The effect of augmented somatosensory feedback on standing postural sway

Sensory Interaction and Balancing Ability Evaluation of the Elderly Using a Simplified Force Plate System

The Wii balance board (WBB) is a simplified force plate system used to evaluate the balancing ability of the elderly via a sensory interaction task to confirm a significant standing balance index. The accuracy of this system has been verified in previous studies. In this study, an instrumented and modified clinical test of sensory interaction on balance (i-mCTSIB) was performed on 84 elderly subjects, and the variables for center of pressure (CoP) were calculated using WBB for each task condition. The results indicate that the visual condition has a significant effect on the sway proprioceptive sensory variables with a foam condition as their complexity increases. In addition, the correlation between the variable and Berg Balance Scale was not confirmed since CTSIB is a sensory interaction on balance ability. Therefore, WBB can be used to evaluate balancing ability based on sensory interactions consisting of the surface condition.

Validity and reliability of balance Y-MED application in chronic mechanical low back pain patients

Background

Low back pain patients suffer from balance disturbance. Balance allows a person to interact with the surrounding environment and to do his daily activities. As recent technology has facilitated patient monitoring and enhanced our ability to monitor patients remotely, smartphone apps have been developed to achieve this goal. There are various balance assessment instruments used nowadays. It may be subjective or objective assessments. This study was applied to verify if the measurements of balance Y-MED smartphone applications are valid and reliable compared to the HUMAC balance board in order to offer easy, fast, cost-effective, and time-effective valid and reliable balance assessment that can be used in a clinical setting.

Methods

Fifty-four patients (12 males and 42 females) with chronic mechanical low back pain for more than 3 months was volunteered to participate in the current study with an age range of 25–60 years and BMI range of 18–34 kg/m2. Compared with the HUMAC balance board, the validity of the balance Y-MED smartphone application is evaluated, and the test-retest reliability of the balance Y-MED smartphone application is obtained by the same examiner 3 times.

Results

For concurrent validity, the correlations between balance measurements by Y-MED smartphone application and HUMAC balance board were not significant in both eyes open (r = − 0.12, p = 0.38) and eyes closed (r = 0.26, p = 0.054). The smartphone application showed poor test-retest reliability measurement of balance with eyes open; (ICC was 0.279, with 95% CI − 0.117–0.554) and with eyes closed (ICC was − 0.159, with 95% CI − 0.814–0.287).

Conclusions

According to the evaluation scheme selected in this study, the researchers were unable to confirm the validity of the balance Y-MED smartphone application in the balance assessment of patients with mechanical chronic low back pain. More than that, the balance Y-MED smartphone application has been shown poor score reliability. This makes it inaccurate for use in assessment balance.

Task-Based Functional Connectivity and Blood-Oxygen-Level-Dependent Activation During Within-Scanner Performance of Lumbopelvic Motor Tasks: A Functional Magnetic Resonance Imaging Study

There are a limited number of neuroimaging investigations into motor control of the lumbopelvic musculature. Most investigation examining motor control of the lumbopelvic musculature utilize transcranial magnetic stimulation (TMS) and focus primarily on the motor cortex. This has resulted in a dearth of knowledge as it relates to how other regions of the brain activate during lumbopelvic movement. Additionally, task-based functional connectivity during lumbopelvic movements has not been well elucidated. Therefore, we used functional magnetic resonance imaging (fMRI) to examine brain activation and ROI-to-ROI task-based functional connectivity in 19 healthy individuals (12 female, age 29.8 ± 4.5 years) during the performance of three lumbopelvic movements: modified bilateral bridge, left unilateral bridge, and right unilateral bridge. The whole brain analysis found robust, bilateral activation within the motor regions of the brain during the bilateral bridge task, and contralateral activation of the motor regions during unilateral bridging tasks. Furthermore, the ROI-to-ROI analysis demonstrated significant connectivity of a motor network that included the supplemental motor area, bilateral precentral gyrus, and bilateral cerebellum regardless of the motor task performed. These data suggest that while whole brain activation reveals unique patterns of activation across the three tasks, functional connectivity is very similar. As motor control of the lumbopelvic area is of high interest to those studying low back pain (LBP), this study can provide a comparison for future research into potential connectivity changes that occur in individuals with LBP.

Effects of increasing temperature in different foot regions on foot sensitivity and postural control in young adults

Despite controversial evidence, foot sensitivity may influence postural control. Since skin temperature changes may induce changes in skin sensitivity, it remains unclear whether this also affects postural control. Here we examined the effects of increasing foot temperature on foot sensitivity and postural control responses. It is hypothesized that increases in foot temperature would improve foot sensitivity and enhance postural control. Furthermore, it was investigated whether warming a larger foot area provides additional benefits. Our hypothesis was tested by warming the foot plantar and the whole foot and ankle area (including foot plantar and instep) using infrared radiation and evaluated the center of pressure (CoP, bilateral, in two conditions: eyes open and eyes closed) and foot tactile sensitivity (Semmes-Weinstein Monofilaments) in 22 young participants. Both warming protocols significantly increased foot temperature by ∼5-6 °C and improved sensitivity, whereas more considerable improvements happened after warming the whole foot and ankle. CoP mediolateral oscillation and velocity with eyes open, and CoP area and velocity with eyes closed reduced after both warming protocols. Foot sensitivity seems to depend on the foot area warmed, whereas postural control improved equally regardless of the warmed regions. These results may support interventions based on the manipulation of foot temperatures to improve postural control with potential clinical applications in populations with impaired foot sensitivity and balance.

Wearing compression garments differently affects monopodal postural balance in high-level athletes

This study investigated the acute effects of compression garments (CG) on balance control in elite athletes. 15 male professional handball players were recruited. They had to stand as motionless as possible in a monopedal stance on a force plate with the eyes closed and on a wobble board with the eyes open, while wearing CG or not. Centre of foot pressure mean velocity and surface area were calculated. Statistics were first calculated with the data from the whole sample. A hierarchical cluster analysis was also performed in order to categorize the participants’ behaviours into subgroups with similar characteristics. The whole group analysis showed that there were no significant effects attributed to CG. The clustering analysis identified two distinct and homogeneous subgroups of participants. Only athletes with the best balance abilities at baseline could benefit from CG wearing to improve their balance control. These athletes, who swayed less and were more sensitive to somatosensory manipulation due to CG wearing, seem to control balance by adopting a support-dependent preferred sensorimotor tactic. Our findings suggest that amongst high-level athletes, the ability to benefit from CG wearing to improve balance control seems to depend on participants’ intrinsic balance skills and/or preferred sensorimotor tactics.

The Influence of Proprioceptive Training with the Use of Virtual Reality on Postural Stability of Workers Working at Height

The aim of the study was to assess the impact of proprioceptive training with the use of virtual reality (VR) on the level of postural stability of high-altitude workers. Twenty-one men working at height were randomly assigned to the experimental group (EG) with training (n = 10) and control group (CG) without training (n = 11). Path length of the displacement of the center of pressure (COP) signal and its components in the anteroposterior and medial-lateral directions were measured with use of an AccuGaitTM force plate before and after intervention (6 weeks, 2 sessions × 30 min a week). Tests were performed at two different platform heights, with or without eyes open and with or without a dual task. Two-way ANOVA revealed statistically significant interaction effects for low-high threat, eyes open-eyes closed, and single task-dual task. Post-training values of average COP length were significantly lower in the EG than before training for all analyzed parameters. Based on these results, it can be concluded that the use of proprioceptive training with use of VR can support, or even replace, traditional methods of balance training.

The center of pressure and ankle muscle co-contraction in response to anterior-posterior perturbations

Though both contraction of agonist muscles and co-contraction of antagonistic muscle pairs across the ankle joint are essential to postural stability, they are perceived to operate independently of each other, In an antagonistic setup, agonist muscles contract generating moment about the joint, while antagonist muscles contract generating stiffness across the joint. While both work together in maintaining robustness in the face of external perturbations, contractions of agonist muscles and co-contractions of antagonistic muscle pairs across the ankle joint play different roles in responding to and adapting to external perturbations. To determine their respective roles, we exposed participants to repeated perturbations in both large and small magnitudes. The center of pressure (COP) and a co-contraction index (CCI) were used to quantify the activation of agonist muscles and antagonistic muscle pairs across the ankle joint. Our results found that participants generated moment of a large magnitude across the ankle joint—a large deviation in the COP curve—in response to perturbations of a large magnitude (p <0.05), whereas the same participants generated higher stiffness about the ankle—a larger value in CCI—in response to perturbations of a small magnitude (p <0.05). These results indicate that participants use different postural strategies pertaining to circumstances. Further, the moment across the ankle decreased with repetitions of the same perturbation (p <0.05), and CCI tended to remain unchanged even in response to a different perturbation following repetition of the same perturbation (p <0.05). These findings suggest that ankle muscle contraction and co-contraction play different roles in regaining and maintaining postural stability. This study demonstrates that ankle moment and stiffness are not correlated in response to external perturbations.