Stroboscopic Vision as a Dynamic Sensory Reweighting Alternative to the Sensory Organization Test

Context: The sensory organization test (SOT) is a standard for quantifying sensory dependence via sway-referenced conditions (sway-referenced support and sway-referenced vision [SRV]). However, the SOT is limited to expensive equipment. Thus, a practical version of the SOT is more commonly employed—the clinical test for sensory integration in balance; however, it fails to induce postural instability to the level of SRV. Objective: Determine if Stroboscopic vision (SV), characterized by intermittent visual blocking, may provide an alternative to the SRV for assessing postural stability. Design: Descriptive laboratory study. Setting: Research laboratory. Participants: Eighteen participants (9 males, 9 females; age = 22.1 [2.1] y, height = 169.8 [8.5] cm, weight = 66.5 [10.6] kg). Intervention: Participants completed the SOT conditions, and then repeated SOT conditions 2 and 5 with SV created by specialized eyewear. Main Outcome Measures: A repeated-measures analysis of variance was completed on the time-to-boundary metrics of center-of-pressure excursion in the anteroposterior and mediolateral directions in order to determine the difference between the full-vision, SV, and SRV conditions. Results: Postural stability with either SRV or SV was significantly worse than with full vision (P < .05), with no significant difference between SV and SRV (P > .05). Limits of agreement analysis revealed similar effects of SV and SRV except for unstable surface mediolateral time-to-boundary. Conclusions: In general, SV was found to induce a degree of postural instability similar to that induced by SRV, indicating that SV could be a portable and relatively inexpensive alternative for the assessment of sensory dependence and reweighting.

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Impact of Virtual Reality–Generated Construction Environments at Different Heights on Postural Stability and Fall Risk

Workplace Health & Safety ◽

10.1177/2165079920934000 ◽

2020 ◽

Vol 69 (1) ◽

pp. 32-40 ◽

Cited By ~ 1

Author(s):

Harish Chander ◽

Alireza Shojaei ◽

Shuchisnigdha Deb ◽

Sachini N. K. Kodithuwakku Arachchige ◽

Christopher Hudson ◽

...

Keyword(s):

Virtual Reality ◽

Repeated Measures ◽

Postural Stability ◽

Postural Sway ◽

Center Of Pressure ◽

Postural Instability ◽

Postural Control System ◽

Environment Exposure ◽

Acute And Chronic Exposure ◽

The Impact

Background Falls due to postural instability are common in construction environments especially from a height. The purpose of the study was to investigate the impact of virtual reality (VR)-generated environments at different virtual heights on postural stability. Methods Nineteen adults were analyzed for postural stability, tested in real (No VR) environment and in three VR environments, randomly assigned, at virtual heights of 0 ft. (VR0), 40 ft. (VR40), and 120 ft. (VR120). Postural stability was quantified using center of pressure postural sway variables and analyzed using a repeated measures analysis of variance (ANOVA). Participants also completed a simulation sickness questionnaire (SSQ) before and after VR exposure and a presence questionnaire (PQ) after VR exposure. Findings Significant postural instability ( p < .05) was identified between VR and No VR, in which increased postural instability was evident in all VR conditions compared with No VR. Scores from SSQ were within a pre–post score difference of five and the PQ score was (104.21 ± 14.03). Conclusion/Application to Practice Findings suggest that VR environments, regardless of virtual height, induced increased postural instability, which can be attributed to visual sensory conflicts to the postural control system created by VR exposure. Participants’ subjective responses on SSQ and PQ confirmed the feasibility of using VR to represent realistic immersions in virtual heights. However, objectively, VR could potentially lead to postural instability, stressing caution. VR can be a potential tool for providing virtual high-altitude environment exposure for fall prevention training, however, more research is needed on postural adaptation with acute and chronic exposure to VR.

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Sensory Organization Test Conditions Influence Postural Strategy Rather than Footwear or Workload

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph181910511 ◽

2021 ◽

Vol 18 (19) ◽

pp. 10511

Author(s):

Harish Chander ◽

Sachini N. K. Kodithuwakku Arachchige ◽

Alana J. Turner ◽

Reuben F. Burch V ◽

Jennifer C. Reneker ◽

...

Keyword(s):

Repeated Measures ◽

Postural Stability ◽

Sensory Feedback ◽

Sensory Organization Test ◽

Ankle Strategy ◽

Sensory Organization ◽

Test Conditions ◽

Repeated Measures Analysis ◽

Alpha Level ◽

Occupational Workload

Background: Postural strategies such as ankle, hip, or combined ankle-hip strategies are used to maintain optimal postural stability, which can be influenced by the footwear type and physiological workload. Purpose: This paper reports previously unreported postural strategy scores during the six conditions of the sensory organization test (SOT). Methods: Fourteen healthy males (age: 23.6 ± 1.2 years; height: 181 ± 5.3 cm; mass: 89.2 ± 14.6 kg) were tested for postural strategy adopted during SOT in three types of occupational footwear (steel-toed work boot, tactical work boot, low-top work shoe) every 30 min during a 4-h simulated occupational workload. Postural strategy scores were analyzed using repeated measures analysis of variance at 0.05 alpha level. Results: Significant differences among postural strategy scores were only evident between SOT conditions, and but not between footwear type or the workload. Conclusions: Findings indicate that occupational footwear and occupational workload did not cause a significant change in reliance on postural strategies. The significant changes in postural strategy scores were due to the availability of accurate and/or conflicting sensory feedback during SOT conditions. In SOT conditions where all three types of sensory feedback was available, the ankle strategy was predominantly adopted, while more reliance on hip strategy occurred in conditions with absent or conflicting sensory feedback.

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“Going Backward”: Effects of age and fatigue on posterior-directed falls in Parkinson disease

Neurorehabilitation ◽

10.3233/nre-210040 ◽

2021 ◽

pp. 1-9

Author(s):

Evan V. Papa ◽

Rita M. Patterson ◽

Nicoleta Bugnariu

Keyword(s):

Postural Control ◽

Parkinson Disease ◽

Repeated Measures ◽

Center Of Pressure ◽

Angular Displacement ◽

Reaction Times ◽

Older Individuals ◽

Peak Knee ◽

Significant Difference ◽

Fatiguing Exercise

BACKGROUND: Nearly half of persons with Parkinson disease (PD) report fatigue as a factor in their fall history. However, it is unknown whether these self-reported falls are caused by a sensation of fatigue or performance fatigue. OBJECTIVE: We sought to investigate the influences of performance fatigue and age on postural control in persons with PD. METHODS: Individuals with PD (n = 14) underwent postural control assessments before (T0) and immediately after (T1) fatiguing exercise. Biomechanical data were gathered on participants completing a treadmill-induced, posterior-directed fall. Performance fatigue was produced using lower extremity resistance exercise on an isokinetic ergometer. Repeated measures ANCOVAs were used with age as a covariate to determine the effects of performance fatigue on biomechanical variables. RESULTS: After adjustment for age, there was a statistically significant difference in peak center of pressure (COP) latency during the support phase of recovery. Pairwise comparisons demonstrated a decrease in peak ankle displacement from T0 to T1. Age was also found to be significantly related to reaction time and peak knee displacement while participants were fatigued. CONCLUSIONS: The decreased peak COP latency, along with decreased ankle angular displacement, suggest that persons with PD adopt a stiffening strategy in response to backward directed falls. Postural stiffening is not uncommon in persons with PD and could be a risk factor for falls. Older individuals with PD demonstrate slower mobility scores and decreased reaction times in the setting of fatigue, suggesting a combined effect of the aging and fatigue processes.

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Attention Deficit Hyperactivity Disorder, Creativity, and the Effects of Methylphenidate

PEDIATRICS ◽

10.1542/peds.91.4.816 ◽

1993 ◽

Vol 91 (4) ◽

pp. 816-819

Author(s):

Jeanne B. Funk ◽

John B. Chessare ◽

Michael T. Weaver ◽

Anita R. Exley

Keyword(s):

Attention Deficit Hyperactivity Disorder ◽

Attention Deficit ◽

Repeated Measures ◽

Creative Thinking ◽

Adhd Group ◽

Hyperactivity Disorder ◽

Significant Difference ◽

Quasi Experimental ◽

The Difference ◽

Clinically Significant

Given that children with attention deficit hyperactivity disorder (ADHD) are more impulsive than peers, this study explored whether they are correspondingly more creative, and whether creativity declines when impulsivity is decreased through methylphenidate (Ritalin) therapy. A repeated-measures quasi-experimental design was used to compare the performance of 19 boys with previously diagnosed ADHD and 21 comparison boys aged 8 through 11 on two administrations of alternate forms of the Torrance Tests of Creative Thinking-Figural (nonverbal). Boys with ADHD received prescribed methylphenidate only for the first session. Overall, mean Torrance summary scores for comparison boys (mean = 115.1, SD = 16.1) were higher than for boys with ADHD (mean = 107.6, SD = 12.7). However, the difference between means was small (7%) and did not meet the 25% criterion for a clinically significant difference. No changes in performance over time (comparison group) or medication state (ADHD group) were observed. These data suggest that, when measured nonverbally, the creative thinking performance of boys with ADHD is not superior to that of peers who do not have ADHD. Regarding the effects of methylphenidate, prescribed therapy did not influence performance on this measure of creative thinking.

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Improved postural control after computerized optokinetic therapy based on stochastic visual stimulation in patients with vestibular dysfunction

Journal of Vestibular Research ◽

10.3233/ves-2007-172-308 ◽

2008 ◽

Vol 17 (2-3) ◽

pp. 131-136

Author(s):

Benjamin Loader ◽

Wolfgang Gruther ◽

Christian A. Mueller ◽

Gerhard Neuwirth ◽

Stefan Thurner ◽

...

Keyword(s):

Postural Stability ◽

Visual Stimulation ◽

Vestibular Dysfunction ◽

Composite Score ◽

Sensory Organization Test ◽

Control Groups ◽

Sensory Organization ◽

Somatosensory Input ◽

And Control ◽

Vestibular Asymmetry

Balance is accomplished by the congruent integration of visual, vestibular and somatosensory input and the execution of adequate control movements. With increasing age, nonlinear dynamics of central control systems become more regular. In unilateral vestibular dysfunction, sensory input to central systems is similarly less complex, because of one sided reduction of information influx. This study aimed to increase postural stability in patients with vestibular asymmetry and resulting disequilibrium by implementing a computerized visual training method relying on the principles of stochastic resonance. 24 subjects (average age 64a, 31–78a, 15 women, 9 men), with minimum 3 months of persisting disequilibrium due to vestibular dysfunction, were either treated with computerized optokinetic therapy (COKT), or solely observed. Treated patients were requested to read texts, stochastically moving in a previously defined matrix, during 10 sessions over three weeks. The Sensory Organization Test (SOT) was used for comparative posturographic measurements. COKT patients showed significant improvement in conditions 4, 6 and composite score. A significant post-therapeutic difference was seen between therapy and control groups in conditions 1, 6 and composite score. The results show a clinical benefit and we conclude COKT to be an effective rehabilitation method in patients with chronic disequilibrium.

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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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Static Balance in Patients with Vestibular Impairments: A Preliminary Study

Scientifica ◽

10.1155/2016/6539858 ◽

2016 ◽

Vol 2016 ◽

pp. 1-4 ◽

Cited By ~ 3

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.

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Effect of Cardiovascular Fatigue on Postural Stability

International Journal of Athletic Therapy & Training ◽

10.1123/ijatt.18.5.38 ◽

2013 ◽

Vol 18 (5) ◽

pp. 38-40 ◽

Cited By ~ 1

Author(s):

Hamid Bateni ◽

Gina Leno ◽

Rebeca Manjarres ◽

Bailey Ouellette ◽

Mark Wolber

Keyword(s):

Outcome Measures ◽

Repeated Measures ◽

Postural Stability ◽

Postural Sway ◽

Center Of Pressure ◽

Standing Position ◽

Treadmill Running ◽

Upper Body ◽

Mean Square Distance ◽

Squat Jumps

Context:Previous research has demonstrated that localized leg muscle fatigue induced by lower extremity exercises (e.g., squat jumps, sprints, and treadmill running) has an adverse effect on postural stability.Objective:To assess the effect of cardiovascular fatigue induced by upper extremity exercise on postural stability.Design:Repeated measures.Participants:Fourteen healthy young adults between the ages of 22 and 30 years (7 male and 7 female).Intervention:Participants performed an exercise protocol on an upper-body ergometer to induce cardiovascular fatigue.Main Outcome Measures:Postural sway, represented by center of pressure excursion, during bilateral standing in two different foot positions.Results:In a tandem standing position, mediolateral mean distance, root mean square distance, resultant power, and centroidal frequency increased signifcantly after inducement of cardiovascular fatigue.Conclusion:Cardiovascular fatigue adversely affects postural stability.

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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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Influences of heel height on human postural stability and functional mobility between inexperienced and experienced high heel shoe wearers

PeerJ ◽

10.7717/peerj.10239 ◽

2020 ◽

Vol 8 ◽

pp. e10239

Author(s):

Yiyang Chen ◽

Jing Xian Li ◽

Lin Wang

Keyword(s):

Postural Control ◽

Postural Stability ◽

Functional Mobility ◽

High Heel ◽

Ankle Strategy ◽

Sensory Organization ◽

Heel Height ◽

Directional Control ◽

Significant Difference ◽

Functional Reach Test

Background High heel shoes (HHS) can affect human postural control because elevated heel height (HH) may result in plantar flexed foot and limit ankle joint range of motion during walking. Effects of HH and HHS wearing experience on postural stability during self-initiated and externally triggered perturbations are less examined in the literature. Hence, the objective of the present study is to investigate the influences of HH on human postural stability during dynamic perturbations, perceived stability, and functional mobility between inexperienced and experienced HHS wearers. Methods A total of 41 female participants were recruited (21 inexperienced HHS wearers and 20 experienced HHS wearers). Sensory organization test (SOT), motor control test (MCT), and limits of stability (LOS) were conducted to measure participant’s postural stability by using computerized dynamic posturography. Functional reach test and timed up and go test were performed to measure functional mobility. The participants’ self-perceived stability was assessed by visual analog scale. Four pairs of shoes with different HH (i.e., 0.8, 3.9, 7.0, and 10.1 cm) were applied to participants randomly. Repeated measures analysis of variance was conducted to detect the effects of HH and HHS wearing experience on each variable. Results During self-initiated perturbations, equilibrium score remarkably decreased when wearing 10.1 cm compared with flat shoes and 3.9 cm HHS. The contribution of vision to postural stability was larger in 10.1 cm HHS than in flat shoes. The use of ankle strategy worsened when HH increased to 7 cm. Similarly, the directional control of the center of gravity (COG) decreased for 7 cm HHS in LOS. Experienced wearers showed significantly higher percentage of ankle strategy and COG directional control than novices. Under externally triggered perturbations, postural stability was substantially decreased when HH reached 3.9 cm in MCT. No significant difference was found in experienced wearers compared with novices in MCT. Experienced wearers exhibited considerably better functional mobility and perceived stability with increased HH. Conclusions The use of HHS may worsen dynamic postural control and functional mobility when HH increases to 3.9 cm. Although experienced HHS wearers exhibit higher proportion of ankle strategy and COG directional control, the experience may not influence overall human postural control. Sensory organization ability, ankle strategy and COG directional control might provide useful information in developing a safety system and prevent HHS wearers from falling.

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