complementary studies: 1 in the lab and 1 in the community. METHODS/STUDY POPULATION: In the community-based study, we used an affordable, user-friendly, portable balance testing system to assess postural stability during quiet standing (feet shoulder-width apart) with eyes open for 30 seconds. Data were generated from a single force plate in the balance platform. Potential participants were screened for other medical and neurological conditions that might impact their postural stability, and those with significant comorbidities were excluded. We tested 15 children with a reported diagnosis of ASD, 8 children with suspected or diagnosed DCD who were enrolled in a motor intervention program, and 30 typically-developing (TD) children with no significant developmental history reported. The ASD group ranged in age from 7 to 20, the DCD group ranged from 7 to 10, and the TD group ranged from 7 to 19. In the lab-based study, we again obtained force plate data during quiet standing (feet shoulder-width apart) with eyes open for 30 seconds, in our system that also included full-body motion capture, virtual reality, and mobile eye tracking. (Data from these additional sources are not discussed in this disseminaton, as our current focus is on identifying a simple, scalable metric that can be used to distinguish ASD from DCD.) We tested 10 children with a diagnosis of ASD that was confirmed by the research team, 10 children with a diagnosis of DCD that was confirmed by the research team, and 5 TD children with no significant developmental history reported. The ASD group ranged in age from 7 to 18, the DCD group ranged from 8 to 12, and the TD group ranged from 9 to 18. RESULTS/ANTICIPATED RESULTS: Primary outcome measures in both studies were related to Center of Pressure (CoP), including CoP sway, CoP velocity, and amount of sway relative to the base of support. Data analysis from both studies is ongoing, but preliminary trends suggest that CoP metrics may effectively differentiate between ASD, DCD, and TD. During quiet standing, individuals with DCD exhibited the greatest postural sway. Individuals with ASD followed, having greater instability than the TD group. Differences were also evident in the velocity profiles of postural sway. DISCUSSION/SIGNIFICANCE OF IMPACT: Preliminary findings suggest that CoP offers a means of differentiating between typical and atypical development specifically with respect to motor symptoms. This simple, quantifiable measure may prove a sensitive and specific means of systematically assessing co-occurrence of ASD and DCD in clinical and educational settings, leading to more accurate diagnostic classification and tailored intervention. Future directions include conducting analyses that account for participant age and developmental stage with respect to motor skills, determining whether trends hold in a larger sample, and using advanced statistical methods to determine whether CoP variables have predictive validity in discriminating between classifications of ASD, DCD, ASD+DCD, and TD. Eye-movement data were also obtained during these tasks, and may further aid in understanding the factors contributing to atypical postural control. These 2 studies also yielded methodological findings, namely that the portable force platform carries the benefit of high ease-of-use, low cost, and portability, but also has important drawbacks. Specifically, it is not capable of registering accurate CoP data for participants who weigh <40 lbs, and the error variance for the load cells is greater than that of most nonportable, higher-end plates like those embedded in our laboratory’s platform. As technological advances continue to facilitate development of more portable, higher-resolution systems, these drawbacks may be significantly reduced. Future directions include further assessment of portable, affordable solutions for this type of testing to identify whether higher-resolution options are available, whether this added resolution increases classification accuracy, and how ease-of-use is perceived by clinical and community health workers.


Obesity Facts ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 499-513
Author(s):  
Gabriel M. Pagnotti ◽  
Amna Haider ◽  
Ariel Yang ◽  
Kathryn E. Cottell ◽  
Catherine M. Tuppo ◽  
...  

<b><i>Introduction:</i></b> 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 &#x3e;30 kg/m<sup>2</sup>) but without isolating the most morbidly obese subset (BMI ≥40 kg/m<sup>2</sup>). We investigated the impact of obesity in perturbing postural stability in morbidly obese subjects elected for bariatric intervention, harboring a higher-spectrum BMI. <b><i>Subjects and Methods:</i></b> 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/m<sup>2</sup> in contrast to 13 nonobese subjects with an average BMI of 30 kg/m<sup>2</sup>. 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. <b><i>Results:</i></b> Mean body weight was 85% (<i>p</i> &#x3c; 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%, <i>p</i> &#x3c; 0.002) and eyes closed (76%, <i>p</i> = 0.04) versus nonobese subjects. Obese subjects also exhibited a higher COP velocity in static tests when subjects’ eyes were open (47%, <i>p</i> = 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%, <i>p</i> &#x3c; 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%, <i>p</i> &#x3c; 0.04). <b><i>Discussion and Conclusion:</i></b> 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.


Sign in / Sign up

Export Citation Format

Share Document