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

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

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

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

10.2196/19580 ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. e19580
Author(s):  
Matthew William Wittstein ◽  
Anthony Crider ◽  
Samantha Mastrocola ◽  
Mariana Guerena Gonzalez
Keyword(s):  
Virtual Reality ◽  
Center Of Pressure ◽  
Force Plate ◽  
Fluctuation Analysis ◽  
Scaling Exponent ◽  
Sensory Organization Test ◽  
Dynamic Posturography ◽  
Sensory Organization ◽  
Intraclass Correlations ◽  
Absolute Agreement

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

Sex-Specific Dependence of Linear and Nonlinear Postural Control Metrics on Anthropometrics During Clinical Balance Tests in Healthy Young Adults

2020 ◽  
Vol 29 (4) ◽  
pp. 405-412
Author(s):  
Stephen M. Glass ◽  
Brian L. Cone ◽  
Christopher K. Rhea ◽  
Donna M. Duffy ◽  
Scott E. Ross
Keyword(s):  
Sexual Dimorphism ◽  
Postural Control ◽  
Center Of Pressure ◽  
Force Plate ◽  
Interactive Effects ◽  
Fluctuation Analysis ◽  
Scaling Exponent ◽  
Cross Sectional ◽  
Linear And Nonlinear ◽  
Positive Effect

Context: Previous work suggests that balance behavior is a sex-dependent, complex process that can be characterized by linear and nonlinear metrics. Although a certain degree of center of pressure variability may be expected based on sexual dimorphism, there is evidence to suggest that these effects are obscured by potential interactions between sex and anthropometric factors. To date, no study has accounted for such interactive effects using both linear and nonlinear measures. Objective: This investigation sought to analyze interactive models featuring sex, height, and weight as predictors of linear and nonlinear aspects of postural control. Design: Cross-sectional study. Setting: Controlled laboratory. Participants: A total of 26 males (23.80 [3.44] y, 177.87 [6.44] cm, 81.70 [10.80] kg) and 28 females (21.14 [2.03] y, 169.57 [8.80] cm, 64.48 [8.86] kg) were sampled from a healthy university population. Main Outcome Measures: Linear (range [RNG], velocity [VEL], and SD) and nonlinear (detrended fluctuation analysis scaling exponent, multivariate multiscale sample entropy [MMSECI]) summary metrics of center of pressure time series. Procedure: Participants stood on a force plate for 20 seconds in 3 conditions: double (D), single (S), and tandem (T) stance. Data for each stance condition were analyzed using regression models with interaction terms for sex × height and sex × weight. In D, weight had a positive, significant main effect on VELy, MMSECId, and MMSECIv. In men, height was observed to have a positive effect on SDy (S), RNGy (S), and RNGx (T) and a negative effect on MMSECIv (T). In women, weight was observed to have a positive effect on SDy and VELx (both T). Conclusions: Our findings suggest that men and women differ with respect to certain linear and nonlinear aspects of balance behavior, and that these differences may reflect sex-specific behavioral patterns in addition to effects related to sexual dimorphism.

Validation of a Portable Force Plate for Evaluating Postural Sway

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

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

A Study on Visual Perturbations Effect on Balance in a VR Environment

2019 ◽  
pp. 67-88
Author(s):  
Markus Santoso ◽  
David Phillips
Keyword(s):  
Virtual Reality ◽  
Center Of Pressure ◽  
Balance Control ◽  
Force Plate ◽  
High Rate ◽  
Environment Design ◽  
Support Condition ◽  
Double Support ◽  
Head Mounted Display ◽  
Human Balance

Users sometimes lost their balance or even fell down when they played virtual reality (VR) games or projects. This may be attributed to degree of content, high-rate of latency, coordination of various sensory inputs, and others. The authors investigated the effect of sudden visual perturbations on human balance in VR environment. This research used the latest VR head mounted display to present visual perturbations to disturb balance. To quantify balance, measured by double-support and single-support stance, the authors measured the subject's center of pressure (COP) using a force plate. The results indicated that visual perturbations presented in virtual reality disrupted balance control in the single support condition but not in the double support condition. Results from this study can be applied to clinical research on balance and VR environment design.

Dizziness: Relating the Severity of Vertigo to the Degree of Handicap by Measuring Vestibular Impairment

2003 ◽  
Vol 128 (3) ◽  
pp. 372-381 ◽  
Author(s):  
Nicolás Pérez ◽  
Eduardo Martin ◽  
Rafael Garcia-Tapia
Keyword(s):  
Caloric Test ◽  
Pathologic Finding ◽  
Sensory Organization Test ◽  
Dizziness Handicap Inventory ◽  
Test Portion ◽  
Dynamic Posturography ◽  
Sensory Organization ◽  
Computerized Dynamic Posturography ◽  
Prospective Assessment ◽  
Vestibular Pathology

OBJECTIVE: We sought to correlate the severity of vertigo and handicap in patients with vestibular pathology according to measures of impairment. STUDY DESIGN AND SETTING: We conducted a prospective assessment of patients with dizziness by means of caloric, rotatory test, and computerized dynamic posturography to estimate impairment. Handicap and severity of vertigo were determined with specific questionnaires (Dizziness Handicap Inventory and UCLA-DQ). RESULTS: A fair relationship were found between severity of dizziness and vestibular handicap. When impairment was taken into consideration, values were still fair and only moderate for a group of patients with an abnormal caloric test as the only pathologic finding. The composite score from the sensory organization test portion of the computerized dynamic posturography is fairly correlated to severity of vertigo and handicap in the whole population of patients, but no correlation was found when they were assigned to groups of vestibular impairment. CONCLUSION: To assess vestibular impairment, the results from several tests must be taken into account. However, vestibular handicap is not solely explained with measurements of impairment and/or severity.

Ankle Joint Proprioception and Postural Control in Basketball Players with Bilateral Ankle Sprains

2005 ◽  
Vol 33 (8) ◽  
pp. 1174-1182 ◽  
Author(s):  
Amy S. N. Fu ◽  
Christina W. Y. Hui-Chan
Keyword(s):  
Standard Deviation ◽  
Postural Control ◽  
Ankle Joint ◽  
Postural Sway ◽  
Plantar Flexion ◽  
Ankle Sprains ◽  
Sensory Organization Test ◽  
Basketball Players ◽  
Dynamic Posturography ◽  
Sensory Organization

Background Deficiencies in ankle proprioception and standing balance in basketball players with multiple ankle sprains have been reported in separate studies. However, the question of how ankle proprioceptive inputs and postural control in stance are related is still unclear. Hypothesis Ankle repositioning errors and the amount of postural sway in stance are increased in basketball players with multiple ankle sprains. Study Design Controlled laboratory study. Methods Twenty healthy male basketball players and 19 male basketball players who had suffered bilateral ankle sprains within the past 2 years were examined. Both groups were similar in age. Passive ankle joint repositioning errors at 5° of plantar flexion were used to test for ankle joint proprioception. The Sensory Organization Test was applied with dynamic posturography to assess postural sway angle under 6 sensory conditions. Results A significant increase in ankle repositioning errors was demonstrated in basketball players with bilateral ankle sprains (P < .05). The mean errors in the right and left ankles were increased from 1.0° (standard deviation, 0.4°) and 0.8° (standard deviation, 0.2°), respectively, in the healthy players to 1.4° (standard deviation, 0.7°) and 1.1° (standard deviation, 0.5°) in the injured group. A significant increase in the amount of postural sway in the injured subjects was also found in conditions 1, 2, and 5 of the Sensory Organization Test (P < .05). Furthermore, there were positive associations between averaged errors in repositioning both ankles and postural sway angles in conditions 1, 2, and 3 of the Sensory Organization Test (r = 0.39-0.54, P < .05). Conclusions Ankle repositioning errors and postural sway in stance increased in basketball players with multiple ankle sprains. A positive relationship was found between these 2 variables. Clinical Relevance Such findings highlight the need for the rehabilitation of patients with multiple ankle sprains to include proprioceptive and balance training.

scholarly journals Reliability and Validity of the Computerized Dynamic Posturography Sensory Organization Test in People with Multiple Sclerosis

2017 ◽  
Vol 19 (3) ◽  
pp. 151-157 ◽  
Author(s):  
Jeffrey R. Hebert ◽  
Mark M. Manago
Keyword(s):  
Multiple Sclerosis ◽  
Scale Score ◽  
Repeated Measures ◽  
Group Versus ◽  
Sensory Organization Test ◽  
Dynamic Posturography ◽  
Sensory Organization ◽  
Computerized Dynamic Posturography ◽  
Disability Group ◽  
Composite Scores

Background: People with multiple sclerosis (MS) frequently have impaired postural control (balance). Psychometric properties of clinical tests of balance for individuals with MS, including the computerized dynamic posturography sensory organization test (CDP-SOT), are poorly understood. This study aimed to determine the reliability and discriminant validity of the CDP-SOT in people with MS. Methods: The CDP-SOT was performed on 30 participants with MS. A 2-week–interval, repeated-measures (sessions 1 and 2) design was implemented to investigate test-retest reliability of the CDP-SOT and the ability of the CDP-SOT to discriminate between participants with lower versus higher disability. Self-reported disability level was based on Patient-Determined Disease Steps (PDDS) scale scores: lower (PDDS scale score, 0–3; n = 17) and higher (PDDS scale score, 4–6; n = 13). Results: All six conditions of the CDP-SOT had good-to-excellent reliability (interclass correlation coefficients, 0.70–0.90) and excellent reliability for composite scores (0.90). Composite scores were significantly greater in the lower-disability group versus the higher-disability group at session 1 (70.89 vs. 48.60, P = .001) and session 2 (74.82 vs. 48.85, P = .002). Conclusions: The CDP-SOT is a reliable measure of balance and accurately differentiates disability status in people with MS. Collectively, the results support clinical application of the CDP-SOT as a reliable and valid measure of disease-related progression of impaired balance related to sensory integration and its utility in determining changes in balance in response to treatment.

scholarly journals Complexity of human walking: the attractor complexity index is sensitive to gait synchronization with visual and auditory cues

2019 ◽  
Author(s):  
Philippe Terrier
Keyword(s):  
Long Range ◽  
Center Of Pressure ◽  
Sensorimotor Synchronization ◽  
Fluctuation Analysis ◽  
Scaling Exponent ◽  
Stepping Stones ◽  
Complexity Index ◽  
Gait Parameters ◽  
Fractal Patterns ◽  
Logistic Regressions

Background. During steady walking, gait parameters fluctuate from one stride to another with complex fractal patterns and long-range statistical persistence. When a metronome is used to pace the gait (sensorimotor synchronization), long-range persistence is replaced by stochastic oscillations (anti-persistence). Fractal patterns present in gait fluctuations are most often analyzed using detrended fluctuation analysis (DFA). This method requires the use of a discrete times series, such as intervals between consecutive heel strikes, as an input. Recently, a new nonlinear method, the attractor complexity index (ACI), has been shown to respond to complexity changes like DFA. But in contrast to DFA, ACI can be applied to continuous signals, such as body accelerations. The aim of this study was to further compare DFA and ACI in a treadmill experiment that induced complexity changes through sensorimotor synchronization. Methods. Thirty-six healthy adults walked 30 minutes on an instrumented treadmill under three conditions: no cueing, auditory cueing (metronome walking), and visual cueing (stepping stones). The center-of-pressure trajectory was discretized into time series of gait parameters, after which a complexity index (scaling exponent alpha) was computed via DFA. Continuous pressure position signals were used to compute the ACI. Correlations between ACI and DFA were then analyzed. The predictive ability of DFA and ACI to differentiate between cueing and no-cueing conditions was assessed using regularized logistic regressions and areas under the receiver operating characteristic curves (AUROC). Results. DFA and ACI were both significantly different among the cueing conditions. DFA and ACI were correlated (Pearson’s r = 0.78). Logistic regressions showed that DFA and ACI could differentiate between cueing/no cueing conditions with a high degree of confidence (AUROC = 1.0 and 0.96, respectively). Conclusion. Both DFA and ACI responded similarly to changes in cueing conditions and had comparable predictive power. This support the assumption that ACI could be used instead of DFA to assess the long-range complexity of continuous gait signals.

scholarly journals The effect of music on body sway when standing in a moving virtual environment

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0258000
Author(s):  
Shaquitta Dent ◽  
Kelley Burger ◽  
Skyler Stevens ◽  
Benjamin D. Smith ◽  
Jefferson W. Streepey
Keyword(s):  
Virtual Reality ◽  
Virtual Environment ◽  
Center Of Pressure ◽  
Force Plate ◽  
The Body ◽  
Body Sway ◽  
Visual Environment ◽  
Auditory Information ◽  
Eyes Closed ◽  
Do So

Movement of the visual environment presented through virtual reality (VR) has been shown to invoke postural adjustments measured by increased body sway. The effect of auditory information on body sway seems to be dependent on context with sounds such as white noise, tones, and music being used to amplify or suppress sway. This study aims to show that music manipulated to match VR motion further increases body sway. Twenty-eight subjects stood on a force plate and experienced combinations of 3 visual conditions (VR translation in the AP direction at 0.1 Hz, no translation, and eyes closed) and 4 music conditions (Mozart’s Jupiter Symphony modified to scale volume at 0.1 Hz and 0.25 Hz, unmodified music, and no music) Body sway was assessed by measuring center of pressure (COP) velocities and RMS. Cross-coherence between the body sway and the 0.1 Hz and 0.25 Hz stimuli was also determined. VR translations at 0.1 Hz matched with 0.1Hz shifts in music volume did not lead to more body sway than observed in the no music and unmodified music conditions. Researchers and clinicians may consider manipulating sound to enhance VR induced body sway, but findings from this study would not suggest using volume to do so.

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