scholarly journals Rest Intervals during Virtual Reality Gaming Augments Standing Postural Sway Disturbance

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6817
Author(s):  
Ross Allan Clark ◽  
Ancret Szpak ◽  
Stefan Carlo Michalski ◽  
Tobias Loetscher
Keyword(s):  
Virtual Reality ◽  
Path Length ◽  
Postural Sway ◽  
Movement Speed ◽  
Signal Frequency ◽  
Fluctuation Analysis ◽  
Continuous Exposure ◽  
Velocity Amplitude ◽  
Total Path Length ◽  
Rest Intervals

Immersive virtual reality (VR) can cause acute sickness, visual disturbance, and balance impairment. Some manufacturers recommend intermittent breaks to overcome these issues; however, limited evidence examining whether this is beneficial exists. The aim of this study was to examine whether taking breaks during VR gaming reduced its effect on postural sway during standing balance assessments. Twenty-five people participated in this crossover design study, performing 50 min of VR gaming either continuously or with intermittent 10 min exposure/rest intervals. Standing eyes open, two-legged balance assessments were performed immediately pre-, immediately post- and 40 min post-exposure. The primary outcome measure was total path length; secondary measures included independent axis path velocity, amplitude, standard deviation, discrete and continuous wavelet transform-derived variables, and detrended fluctuation analysis. Total path length was significantly (p < 0.05) reduced immediately post-VR gaming exposure in the intermittent rest break group both in comparison to within-condition baseline values and between-condition timepoint results. Conversely, it remained consistent across timepoints in the continuous exposure group. These changes consisted of a more clustered movement speed pattern about a lower central frequency, evidenced by signal frequency content. These findings indicate that caution is required before recommending rest breaks during VR exposure until we know more about how balance and falls risk are affected.

scholarly journals Differences between Tempos of Step Error and Postural Sway in the Stipulated Tempo Step Test for Children and Their Relationships

2021 ◽  
Vol 11 (6) ◽  
pp. 31
Author(s):  
Hiroki Aoki ◽  
Shin-ichi Demura ◽  
Kenji Takahashi ◽  
Hiroshi Hirai
Keyword(s):  
Repeated Measures ◽  
Path Length ◽  
Postural Sway ◽  
Dynamic Balance ◽  
Step Test ◽  
Total Path Length ◽  
Fast Tempo ◽  
Balance Ability ◽  
Path Lengths ◽  
Slow Tempo

Recently, to evaluate dynamic balance ability, a stipulated tempo step test has been developed, and a step error between tempo and contact time of feet has been used as an evaluation variable. The step error, postural sway, and their relationships may differ between the slow tempo (40 bpm) and fast tempo (120 bpm). This study aimed to examine the aforementioned problem with 62 participant children (30 boys and 32 girls). The step error and postural sway variables (X-axis path length, Y-axis path length, total path length, peripheral area, and rectangular area) during stepping while matching both tempos were measured. Means of one minute and three intervals (0–20 sec, 20–40 sec, and 40–60 sec) for each variable were calculated in both tempos. The results of the paired t-test showed that means of all variables were larger in the 40 bpm tempo than in the 120 bpm tempo. In the multiple comparison tests after the results of the two-way repeated measures ANOVA, the means of three intervals in all variables were larger in the 40 bpm tempo than in the 120 bpm tempo; the means of the sway variables, excluding that of the X-axis path length, in the 40 bpm tempo were larger in the 0–20 sec interval than in the 20–40 sec interval or the 40–60 sec interval. Correlations between step errors and those between the step error and sway variables of both tempos were insignificant or under moderation. The correlations between the step error and sway variables in both tempos were insignificant or significant but low, and those among sway variables were high, except between the X- and Y-axis path lengths. The relationship between both axis path lengths differed according to the tempo. In conclusion, in the case of the stipulated tempo step test targeting children, the slow tempo has a greater step error and postural sway than the fast tempo, and the sway in the early step stage is greater in the slow tempo. The relationships between step errors and between the step error and sway variables of both tempos are low; hence, the ability related to the test may differ in both tempos. The relationships among sway variables in both tempos are high, except between the X- and Y-axis path lengths.

Control of Stance and Developmental Coordination Disorder: The Role of Visual Information

2004 ◽  
Vol 21 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Eryk P. Przysucha ◽  
M. Jane Taylor
Keyword(s):  
Visual Information ◽  
Path Length ◽  
Developmental Coordination Disorder ◽  
Postural Sway ◽  
Quiet Standing ◽  
Eyes Closed ◽  
Total Path Length ◽  
Eyes Open ◽  
Stability Limits ◽  
Coordination Disorder

The purpose of this study was to compare the postural sway profiles of 20 boys with and without Developmental Coordination Disorder (DCD) on two conditions of a quiet standing task: eyes open and eyes closed. Anterior-posterior (AP) sway, medio-lateral sway (LAT), area of sway, total path length, and Romberg’s quotient were analyzed. When visual information was available, there was no difference between groups in LAT sway or path length. However, boys with DCD demonstrated more AP sway (p < .01) and greater area of sway (p < .03), which resulted in pronounced excursions closer to their stability limits. Analysis of Romberg’s quotient indicated that boys with DCD did not over-rely on visual information.

Static Foot Posture and Mobility Associated With Postural Sway in Elderly Women Using a Three-dimensional Foot Scanner

2015 ◽  
Vol 105 (5) ◽  
pp. 412-417 ◽  
Author(s):  
Mahshid Saghazadeh ◽  
Kenji Tsunoda ◽  
Yuki Soma ◽  
Tomohiro Okura
Keyword(s):  
Path Length ◽  
Elderly Women ◽  
Postural Sway ◽  
Community Sample ◽  
Three Dimensional ◽  
Community Dwelling ◽  
Analysis Of Covariance ◽  
Total Path Length ◽  
Foot Posture ◽  
Foot Mobility

Background Maintaining balance is a complex phenomenon that is influenced by a range of sensorimotor factors. Foot posture and mobility may also influence balance and postural sway. Recently, three-dimensional foot scanners have been used to assess foot posture. This tool allows many individuals to be scanned quickly and easily and helps eliminate patients' radiation exposure. The objective of this study was to determine whether static foot posture and mobility are independently associated with postural sway in a large community sample of older women using objective measures of balance status and the recently launched technology of three-dimensional foot scanning. Methods This cross-sectional study included 140 community-dwelling elderly women (mean ± SD age, 73.9 ± 5.1 years) recruited in Kasama City, Japan. The postural sway variables were total path length and area and were measured by force plate. We measured static foot posture, sitting and standing navicular height, and mobility using a three-dimensional foot scanner. Foot mobility was determined as the amount of vertical navicular excursion between the positions of the subtalar joint, from neutral in sitting position to relaxed bilateral standing. Results After adjusting for potential cofounders, analysis of covariance revealed that sitting navicular height was associated with total path length (P = .038) and area (P = .031). Foot mobility was associated with total path length (P = .018). Conclusions These findings suggest that sitting navicular height and foot mobility are associated with postural sway in elderly women and might be an important factor in defining balance control in older adults.

scholarly journals The Dimensionless Squared Jerk: An Objective Parameter That Improves Assessment of Hand Motion Analysis during Simulated Shoulder Arthroscopy

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Erica Kholinne ◽  
Maulik J. Gandhi ◽  
Arnold Adikrishna ◽  
Hanpyo Hong ◽  
Haewon Kim ◽  
...  
Keyword(s):  
Motion Analysis ◽  
Path Length ◽  
Shoulder Arthroscopy ◽  
Tracking System ◽  
Arthroscopic Surgery ◽  
Optical Tracking ◽  
Hand Movements ◽  
Total Path Length ◽  
Acceleration Threshold ◽  
Objective Parameter

Purpose. Attempts to quantify hand movements of surgeons during arthroscopic surgery faced limited progress beyond motion analysis of hands and/or instruments. Surrogate markers such as procedure time have been used. The dimensionless squared jerk (DSJ) is a measure of deliberate hand movements. This study tests the ability of DSJ to differentiate novice and expert surgeons (construct validity) whilst performing simulated arthroscopic shoulder surgical tasks. Methods. Six residents (novice group) and six consultants (expert group) participated in this study. Participants performed three validated tasks sequentially under the same experimental setup (one performance). Each participant had ten performances assessed. Hand movements were recorded with optical tracking system. The DSJ, time taken, total path length, multiple measures of acceleration, and number of movements were recorded. Results. There were significant differences between novices and experts when assessed using time, number of movements with average and minimal acceleration threshold, and DSJ. No significant differences were observed in maximum acceleration, total path length, and number of movements with 10m/s2 acceleration threshold. Conclusion. DSJ is an objective parameter that can differentiate novice and expert surgeons’ simulated arthroscopic performances. We propose DSJ as an adjunct to more conventional parameters for arthroscopic surgery skills assessment.

Two Models of Additional Adjacencies between the Root and Descendants in a Complete Binary Tree Minimizing Total Path Length

2009 ◽  
Author(s):  
Kiyoshi Sawada ◽  
Sio-Iong Ao ◽  
Alan Hoi-Shou Chan ◽  
Hideki Katagiri ◽  
Osca Castillo ◽  
...  
Keyword(s):  
Binary Tree ◽  
Path Length ◽  
Complete Binary Tree ◽  
Total Path Length

scholarly journals A Novel MFDFA Algorithm and Its Application to Analysis of Harmonic Multifractal Features

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 209 ◽  
Author(s):  
Jiming Li ◽  
Xinyan Ma ◽  
Meng Zhao ◽  
Xuezhen Cheng
Keyword(s):  
Detrended Fluctuation Analysis ◽  
Harmonic Signal ◽  
Signal Frequency ◽  
Fluctuation Analysis ◽  
The Novel ◽  
Multifractal Detrended Fluctuation Analysis ◽  
Fractal Characteristic ◽  
Harmonic Signals ◽  
Mode Decomposition ◽  
Detrended Fluctuation

A power grid harmonic signal is characterized as having both nonlinear and nonstationary features. A novel multifractal detrended fluctuation analysis (MFDFA) algorithm combined with the empirical mode decomposition (EMD) theory and template movement is proposed to overcome some shortcomings in the traditional MFDFA algorithm. The novel algorithm is used to study the multifractal feature of harmonic signals at different frequencies. Firstly, the signal is decomposed and the characteristics of wavelet transform multiresolution analysis are employed to obtain the components at different frequency bands. After this, the local fractal characteristic of the components is studied by utilizing the novel MFDFA algorithm. The experimental results show that the harmonic signals exhibit obvious multifractal characteristics and that the multifractal intensity is related to the signal frequency. Compared with the traditional MFDFA algorithm, the proposed method is more stable in curve fitting and can extract the multifractal features more accurately.

scholarly journals Approximation algorithms for the shortest total path length spanning tree problem

2000 ◽  
Vol 105 (1-3) ◽  
pp. 273-289 ◽  
Author(s):  
Bang Ye Wu ◽  
Kun–Mao Chao ◽  
Chuan Yi Tang
Keyword(s):  
Approximation Algorithms ◽  
Spanning Tree ◽  
Path Length ◽  
Total Path Length

scholarly journals The total path length of split trees

2012 ◽  
Vol 22 (5) ◽  
pp. 1745-1777 ◽  
Author(s):  
Nicolas Broutin ◽  
Cecilia Holmgren
Keyword(s):  
Path Length ◽  
Total Path Length ◽  
Split Trees
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