Posture enhancement with cerebellum transcranial electrical stimulation: a systematic review of current methods and findings.

Recently, transcranial electrical stimulation (tES) has gained increasing popularity among researchers, especially for recovery and improvement, but interpretation of these results is difficult due to variations in study methods and outcome measurements. The main goal of this study was to better understand the postural and balance indicators affected by cerebellar tES, as the cerebellum is the main brain region responsible for controlling balance. For this systematic literature review, three databases were searched for articles where the cerebellum was stimulated by any type of tES in either healthy participants or those with neurologic disorders. Postural, dynamic, and/or static stability measurements were recorded, and risk of bias was assessed on the PEDro scale. A total of 21 studies were included in the analysis. 17 studies reported improvements after application of tES. 14 studies stimulated the cerebellum unilaterally and 15 used this modality for 20 min. Moreover, all studies exclusively used transcranial direct current as the type of stimulation. Evaluation of PEDro results showed that studies included in the analysis utilized good methodology. Although there were some inconsistencies in study results, overall, it was demonstrated that tES can improve balance and postural index under both healthy and neurological conditions. Further research of bilateral cerebellar stimulation or the use of transcranial alternating current stimulation, transcranial random noise stimulation, and transcranial pulsed current stimulation is needed for a more comprehensive assessment of the potential positive effects of cerebellar tES on the balance system.

Functional electrical stimulation to enhance reactive balance among people with hemiparetic stroke.

BACKGROUND: Individuals with stroke demonstrate a twofold higher fall incidence compared to healthy counterparts, potentially associated with deficits in reactive balance control, which is crucial for regaining balance from unpredictable perturbations to the body. Moreover, people with higher stroke-related motor impairment exhibit greater falls and cannot recover balance during higher perturbation intensities. Thus, they might need supplemental agents for fall prevention or even to be included in a perturbation-based protocol. Functional electrical stimulation is a widely used clinical modality for improving gait performance; however, it remains unknown whether it can enhance or interfere with reactive balance control. METHODS: We recruited twelve ambulatory participants with hemiparetic stroke (61.48 ± 6.77 years) and moderate-to-high motor impairment (Chedoke-McMaster Stroke Leg Assessment ≤ 4/7). Each participant experienced 4 unpredicted paretic gait-slips, with and without functional electrical stimulation (provided 50-500 ms after perturbation) in random order. The paretic quadriceps muscle group was chosen to receive electrical stimulation, considering the role of support limb knee extensors for preventing limb-collapse. Outcomes including primary (laboratory falls), secondary (reactive stability, vertical limb support) and tertiary (compensatory step length, step initiation, execution time) measures were compared between the two conditions. RESULTS: Participants demonstrated fewer falls, higher reactive stability, and higher vertical limb support (p < 0.05) following gait-slips with functional electrical stimulation compared to those without. This was accompanied by reduced step initiation time and a longer compensatory step (p < 0.05). CONCLUSION: The application of functional electrical stimulation to paretic quadriceps following gait-slips reduced laboratory fall incidence with enhanced reactive balance outcomes among people with higher stroke-related motor impairment. Our results lay the preliminary groundwork for understanding the instantaneous neuromodulatory effect of functional electrical stimulation in preventing gait-slip falls, future studies could test its therapeutic effect on reactive balance. Clinical registry number: NCT04957355.

Age-related differences in the capacity and neuromuscular control of the foot core system during quiet standing.

The foot core system is essential for upright stability. However, aging-induced changes in the foot core function remain poorly understood. The present study aimed to examine age-related differences in postural stability from the perspective of foot core capacity and neuromuscular control during quiet standing. Thirty-six older and 25 young adults completed foot core capacity tests including toe flexion strength, muscle ultrasonography, and plantar cutaneous sensitivity. The center of pressure (COP) and electromyography (EMG) of abductor hallucis (ABH), peroneus longus (PL), tibialis anterior (TA) and medial gastrocnemius (GM) were simultaneously recorded during double-leg and single-leg standing (SLS). EMG data were used to calculate muscle synergy and intermuscular coherence across three frequency bands. Compared to young adults, older adults exhibited thinner hallucis flexors, weaker toe strength, and lower plantar cutaneous sensitivity. The ABH thickness and plantar cutaneous sensitivity were negatively associated with the COP mean peak velocity in older adults, but not in young adults. Besides, older adults had higher cocontraction of muscles spanning the arch (ABH-PL) and ankle (TA-GM), and had lower beta- and gamma-band coherence of the ABH-PL and TA-PL during SLS. Foot core capacities became compromised with advancing age, and the balance control of older adults was susceptible to foot core than young adults in balance tasks. To compensate for the weakened foot core, older adults may adopt arch and ankle stiffening strategies via increasing muscle cocontraction. Furthermore, coherence analysis indicated that aging may increase the demand for cortical brain resources during SLS.

Trend change analysis of postural balance in Parkinson's disease discriminates between medication state.

BACKGROUND: Maintaining static balance is relevant and common in everyday life and it depends on a correct intersegmental coordination. A change or reduction in postural capacity has been linked to increased risk of falls. People with Parkinson's disease (pwPD) experience motor symptoms affecting the maintenance of a stable posture. The aim of the study is to understand the intersegmental changes in postural sway and to apply a trend change analysis to uncover different movement strategies between pwPD and healthy adults. METHODS: In total, 61 healthy participants, 40 young (YO), 21 old participants (OP), and 29 pwPD (13 during medication off, PDoff; 23 during medication on, PDon) were included. Participants stood quietly for 10 s as part of the Short Physical Performance Battery. Inertial measurement units (IMU) at the head, sternum, and lumbar region were used to extract postural parameters and a trend change analysis (TCA) was performed to compare between groups. OBJECTIVE: This study aims to explore the potential application of TCA for the assessment of postural stability using IMUs, and secondly, to employ this analysis within the context of neurological diseases, specifically Parkinson's disease. RESULTS: Comparison of sensors locations revealed significant differences between head, sternum and pelvis for almost all parameters and cohorts. When comparing PDon and PDoff, the TCA revealed differences that were not seen by any other parameter. CONCLUSIONS: While all parameters could differentiate between sensor locations, no group differences could be uncovered except for the TCA that allowed to distinguish between the PD on/off. The potential of the TCA to assess disease progression, response to treatment or even the prodromal PD phase should be explored in future studies. TRIAL REGISTRATION: The research procedure was approved by the ethical committee of the Medical Faculty of Kiel University (D438/18). The study is registered in the German Clinical Trials Register (DRKS00022998).

Repetitive temporal interference stimulation improves jump performance but not the postural stability in young healthy males: a randomized controlled trial.

BACKGROUND: Temporal interference (TI) stimulation, an innovative non-invasive brain stimulation technique, has the potential to activate neurons in deep brain regions. The objective of this study was to evaluate the effects of repetitive TI stimulation targeting the lower limb motor control area (i.e., the M1 leg area) on lower limb motor function in healthy individuals, which could provide evidence for further translational application of non-invasive deep brain stimulation. METHODS: In this randomized, double-blinded, parallel-controlled trial, 46 healthy male adults were randomly divided into the TI or sham group. The TI group received 2 mA (peak-to-peak) TI stimulation targeting the M1 leg area with a 20 Hz frequency difference (2 kHz and 2.02 kHz). Stimulation parameters of the sham group were consistent with those of the TI group but the current input lasted only 1 min (30 s ramp-up and ramp-down). Both groups received stimulation twice daily for five consecutive days. The vertical jump test (countermovement jump [CMJ], squat jump [SJ], and continuous jump [CJ]) and Y-balance test were performed before and after the total intervention session. Two-way repeated measures ANOVA (group × time) was performed to evaluate the effects of TI stimulation on lower limb motor function. RESULTS: Forty participants completed all scheduled study visits. Two-way repeated measures ANOVA showed significant group × time interaction effects for CMJ height (F = 8.858, p = 0.005) and SJ height (F = 6.523, p = 0.015). The interaction effect of the average CJ height of the first 15 s was marginally significant (F = 3.550, p = 0.067). However, there was no significant interaction effect on the Y balance (p > 0.05). Further within-group comparisons showed a significant post-intervention increase in the height of the CMJ (p = 0.004), SJ (p = 0.010) and the average CJ height of the first 15 s (p = 0.004) in the TI group. CONCLUSION: Repetitive TI stimulation targeting the lower limb motor control area effectively increased vertical jump height in healthy adult males but had no significant effect on dynamic postural stability.

Characteristics of static balance performance in 4-stage balance test in the healthy older adults.

BACKGROUND: The 4-Stage Balance test is one of the most commonly used tests to assess balance for older adults. Although it is generally accepted that the four positions (including side-by-side (SBSS), semi-tandem (STS), tandem (TS), and single-leg stance (SLS)) in this test are progressively more difficult, there are no studies comparing the balance parameters of the four positions in older adults to prove this result. The purpose of this study is to determine the difficulty of 4 positions in the 4-Stage Balance test and the effect of the dominant and non-dominant lower extremities on static balance among healthy older adults. METHODS: A total of 115 community-dwelling healthy older adults were included. The postural parameters (including sway range standard deviation (SR), velocity of body sway (V), total sway area (TSA) and sway perimeter (TSP) of the center of pressure) were measured during 8 static postures (including SBSS, left STS, right STS, left TS, right TS, left SLS, right SLS and comfortable stance (CS)). Repeated measures ANOVA was used to analyze the postural parameters in 8 static postures. RESULTS: The static balance stability of the five stances in older adults can be ranked in the following sequence: CS > SBSS/STS > TS > SLS. Moreover, changing foot placement in STS, TS and SLS tasks has no influence on stability. This study has been registered in China Clinical Trial Registry (ChiCTR2200065803). CONCLUSIONS: Our findings suggest that it is feasible to simplify the 4-Stage Balance test to a 3-Stage Balance test in the older adults.

Research on the Postural Stability of Underwater Bottom Platforms with Different Burial Depths.

The bottom platform is an important underwater sensor that can be used in communications, early warning, monitoring, and other fields. It may be affected by earthquakes, winds, waves, and other loads in the working environment, causing changes in posture and affecting its sensing function. Therefore, it is of practical engineering significance to analyze the force conditions and posture changes in the bottom platform. In order to solve the problem of postural stability of the underwater bottom platform, this paper establishes a fluid and structural simulation model of the underwater bottom platform. First, computational fluid dynamics (CFD) technology is used to solve the velocity distribution and forces in the watershed around the bottom platform under a 3 kn ocean current, where the finite element method (FEM) numerical calculation method is used to solve the initial equilibrium state of the bottom platform after it is buried. On this basis, this paper calculates the forces on the bottom platform and the posture of the bottom platform at different burial depths under the action of ocean currents. Additionally, the effects of different burial depths on the maximum displacement, deflection angle, and postural stability of the bottom platform are studied. The calculation results show that when the burial depth is greater than 0.6 m, and the deflection angle of the bottom platform under the action of the 3 kn sea current is less than 5°, the bottom platform can maintain a stable posture. This paper could be used to characterize the postural stability of underwater bottom platforms at different burial depths for the application of underwater sensors in ocean engineering.

Postural Stability and Pedobarography After Reconstruction of Peroneus Brevis Tendon Split Lesion.

PURPOSE: Lesions of the peroneal tendons are frequently overseen after ankle sprain. The symptoms consist of stress-dependent pain that extends from the inframalleolar to the proximal part along the course of the peroneal tendons as well as ankle instability and soft-tissue swelling. In case of unsuccessful conservative treatment, surgical therapy is recommended. The aim of the study was to evaluate the clinical and functional outcome after open reconstruction of the peroneus brevis tendon. METHODS: 13 patients were included in this retrospective study. All of them received a single reconstruction of the peroneus brevis tendon in open technique. Postoperative results were evaluated with the AOFAS score, a functional and perdobargraphic analysis as well as measuring postural stability with the Biodex balance system. The participants were matched with a healthy control group according to age, sex and BMI. RESULTS: The results of the AOFAS score showed significantly convincing results in all subscores postoperatively. A bilateral comparison of the postural stability showed that the affected side had become functionally similar to the healthy side. No statistical significant difference was detected concerning both one-legged and two-legged standing with the control group. Pedobarographic results revealed no difference between the affected and contralateral side, as well as between the patients and the healthy control group. CONCLUSION: Open reconstruction of the peroneus brevis tendon leads to significant better postoperative results and can be recommended after unsuccessful conservative treatment as promising option.

Effects of Plyometric-Based Hydro-Kinesiotherapy on Pain, Muscle Strength, Postural Stability, and Functional Performance in Children with Hemophilic Knee Arthropathy: A Randomized Trial.

AIM: To explore how plyometric-based hydro-kinesiotherapy (Plyo-HKT) would affect pain, muscle strength, postural stability, and functional performance in a convenience sample of children with hemophilic knee arthropathy (HKA). METHODS: Forty-eight children with HKA (age: 8-16 years) were randomly allocated to the Plyo-HKT group (n = 24; underwent the Plyo-HKT for 45 min, twice/week over 12 wk in succession) or the comparison group (n = 24; performed the standard exercise rehabilitation at an equivalent frequency and duration). Pain, peak concentric torque of quadriceps and hamstring (produced at two angular velocities: 120 and 180 o/sec), dynamic limits of postural stability (DLPS), and functional performance [Functional Independence Score in Hemophilia (FISH) and 6-Minute Walk Test (6-MWT)] were assessed pre- and post-intervention. RESULTS: In contrast with the comparison group, the Plyo-HKT group achieved more favorable pre-to-post changes in pain (p = .028, η2p = 0.10), peak torque of quadriceps [120°/sec (p = .007, η2P = 0.15); 180°/sec (p = .011, η2P = 0.13)] and hamstring [120°/sec (p = .024, η2P = 0.11); 180°/sec (p = .036, η2P = 0.09)], DLPSdirectional [forward (p = .007, η2P = 0.15); backward (p = .013, η2P = 0.12); affected side (p = .008, η2P = 0.14); non-affected side (p = .002, η2P = 0.20)], DLPSoverall (p < .001, η2P = 0.32), and functional performance [FISH (p < .001, η2p = 0.26); 6-MWT (p = .002, η2p = 0.19)]. CONCLUSION: Plyo-HKT is likely helpful for reducing pain, improving strength, enhancing postural stability, and boosting functional capabilities in children with HKA. Physical rehabilitation practitioners should, therefore, consider this intervention strategy.

Characterizing Longitudinal Alterations in Postural Control Following Lower Limb Injury in Professional Rugby Union Players.

Assessment of player's postural control following a lower limb injury is of interest to sports medicine practitioners due to its fundamental role in daily tasks and sporting activities. The aim was to longitudinally monitor professional rugby union players' postural control during each phase of the rehabilitation program (acute, middle, and late) following a lower limb injury. Seven male rugby union players (height 1.80 [0.02] m; mass 100.3 [11.4] kg; age 24 [4] y) sustained a time loss, noncontact lower limb injury. Static postural control was assessed via sway path (in meters), and dynamic postural control was assessed via vertical postural stability index. Group differences (P < .05) were reported across the acute, middle, and late phase. Smaller magnitudes of sway path were observed for eyes-open sway path, and for the middle and late phase smaller magnitudes of vertical postural stability index (P < .05) at the end session compared with first session. Whereas larger magnitudes of vertical postural stability index were found between baseline and the last session (P < .05). Large interindividual and intraindividual variation was apparent across the 3 phases of rehabilitation. Postural control improvements were identified during rehabilitation. However, postural control did not return to baseline, with altered kinetics throughout each rehabilitation phase.

Evaluation of measurement reliability for selected indices of postural stability based on data from the GYKO Inertial Sensor System.

The main aim of this study is to use comprehensive statistical analyses to evaluate measurement reliability of selected variables that characterize postural stability. The study examined twenty-nine healthy non-athlete students. The examinations were performed twice, with a one-week interval. The Microgate GYKO inertial sensor system was used to evaluate the reliability of variables that characterize postural stability. The relative reliability of the repeated test was evaluated using the intraclass correlation coefficient (ICC) with 95% confidence interval (95% CI). Next, the standard error of measurement (SEM) and minimal detectable change (MDC) were computed. Relative reliability of the repeated test for all analysed variables of ICC ranged from 0.31 to 0.75. For four variables, ICC values were ca. 0.7, i.e., they can be considered as good. For four other variables, ICC ranged from 0.41 to 0.54, with these values considered fair. Satisfactory reproducibility of postural stability measurements using the GYKO inertial sensor system demonstrates that it can offer an inexpensive and efficient alternative to measurements that use force balance platforms.

Correlation between postural stability and fall risk in trans-femoral amputees due to muscle fatigue.

[Purpose] This study aimed to establish a connection between postural stability and falling in individuals with transfemoral amputation (TFA), particularly with muscle fatigue. [Participants and Methods] Fourteen participants were recruited. Muscle fatigue was induced using a sit-to-stand (STS) fatigue protocol. Pre-fatigue and post-fatigue assessments were conducted using the Biodex Balance System (BBS). [Result] The findings of the study revealed significant increases in the postural stability index between the pre-fatigue and post-fatigue conditions for the TFA group, particularly in the overall stability index (OSI) and anterior-posterior stability index (APSI) components. The mean postural stability index scores for the TFA group exhibited a percentage increase of 65.2% for OSI, 52.7% for APSI, and 50% for medial-lateral stability index (MLSI). Furthermore, the TFA fall risk index surged by 61.4%. Regarding the relationships observed, a significant correlation emerged between fall risk and both OSI and APSI. [Conclusion] These findings underscore the impact of muscle fatigue on postural stability and an increase in fall risk among TFA. By mitigating the effects of muscle fatigue, therapists can play an important role in reducing the risk of falls and promoting better postural stability in this population.

Transcranial direct current stimulation over dorsolateral prefrontal cortex improves postural stability in non-specific chronic low back pain patients with high fear of pain: A randomized sham-controlled trial.

Deficits in postural stability in response to environmental challenges are seen in chronic low back pain (CLBP) patients with high fear of pain (HFP). Hence, it is essential to follow effective approaches to treat postural stability deficits and improve the health status of these patients. The current study aimed to compare the effects of cathodal and anodal transcranial direct current stimulation (c-tDCS and a-tDCS) over the left dorsolateral prefrontal cortex (DLPFC) on postural stability in non-specific CLBP patients with HFP. In this randomized clinical trial study, 75 patients were randomly assigned to left DLPFC a-tDCS, left DLPFC c-tDCS and sham stimulation groups (n = 25 in each group). All groups received a single-session 2 mA tDCS for 20 min, but the stimulation was slowly turned off after 30 s in the sham group. Before, immediately, 24 h and 1 week after the interventions, postural stability indices were assessed using a Biodex Balance System. A significant reduction in most indices was shown in both a-tDCS and c-tDCS groups after interventions (immediately, 24 h and 1 week follow-up) during static and dynamic postural tasks compared with the sham tDCS group (p < .01). In addition, some tests showed a significant difference between a-tDCS and c-tDCS (p < .05). The findings indicated positive effects of both a-tDCS and c-tDCS on the left DLPFC, with more efficacy of a-tDCS on postural stability in LBP patients with HFP.

Postural stability and its relation to knee flexor/extensor strength ratio in women with mild to moderate unilateral knee osteoarthritis: a case-control study.

PURPOSE/AIM: Knee muscles strength is an important factor influencing postural stability in patients with knee osteoarthritis (KOA). However, there is no evidence regarding the relationship between the knee flexor/extensor strength ratio, which is suggested to be a good indicator of knee stability, and postural stability. We aimed to investigate postural stability and its relation to knee flexor and extensor strength and strength symmetry in women with KOA. MATERIALS AND METHODS: Thirty-five women with unilateral KOA and thirty-five asymptomatic women were assessed with the Prokin system to collect the following parameters during quiet standing with eyes-open and eyes-closed: ellipse area, perimeter, forward-backward standard deviation, mediolateral standard deviation, the average centre of pressure displacement on the x- and y-axises (COPX and COPY), and the limit of stability (LoS) score. Higher scores mean better balance for LoS and poorer balance for other parameters. Knee flexor and extensor strength were assessed bilaterally with the Lafayette hand-held dynamometer. RESULTS: The COPX during standing with eyes-closed was higher in women with KOA than controls and the LoS score was lower (p < 0.05, Cohens'd = 0.72 and 0.65). Postural stability was correlated with knee muscles strength and the flexor/extensor strength ratios in both groups (r = between 0.395 and 0.456 for LoS, r = between -0.335 and -0.639 for the others, p < 0.05). CONCLUSIONS: Women with KOA had poorer postural stability in the mediolateral direction during standing with eyes-closed and a worse LoS score than controls. Postural stability was related to knee flexor and extensor strength and the flexor/extensor strength ratio in women.

Postural stability measures in healthy miniature Dachshunds obtained using a pressure mat and a force platform: a validity and reliability study.

BACKGROUND: Miniature Dachshunds have a high prevalence of neurological and musculoskeletal diseases potentially affecting their balance. The postural stability of dogs in quiet standing is an indicator of postural control and can aid in diagnosing and monitoring lameness and other pathologies affecting balance. Measures of centre of pressure (CoP) can be obtained from force and pressure platform systems to evaluate postural stability, however the two systems have not been compared and the latter has not been validated in dogs. The aims of this study were to assess the validity and reliability of using a pressure mat compared to a force platform and report normative values of CoP measures in healthy miniature Dachshunds. Forty two healthy miniature Dachshunds of smooth, long and wire-haired breed types stood still on a pressure mat (Tekscan MatScan®) placed on a force platform and the two systems were synchronised. Maximum anterior-posterior (AP) and medial-lateral (ML) ranges, sway path and 95% area of a best-fit ellipse were computed. Bland-Altman plots and coefficients of correlation assessed validity; intra-class correlation coefficients (ICC) assessed inter-test reliability for both systems. Non-linear regression analyses were used to describe the relationship between CoP and demographic measures. RESULTS: Strong correlations for AP range, ML range and 95% ellipse area and moderate correlation for sway path were found between the two devices. ICC showed good reliability (0.75-0.90) for AP range and moderate (0.5-0.75) for ML range and the 95% ellipse area for both devices. Sway path reliability was excellent (> 0.90) with the force platform but moderate with the pressure mat. Age was positively correlated with balance (inversely correlated with all measures except sway path), while weight explained 94% (force platform) and 27% (pressure mat) of the variance in sway path. CONCLUSIONS: Pressure mats can be used to obtain valid and reliable measures of CoP and replace use of force platforms. Older (non-senior) and heavier (non-obese) dogs show better postural stability. Clinical examinations should include the use of a range of CoP measures when assessing postural balance, while accounting for the effects of age and body weight.

Factors associated with balance impairments in the community-dwelling elderly in urban China.

BACKGROUND: Identification of factors relevant to balance performance impairments in the elderly population was critical for developing effective interventions and preventions. However, there have been very limited data available based on large scale studies. The present study identified factors that independently contributed to performance impairments in overall balance, domains of static balance, postural stability, and dynamic balance, and individual items. METHODS: A total of 1984 community-dwelling Chinese elderly from urban areas of Shanghai were recruited. Information on demographic characteristic, exercise, and health status were collected with a face-to-face interview. Balance performances were assessed on site by trained investigators based on the X16 balance testing scale. To identify the effectors, ordinal logistic regression analysis was applied for overall balance, static balance, postural stability, and dynamic balance. Binary logistic regression analysis was used for 16 items. RESULTS: The community-dwelling elderly residents were aged from 60 to 97 years old. With increases of age, risks of impairments in overall balance increased gradually (ORs from 1.26 to 3.20, all P < 0.01). In the elderly with overweight and obesity, there was higher proportion of balance impairments compared to the elderly with normal BMI (OR = 1.26, P < 0.001). Regular exercise every week was associated with reduced risks of balance impairments (ORs from 0.63 to 0.73, all P < 0.001). Presences with vision lesion (ORs from 1.28 to 1.59, all P < 0.001), moderate hearing impairment (OR = 1.54, P < 0.001), somesthesis dysfunction (ORs from 1.59 to 13.26, all P < 0.001), and cerebrovascular disease (OR = 1.45, P = 0.001) were related to increased risks of balance impairments. Likewise, age, exercise, vision, hearing, somesthesis, and cerebrovascular disease were significantly associated with static balance, postural stability, and dynamic balance. Both overweight and obesity and underweight were associated with higher proportions of dynamic balance impairments. Regular exercise was significantly related to reduced risks of impairments in 15 out of the 16 items. CONCLUSIONS: In the elderly, age, overweight and obesity, exercise, vision, hearing, somesthesia, and cerebrovascular disease were dominant factors associated with impairments in overall balance, domains of static balance, postural stability, and dynamic balance, and most individual items. TRIAL REGISTRATION: Not applicable.

New balance capability index as a screening tool for mild cognitive impairment.

BACKGROUND: Mild cognitive impairment (MCI) is not just a prodrome to dementia, but a very important intervention point to prevent dementia caused by Alzheimer's disease (AD). It has long been known that people with AD have a higher frequency of falls with some gait instability. Recent evidence suggests that vestibular impairment is disproportionately prevalent among individuals with MCI and dementia due to AD. Therefore, we hypothesized that the measurement of balance capability is helpful to identify individuals with MCI. METHODS: First, we developed a useful method to evaluate balance capability as well as vestibular function using Nintendo Wii balance board as a stabilometer and foam rubber on it. Then, 49 healthy volunteers aged from 56 to 75 with no clinically apparent cognitive impairment were recruited and the association between their balance capability and cognitive function was examined. Cognitive functions were assessed by MoCA, MMSE, CDR, and TMT-A and -B tests. RESULTS: The new balance capability indicator, termed visual dependency index of postural stability (VPS), was highly associated with cognitive impairment assessed by MoCA, and the area under the receiver operating characteristic (ROC) curve was more than 0.8, demonstrating high sensitivity and specificity (app. 80% and 60%, respectively). CONCLUSIONS: Early evidence suggests that VPS measured using Nintendo Wii balance board as a stabilometer helps identify individuals with MCI at an early and preclinical stage with high sensitivity, establishing a useful method to screen MCI.

Postural adaptations within normalized stability between older adults with and without chronic low back pain.

BACKGROUND: Adaptations of dynamic balance performance are related to sway excursions in older adults with chronic low back pain (LBP). However, there is a lack of understanding on postural control within different thresholds of radius from the center of pressure (COP). PURPOSE: This study was conducted to compare the normalized stability based on the time-in-boundary (TIB) during repeated unilateral limb standing trials between subjects with and without chronic LBP. METHODS: There were 26 older adults with LBP and 39 control subjects who completed three trials of repeated unilateral limb standing on a force plat. RESULTS: The TIB based on the seven thresholds was analyzed, and the groups demonstrated a significant interaction on thresholds for TIB (F = 8.76, p = 0.01). The TIB was significantly different in the 10 mm (F = 4.01, p = 0.04), 15 mm (F = 5.21, p = 0.03), and 20 mm (F = 4.48, p = 0.04) radius of thresholds only in the second trial. However, there was no group difference on TIB at the first and third trials due to potential compensatory and/or adaptive reactions to avoid fall risks. CONCLUSION: The LBP group lacked postural stability within the thresholds less than a 20 mm radius at the second trial of unilateral standing. The significant group interaction with the thresholds indicates an adaptation strategy on sway thresholds. This postural reaction from repeated trials should be considered with sway excursion adjustments and fall prevention in older adults with LB.

Effects of non-extensible lumbar belts on static and dynamic postural stability.

BACKGROUND: Previous studies have found that increased intra-abdominal pressure helps to reduce spinal loading and improve spine stability. Non-extensible lumbar belts (NEBs) could elevate intra-abdominal pressure and augment spinal stability. NEBs have been used in the healthcare field to help reduce pain and improve spine function for people with low back pain. However, the effect of NEBs on static and dynamic postural stability is not clear. METHODS: This study aimed to investigate whether NEBs affect static and dynamic postural stability. Twenty-eight healthy male subjects were recruited to finish four static postural stability tasks and two dynamic postural stability tests. Center of pressure (COP) values during 30 s of quiet standing, dynamic postural stability index (DPSI) and Y balance test (YBT) score with and without NEBs were analyzed. RESULTS: NEBs had no significant effect in all COP variables in the static postural tasks. The results of a repeated measure two-way ANOVA indicated the NEBs significantly improved the dynamic postural stability in YBT score and DPSI (F (1,27) = 5.506, p = .027, [Formula: see text] and F (1,27) = 83.94, p = .000, [Formula: see text] respectively). CONCLUSIONS: The study results indicate that non-extensible belts improve dynamic stability in healthy male participants, with potential implications for rehabilitation and performance enhancement programs.

Balance assessment in selected stages of Parkinson's disease using trend change analysis.

BACKGROUND: Balance disorders in patients diagnosed with Parkinson's disease (PD) are associated with a change in balance-keeping strategy and reflex disorders which regulate the maintenance of vertical body posture. Center of foot pressure (COP) displacement signals were analyzed during quiet standing experiments to define such changes. The research aimed to apply stock exchange indices based on the trend change analyses to the assessment of a level of the Parkinson disease progression on the grounds of the analysis of the COP signals. METHODS: 30 patients in two stages of PD, 40 elderly participants, and 20 individuals at a young age were studied. Each person was subjected to 3 measurements with open and closed eyes. A technical analysis of the COP displacement signal was performed, and the following quantities were determined: indices related to the number of trend changes (TCI), indices defining a mean time (TCI_dT), and mean displacement (TCI_dS) and mean velocity (TCI_dV) between such changes. RESULTS: The results indicate a higher TCI value for PD than for aged-matched control group (p < 0.05). In the case of PD patients, there was also an increase in the TCI_dS value by 2-5 mm, which mainly contributed to the increase in TCI_dV. Statistically significant differences for the TCI_dT values occurred between all groups in which differences in the average COP velocity were noted. CONCLUSIONS: The TCI and TCI_dV results obtained for the healthy participants enabled the development of indices supporting PD diagnostics. The causes of the TCI_dV changes in patients were determined, i.e., whether they resulted from an increase in the TCI_dT or TCI_dS between the moments of trend changes indicated by the developed algorithm. The developed methodology provides new information on the impact of PD on the strategy of maintaining balance, which was impossible to obtain using currently used analyses. Trial registration The conducted research is an observational study and does not include a health care intervention. Participants gave their consent to participate in the research and the procedure was approved by the Institutional Bioethics Committee.