Sway Velocity Research Articles

COVID-19 and postural sway: a comparison of individuals with a SARS-CoV-2 history and healthy sedentary women

Purpose The aim of the study was to evaluate the effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postural sway in subjects who have recently recovered from infection. Materials and methods Fifty-six female individuals with a mild to moderate history of SARS-CoV-2 (n = 25, mean age; 21.13 ± 0.64 years) and healthy sedentary controls (n = 31, mean age; 20.09 ± 1.05 years) were included in the study. Postural sway tests were performed in double and single-leg stance on a force plate with eyes open before and after the neuromuscular fatigue test. The Wingate test was used to induce neuromuscular fatigue. To evaluate the change of the variables determined by the measurements of the groups over time and the group-time interactions, a two-way analysis of variance in repeated measures (mixed design repeated measures ANOVA) was used. Results It was found that the SARS-CoV-2 group showed increased total sway path, velocity, and area than those in the healthy group on double and single-leg (right-left) stance (p < 0.05). Conclusions Even if SARS-CoV-2 group individuals have been reported in a mild to moderate outpatient COVID-19 process, they showed deterioration in postural control compared to healthy individuals. In addition, it was found that SARS-CoV-2 accelerated neuromuscular fatigue effects. This can cause more fatigue during activities than individuals who have not had SARS-CoV-2.

Effects of the direction of Kinesio taping on sensation and postural control before and after muscle fatigue in healthy athletes

In this study, Kinesio tape (KT) was applied in two different directions to the gastrocnemius muscle, the most important muscle in stance stability, to investigate the effect of different taping directions on overall balance and sensation systems before versus after muscle fatigue. The participants, comprising 45 healthy athletes, were randomly divided into three groups: the placebo taping group (PTG), the facilitation KT group (FKTG), and the inhibition KT group (IKTG). The tests involved in this study were a balance test, a superficial sensory function test, and a combined cortical sensation test. The data from these tests were collected before taping, after taping and a 10-min rest, and immediately after continuous heel raises were performed to fatigue. The results of the balance tests showed no significant group × time interaction, whether subjects stood barefoot on one foot or stood on a soft mat with eyes open or closed (p > 0.05). Only the sway distance and sway velocity of the center of pressure (COP) when subjects stood barefoot on one foot with eyes open were significantly higher in the inhibition taping group than in the placebo taping group (p < 0.05). In addition, significant differences were noted in the sway area and sway distance of the COP before taping, after taping, and after exercise to fatigue when the participants stood on the soft mat with their eyes open (p < 0.05). When the participants stood on the soft mat on one foot with their eyes closed, no significant differences were noted among the groups. When subjects stood on a soft mat on one foot with eyes open, significant improvements were noted after fatiguing exercise versus before taping for all three groups (p < 0.05). The results of the superficial sensory test showed no significant group × time interaction and no difference among the three taping conditions or before/after taping and after fatiguing exercise. Only in the two-point discrimination test was a sensory difference observed, with the facilitation taping group having a significantly shorter discrimination distance than the placebo taping and inhibition taping groups (p < 0.05). The present study showed that KT application for a simple balance task (e.g., barefoot on a hard floor with eyes open) may slightly influence postural control, especially when the inhibition method is used. However, more difficult balance tasks (e.g., barefoot on a soft mat with eyes closed) show no effect of KT application—either the facilitation method or the inhibition method—on posture control.

Influence of Auditory Information on Postural Control During Different Gait Tasks in the Elderly.

Hearing loss is frequently associated with reduced postural control. This is possibly not only related to simultaneous pathophysiological changes within the hearing and vestibular system. The auditory input itself could provide helpful information for maintaining postural control. Previous studies of our group already showed that continuous or interrupted white noise can significantly improve postural control during gait conditions in young healthy individuals. The present study aimed at investigating if those effects are also active in the elderly. Elderly volunteers (mean age 67 years) without any history of disorders to influence gait performance successfully completed 5 walking tasks under 4 different acoustic conditions. Angular sway velocity was measured close to the center of gravity with the Vertiguard® system. Significant changes in body sway velocity were found in 4 of 5 investigated tasks. Only "walking with turning head in rhythm" was not associated with any change in the acoustic input. The sway increased by 8.9% during "walking with open eyes" in the pitch direction and by 11.5% during "tandem walking" in the roll direction if ear protection was applied. The sway was reduced by 9.1% during "walking over barriers" in the pitch direction and by 16.7% in the roll direction during "walking with closed eyes" if a stationary source of continuous white noise was presented. The data of the present study indicate that auditory information could significantly alter postural control during walking in the elderly. Continuous white noise seems to be helpful for maintaining balance in different walking tasks.

Tremor, Gait, and Balance Disorders in Essential Tremor and the Efficacy of Atenolol

ABSTRACT Background: To assess gait and balance in patients with essential tremor (ET), which is the most common tremor disorder characterized by bilateral action tremor of the hands with possible involvement of further tremor locations and to test the efficacy of atenolol on tremor and gait and balance. Methods: In this prospective study, gait and balance were evaluated by static posturography in addition to International Cooperative Ataxia Rating Scale (ICARS) in 22 ET patients without any additional neurologic signs on examination. Tremor severity was assessed by The Essential Tremor Rating Assessment Scale (TETRAS). The efficacy of atenolol 100 mg/day both on tremor and gait and balance was investigated. Posturographic recordings were performed in gender, age-, and height-matched healthy volunteers who constituted the control group. Results: The mean center of gravity sway velocity of the ET patients recorded on firm and foam surfaces with eyes open and closed was not significantly different from the healthy controls but sway velocity on tandem stance was significantly increased (P = 0.032). Gait speed (P = 0.015) was decreased and step width was increased (P = 0.001). An improvement in TETRAS scores was recorded with atenolol treatment (P = 0.046). An improvement not reaching statistical significance was present in ICARS scores (P = 0.059). However, posturographic parameters did not change significantly (P &gt; 0.05). Conclusion: Increased sway velocity on tandem stance, decreased gait speed and increased step width are consistent with midline cerebellar dysfunction in ET patients with no obvious gait and balance deficits on clinical examination. Atenolol seems to be effective on tremor but does not cause a significant improvement in gait and balance deficits.

Comparative Assessment of Gait and Balance in Patients with Parkinson's Disease and Normal Pressure Hydrocephalus.

We aim to compare balance and gait parameters in patients diagnosed with Parkinson's disease (PD) and normal pressure hydrocephalus (NPH). A total of 13 patients with NPH, 20 with PD, and 13 healthy controls (HC) recruited in the study. Three IMU sensors (Ambulatory PD Monitoring Inc., OR, USA) were placed on the lumbar area and the feet of the participants. The balance evaluations comprised eight successive standing tasks; the modified clinical test of sensory interaction on balance test. These tasks involved standing with feet apart and eyes open as well as eyes closed on a firm and foam surface, standing with feet together and eyes open as well as eyes closed, and tandem stance with the right foot front and the left foot front. Functional evaluations of gait were conducted using the 10-M Walk Test (10 MWT), the 2 min-Walk Test (2 MWT), and the timed-up and go (TUG). Parameters of the gait and balance were analyzed and then compared. NPH patients displayed a notable decrease in both stride length and gait speed as compared with both PD patients and healthy participants. The balance tests revealed that the NPH group demonstrated significantly poorer performance, specifically in the feet-apart eyes-closed foam-surface test, and the tandem stance test. During the tasks while eyes were open on firm and foam surfaces, PD and NPH groups showed an increase in root mean square sway, range, and mean velocity (p<0.05) of sway in the anteroposterior plane. In addition, during the TUG test, the NPH group exhibited a significant prolongation in the time needed to complete the task and a decline in turning velocity as compared to PD, but no notable difference was seen in comparison to the HC group. Our study indicated that the patients with NPH exhibited notably worse gait and balance measurements in comparison to both the PD patients and HC groups. These findings emphasize the significance of monitoring and managing gait and balance impairments in NPH patients. Sensor-based technologies may offer objective parameters for a more precise and efficient follow-up of these patients in terms of gait and balance.

Feasibility of Combining Disease-Specific and Balance-Related Measures as Risk Predictors of Future Falls in Patients with Parkinson's Disease.

Evidence supports the view that postural sway in a quiet stance increases with clinical disease severity and dopaminergic therapy in idiopathic Parkinson’s disease (PD), which, in turn, increases the risk of falling. This study evaluated the feasibility of combining disease-specific and balance-related measures as risk predictors for future falls in patients with PD. The patients with PD underwent postural sway measurements (area, length, and velocity traveled by the excursion of the center of pressure) and clinical functional scores (Parkinson’s Disease Rating Scale [UPDRS] and Tinetti balance and gait score assessment) in both the on- and off-states of dopaminergic therapy. The outcome was defined as the development of a new fall. The sway area, velocity, and length increased after the medication administration. The Cox proportional hazards model showed that only previous fall history, Tinetti balance and gait score (on-state), and levodopa equivalent daily dose (LEDD) were associated with the development of future falls. The cumulative risk of fall development showed that the sway length and velocity were associated with future falls after more than six months. The combined LEDD, Tinetti balance and gait score (on-state), and velocity and length of postural sway (on-state) had the highest diagnostic accuracy (area under the curve = 0.9, p < 0.0001). Dopaminergic therapy can improve clinical functional scores but worsen balance-related measures. Increased sway length and velocity during the medication state are hallmarks of future falls, particularly in advanced PD. Combining disease-specific and balance-related measures can serve as an auxiliary diagnosis as risk predictors for future falls.

PHYSICAL ACTIVITY, BALANCE, AND BICYCLING IN OLDER ADULTS

Abstract Falls are a critical public health issue among older adults. One notable factor contributing to falls in older adults is a deterioration of the structures supporting balance and overall balance control. Preliminary evidence suggests older adults who ride a bicycle have better balance than those who do not. Cycling may be an effective intervention to prevent falls among older adults. This study aims to objectively measure the relationship between bicycling, physical activity, and balance for older adults. Older adult cyclists (n=19) and non-cyclists (n=27) were recruited to (1) complete a survey that assessed demographics; (2) wear an accelerometer for 3 weeks to objectively assess physical activity; and (3) complete balance-related tasks on force platforms. Mann-Whitney U-tests were performed to understand differences in balance and physical activity between cyclists and non-cyclists. Cyclists are significantly more physically than non-cyclists (U = 102.00, p = .015; U = 81.00, p=.002). Cyclists had less sway velocity in eyes open conditions than non-cyclists (U = 360.00, p=.009), indicating a more tightly regulated postural control strategy that may relate to higher stability in cyclists. Task duration among cyclists in single-leg stand was longer than non-cyclists (left leg: p &amp;lt; .001 and right leg: p &amp;lt; .005) indicating increased postural stability. This study demonstrates the possible implications for cycling on balance and reducing fall risk.

THE EFFECTS OF TYPE 2 DIABETES MELLITUS ON POSTURAL ADAPTATION DURING A VISUAL SEARCH TASK IN OLDER ADULTS

Abstract Type II diabetes mellitus (T2DM) is associated with a reduction in sensory integration capacity that often results in cognition and postural control deficits. The effects of T2DM on the ability to adapt one’s postural sway while standing and performing a visual search task (VST) are unknown. Twenty-three healthy older adults (HOA) (70–90 years) and 20 older adults with T2DM (67–93 years) performed multiple trials of quiet standing with and without a VST (i.e., counting 1 target letter in a grid of random letters). Postural sway acceleration measures were jerk, velocity, range, and pathlength in the anterior-posterior (AP) and medial-lateral (ML) direction, as well as elliptical area. Postural adaptation to the VST was defined as the absolute change between conditions. VST accuracy (%) was defined as the percentage of participant-reported target letters compared to total target letters. In general, for both groups, performing the VST resulted in an average reduction in sway jerk, velocity, pathlength, and range when performing the VST, compared to control (T2DM &amp; HOA, p &amp;lt; 0.04). VST accuracy and the magnitude of postural adaptation to the VST were similar between groups (p&amp;gt;0.15). Within the T2DM group, those who performed worse on the VST exhibited less adaptation (i.e., smaller decrease) in ML velocity (r=0.47, p=0.04). No other differences or associations were observed. Compared to healthy older adults, those with T2DM demonstrated a similar capacity to adapt their postural control in response to a VST. However, this group exhibited different characteristic changes in sway which were linked to task performance.

Characterizing The State Of Heart Rate Autonomic Regulation And EEG In Elderly Women With Falls Syndrome

Objective — The goal of our study was to evaluate the contribution of the central and autonomic nervous systems to the maintenance of postural balance in the elderly. Material and Methods ― This study included 120 healthy women 60-74 YO living in the community. They were distributed among two subgroups: (1) fallers (n=60) and (2) non-fallers (n=60). Fallers had falls in the past 12 months, while non-fallers had none. Walk tests were performed using Balance Master® posturography machine (NeuroCom, Natus, USA). The state of the central nervous system was assessed by Geodesic 300 EEG system (GSN; Electrical Geodesics, Inc.; Eugene, OR, USA). The state of the autonomic nervous system was assessed by the VNS-Spectrum (Neurosoft, Russia) via cardiointervalography. Results ― In Sit to Stand test, the postural sway velocity was higher (p=0.047) and the walking speed (p=0.008) in Tandem Walk test was lower in fallers, compared with non-fallers. The results of the Step Quick Turn test showed that the movement times of the left and right legs were longer for the fallers vs. non-fallers (p=0.044 and p=0.036, respectively), and postural sway values during turning left or right were higher in fallers as well (p=0.001 and p=0.003, correspondingly). At the same time, Step Up and Over test revealed that lift-up index values were higher in fallers vs. non-fallers (p=0.016). There were no statistically significant differences between the groups in the state of the autonomic nervous system. The absolute spectral power of the EEG was lower in the frontal region of the right hemisphere in the alpha and beta EEG bands in the study group, compared with the control. Conclusion ― A deterioration in the quality of performing complex motor actions and a decrease in postural control in elderly women with falls syndrome were which may have caused their postural instability. Our results confirmed the need for early assessment of the dynamic components of postural control to prevent the development of falls as a geriatric syndrome.

Rating of perceived difficulty scale for measuring intensity of standing balance exercises in individuals with vestibular disorders.

A method for prescribing the difficulty or intensity of standing balance exercises has been validated in a healthy population, but requires additional validation in individuals with vestibular disorders. This study validated the use of ratings of perceived difficulty for estimation of balance exercise intensity in individuals with vestibular disorders. Eight participants with a confirmed diagnosis of a vestibular disorder and 16 healthy participants performed two sets of 16 randomized static standing exercises across varying levels of difficulty. Root Mean Square (RMS) of trunk angular velocity was recorded using an inertial measurement unit. In addition, participants rated the perceived difficulty of each exercise using a numerical scale ranging from 0 (very easy) to 10 (very difficult). To explore the concurrent validity of rating of perceived difficulty scale, the relationship between ratings of perceived difficulty and sway velocity was assessed using multiple linear regression for each group. The rating of perceived difficulty scale demonstrated moderate positive correlations RMS of trunk velocity in the pitch (r = 0.51, p < 0.001) and roll (r = 0.73, p < 0.001) directions in participants with vestibular disorders demonstrating acceptable concurrent validity. Ratings of perceived difficulty can be used to estimate the intensity of standing balance exercises in individuals with vestibular disorders.

Reliability of Force Plate Metrics During Standard Jump, Balance, and Plank Assessments in Military Personnel.

Prevention of musculoskeletal injury is vital to the readiness, performance, and health of military personnel with the use of specialized systems (e.g., force plates) to assess risk and/or physical performance of interest. This study aimed to identify the reliability of one specialized system during standard assessments in military personnel. Sixty-two male and ten female Australian Army soldiers performed a two-leg countermovement jump (CMJ), one-leg CMJ, one-leg balance, and one-arm plank assessments using a Sparta Science force plate system across three testing sessions. Sparta Science (e.g., total Sparta, balance and plank scores, jump height, and injury risk) and biomechanical (e.g., average eccentric rate of contraction, average concentric force, and sway velocity) variables were recorded for all sessions. Mean ± SD, intraclass correlation coefficients (ICCs), coefficient of variation, and bias and limits of agreement were calculated for all variables. Mean results were similar between sessions 2 and 3 (P > .05). The relative reliability for the Sparta Science (ICC = 0.28-0.91) and biomechanical variables (ICC = 0.03-0.85) was poor to excellent. The mean absolute reliability (coefficient of variation) for Sparta Science variables was similar to or lower than that of the biomechanical variables during the CMJ (1-10% vs. 3-7%), one-leg balance (4-6% vs. 9-14%), and one-arm plank (5-7% vs. 12-17%) assessments. The mean bias for most variables was small (<5% of the mean), while the limits of agreement varied with most unacceptable (±6-87% of the mean). The reliability of most Sparta Science and biomechanical variables during standard assessments was moderate to good. The typical variability in metrics documented will assist practitioners with the use of emerging technology to monitor and assess injury risk and/or training interventions in military personnel.

Advancing age is associated with more impaired mediolateral balance control after step down task

BackgroundTo prevent the risk of stair descent falls and associated injuries in the older adults, it is important to understand the factors that affect this frequent locomotion of daily living. The fact that falls are in most cases the result of the interaction between intrinsic and extrinsic factors is very often underestimated when designing test protocols. Research question: This study aimed at evaluating balance control during and immediately after step down onto an unstable surface. Methods: Physically active men and women aged 60–69 years (n = 28) and 70–79 years (n = 18) were asked to perform a step down onto a foam pad and stand still for 30 s (restabilization phase). Centre of pressure (CoP) velocity and standard deviation of CoP sway in anteroposterior and mediolateral direction were evaluated during the step down (CoP VAP, CoP VML, CoP SDAP, CoP SDML) and in the first 5 s of restabilization (CoP VAP5, CoP VML5, CoP SDAP5, CoP SDML5). In addition, time to complete step was investigated. Results: Participants aged 70–79 years presented worse ML balance control after step down onto an unstable surface than their younger counterparts. This was represented by the significantly higher values of CoP SDML5 and CoP VML5 (p = 0.022 and p = 0.017). No other significant differences were detected. Significance: Age is associated with a more significant ML center of pressure velocity and sway after step down onto a foam pad in physically active older adults. Exercises aimed at improving ML balance control in unstable conditions should be the subject of physical interventions even in older adults with overall good state of health and physical fitness.

The impact of eye movement on postural control depends on the type of oculomotor behavior and the visual task

Recent evidence suggests that performing a task inducing saccades will improve stability when compared to static fixation. However, they assume the linearity of postural control by only interpreting the area of displacement and/or the velocity of sway. Conversely, non-linear measures could bring a complementary understanding of postural control. The aim is to examine the effect of eye movements on different linear and non-linear measures of stability. 21 healthy adults (24.0 ± 3.3 years) were asked to stand on a force platform with their feet together and look at the monitor in front of them. Five conditions were tested: eyes closed, random looking, fixed static point, saccade, and visual pursuit (gaze shift angle of 15°). Five 60-second trials per condition were performed. An ANOVA with repeated measures was completed for each postural control variables in each direction: antero-posterior (AP) and medio-lateral (ML). The absence of vision had a negative impact on sway, as seen by an increase in sway area and variability as well as reduced contributions from the ultra-low band. The saccade led to greater stability than the random looking, as evidenced by a smaller area. However, the visual pursuit led to decreased stability compared to random looking, as evidenced by a larger area, as well as increased variability. Of note, the energy contained in the very-low band, which indicates the contribution of the vestibular system, was highest in the visual pursuit compared to the fixed static point. The findings support that the visual system is an important, but complex contributor to stability as different eye movements result in distinct postural responses with saccade and visual pursuit causing a decrease and an increase in sway, respectively.

Effects of spatial working memory capacity and resolution loads on postural stability while dual-tasking.

Increased spatial processing demands, e.g., working memory loads, which include capacity load and resolution load, may interfere with postural stability. To date, there has been little evidence to demonstrate whether capacity load and resolution load affect postural stability. Therefore, this study manipulated capacity load and resolution load in a spatial working memory task to examine how postural stability is affected. Sixteen healthy young participants were tested in a dual-task paradigm that consisted of a postural task with a tandem Romberg stance and a spatial working memory task with different capacity loads and resolution loads in different sessions. Participants were required to detect a salient change (45° in low resolution) or a subtle change (15° in high resolution) in the bar orientation as a resolution load. Capacity load was manipulated by storing the number of bars, with two bars in low capacity and four in high capacity. The results showed significant interactions between capacity load and resolution load on dual-task effects of sway velocity. In the low-resolution condition, the dual-task effects of anteroposterior and mediolateral sway velocity were significantly lower in the high capacity than in the low capacity, yet no significant differences occurred in the high-resolution load condition. Our results suggest that increased capacity loads interfere with postural stability only in low-resolution loads while dual-tasking.

Effects of freezing of gait on balance in patients with Parkinson’s disease

ABSTRACT Objectives The aim of the study was to evaluate the effects of freezing of gait (FOG) on static and dynamic balance. Methods Twenty patients with Parkinson’s disease with and without FOG [PD+FOG (68,6±6,39 years) and PD-FOG group (70,6±4,57 years)] and 10 healthy individuals (68,4±4,92 years) with similar demographic characteristics were included in the study. Balance was compared between the three groups. Balance was evaluated with clinical tests Limits of stability (LoS) and body sway were measured using the E-LINK FP3 Force Plate and the Korebalance Balance Evaluation System, which measure the balance in static and dynamic conditions. Center of pressure (COP) change and average sway velocity were evaluated with the Zebris RehaWalk system. Results Total and subscale scores of the Unified Parkinson’s Disease Rating Scale were significantly higher in the PD+FOG group (p<0.05). The balance test results for both groups were similar (p>0.05). The PD+FOG group performed worse on the computerized static balance tests, the COP analysis, and the dynamic balance total score than the other two groups (p<0.05). The PD+FOG group had significantly greater sustained weight deviation than the healthy controls (p<0.05). Patients with Parkinson’s disease had a lower LoS in the posterior direction than healthy controls (p<0.05). Discussion FOG affects the dynamic balance more negatively than the static balance. In addition, FOG reduces LoS in the posterior direction and increases body sway in the anterior-posterior direction, which can lead to falls. Keywords Center of pressure, Freezing of gait, Limits of stability, Parkinson’s disease, Postural Balance.

The effect of six week virtual reality training on the improvement of functional balance in women with type-I osteoporosis: A preliminary study.

This preliminary study aimed to investigate the effects of exergames in a virtual reality environment to improve functional balance during goal-directed functional tasks in postmenopausal women with osteoporosis. Twelve volunteer postmenopausal women with osteoporosis were randomly assigned to virtual reality (VRT, n = 6) and conventional multimodal (CMT, n = 6) training groups. The exercise was performed for 6weeks, 3days weekly, and 18 sessions. Using a force platform, functional balance assessments were made through four dynamic tasks, including performance-based limits of stability (LOS), curve tracking (CT), sit-to-stand (STS), and turning before and after 18 sessions of treatment. Each task's time-dependent center of pressure (COP) variables was separately calculated via Kistler-Mars software. The COP variables of LOS and CT tasks were significantly improved after 6weeks of CMT and VRT (P ≤ 0.05). In the VRT group, the rising index (P < 0.00), COP sway velocity in STS, and Turn sway were significantly reduced (P < 0.05). Following the VRT, the mean difference of forwarding maximum COP excursion increased (P = 0.03), and errors in CT (P = 0.03) significantly decreased. The VRT and CMT improved the COP sway parameters during weight-shifting tasks. The VRT was more effective than CMT in increasing the ability to control weight-shifting and dynamic functional tasks in postmenopausal women with osteoporosis. This approach in training has suitable potential to provide convenient error feedback learning.

Brain activity during dual-task standing in older adults

BackgroundIn older adults, the extent to which performing a cognitive task when standing diminishes postural control is predictive of future falls and cognitive decline. The neurophysiology of such “dual-tasking” and its effect on postural control (i.e., dual-task cost) in older adults are poorly understood. The purpose of this study was to use electroencephalography (EEG) to examine the effects of dual-tasking when standing on brain activity in older adults. We hypothesized that compared to single-task “quiet” standing, dual-task standing would decrease alpha power, which has been linked to decreased motor inhibition, as well as increase the ratio of theta to beta power, which has been linked to increased attentional control.MethodsThirty older adults without overt disease completed four separate visits. Postural sway together with EEG (32-channels) were recorded during trials of standing with and without a concurrent verbalized serial subtraction dual-task. Postural control was measured by average sway area, velocity, and path length. EEG metrics included absolute alpha-, theta-, and beta-band powers as well as theta/beta power ratio, within six demarcated regions-of-interest: the left and right anterior, central, and posterior regions of the brain.ResultsMost EEG metrics demonstrated moderate-to-high between-day test–retest reliability (intra-class correlation coefficients > 0.70). Compared with quiet standing, dual-tasking decreased alpha-band power particularly in the central regions bilaterally (p = 0.002) and increased theta/beta power ratio in the anterior regions bilaterally (p < 0.001). A greater increase in theta/beta ratio from quiet standing to dual-tasking in numerous demarcated brain regions correlated with greater dual-task cost (i.e., absolute increase, indicative of worse performance) to postural sway metrics (r = 0.45–0.56, p < 0.01). Lastly, participants who exhibited greater alpha power during dual-tasking in the anterior-right (r = 0.52, p < 0.01) and central-right (r = 0.48, p < 0.01) regions had greater postural sway velocity during dual-tasking.ConclusionIn healthy older adults, alpha power and theta/beta power ratio change with dual-task standing. The change in theta/beta power ratio in particular may be related to the ability to regulate standing postural control when simultaneously performing unrelated, attention-demanding cognitive tasks. Modulation of brain oscillatory activity might therefore be a novel target to minimize dual-task cost in older adults.

Associations of Masticatory Muscles Asymmetry and Oral Health with Postural Control and Leg Injuries of Elite Junior Soccer Players.

The influence of asymmetry between masticatory muscles on postural control is still under debate and only few studies examined the impact of oral health on injury risk. The present study investigated the relationships between masticatory muscles asymmetry, oral health, postural control and the prevalence of (non-contact or traumatic) leg injuries in a sample of 144 male elite junior soccer players. sEMG of the masseter and temporal muscles was performed during maximum teeth clenching, postural control was tested by measuring sway velocity during the unipedal stance with eyes closed, while oral health and the number of leg injuries were assessed using a questionnaire. The time-1 assessment was repeated in a subgroup of 69 players after one year. Pearson and partial correlation coefficients and adjusted odds ratios (OR) were used to assess associations. Asymmetry between the masseter and temporalis muscles (AMTM, quantified as anteroposterior coefficient, APC) was associated with higher sway velocity on the dominant leg (using time-1 data partial r = -0.24, p = 0.004, using longitudinal data partial r = -0.40, p = 0.005). Higher prevalence of two or more leg injuries throughout a competitive season was associated with poor oral health (adjusted OR (95%CI) using time-1 data = 2.14 (1.02-4.46), using longitudinal data = 4.47 (1.25-15.96)). These results indicate that AMTM has a negative influence on the sway velocity of the dominant leg only, possibly because frequent balancing exercises on the non-dominant leg may counteract negative influences of AMTM. The association of oral health with leg injuries underlines the need for oral health promotion and monitoring strategies in sports.

만성 발목 불안정성에 대한 엉덩관절 훈련프로그램이 자세제어와 발목기능에 미치는 영향

This study aimed to investigate the effects of hip joint training on static and dynamic posture control and ankle joint function in individuals with chronic ankle instability (CAI) and to provide useful information on various rehabilitation strategies. A total of 25 subjects who met the criteria for International Ankle Consortium were participated in this study and they were applied 6-week training program consisting of neuromuscular training and hip (EG, n=12) or ankle (CG, n=13) joint training program. The static posture control consisted of total length (TL), sway velocity (SV), and envelope area (ENV) of the conter of pressure (COP) on stable and unstable surface with eyes open and closed, and lower quarter Y-balance test (YBT-LQ) was performed to measure dynamic posture control. The ankle joint function was tested using 4 hop tests.BR After 6-week training program, the TL and SV of COP in both groups were significantly reduced during one leg standing on stable surface with eyes closed. And in only CG, they were significantly reduced on unstable surface with eyes closed. The ENV of COP in only CG was reduced during both one leg standing on stable and unstable with eyes closed after 6-week training program. The score of YBT-LQ after the application of 6-week training program was significantly higher in both EG and CG. The ankle joint function using 4 hop test was improved in both EG and CG. This study showed that 6-week hip training program improved the static and dynamic posture control and ankle joint function similar to conventional ankle training, and the hip training program had a positive effect on chronic ankle instability (CAI).

Gait and Postural Control Characteristics among Individuals with Benign Paroxysmal Positional Vertigo: A Scoping Review

Benign paroxysmal positional vertigo (BPPV) is a common peripheral vestibular disorder. Besides vertigo, unsteadiness is a common subjective complaint. This study aims to gain an overview of gait and postural control changes among individuals with BPPV compared to healthy individuals. Relevant case-control studies were searched from their inception until April 2020 using the Scopus, Web of Science and Science Direct databases. Two independent reviewers assessed the methodological quality using the Newcastle-Ottawa Scale (NOS) for case-control studies. A total of 15 studies which satisfied the eligibility criteria were included. The findings suggest evidence of gait and postural control alteration characterized by slower gait speed, reduced gait velocity, increased anterior-posterior centre of pressure, and increased sway velocity compared to controls. Individuals with BPPV showed evidence of gait and postural control alteration. Future exploration on this issue is vital to support gait and postural control alteration among individuals with BPPV.