Standing Balance Performance Research Articles

Investigating the Effects of Center of Gravity (CoG) Shift Due to a Simulated Exploration Extravehicular Mobility Unit (xEMU) Suit on Balance

Maintaining balance is critical to minimizing astronauts’ risk of falling and reducing injury or suit damage. Previous studies involving spacesuits have not examined the effects of the superior shift of the center of gravity (CoG) on astronauts’ ability to balance. Here, the purpose of our study was to investigate the effects of CoG shift due to a simulated Extravehicular Mobility Unit (xEMU) on balance. Seventeen participants’ standing balance was examined for three test configurations: unsuited, weighted with an Extravehicular Mobility Unit (xEMU) vest, and xEMU hard upper body torso (HUT). Using a Tekscan forceplate walkway, the CoG locations were determined. Balance assessments were performed to determine the limits of stability and standing balance performance during wide or tandem stances with eyes open/closed. The center of pressure (CoP) time series was examined in terms of displacement, velocity, and frequency measures. During the eyes-open wide stance, the xEMU vest significantly increased the mediolateral balance parameters, while the HUT significantly increased the total displacement (TOTEX), mean velocity (MVELO), and mean frequency (MFREQ) of the CoP. In the eyes-closed wide stance, the HUT significantly increased these parameters. In the eyes-closed tandem stance, the xEMU vest significantly decreased the parameters. The xEMU vest significantly reduced the TOTEX, MVELO, and MFREQ (improved standing balance), while the HUT decreased standing balance ability, seen with significant increases in said parameters. By quantifying CoG’s effect on balance, our results form the basis for future balance and posture studies of xEMU spacesuits.

Changes in standing stability when wearing different colored glasses cannot be determined by participants’ subjective preference – A crossover randomized single-blinded pilot study

BackgroundThe use of individually preferred colored glasses has gained popularity with the expectation that it may improve balance control and sports performance, however, the results of previous studies remain inconclusive. Aim of the studyIn the present pilot study, we aimed to determine the association between participants’ subjective preference and standing balance performance when wearing five different colored glasses. MethodsThirteen participants stood on one or two legs on a pair of synchronized force platforms for 30 seconds with 60 seconds rest between the five-five randomized stance trials, while wearing red, blue, yellow, green, or transparent colored glasses. In addition to 7 CoP-related variables, we analyzed five features of EMG data from three lower limb muscles on both legs. ResultsNo significant effect of colored glasses was found. Some CoP (velocity: χ²(4, 13) = 10.086; p = 0.039; Kendall’s W = 0.194, root mean square [RMS]: χ²(4, 13) = 12.278; p = 0.015; Kendall’s W = 0.236) and EMG-related (RMS of biceps femoris: χ²(4, 13) = 13.006; p = 0.011; Kendall’s W = 0.250) variables showed differences between the colored glass conditions during dominant-leg stance, however, participants failed to consecutively determine these differences in standing stability. ConclusionsOverall, our results may suggest that lens color preference, irrespective of the color itself, may influence dominant leg standing balance most probably due to psychological factors, however, only subjective determination have no potential to determine the color of the glasses that would support the individual’s standing balance the most.

PREDICTING FALLS IN OLDER ADULTS

Abstract Falls are detrimental to older adults causing injury and mortality. Although clinical assessments of balance deficits exist, it is not well understood how well they predict falls. Longitudinal analysis utilized data from 688 men and women aged 60-97 enrolled in the Baltimore Longitudinal Study of Aging with index and subsequent visits approximately 1.7 years apart. Inclusion criteria included objective balance assessment at index visit and answering the question “Have you fallen in the past 12 months?” at both visits. Predictors of interest included thigh muscle strength, progressive static balance test performance, narrow walk, and sway reference with eyes closed/feet together. Tests were parameterized using validated methods. Adjusted logistic regression was modeled to estimate the association between objective measures of balance and fall risk. Adjustment variables included age, sex, race, height, and weight. Results reported those who failed the eyes closed/feet together position had 3.6 (95% CI 1.03, 12.81) times the odds of future falls compared with those who passed. Those who failed the semi-tandem, tandem, and single leg stance, had respectively 3.1 (1.44, 6.75), 3.6 (1.59, 8.06) and 4.8 (1.93, 12.09) times greater odds of history of falls compared with those who did not fail. Progressive standing balance performance did not predict future falls. The eyes closed/feet together test is easily administered, requires no equipment, and takes less than 30 seconds to complete. Failure of eyes closed/feet together may predict future falls, which is clinically relevant as this may suggest shifting the momentum towards proactively preventing an initial fall.

Effects of Motor-Cognitive Dual-Task Standing Balance Exergaming Training on Healthy Older Adults' Standing Balance and Walking Performance.

Objective: This study examined the effects of motor-cognitive dual-task exergaming standing balance training on healthy older adults' static, dynamic, and walking balance. Methods: Twenty-four adults older than 70 years (control group: n = 9, males = 6, balance training group: n = 15, males = 8) completed the experiment. Dual-tasking standing balance training comprised the accurate control of a ping-pong ball on a tray held with both hands, while standing on one leg (analog training) and three modules of Wii Fit™ exergaming (digital training). The duration of balance training was ∼15 minutes per day, 2 days per week for 8 weeks, in total 16 sessions. We measured one-leg standing time, functional reach distance, walking balance evaluated by the distance walked on a narrow beam (4-cm long, 4-cm wide, and 2-cm high) with single and dual tasking, habitual and maximal walking speed, and muscle strength of the hip extensor, hip abductor, hip adductor, knee extensor, and plantarflexor muscle groups in the right leg at baseline and after 8 weeks. Results: Control group decreased, but balance training group increased one-leg standing time. Only the balance training group improved functional reach distance and hip and knee extensor strength. There was no change in walking speed and walking balance in either group. In the balance training group, changes in maximal speed correlated with changes in dual-tasking walking balance and changes in one-leg standing time correlated with changes in single-tasking walking balance. Conclusion: These results suggest that 16 sessions of motor-cognitive dual-task standing exergaming balance training substantially improved healthy older adults' static and dynamic balance and leg muscle strength but failed to improve walking speed and walking balance. Balance exercises specific to walking balance need to be included in balance training to improve walking balance.

The Impact of Hoffmann Reflex on Standing Postural Control Complexity in the Elderly with Impaired Plantar Sensation

In people with peripheral neuropathy (PN), impaired plantar sensation can cause adaptive changes in the central nervous system (CNS), resulting in changes in the standing postural control, which is reflected in the variability of standing output signals. Standard deviation (SD) and entropy are reliable indicators of system variability, especially since entropy is highly sensitive to diseased populations. The relation between SD and entropy, CNS and center of pressure (COP) variability is unclear for people with severe PN. The purpose of this study was to explore the adaptability of the CNS to the severe of PN and its effect on the degree and complexity of COP variability. Here, people with PN were divided into less affected (LA) and more affected (MA) groups based on plantar pressure sensitivity. We studied Hoffmann reflex (H-reflex) and standing balance performance with the control group (n = 8), LA group (n = 10), and MA group (n = 9), recording a 30 s COP time series (30,000 samples) of double-leg standing with eyes open. We observed that the more affected group had less COP complexity than people without PN. There is a significant negative correlation between the SD and sample entropy in people without PN, less affected and more affected. The COP complexity in people without PN was inversely correlated with H-reflex. We concluded that: (1) The complexity of COP variability in patients with severe plantar sensory impairment is changed, which will not affect the degree of COP variability; (2) The independence of the COP entropy in the AP and ML directions decreased, and the interdependence increased in people with PN; (3) Although the CNS of people with PN has a greater contribution to standing balance, its modulation of standing postural control is decreased.

Multisensory visual-vestibular training improves visual heading estimation in younger and older adults.

Self-motion perception (e.g., when walking/driving) relies on the integration of multiple sensory cues including visual, vestibular, and proprioceptive signals. Changes in the efficacy of multisensory integration have been observed in older adults (OA), which can sometimes lead to errors in perceptual judgments and have been associated with functional declines such as increased falls risk. The objectives of this study were to determine whether passive, visual-vestibular self-motion heading perception could be improved by providing feedback during multisensory training, and whether training-related effects might be more apparent in OAs vs. younger adults (YA). We also investigated the extent to which training might transfer to improved standing-balance. OAs and YAs were passively translated and asked to judge their direction of heading relative to straight-ahead (left/right). Each participant completed three conditions: (1) vestibular-only (passive physical motion in the dark), (2) visual-only (cloud-of-dots display), and (3) bimodal (congruent vestibular and visual stimulation). Measures of heading precision and bias were obtained for each condition. Over the course of 3 days, participants were asked to make bimodal heading judgments and were provided with feedback (“correct”/“incorrect”) on 900 training trials. Post-training, participants’ biases, and precision in all three sensory conditions (vestibular, visual, bimodal), and their standing-balance performance, were assessed. Results demonstrated improved overall precision (i.e., reduced JNDs) in heading perception after training. Pre- vs. post-training difference scores showed that improvements in JNDs were only found in the visual-only condition. Particularly notable is that 27% of OAs initially could not discriminate their heading at all in the visual-only condition pre-training, but subsequently obtained thresholds in the visual-only condition post-training that were similar to those of the other participants. While OAs seemed to show optimal integration pre- and post-training (i.e., did not show significant differences between predicted and observed JNDs), YAs only showed optimal integration post-training. There were no significant effects of training for bimodal or vestibular-only heading estimates, nor standing-balance performance. These results indicate that it may be possible to improve unimodal (visual) heading perception using a multisensory (visual-vestibular) training paradigm. The results may also help to inform interventions targeting tasks for which effective self-motion perception is important.

Game-Based Dual-Task Exercise Program for Children with Cerebral Palsy: Blending Balance, Visuomotor and Cognitive Training: Feasibility Randomized Control Trial.

The objective of this exploratory randomized controlled trial (RCT) was to provide evidence for the feasibility and therapeutic value of a novel game-based dual-task balance exercise program in children with cerebral palsy (CP). Twenty children with CP were recruited and randomized into two groups: (a) the conventional balance training group (CG) and (b) the experimental group (XG), which received a game-based dual-task (DT) balance exercise program. Both groups received their respective therapy programs for 12 weeks at a frequency of three sessions per week. Semi-structured interviews with the parents and children and qualitative analysis were conducted to evaluate the children’s experiences with the game-based exercise program. The quantitative analysis included (a) the Pediatric Balance Scale (PBS), (b) Gross Motor Function Measure-88 (GMFM-88), and (c) computerized measures of standing balance performance during various dual-task conditions. Compliance was 100% for all 20 participants. Four themes captured the range of each participant’s experiences and opinions: (a) reasons for participation, (b) likes and dislikes with the technologies, (c) positive effects of the program, and (d) future expectations. Children in the XG demonstrated greater improvements in PBS, GMFM, and DT balance measures as compared to children in the CG. The findings demonstrate feasible trial procedures and acceptable DT-oriented training with a high compliance rate and positive outcomes. These findings support further research and development and progression to the next phase of a full-scale RCT to evaluate the clinical effectiveness of the game-based DT balance exercise program for children with CP.

Pelvic floor muscle training and postural balance in elderly women: An exploratory single arm trial

IntroductionTo investigate the influence of a training of mobility, gait speed and postural balance of pelvic floor muscles (PFM). MethodsA single-arm clinical trial study was approved and registered at the Brazilian Clinical Trials Registry (RBR-4rxhd4). Eighteen women over the age of 60 with pelvic floor dysfunction complaints were subjected to 10 sessions of functional electrical stimulation and digital palpation of PFM. Mobility and gait speed were evaluated by the Timed up and Go and the 10-m walk tests respectively. Standing balance was evaluated using a force plate. ResultsNo significant differences were found in mobility, gait speed, and standing balance. PFM contraction worsened mobility, gait speed, and standing balance performance. ConclusionsThe training protocol enhanced PFM strength and endurance, but the improved ability to recruit PFM did not positively affect balance, mobility, and gait speed.

Dual-Task Training Program for Older Adults: Blending Gait, Visuomotor and Cognitive Training.

Objective: Physical and cognitive impairments are common with aging and often coexist. Changes in the level of physical and mental activity are prognostic for adverse health events and falls. Dual-task (DT) training programs that can improve mobility and cognition simultaneously can bring significant improvements in rehabilitation. The objective of this mixed methods exploratory RCT was to provide evidence for the feasibility and therapeutic value of a novel game-assisted DT exercise program in older adults. Methods: Twenty-two community dwelling participants, between the ages of 70-85 were randomized to either dual-task treadmill walking (DT-TR) or dual-task recumbent bicycle (DT-RC). Both groups viewed a standard LED computer monitor and performed a range of cognitive game tasks while walking or cycling; made possible with the use of a "hands-free", miniature, inertial-based computer mouse. Participants performed their respective 1-h DT exercise program twice a week, for 12weeks at a community fitness centre. Semi-structured interviews and qualitative analysis was conducted to evaluate the participant's experiences with the exercise program. Quantitative analysis included measures of standing balance, gait function (spatiotemporal gait variable), visuomotor and executive cognitive function, tested under single and DT walking conditions. Results: Compliance was 100% for all 22 participants. Four themes captured the range of participant's experiences and opinions: 1) reasons for participation, 2) difficulties with using the technologies, 3) engagement with the computer games, and 4) positive effects of the program. Both groups showed significant improvements in standing balance performance, visuomotor and visuospatial executive function. However, significant improvement in dual task gait function was observed only in the DT-TR group. Medium to large effect sizes were observed for most balance, spatiotemporal gait variables, and cognitive performance measure. Conclusion: With only minor difficulties with the technology being reported, the findings demonstrate feasible trial procedures and acceptable DT oriented training with a high compliance rate and positive outcomes. These findings support further research and development, and will direct the next phase of a full-scale RCT.

Post-Drive Standing Balance of Vehicle Passengers Using Wearable Sensors: The Effect of On-Road Driving and Task Performance.

Postural sway has been demonstrated to increase following exposure to different types of motion. However, limited prior studies have investigated the relationship between exposure to normative on-road driving conditions and standing balance following the exposure. The purpose of this on-road study was to quantify the effect of vehicle motion and task performance on passengers’ post-drive standing balance performance. In this study, trunk-based kinematic data were captured while participants performed a series of balance exercises before and after an on-road driving session in real-time traffic. Postural sway for all balance exercises increased following the driving session. Performing a series of ecologically relevant visual-based tasks led to increases in most post-drive balance metrics such as sway position and velocity. However, the post-drive changes following the driving session with a task were not significantly different compared to changes observed following the driving session without a task. The post-drive standing balance performance changes observed in this study may increase vulnerable users’ risk of falling. Wearable sensors offer an opportunity to monitor postural sway following in-vehicle exposures.

Increased Likelihood of Falling in Older Cannabis Users vs. Non-Users.

Cannabis is one of the most common drugs in the United States and is the third most prevalent substance consumed by adults aged 50 years and older. Normal aging is associated with physiological changes that make older adults vulnerable to impaired function and geriatric conditions (e.g., falls, cognitive impairment). However, the impact of medical cannabis use on fall risk in older adults remains unexplored. The purpose of this study was to investigate if cannabis use in older adults influences fall risk, cognitive function, and motor function. It was hypothesized that older chronic cannabis users would perform worse than non-users on gait, balance, and cognitive tests. Sixteen older adults, split into cannabis Users and age- and sex-matched Non-Users groups (n = 8/group), participated in the study. The results indicate a higher fall risk, worse one leg standing balance performance, and slower gait speed in Users vs. Non-Users. No significant differences in cognitive function were found. Thus, chronic cannabis use was purported to exacerbate the poorer balance control and slower gait velocity associated with normal aging. Future mechanistic (e.g., neuroimaging) investigations of the short- and long-term effects of using a variety of cannabis products (e.g., THC/CBD ratios, routes of administration) on cognitive function, motor function, and fall incidence in older adults are suggested.

Effect of Yogasana Intervention on Standing Balance Performance among People with Diabetic Peripheral Neuropathy: A Pilot Study.

Background:Diabetic peripheral neuropathy (DPN) is known to cause impaired balance and eventually increased risk of fall. Yogasanas characterized by slow, gentle transitions into postures with a varying base of support and focus on body awareness during movement hold potential for training balance control. Therefore, the current study aimed to evaluate effect of structured Yogasana intervention compared to conventional balance exercise on static and dynamic balance performance among people with diabetic neuropathy.Methods: Thirty-five people with DPN aged 42–70 years were recruited to Yogasana intervention group (n = 11), conventional balance exercises group (n = 10), and Control group (n = 14) following ethical approval. All participants were evaluated at baseline and post 12-week intervention on star excursion balance test, single-limb stance test, and center of pressure (CoP) excursion for balance performance, Modified fall efficacy scale for fear of falls and lower extremity strength using chair stand test and step-up test.Results:Balance performance (static and dynamic measured by star excursion balance test, single-limb stance test, and CoP excursion, lower extremity strength (using chair stand test and step-up test) demonstrated improvement and fear of fall reduced among Yogasana intervention group (p = 0.05) and conventional balance exercises group (p = 0.05) post 12-week intervention. CoP excursion increased in the control group indicating deterioration in balance performance after 12 weeks (p = 0.05). Post hoc comparison revealed that Yogasana intervention was marginally more effective in improving static and dynamic balance performance compared to conventional balance exercises in all variables of standing balance performance (p = 0.025).Conclusion:Yogasana and conventional balance exercises were effective in improving static and dynamic balance performance, lower extremity muscle strength, and reducing fear of fall among people with DPN. Yogasana intervention demonstrated marginally greater improvement in static and dynamic balance performance and lower extremity muscle strength compared to conventional exercise.

Age-Related Differences in the Effect of Prolonged Vibration on Maximal and Rapid Force Production and Balance Ability.

We tested the hypothesis that older adults would not likely experience deficits in maximal and explosive plantar flexion strength and standing balance performance induced by prolonged Achilles tendon vibration compared with young adults. Fifteen older men (OM, 73 ± 5 years) and 15 young men (YM, 24 ± 4 years) participated in two interventions on different days: lying in a quiet supine position for 30 min with or without prolonged vibration to the Achilles tendon. Before and after the interventions, maximal voluntary contraction (MVC) torque during plantar flexion, rate of torque development (RTD), and center of pressure (COP) speed during single-leg standing were measured. The root mean square of the electromyogram (RMS-EMG) during performance and V-wave and voluntary activation during MVC were assessed. The MVC torque (7 ± 7%) and RTD (16 ± 15%) of YM but not OM significantly decreased after vibration. In addition, the relative changes observed in YM positively correlated with changes in RMS-EMG of the medial gastrocnemius (MG) (MVC torque and RTD) and in MG V-wave and voluntary activation (MVC torque). COP speed significantly increased (16 ± 20%) in YM only after vibration and was accompanied by increased activation of the lateral gastrocnemius. This is the first study to show that the effects of prolonged Achilles tendon vibration on strength and balance performances were apparent in young adults only. The differences between the age groups may be related to the attenuated gastrocnemius neuromuscular function in older adults.

Associations of sitting and physical activity with grip strength and balance in mid-life: 1970 British Cohort Study.

Strength and balance training are now recommended in many physical activity (PA) guidelines. However, it is unclear whether these recommendations are applicable to middle‐aged adults. We aimed to examine the associations of sitting and physical activity times with grip strength and standing balance performance in mid‐life. Up to 4726 participants from the 1970 British Cohort study, with data on sitting and activity (measured using a thigh‐worn accelerometer (activPAL3‐micro)), grip strength and balance times at age 46 years were included in analyses. Associations of sitting, moderate‐vigorous, and total PA times with grip strength and balance performance were tested using linear and multinomial logistic regression models, respectively. Greater time spent sitting was associated with weaker grip strength even after adjustment for potential confounders and MVPA time (fully adjusted regression coefficient: −0.51 kg (95% CI: −0.63, −0.39) per 1‐hour sitting/day). Associations of PA time with grip strength were not independent of sitting time. There was only a weak association between sitting time and balance performance but greater MVPA and total PA times were associated with higher relative risks of successfully balancing for 30 seconds with eyes closed (vs poor balance). However, these associations were fully attenuated after adjustments for covariates. In summary, among a sample of middle‐aged adults a robust association between sitting time and grip strength was observed. These findings suggest potential benefits of actively promoting less sitting alongside activities that specifically benefit muscle strength and balance performance in mid‐life to ensure that people maintain all important aspects of their physical capability as they age.

Functional Electrical Stimulation Plus Visual Feedback Balance Training for Standing Balance Performance Among Individuals With Incomplete Spinal Cord Injury: A Case Series.

Individuals with an incomplete spinal cord injury (iSCI) are highly susceptible to falls during walking or standing. Our objective was to evaluate a therapeutic tool for standing balance that combined functional electrical stimulation, applied bilaterally to the plantarflexors and dorsiflexors, with visual feedback balance training (FES+VFBT). Five adults with iSCI completed 12 FES+VFBT sessions over 4 weeks. During the training sessions, participants completed each of the four balance exercises twice. Visual feedback of the center-of-pressure (COP) location was provided as participants completed the balance exercises and received FES to assist with performance of the exercises. A closed-loop FES system was used in which the COP was continually monitored and the level of electrical current administered was automatically adjusted. Balance abilities were assessed pre- and post- training using clinical balance scales (i.e., Berg Balance Scale, Mini-Balance Evaluation Systems Test, and Activities-specific Balance Confidence Scale) and biomechanical assessments (i.e., postural sway measures and limits of stability test during standing). User acceptability was explored through semi-structured interviews. Improvements were seen for four of the five participants on at least one of the clinical scales following completion of the training intervention. All participants showed greater maximal COP excursion area during the limits of stability test after the training intervention, whereas only one participant demonstrated a reduction in postural sway. Specific components of FES+VFBT, including the ability to safely practice challenging balance exercises, were deemed important by the participants. These results suggest that FES+VFBT has potential as an intervention for standing balance after iSCI.

Impact of Prolonged Tablet Computer Usage with Head Forward and Neck Flexion Posture on Pain Intensity, Cervical Joint Position Sense and Balance Control in Mechanical Neck Pain Subjects

The prolonged head forward and neck flexion posture associated with tablet computer use is a known risk factor for neck pain. Neck pain related dysfunction may cause proprioceptive errors and deficits in balance control. Thus, this study aimed to investigate the impact of prolonged tablet computer use with head forward and neck flexion posture on the pain intensity, cervical position sense and balance control in mechanical neck pain patients. The prolonged head forward and neck flexion posture associated with tablet computer use is a known risk factor for neck pain. Neck pain related dysfunction may cause proprioceptive errors and deficits in balance control. Thus, this study aimed to investigate the impact of prolonged tablet computer use with head forward and neck flexion posture on the pain intensity, cervical position sense and balance control in mechanical neck pain patients.The prolonged head forward and neck flexion posture associated with tablet computer use is a known risk factor for neck pain. Neck pain related dysfunction may cause proprioceptive errors and deficits in balance control. Thus, this study aimed to investigate the impact of prolonged tablet computer use with head forward and neck flexion posture on the pain intensity, cervical position sense and balance control in mechanical neck pain patients. Twenty subjects with mechanical neck pain (24.1 ± 3.4 years) and 20 healthy controls (23.7 ± 3.3 years) were recruited from a university environment. A neck pain inducing protocol simulating prolonged tablet computer usage with neck flexion posture was performed by the mechanical neck pain subjects until the point of moderate pain. The neck pain related scores, cervical range of motion and neck tissue hardness were evaluated in both the healthy controls and the neck pain subjects before the neck pain inducing protocol. Differences in the cervical joint position sense, neck tissue hardness and static standing balance performance of the healthy controls and mechanical neck pain subjects were investigated after the neck pain inducing protocol. The mechanical neck pain subjects demonstrated a lower cervical range of motion and a harder neck tissue status than the control subjects. The pain intensity reported by the neck pain subjects after the neck pain inducing protocol was similar to that experienced by the subjects in previous pain attacks. Significant differences in the absolute neck joint positioning error were observed between the mechanical neck pain group and the control group. Prolonged tablet computer use with head forward and neck flexion posture did not significantly increase the joint positioning error in the mechanical neck pain group. However, prolonged tablet computer use with head forward and neck flexion posture resulted in a poorer static standing balance performance in the subjects with mechanical neck pain than in the healthy controls. The subjects with mechanical neck pain exhibited a decreased cervical range of motion, a harder neck tissue status and greater neck joint position errors than the healthy controls. In addition, prolonged tablet computer use with head forward and neck flexion posture reproduced the neck pain severity and reduced the balance control ability of the mechanical neck pain subjects.

Standing Balance Performance and Knee Extensors' Strength in Diabetic Patients with Neuropathy.

Diabetes peripheral neuropathy (DPN) leads to balance impairment among diabetes mellitus (DM). The aims of this study were to (1)distinguish between DM patients who have/do not have DPN and to (2)compare quadriceps' strength and balance performance of DM, DPN, and healthy groups. Fifteen healthy females and 33 females with type 2 diabetic patients participated. The electrodiagnostic method was used to classify diabetic patients into DM and DPN. A dynamometer was used to measure quadriceps' strength. Single-leg standing on a force plate was also used to quantify participants' balance. Smaller conduction velocity and amplitude and greater distal latency of all nerves were observed in the DPN compared with the DM in particular for sensory nerve. In DPN, conduction velocity was asymmetrical. The quadriceps' strength of both legs in DPN and the right leg in DM was smaller than in the control group. The root mean square of the center of pressure was similar between DM and DPN. But it was larger in DPN than in the control group. DPN is associated with asymmetrical conduction velocity, smaller quadriceps' strength, and weaker balance performance that is suggestive of higher risk of falling. Balance training is recommended for the DPN group during their rehabilitation to reduce their falling risk.

Acute Effects of High-Definition Transcranial Direct Current Stimulation on Foot Muscle Strength, Passive Ankle Kinesthesia, and Static Balance: A Pilot Study.

This study aimed to examine the effects of single-session anodal high-definition transcranial direct current stimulation (HD-tDCS) on the strength of intrinsic foot muscles, passive ankle kinesthesia, and static balance. Methods: In this double-blinded self-controlled study, 14 healthy younger adults were asked to complete assessments of foot muscle strength, passive ankle kinesthesia, and static balance before and after a 20-minute session of either HD-tDCS or sham stimulation (i.e., control) at two visits separated by one week. Two-way repeated-measures analysis of variance was used to examine the effects of HD-tDCS on metatarsophalangeal joint flexor strength, toe flexor strength, the passive kinesthesia threshold of ankle joint, and the average sway velocity of the center of gravity. Results: All participants completed all study procedures and no side effects nor risk events were reported. Blinding was shown to be successful, with an overall accuracy of 35.7% in the guess of stimulation type (p = 0.347). No main effects of intervention, time, or their interaction were observed for foot muscle strength (p > 0.05). The average percent change in first-toe flexor strength following anodal HD-tDCS was 12.8 ± 24.2%, with 11 out of 14 participants showing an increase in strength, while the change following sham stimulation was 0.7 ± 17.3%, with 8 out of 14 participants showing an increase in strength. A main effect of time on the passive kinesthesia threshold of ankle inversion, dorsiflexion, and anteroposterior and medial–lateral average sway velocity of the center of gravity in one-leg standing with eyes closed was observed; these outcomes were reduced from pre to post stimulation (p < 0.05). No significant differences were observed for other variables between the two stimulation types. Conclusion: The results of this pilot study suggested that single-session HD-tDCS may improve the flexor strength of the first toe, although no statistically significant differences were observed between the anodal HD-tDCS and sham procedure groups. Additionally, passive ankle kinesthesia and static standing balance performance were improved from pre to post stimulation, but no significant differences were observed between the HD-tDCS and sham procedure groups. This may be potentially due to ceiling effects in this healthy cohort of a small sample size. Nevertheless, these preliminary findings may provide critical knowledge of optimal stimulation parameters, effect size, and power estimation of HD-tDCS for future trials aiming to confirm and expand the findings of this pilot study.

Evaluation of Standing Balance Performance in Indian Classical Dancers.

Indian classical dance involves a constant change of the base of support from stance to low jumps and spins along with intricate footwork. Graceful movement of the torso, shifting from side to side and turning around the axis of the spine, challenges balance. Yet, balance performance remains unexplored in Indian classical dancers. Therefore, the present study aimed to compare the standing balance of 36 active female dancers (18 to 25 years of age) who had performed Indian classical dance for a minimum of 10 years with 36 healthy age-matched women not involved in regular physical activity. Balance was evaluated in static and dynamic conditions of single and dual-limb stance on a force plate using center-of-pressure trajectory and the Star Excursion Balance Test (SEBT). Dancers demonstrated better balance on both instrumented and non-instrumented outcome variables: wide base of support with eyes open and with eyes closed; for 30-second single limb stance with eyes open and with eyes closed; for 13-second dual task in single limb stance; and for 22-second dual task in wide base of support. The SEBT revealed significantly better balance performance of dancers in the three directions tested: anterior, posteromedial, and posterolateral. There was also a strength component of the study on which the dancers achieved significantly higher scores than controls for the three muscle groups tested (gastrocsoleus, gluteus medius, and quadriceps), which can be attributed to their training. These findings can be used to recommend classical dance training to achieve the dual purpose of deriving better balance and stronger bodies and maintaining the Indian dance heritage.

Psychometric properties of instrumented postural sway measures recorded in community settings in independent living older adults

BackgroundIn the last few decades, research related to balance in older adults has been conducted in lab-based settings. The lack of portability and high cost that is associated with the current gold standard methods to quantify body balance limits their application to community settings such as independent living facilities. The purpose of the study was to examine the relative and absolute reliability and the convergent validity of static standing balance performance using an accelerometer device.MethodsA total of 131 participants (85% female, mean age 80 ± 8 years) were included for the validity aim, and a subsample of 38 participants were enrolled in the reliability testing (89% female, mean age 76 ± 7 years). The root-mean-square (RMS) and normalized path length (NPL) for sway in antero-posterior (AP) and medio-lateral (ML) directions were calculated for different standing balance conditions. Test-retest reliability was assessed over two testing visits occurring 1 week apart using the intraclass correlation coefficient (ICC) for relative reliability, and the minimal detectable change (MDC) was calculated for the absolute reliability. Spearman’s rank correlation coefficient was used to test convergent validity at baseline between balance measurements and related mobility measures.ResultsReliability of balance performance using accelerometers was good to excellent with ICC values ranging from 0.41 to 0.83 for RMS sway and from 0.49 to 0.82 for NPL sway. However, the ICC during semi-tandem stance in A-P direction was 0.35, indicating poor reliability. The MDC of the sway measurements ranged from 2.4 to 9.4 for the RMS and 5.2 to 13.8 for the NPL. Balance measurements were correlated with mobility measurements.ConclusionsUsing a portable accelerometer to quantify static standing postural control provides reliable measurements in community settings.