Evaluation of the balance function before and after total knee arthroplasty using Berg balance scale.

INTRODUCTION: The purpose of this study was to evaluate balance function before and after total knee arthroplasty (TKA) using Berg balance scale (BBS). The study also aimed to identify factors associated with balance impairment. MATERIALS AND METHODS: Ninety-three knees in 90 patients were prospectively evaluated using their BBS scores, passive knee extension/flexion angles, Visual analogue scale for pain scores, hip-knee-ankle angles, and knee extensor/flexor muscle strengths before and after TKA. A total BBS score of less than 45 indicates an enhanced risk of multiple falls. Multivariate logistic regression models were performed to elucidate factors associated with post-operative BBS score. RESULTS: A significant difference in mean pre- and post-operative BBS scores were noted (49.3 ± 6.4 vs. 52.2 ± 4.7) (p < 0.05). The percentage of pre- and post-operative BBS scores less than 45 were 20% and 10% (p < 0.05). Rheumatoid Arthritis (RA), lower pre-operative BBS score, and larger post-operative knee flexion contracture were significantly associated with lower post-operative BBS score (p < 0.01). The post-operative knee flexion contracture greater than 10° was significantly associated with substantially high odds of post-operative BBS scores less than 45 (Odds ratio 7.6; 95% confidential interval 1.69-34.17). CONCLUSIONS: While TKA significantly improved BBS scores, 10% of the patients remained at a risk for multiple falls. RA, lower pre-operative BBS score, and post-operative knee flexion contracture greater than 10° retained balance impairment even after TKA.

Balance and vestibular function and survival in US cancer survivors.

BACKGROUND: Cancer and its treatment damage the musculoskeletal system and induce neurotoxicity, affecting the key sensory inputs for maintaining balance. The present study describes the pattern of balance impairment and evaluated its association with mortality among US cancer survivors. METHODS: Data on a nationally representative sample of cancer survivors from the US National Health and Nutrition Examination Survey from 1999 to 2015 was analyzed. Sensory-specific balance impairment was measured at baseline by the modified Romberg test of standing balance on firm and compliant support surfaces. The linked mortality data were updated through December 31, 2015. RESULTS: Among 511 cancer survivors, 282 (48.3%) had a balance impairment, predominantly attributing to vestibular dysfunction (251; 89.0% of 282 and 44.5% of 511). A higher prevalence of balance impairment was observed among cancer survivors with advanced age, lower socioeconomic status or educational attainment, body mass index <25 kg/m2 , and an inactive lifestyle. During up to 16.4 years of follow-up (median, 11.3 years; 5088 person-years), 253 cancer survivors had died. Cancer survivors with a balance impairment had a 63% higher risk of death from all causes (hazard ratio, 1.63; 95% confidence interval [CI], 1.12-2.38) after adjusting for sociodemographic factors, comorbidities, and cancer type. Specifically, those with vestibular dysfunctions had approximately 1.54 (95% CI, 1.05-2.27) times the risk of death compared to those without any balance impairment. These associations were stronger in males than in females. CONCLUSIONS: In a US nationally representative sample of cancer survivors, balance impairment and vestibular dysfunctions were prevalent and associated with heightened all-cause mortality.

Mild hyponatremia is associated with low skeletal muscle mass, physical function impairment, and depressive mood in the elderly.

BACKGROUND: Mild hyponatremia (serum sodium 130-135 mEq/L) is a common electrolyte disorder in the elderly. However, its association with both sarcopenia and cognitive function remains to be clarified. Therefore, here we investigated the association of mild hyponatremia with skeletal muscle mass, physical function, and cognitive function in the elderly. METHODS: We enrolled 75 participants with mild hyponatremia and 2907 with normonatremia (serum sodium, 136-145 mEq/L) aged ≥70 years who visited the Memory Disorder Outpatient Center of Japan's National Center for Geriatrics and Gerontology. Skeletal muscle mass index (SMI), grip strength (GS), walking speed (WS), one-leg standing (OLS) test times, and neuropsychological test scores were determined. RESULTS: One-way analysis of covariance showed that elderly participants with mild hyponatremia had lower SMI (7.1 ± 0.2, 7.2 ± 0.2 kg/m2, p = 0.04), weaker GS (19.1 ± 1.9 vs 21.4 ± 1.8 kg, p = 0.01), slower WS (0.9 ± 0.1 vs 1.1 ± 0.1 m/s, p = 0.001), and higher GDS- 15 score (6.4 ± 0.9 vs 5.2 ± 0.9, p = 0.002) than those with normonatremia. Multiple logistic regression analysis indicated that mild hyponatremia was independently associated with sarcopenia (odds ratio [OR]: 2.2, p = 0.02), slower WS (OR: 5.3, p = 0.04) and shorter OLS time (OR: 2.5, p = 0.02) as well as with severe depressive mood (OR: 2.6 p = 0.006) but not with SMI (OR: 1.6, p = 0.2) or GS (OR: 1.9, p = 0.09). CONCLUSIONS: Our results suggest that elderly people with even mild hyponatremia had physical function impairment and depressive mood.

Deep Neural Networks for Human's Fall-risk Prediction using Force-Plate Time Series Signal.

Early and accurate identification of the balance deficits could reduce falls, in particular for older adults, a prone population. Our work investigates deep neural networks' capacity to identify human balance patterns towards predicting fall-risk. Human balance ability can be characterized based on commonly-used balance metrics, such as those derived from the force-plate time series. We hypothesized that low, moderate, and high risk of falling can be characterized based on balance metrics, derived from the force-plate time series, in conjunction with deep learning algorithms. Further, we predicted that our proposed One-One-One Deep Neural Networks algorithm provides a considerable increase in performance compared to other algorithms. Here, an open source force-plate dataset, which quantified human balance from a wide demographic of human participants (163 females and males aged 18-86) for varied standing conditions (eyes-open firm surface, eyes-closed firm surface, eyes-open foam surface, eyes-closed foam surface) was used. Classification was based on one of the several indicators of fall-risk tied to the fear of falling: the clinically-used Falls Efficacy Scale (FES) assessment. For human fall-risk prediction, the deep learning architecture implemented comprised of: Recurrent Neural Network (RNN), Long-Short Time Memory (LSTM), One Dimensional Convolutional Neural Network (1D-CNN), and a proposed One-One-One Deep Neural Network. Results showed that our One-One-One Deep Neural Networks algorithm outperformed the other aforementioned algorithms and state-of-the-art models on the same dataset. With an accuracy, precision, and sensitivity of 99.9%, 100%, 100%, respectively at the 12th epoch, we found that our proposed One-One-One Deep Neural Network model is the most efficient neural network in predicting human's fall-risk (based on the FES measure) using the force-plate time series signal. This is a novel methodology for an accurate prediction of human risk of fall.

Development and Validation of an Exercise Programme for Recovery Balance Impairments in Poststroke Patients.

BACKGROUND: Deterioration of balance is one of the most common and disabling physical-motor deficits in patients after a stroke that have a negative impact on quality of life and increase the risk of falls. Previous studies have evaluated the effectiveness of the exercises on specific aspects of balance. However, there is no structured exercise program divided by levels for balance impairment in poststroke patients. METHODS: Delphi method was used to design the exercise programme, and then a pilot study was performed. For the pilot study, we included 14 poststroke adults patients (n = 7 in each group), with balance impairment, without previous severe functional dependence, sensorial deficit or dementia. Our 4 weeks intervention (5 times/week) is based on 9 exercise of progressive difficulty, offering a multidimensional approach training (biomechanical constraints, stability limits, anticipatory, postural responses, and sensory orientation). Patients in the intervention arm received 45 minutes of usual rehabilitation plus 15 minutes of the intervention proposed. The usual-care arm received 60 minutes of usual rehabilitation. Balance impairment (Mini BESTest) was assessed at the baseline and at 4 weeks. Differences between groups were analysed using Mann-Whitney U test. RESULTS: The agreement for the intervention designed was reached after 2 rounds. Participants in pilot study were 69 (SD = 9.7) years, 21.4% females. Post-treatment, median improvements in Mini BESTest were 20 (SD = 8) and 11 (SD = 10) points, P < .01 for intervention and control group respectively. CONCLUSION: A multidimensional approach of balance impairments in poststroke patients through the validated exercise programme proposed, may improve balance deficits.

The Influence of Audio-Visual Cueing (Traffic Light) on Dual Task Walking in Healthy Older Adults and Older Adults with Balance Impairments.

BACKGROUND: The walking gait of older adults with balance impairment is affected by dual tasking. Several studies have shown that external cues can stimulate improvement in older adults' performance. There is, however, no current evidence to support the usefulness of external cues, such as audio-visual cueing, in dual task walking in older adults. Thus, the aim of this study was to investigate the influence of an audio-visual cue (simulated traffic light) on dual task walking in healthy older adults and in older adults with balance impairments. METHODS: A two-way repeated measures study was conducted on 14 healthy older adults and 14 older adults with balance impairment, who were recruited from the community in Chiang Rai, Thailand. Their walking performance was assessed using a four-metre walking test at their preferred gait speed and while walking under two further gait conditions, in randomised order: dual task walking and dual task walking with a simulated traffic light. Each participant was tested individually, with the testing taking between 15 and 20 minutes to perform, including two-minute rest periods between walking conditions. Two Kinect cameras recorded the spatio-temporal parameters using MFU gait analysis software. Each participant was tested for each condition twice. The mean parameters for each condition were analysed using a two-way repeated measures analysis of variance (ANOVA) with participant group and gait condition as factors. RESULT: There was no significant between-group effect for walking speed, stride length and cadence. There were also no significant effects between gait condition and stride length or cadence. However, the effect between gait condition and walking speed was found to be significant [F(1.557, 40.485) = 4.568, P = 0.024, [Formula: see text]]. CONCLUSION: An audio-visual cue (simulated traffic light) was found to influence walking speed in both healthy older adults and in older adults with balance impairment. The results suggest that audio-visual cues could be incorporated into healthy lifestyle promotion in older adults with balance impairment.

Stroke walking and balance characteristics via principal component analysis.

Balance impairment is associated gait dysfunction with several quantitative spatiotemporal gait parameters in patients with stroke. However, the link between balance impairments and joint kinematics during walking remains unclear. Clinical assessments and gait measurements using motion analysis system was conducted in 44 stroke patients. This study utilised principal component analysis to identify key joint kinematics characteristics of patients with stroke during walking using average joint angles of pelvis and bilateral lower limbs in every gait-cycle percentile related to balance impairments. Reconstructed kinematics showed the differences in joint kinematics in both paretic and nonparetic lower limbs that can be distinguished by balance impairment, particularly in the sagittal planes during swing phase. The impaired balance group exhibited greater joint variability in both the paretic and nonparetic limbs in the sagittal plane during entire gait phase and during terminal swing phase respectively compared with those with high balance scores. This study provides a more comprehensive understanding of stroke hemiparesis gait patterns and suggests considering both nonparetic and paretic limb function, as well as bilateral coordination in clinical practice. Principal component analysis can be a useful assessment tool to distinguish differences in balance impairment and dynamic symmetry during gait in patients with stroke.

Improvement in Body's Dynamic Adaptation during Walking with Vestibular Rehabilitation Therapy in Patients with Cerebellopontine Angle Tumor Resection.

BACKGROUND: Our study aimed to investigate the effects of vestibular rehabilitation therapy on functional gait performance in patients with balance disorders. METHODS: A total of 40 post-operative patients with balance disorders were included in the study. They were divided into two groups and participated in a vestibular rehabilitation program during their hospital stay. After discharge, the intervention group performed vestibular exercises at home, while the control group did not. Balance was assessed using the Functional Gait Assessment Scale at discharge and three months after surgery. RESULTS: The intervention group included 15 women and 5 men with an average age of 45 years, while the control group included 7 women and 13 men with an average age of 50 years. Three months after surgery, the change in Functional Gait Assessment (FGA) scores exceeded the clinically significant threshold of 5 points in 17 patients in the intervention group and 14 in the control group. There was a statistically significant difference in FGA progression between the groups (p = 0.034). After three months post-surgery, 7 patients in the intervention group experienced falls compared to 12 in the control group. CONCLUSION: Three months after surgery, we observed a significant improvement in the performance of balance tasks while walking and a lower risk of falls in the intervention group.

Comparison of the Ability of Static and Dynamic Balance Tests to Determine the Risk of Falls among Older Community-Dwelling Individuals.

This study aimed to examine the validity of balance tests and compare their diagnostic accuracy to determine the risk of falls among older community-dwelling individuals. Eighty-five older participants were assessed based on their demographics and fall data. They were then assessed for the ability to perform balance measures, including five times sit-to-stand tests (FTSSTs), timed up and go tests (TUGs), three times stand and walk tests (TTSWs), functional reach tests (FRTs), and single-leg stance tests (SLSs). The correlation between fall data and balance measures was found to be significant for all parameters (p < 0.05). The TTSW showed the highest level of ability to indicate the risk of falls among older community-dwelling adults with sensitivity = 92.68%, specificity = 84.09%, and AUC = 0.931 (95%CI = 0.860 to 1.000). These findings confirm the benefits of the practical functional balance measures to determine the risk of falls among older community-dwelling individuals.

Struggling to Keep Up and Have a Good Life: A Qualitative Study of Living With Impaired Balance Control Due to Multiple Sclerosis.

OBJECTIVE: We aimed to explore and describe the experiences of people with multiple sclerosis (MS) living with impaired balance control and how balance impairment can be managed in everyday life. METHODS: A qualitative design was used. Data were collected through semistructured interviews. Transcripts were analyzed using qualitative inductive content analysis. Sixteen participants (12 women) with MS and variation in level of balance control were interviewed. Age ranged between 35 and 64 years, and overall MS-disability ranged between 2.0 (mild) and 5.5 (moderate) according to the Expanded Disability Status Scale. RESULTS: Five main categories emerged: Balance is an automatic skill that now requires attention; contributors to balance impairment; burdens of balance impairment; management of balance impairment; and negotiation between capacity and ambition for continuing the good life. Body functions emphasized as central to keeping balance were somatosensory-motor functions, vision, and management of fatigue. Day-to-day variation in capacity and being in stimuli-rich environments were conditions highlighted as impacting balance. The main categories yielded the overarching theme of being restrained by impaired balance control and struggling to keep up. CONCLUSION: Participants with MS described balance impairment as balance no longer being an automatic skill and having an adverse impact on everyday life. A strong effort was shown to not let shortcomings control and determine quality of life. To manage limitations and restrictions and to move forward in the struggle to keep up a good life, an extensive toolbox of strategies aiming to minimize the impact of balance impairment was used to maintain quality of life. IMPACT: This study highlights the importance of person-centered health care in MS, with increased awareness of the individual perspective of how balance impairment is perceived. The person-centered focus increases both quality and efficiency in therapy since it involves the individual's thoughts of a life where participation in valued activities is less restricted.

The Effect of Upper Extremity Slings (UESs) on Balance in Young Adults.

INTRODUCTION: Upper extremity slings (UESs) are frequently provided for patients with a hand or forearm injury. However, their effect on balance has not been well explored. We sought to characterize the effect of a UES on balance in young adults. METHODS: Healthy young adult participants with no injuries acting as a proxy for the general young adult patient population using UESs balanced on a BioDex Balance System platform: once while wearing a UES and once without wearing it, to serve as their own control. Participant weight, height, gender, hand dominance, overall stability index, anterior/posterior stability index, and medial/lateral stability index were recorded. Comparisons were analyzed with paired t-tests and linear regression analysis.  Results: No significant difference in the three stability index scores were found between UES and no UES usage. Height and weight were found to have positive significant relationships with the overall stability index during UES usage.  Conclusions: Our study demonstrates the feasibility of assessing balance discrepancies between the sling and nonsling usage in a broader patient population and suggests that height and weight may impact balance negatively during UES use.

Differential Item Functioning of the Mini-BESTest Balance Measure: A Rasch Analysis Study.

The Mini-Balance Evaluation Systems Test (Mini-BESTest), a 14-item scale, has high content validity for balance assessment. This study further examines the construct validity of the Mini-BESTest with an emphasis on its measurement invariance. The Mini-BESTest was administered to 292 neurological patients in two sessions (before and after rehabilitation) and evaluated with the Rasch analysis (Many-Facet Rating Scale Model: persons, items, sessions). Categories' order and fit to the model were assessed. Next, maps, dimensionality, and differential item functioning (DIF) were examined for construct validity evaluation. DIF was inspected for several clinically important variables, including session, diagnosis, and assistive devices. Mini-BESTest items had ordered categories and fitted the Rasch model. The item map did not flag severe construct underrepresentation. The dimensionality analysis showed that another variable extraneous to balance affected the score of a few items. However, this multidimensionality had only a modest impact on measures. Session did not cause DIF. DIF for assistive devices affected six items and caused a severe measurement artefact. The measurement artefact caused by DIF for diagnosis was negligible. The Mini-BESTest returns interval measures with robust construct validity and measurement invariance. However, caution should be used when comparing Mini-BESTest measures obtained with and without assistive devices.

The influence of cognitive load on static balance in chronic obstructive pulmonary disease patients.

INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) may demonstrate cognitive function and balance deterioration. These two phenomena are often realized simultaneously during daily living activities, where the risk of falling may be increased due to possible postural disturbance when focusing on a cognitive task during motion. Despite the high rate of falls in COPD, there is currently a lack of affordable clinical instruments to quantify the interaction between cognitive tasks and static balance in these patients. Therefore, this study aims to assess the balance perturbation induced by cognitive tasks using a new cost-effective protocol which can easily be implemented in clinical settings. METHOD: A total of 21 COPD patients (Age: 64 ± 8 yrs, Forced Expiratory Volume in one second = 41 ± 17%, Women: 7) and 21 matched healthy controls participated in the study. They performed two cognitive tasks (counting backward by 3s and naming animals) with eyes open and with eyes closed. Each trial lasted 60 s, with balance-related parameters recorded and quantified using a Wii Balance Board. A three-way ANOVA (cognitive task, eyes action, and health status) for balance-related parameters derived from the center of pressure displacement was performed. RESULTS: COPD, vision, and cognitive tasks altered the balance; no interaction between conditions was observed. There was no correlation between cognitive ability, respiratory function, and the balance-related parameters. CONCLUSION: Compared to healthy controls, the COPD patients had impaired balance. Cognitive tasks altered postural control in both COPD and controls, where this alteration was more pronounced with eyes closed.

U-turn speed is a valid and reliable smartphone-based measure of multiple sclerosis-related gait and balance impairment.

BACKGROUND: People living with multiple sclerosis (MS) experience impairments in gait and mobility, that are not fully captured with manually timed walking tests or rating scales administered during periodic clinical visits. We have developed a smartphone-based assessment of ambulation performance, the 5 U-Turn Test (5UTT), a quantitative self-administered test of U-turn ability while walking, for people with MS (PwMS). RESEARCH QUESTION: What is the test-retest reliability and concurrent validity of U-turn speed, an unsupervised self-assessment of gait and balance impairment, measured using a body-worn smartphone during the 5UTT? METHODS: 76 PwMS and 25 healthy controls (HCs) participated in a cross-sectional non-randomised interventional feasibility study. The 5UTT was self-administered daily and the median U-turn speed, measured during a 14-day session, was compared against existing validated in-clinic measures of MS-related disability. RESULTS: U-turn speed, measured during a 14-day session from the 5UTT, demonstrated good-to-excellent test-retest reliability in PwMS alone and combined with HCs (intraclass correlation coefficient [ICC] = 0.87 [95 % CI: 0.80-0.92]) and moderate-to-excellent reliability in HCs alone (ICC = 0.88 [95 % CI: 0.69-0.96]). U-turn speed was significantly correlated with in-clinic measures of walking speed, physical fatigue, ambulation impairment, overall MS-related disability and patients' self-perception of quality of life, at baseline, Week 12 and Week 24. The minimal detectable change of the U-turn speed from the 5UTT was low (19.42 %) in PwMS and indicates a good precision of this measurement tool when compared with conventional in-clinic measures of walking performance. SIGNIFICANCE: The frequent self-assessment of turn speed, as an outcome measure from a smartphone-based U-turn test, may represent an ecologically valid digital solution to remotely and reliably monitor gait and balance impairment in a home environment during MS clinical trials and practice.

Preliminary Clinical Trial of Balance Compensation System for Improvement of Balance in Patients With Spinocerebellar Ataxia.

OBJECTIVE: To determine the immediate and short-term impact of the application of wearable balance compensation system (BCS) on balance impairment in patients with spinocerebellar ataxia (SCA). METHODS: The study enrolled 6 participants with SCA with varying degrees of balance impairment. After adjustment for individual fitting, wearable BCS with up to 3% body weight was placed in a garment on the trunk. Sway direction and magnitude were measured with sensors placed posteriorly at the lumbosacral junction, immediately before and after, and at day 1, day 2, and day 7 after wearing the BCS. Timed Up & Go test (TUG) and 25-foot timed walk test were performed, and static foot pressure was measured. RESULTS: A significant improvement in static and dynamic balance was found during the 25-foot timed walk and in static foot pressure measurement results after wearing the BCS, when compared with that at baseline (p=0.044 vs. p=0.011). Anterior and posterior sway showed improvements from baseline after wearing the BCS. Improvement in the lateral swaying movement control was also seen. CONCLUSION: Application of the BCS might be beneficial in the improvement ofthe static and dynamic balance in patients with SCA. Further research on long-term effects and with a larger sample size is indicated.

Prevalence of Pediatric Dizziness and Imbalance in the United States.

OBJECTIVES: Understand the prevalence of vestibular symptoms in US children. STUDY DESIGN: Cross-sectional analysis. SETTING: 2016 National Health Interview Survey. SUBJECTS AND METHODS: Responses from the 2016 National Health Interview Survey for children ages 3 to 17 years were examined to determine the prevalence of vestibular symptoms and provider-assigned diagnoses. RESULTS: Dizziness or imbalance was reported in 3.5 (95% confidence interval, 3.1-3.9) million patients (5.6%) with a mean age of 11.5 years. Dizziness was reported in 1.2 million patients (2.0%) with a mean age of 12.7 years and balance impairment in 2.3 million patients (3.7%) with a mean age of 10.6 years. Prevalence of dizziness and imbalance did not vary by sex (P = .6, P = .2). Evaluation by a health professional was reported for 42% of patients with dizziness and 43% of patients with imbalance, with diagnoses reported in 45% and 48% of patients with dizziness and imbalance, respectively. The most common diagnoses reported for dizziness were depression or child psychiatric disorder (12%), side effects from medications (11%), head/neck injury or concussion (8.4%), and developmental motor coordination disorder (8.3%). The most common diagnoses reported for imbalance were blurred vision with head motion, "bouncing" or rapid eye movements (9.1%), depression or child psychiatric disorder (6.2%), head/neck injury or concussion (6.1%), and side effects from medications (5.9%). CONCLUSION: The national prevalence of childhood vestibular symptoms is more common than previously thought. Reported diagnoses varied greatly from the literature, suggesting a need for increased awareness of causes of vestibular symptoms in children.

The effect of working memory intervention on the gait patterns of the elderly.

INTRODUCTION: The purpose of this study was to evaluate the role of working memory (WM) training on walking patterns in elderly people. METHODS: 20 elderly adults were selected and assigned randomly to two groups: WM training group and control group. WM training group received 6 weeks of computerized training on various spatial and verbal WM tasks. The spatial-temporal parameters, the ground reaction force and the timing activity of muscles in pre-posttest and in a follow-up were taken. RESULT: The results indicated that a significant change in gait speed, double support time and stride time (p < 0.05). Alternations in ground reaction force (GRF) components were found significant. Timing of muscle activity also showed non-significant change after WM intervention. CONCLUSION: Based on the results of this study, it can be concluded that WM intervention can be applied to improve gait parameters. The improvements in vertical ground reaction force after training may result in an increase upright stability and a decreased in rate falls.

Direction-Specific Instability Poststroke Is Associated With Deficient Motor Modules for Balance Control.

Defective muscle coordination for balance recovery may contribute to stroke survivors' propensity for falling. Thus, we investigated deficits in muscle coordination for postural control and their association to body sway following balance perturbations in people with stroke. Specifically, we compared the automatic postural responses of 8 leg and trunk muscles recorded bilaterally in unimpaired individuals and those with mild to moderate impairments after unilateral supratentorial lesions (>6 months). These responses were elicited by unexpected floor translations in 12 directions. We extracted motor modules (ie, muscle synergies) for each leg using nonnegative matrix factorization. We also determined the magnitude of perturbation-induced body sway using a single-link inverted pendulum model. Whereas the number of motor modules for balance was not affected by stroke, those formed by muscles with long latency responses were replaced by atypically structured paretic motor modules (atypical muscle groupings), which hints at direct cerebral involvement in long-latency feedback responses. Other paretic motor modules had intact structure but were poorly recruited, which is indicative of indirect cerebral control of balance. Importantly, these paretic deficits were strongly associated with postural instability in the preferred activation direction of the impaired motor modules. Finally, these deficiencies were heterogeneously distributed across stroke survivors with lesions in distinct locations, suggesting that different cerebral substrates may contribute to balance control. In conclusion, muscle coordination deficits in the paretic limb of stroke survivors result in direction-specific postural instability, which highlights the importance of targeted interventions to address patient-specific balance impairments.

The iFST: An instrumented version of the Fukuda Stepping Test for balance assessment.

The maintenance of the upright posture during dynamic balance requires the integration of sensory inputs regulated by the brain. After a neurological event, the assessment of balance control impairments is crucial for supporting health professionals in the design of personalized rehabilitation protocols. A commonly used test to assess balance ability is the Fukuda Stepping Test (FST). However, the clinical parameters traditionally considered are not fully representative of the patient's motor ability. The purpose of this study was to devise an instrumented version of the FST (iFST) that embodies inertial sensors and allows to obtain individual motor strategy information. Twenty-seven sub-acute stroke patients and 18 healthy adults performed a repeated stepping task with closed eyes wearing five inertial sensors located on both distal tibiae and at pelvis, sternum, and head levels. From final foot position, body rotation and linear displacements were measured. A set of indices related to upper-body stability were estimated from pelvis, sternum, and head accelerations: Root Mean Square, Attenuation Coefficients, and improved Harmonic Ratio. Two additional parameters based on upper-body angular velocities were devised to assess step-by-step repeatability and inter-segment velocity variations. The results suggest that the clinical parameters do not provide enough information about the two groups' motor strategies. Conversely, five iFST parameters were identified as predictors of patients' motor ability, discriminating not only between healthy and pathological subjects, but also between different motor deficit levels within the same pathology. The iFST could be included in the clinical routine assessment of balance impairments, supporting the design of personalized treatments.

Does the single-limb stance reflect chronic ankle instability in an athlete?

BACKGROUND: The single-limb stance with closed eyes has been widely used to evaluate chronic ankle instability as static balance; however, there was lack of consideration of whether difference in age, frequency of previous ankle sprain or physical ability influenced single-limb stance. RESEARCH QUESTION: We hypothesized that the single-limb stance might not reflect subjective ankle instability and function on physical activity in people who perform sports activities. METHODS: In total, 102 high school basketball players were recruited to evaluate their physical performance at the beginning of the season. Participants were divided into five groups based on the frequency of previous ankle sprain. Karlsson ankle function score (K score) was considered as a subjective ankle function score, that was divided into various components. Each component and the single-limb stance test with center of pressure (COP) analysis was observed between the frequency of ankle sprains with one-way ANOVA and compared using Spearman's rank correlation coefficient to verify the relationship between the K score and COP. RESULTS: For COP parameters, no difference was observed in the history of ankle sprains. The K score was lower in participants with three previous ankle sprains than in those with a different number of ankle sprains for instability, stiffness, running, work activities, support, and total K score for all parameters. There were weak negative correlations (r = -0.19∼-0.35) between K score and COP parameters among participants with no history of ankle sprain or only once. In contrast, there were strong positive correlations (r = 0.69∼0.87) among history of ankle sprain at third. SIGNIFICANCE: The single-limb stance might not accurately reflect an athlete's ankle instability and function on physical activity. Clinically, therapists should choose suitable evaluation tools depending on the athlete's activity level to check for chronic ankle instability.