Postural stability in the elderly: a comparison between fallers and non-fallers

Age-related changes in static balance in older women aged in their early sixties to their late eighties: different aging patterns in the anterior-posterior and mediolateral directions

Objective

The aim of this study was to cross-sectionally investigate how static balance changes throughout the aging process in older women aged from their early sixties to their late eighties.

Methods

Forty-six older women (aged 62-89 years) were requested to stand barefoot and quietly on a force platform for 30 s with their eyes either open or closed. During the trials, the position of the center of foot pressure (CoP) and the acceleration of the body's center of mass (ACC) were measured. The root mean square (RMS) of the CoP and ACC values was calculated to evaluate the amplitude of postural sway and the level of regulatory activity, respectively. The mean power frequency of the ACC was also calculated to represent the temporal characteristics of regulatory activity.

Results

In the anterior-posterior direction, there was no significant relationship between the RMS of CoP and the participants' age, whereas the RMS of ACC significantly increased with increasing age. In the mediolateral direction, however, the RMS of CoP significantly increased with increasing age, whereas the RMS of ACC did not change with age. The mean power frequency of ACC did not exhibit any age-related change in either the anterior-posterior or the mediolateral direction.

Conclusion

The results indicate that static balance in older women aged in their early sixties to their late eighties exhibits distinctly contrasting aging patterns between the anterior-posterior and mediolateral directions. To prevent falls in older women, it is necessary to elucidate the physiological mechanisms responsible for the increase in mediolateral sway that occurs throughout old age.

Associations of lower-limb muscle strength performance with static and dynamic balance control among older adults in Taiwan

Background

Aging is an inevitable process of life development. These physical changes can cause a decline in the functional adaptability and health status of older adult individuals.

Aims

The purpose of this study was to investigate the association of lower-limb muscle strength performance with static and dynamic balance control among older adults in Taiwan.

Methods

We conducted a cross-sectional study and reviewed data derived from the National Physical Fitness Survey in Taiwan 2015-2016. A total of 20,846 Taiwanese older adult individuals aged 65 years old or older were recruited as study participants. Demographic characteristics, anthropometric assessments, lifestyle habits, and health-related physical fitness measurements from this dataset were analyzed using the chi-square test, one-way analysis of variance, and linear regression analysis. Lower-limb muscle strength performance was classified into 4 groups based on quartile (Quartile 1 [Q1], Quartile 2 [Q2], Quartile 3 [Q3], and Quartile 4 [Q4]) values.

Results

Increased lower-limb muscle strength levels were significantly associated with static balance in men (Q2: β = 2.539, p < 0.0001; Q3: β = 4.590, p < 0.0001; Q4: β = 7.700, p < 0.0001) and women (Q2: β = 2.022, p < 0.0001; Q3: β = 4.179, p < 0.0001; Q4: β = 6.920, p < 0.0001) after adjusting for potential confounders. In addition, we observed that increased lower-limb muscle strength levels were significantly associated with dynamic balance in men (Q2: β = -1.661, p < 0.0001; Q3: β = -2.434, p < 0.0001; Q4: β = -3.091, p < 0.0001) and women (Q2: β = -1.660, p < 0.0001; Q3: β = -2.548, p < 0.0001; Q4: β = -3.196, p < 0.0001) after adjusting for potential confounders.

Conclusion

Lower-limb muscle strength was the most important factor, as it was an improved method for static and dynamic balance control in both genders.

Does the effect of walking balance perturbations generalize across contexts?

Balance perturbations are used to study locomotor instability. However, these perturbations are designed to provoke a specific context of instability that may or may not generalize to a broader understanding of falls risk. The purpose of this study was to determine if the effect of balance perturbations on instability generalizes across contexts. 29 younger adults and 28 older adults completed four experimental trials, including unperturbed walking and walking while responding to three perturbation contexts: mediolateral optical flow, treadmill-induced slips, and lateral waist-pulls. We quantified the effect of perturbations as an absolute change in margin of stability from unperturbed walking. We found significant changes in mediolateral and anteroposterior margin of stability for all perturbations compared to unperturbed walking in both cohorts (p-values ≤ 0.042). In older adults, the mediolateral effects of lateral waist-pulls significantly correlated with those of optical flow perturbations and treadmill-induced slips (r ≥ 0.398, p-values ≤ 0.036). In younger adults but not in older adults, we found positive and significant correlations between the anteroposterior effect of waist-pull perturbations and optical flow perturbations, and the anteroposterior and mediolateral effect of treadmill-induced slips (r ≥ 0.428, p-values ≤ 0.021). We found no "goldilocks" perturbation paradigm to endorse that would support universal interpretations about locomotor instability. Building the most accurate patient profiles of instability likely requires a series of perturbation paradigms designed to emulate the variety of environmental contexts in which falls may occur.

Effect of test duration and sensor location on the reliability of standing balance parameters derived using body-mounted accelerometers

BACKGROUND

Balance parameters derived from wearable sensor measurements during postural sway have been shown to be sensitive to experimental variables such as test duration, sensor number, and sensor location that influence the magnitude and frequency-related properties of measured center-of-mass (COM) and center-of-pressure (COP) excursions. In this study, we investigated the effects of test duration, the number of sensors, and sensor location on the reliability of standing balance parameters derived using body-mounted accelerometers.

METHODS

Twelve volunteers without any prior history of balance disorders were enrolled in the study. They were asked to perform two 2-min quiet standing tests with two different testing conditions (eyes open and eyes closed). Five inertial measurement units (IMUs) were employed to capture postural sway data from each participant. IMUs were attached to the participants' right legs, the second sacral vertebra, sternum, and the left mastoid processes. Balance parameters of interest were calculated for the single head, sternum, and sacrum accelerometers, as well as, a three-sensor combination (leg, sacrum, and sternum). Accelerometer data were used to estimate COP-based and COM-based balance parameters during quiet standing. To examine the effect of test duration and sensor location, each 120-s recording from different sensor locations was segmented into 20-, 30-, 40-, 50-, 60-, 70-, 80-, 90-, 100-, and 110-s intervals. For each of these time intervals, time- and frequency-domain balance parameters were calculated for all sensor locations.

RESULTS

Most COM-based and COP-based balance parameters could be derived reliably for clinical applications (Intraclass-Correlation Coefficient, ICC ≥ 0.90) with a minimum test duration of 70 and 110 s, respectively. The exceptions were COP-based parameters obtained using a sacrum-mounted sensor, especially in the eyes-closed condition, which could not be reliably used for clinical applications even with a 120-s test duration.

CONCLUSIONS

Most standing balance parameters can be reliably measured using a single head- or sternum-mounted sensor within a 120-s test duration. For other sensor locations, the minimum test duration may be longer and may depend on the specific test conditions.

Good times, bad times? An evaluation of event detection strategies in time to boundary postural assessments

Time-to-boundary (TtB) is a popular balance metric that identifies minimum reaction times available to correct balance challenges during quiet standing. Minimum event criteria is a critical methodological consideration to determine physiologically relevant TtB outcomes yet selection methodology appears inconsistent and/or vaguely defined across studies. This study aimed to identify a robust, objective methodology to select meaningful TtB outcomes. Ninety-seven healthy adults stood quietly on a force platform with eyes open and feet together. Anterior-posterior (AP) and medial-lateral (ML) center-of-pressure data from 150 s were utilized to compute a TtB series. The MATLAB findpeaks function identified minima with and without a time delay following selected events and/or a vertical axis threshold. An individualized time delay excluded excessively large values that hold no clinically relevant information, and this effect was enhanced by a vertical threshold at 22 s. The absolute minimum TtB was unaffected by any findpeaks criteria. The recommendations implicated by these results will help improve clarity and consistency among TtB studies, thereby enhancing the applicability of clinical findings.

Influence of Concurrent Exercise Training on Ankle Muscle Activation during Static and Proactive Postural Control on Older Adults with Sarcopenic Obesity: A Multicenter, Randomized, and Controlled Trial

Sarcopenic obesity (SO), characterized by age-related muscle loss and excess body fat, significantly impairs postural control. However, limited research has explored the effects of concurrent exercise training on neuromuscular strategies during postural control in older adults with SO. The study enrolled 50 older adults with SO, split into an intervention group (IG, n = 25, mean age = 76.1 ± 3.5 years; mean BMI = 34.4 ± 4.0 kg/m2) and a control group (CG, n = 25, mean age = 75.9 ± 5.4 years; mean BMI = 32.9 ± 2.3 kg/m2). Participants in the IG were engaged in 60-min Total Mobility Plus Program (TMP) sessions three times a week for four months, while the CG maintained their typical daily activities. Standardized evaluations were conducted both before and after the intervention. These assessments included the Romberg and Timed Up and Go (TUG) tests, as well as the measurement of Center of Pressure (CoP) displacements parameters under various conditions. Additionally, ankle muscle activities were quantified during postural control evaluations and maximal voluntary contractions of plantar and dorsal flexors. Post-intervention results revealed a significant reduction of the standing time measured in the Romberg (-15.6%, p < 0.005) and TUG (-34.6%, p < 0.05) tests. Additionally, CoP area and velocity were notably reduced in various conditions (p < 0.05). Postural control improvements were associated with an increase of strength (p < 0.05) and decrease of ankle muscle activation (p < 0.05). These findings highlight the reversibility of neuromuscular system alterations associated with the synergistic effects of sarcopenia and obesity, emphasizing the trainability of postural control regulation within this population. By incorporating these insights into clinical practice and public health strategies, it seems possible to optimize the health and well-being of older adults with SO.

Effects of postural-control training with different sensory reweightings in a patient with body lateropulsion: a single-subject design study

INTRODUCTION

Body lateropulsion (BL) is an active lateral tilt of the body during standing or walking that is thought to be affected by a lesion of the vestibulospinal tract (VST) and the subjective visual vertical (SVV) tilt. Interventions for BL have not been established.

OBJECTIVE

We examined the effects of postural-control training with different sensory reweighting on standing postural control in a patient with BL.

METHODS

The patient had BL to the left when standing or walking due to a left-side medullary and cerebellar infarct. This study was a single-subject A-B design with follow-up: Phase A was postural-control training with visual feedback; phase B provided reweighting plantar somatosensory information. Postural control, VST excitability, and SVV were measured.

RESULTS

At baseline and phase A, the patient could not stand with eyes-closed on a rubber mat, but became able to stand in phase B. The mediolateral center of pressure (COP) position did not change significantly, but the COP velocity decreased significantly during phase B and the follow-up on the firm surface. VST excitability was lower on the BL versus the non-BL side, and the SVV deviated to the right throughout the study.

CONCLUSION

Postural-control training with reweighting somatosensory information might improve postural control in a patient with BL.

A machine learning approach to identify important variables for distinguishing between fallers and non-fallers in older women

Falls are a significant ongoing public health concern for older adults. At present, few studies have concurrently explored the influence of multiple measures when seeking to determine which variables are most predictive of fall risks. As such, this cross-sectional study aimed to identify those functional variables (i.e. balance, gait and clinical measures) and physical characteristics (i.e. strength and body composition) that could best distinguish between older female fallers and non-fallers, using a machine learning approach. Overall, 60 community-dwelling older women (≥65 years), retrospectively classified as fallers (n = 21) or non-fallers (n = 39), attended three data collection sessions. Data (281 variables) collected from tests in five separate domains (balance, gait, clinical measures, strength and body composition) were analysed using random forest (RF) and leave-one-variable-out partial least squares correlation analysis (LOVO PLSCA) to assess variable importance. The strongest discriminators from each domain were then aggregated into a multi-domain dataset, and RF, LOVO PLSCA, and logistic regression models were constructed to identify the important variables in distinguishing between fallers and non-fallers. These models were used to classify participants as either fallers or non-fallers, with their performance evaluated using receiver operating characteristic (ROC) analysis. The study found that it is possible to classify fallers and non-fallers with a high degree of accuracy (e.g. logistic regression: sensitivity = 90%; specificity = 87%; AUC = 0.92; leave-one-out cross-validation accuracy = 63%) using a combination of 18 variables from four domains, with the gait and strength domains being particularly informative for screening programmes aimed at assessing falls risk.

Influences of smart glasses on postural control under single- and dual-task conditions for ergonomic risk assessment

Head worn displays have become increasingly popular at workplaces in logistics and assembly lines in recent years. Such displays are expected to improve productivity and safety at the workplace. However, their impact on balance in the workforce is still an open research question. Therefore, we investigated the influence of the Vuzix M400 and Realwear HMT1 smart glasses on postural control. A laboratory study was conducted with eleven participants. Balance parameters were recorded during bilateral quiet stance, together with parameters of cognitive load. The two different smart glasses used in this study were compared with a monitor and a tablet under single-task conditions and while performing a spatial 2-back task. As balance parameters, the prediction ellipse and sample entropy in anteroposterior as well as mediolateral direction of the center-of-pressure data were examined. No significant differences were observed in the cognitive task performance between the devices. The prediction ellipse of the smart glasses was smaller than the tablets but larger than the smartboard. The dynamic of sample entropy data suggests that the use of the spatial 2-back task induces postural sway in the participants. This effect was most profound when looking at the monitor and least recognizable in the data of the tablet.

KINECAL: A Dataset for Falls-Risk Assessment and Balance Impairment Analysis

The field of human action recognition has made great strides in recent years, much helped by the availability of a wide variety of datasets that use Kinect to record human movement. Conversely, progress towards the use of Kinect in clinical practice has been hampered by the lack of appropriate data. In particular, datasets that contain clinically significant movements and appropriate metadata. This paper proposes a dataset to address this issue, namely KINECAL. It contains the recordings of 90 individuals carrying out 11 movements, commonly used in the clinical assessment of balance. The dataset contains relevant metadata, including clinical labelling, falls history labelling and postural sway metrics. KINECAL should be of interest to researchers interested in the clinical use of motion capture and motion analysis.

Effects of Power Training on Functional Capacity Related to Fall Risk in Older Adults: A Systematic Review and Meta-analysis

OBJECTIVE

Functional capacity is 1 of the main risk factors for falls among older adults. The aim of this systematic review and meta-analysis was to determine the effect of power training on functional capacity test (FCT) related to fall risk in older adults.

DATA SOURCES

Systematic searches were conducted in 4 databases, including PubMed, Web of Science, Scopus, and SPORTDiscus, from inception to November 2021.

STUDY SELECTION

Randomized controlled trials (RCTs) assessing the effect of power training on functional capacity compared with another type of training program or control group in older adults with the ability to exercise independently.

DATA EXTRACTION

Two independent researchers evaluated eligibility and used the PEDro scale to assess risk of bias. The information extracted was related to article identification (authors, country and year of publication), participant characteristics (sample, sex, and age), strength training protocols (exercises/intensity/weeks), and the outcome of the FCT used related to fall risk. The Cochran Q statistic and I2 statistics was used to assess heterogeneity. Random-effects model were conducted to pool the effect sizes expressed as mean differences (MD).

DATA SYNTHESIS

Twelve studies (478 subjects) were selected for systematic review. A meta-analysis comprised 6 studies (217 subjects) where the outcome measure was the 30-second Sit to Stand (30s-STS) test, and another comprised 4 studies (142 subjects) where the outcome measure was the timed Up and Go (TUG) test. There was an improvement in performance in favor of the experimental group in both the TUG subgroup (MD -0.31 s; 95% CI -0.63, 0.00 s; P=.05), and the 30s-STS subgroup (MD 1.71 reps; 95% CI -0.26, 3.67 reps; P=.09).

CONCLUSIONS

In conclusion, power training increases functional capacity related to fall risk further than other types of exercise in older adults.

The Influence of Age and Physical Activity on Locomotor Adaptation

BACKGROUND

Aging increases individual susceptibility to falls and injuries, suggesting poorer adaptation of balance responses to perturbation during locomotion, which can be measured with the locomotor adaptation task (LAT). However, it is unclear how aging and lifestyle factors affect these responses during walking. Hence, the present study investigates the relationship between balance and lifestyle factors during the LAT in healthy individuals across the adult lifespan using a correlational design.

METHODS

Thirty participants aged 20-78 years performed an LAT on a split-belt treadmill (SBT). We evaluated the magnitude and rate of adaptation and deadaptation during the LAT. Participants reported their lifelong physical and cognitive activity.

RESULTS

Age positively correlated with gait-line length asymmetry at the late post-adaptation phase (p = 0.007). These age-related effects were mediated by recent physical activity levels (p = 0.040).

CONCLUSION

Our results confirm that locomotor adaptive responses are preserved in aging, but the ability to deadapt newly learnt balance responses is compromised with age. Physical activity mediates these age-related effects. Therefore, gait symmetry post-adaptation could effectively measure the risk of falling, and maintaining physical activity could protect against declines in balance.

Postural Instability and Risk of Falls in Patients with Parkinson's Disease Treated with Deep Brain Stimulation: A Stabilometric Platform Study

Postural instability (PI) in Parkinson's disease (PD) exposes patients to an increased risk of falls (RF). While dopaminergic therapy and deep brain stimulation (DBS) improve motor performance in advanced PD patients, their effects on PI and RF remain elusive. PI and RF were assessed using a stabilometric platform in six advanced PD patients. Patients were evaluated in OFF and ON dopaminergic medication and under four DBS settings: with DBS off, DBS bilateral, and unilateral DBS of the more- or less-affected side. Our findings indicate that dopaminergic medication by itself exacerbated PI and RF, and DBS alone led to a decline in RF. No combination of medication and DBS yielded a superior improvement in postural control compared to the baseline combination of OFF medication and the DBS-off condition. Yet, for ON medication, DBS significantly improved both PI and RF. Among DBS conditions, DBS bilateral provided the most favorable outcomes, improving PI and RF in the ON medication state and presenting the smallest setbacks in the OFF state. Conversely, the more-affected side DBS was less beneficial. These preliminary results could inform therapeutic strategies for advanced PD patients experiencing postural disorders.

Association between functional disability with postural balance among patients with chronic low back pain

Introduction

Postural balance is impaired in patients with chronic low back pain (CLBP). In addition, the swaying velocity can be affected by low back pain (LBP) dysfunction. However, the extent to which the dysfunction affects postural balance in CLBP patients remains unclear. Therefore, this study aimed to investigate the effect of LBP-related disability on postural balance among CLBP patients and determine factors associated with postural balance impairments.

Methods

Participants with CLBP were recruited and instructed to complete the one-leg stance and Y-balance test. Moreover, they were divided into two subgroups (i.e., low and medium to high LBP-related disability groups) to compare the difference in postural balance based on the degree of LBP-related disability measured by the Roland Morris Disability Questionnaire. The relationships between postural balance and negative emotions as well as LBP characteristics were determined using the Spearman correlations.

Results

A total of 49 participants with low LBP-related disabilities and 33 participants with medium to high LBP-related disabilities participated in the study. Compared to the medium to high LBP-related disability group, patients in the low LBP-related disability group performed better in one-leg stance on the left leg (z = -2.081, p = 0.037). For Y-balance test, patients in the low LBP-related disability group also had greater normalized values of left leg reach in posteromedial (t = 2.108, p = 0.038) direction and composite score (t = 2.261, p = 0.026) and of right leg reach in posteromedial (t = 2.185, p = 0.032), and posterolateral (t = 2.137, p = 0.036) directions as well as composite score (t = 2.258, p = 0.027). Factors associated with postural balance impairments were also revealed, such as anxiety, depression, and fear avoidance belief.

Discussion

The greater the dysfunction degree, the worse the CLBP patient's postural balance impairment. Negative emotions could also be considered contributing factors for postural balance impairments.

The Instrumented Stand and Walk (ISAW) test to predict falls in older men

Objective measures of balance and gait have the potential to improve prediction of future fallers because balance and gait impairments are common precursors. We used the Instrumented Stand and Walk Test (ISAW) with wearable, inertial sensors to maximize the domains of balance and gait evaluated in a short test. We hypothesized that ISAW objective measures across a variety of gait and balance domains would improve fall prediction beyond history of falls and better than gait speed or dual-task cost on gait-speed. We recruited 214 high-functioning older men (mean 82 years), of whom 91 participants (42.5%) had one or more falls in the 12 months following the ISAW test. The ISAW test involved 30 s of stance followed by a 7-m walk, turn, and return. We examined regression models for falling using 17 ISAW metrics, with and without age and fall history, and characterize top-performing models by AUC and metrics included. The ISAW test improved distinguishing between future fallers and non-fallers compared to age and history of falls, alone (AUC improved from 0.69 to 0.75). Models with 1 ISAW metric usually included a postural sway measure, models with 2 ISAW measures included a turning measure, models with 3 ISAW measures included a gait variability measure, and models with 4 or 5 measures added a gait initiation measure. Gait speed and dual-task cost did not distinguish between fallers and non-fallers in this high-functioning cohort. The best fall-prediction models support the notion that older people may fall due to a variety of balance and gait impairments.

Community-based postural control assessment in autistic individuals indicates a similar but delayed trajectory compared to neurotypical individuals

Autistic individuals exhibit significant sensorimotor differences. Postural stability and control are foundational motor skills for successfully performing many activities of daily living. In neurotypical development, postural stability and control develop throughout childhood and adolescence. In autistic development, previous studies have focused primarily on individual age groups (e.g., childhood, adolescence, adulthood) or only controlled for age using age-matching. Here, we examined the age trajectories of postural stability and control in autism from childhood through adolescents using standardized clinical assessments. In study 1, we tested the postural stability of autistic (n = 27) and neurotypical (n = 41) children, adolescents, and young adults aged 7-20 years during quiet standing on a force plate in three visual conditions: eyes open (EO), eyes closed (EC), and eyes open with the head in a translucent dome (Dome). Postural sway variability decreased as age increased for both groups, but autistic participants showed greater variability than neurotypical participants across age. In study 2, we tested autistic (n = 21) and neurotypical (n = 32) children and adolescents aged 7-16 years during a dynamic postural control task with nine targets. Postural control efficiency increased as age increased for both groups, but autistic participants were less efficient compared to neurotypical participants across age. Together, these results indicate that autistic individuals have a similar age trajectory for postural stability and control compared to neurotypical individuals, but have lower postural stability and control overall.

Preventing falls: the use of machine learning for the prediction of future falls in individuals without history of fall

Nowadays, it becomes of paramount societal importance to support many frail-prone groups in our society (elderly, patients with neurodegenerative diseases, etc.) to remain socially and physically active, maintain their quality of life, and avoid their loss of autonomy. Once older people enter the prefrail stage, they are already likely to experience falls whose consequences may accelerate the deterioration of their quality of life (injuries, fear of falling, reduction of physical activity). In that context, detecting frailty and high risk of fall at an early stage is the first line of defense against the detrimental consequences of fall. The second line of defense would be to develop original protocols to detect future fallers before any fall occur. This paper briefly summarizes the current advancements and perspectives that may arise from the combination of affordable and easy-to-use non-wearable systems (force platforms, 3D tracking motion systems), wearable systems (accelerometers, gyroscopes, inertial measurement units-IMUs) with appropriate machine learning analytics, as well as the efforts to address these challenges.

Effects of Music Listening on Postural Balance in Adolescents with Visual Impairment

We aimed to investigate the effect of music on visually impaired adolescents' postural balance across different somatosensory and vestibular input conditions. We recruited 19 adolescent participants (9 males, 10 females) with severe congenital visual impairment. We recorded their mean center of pressure velocity (CoP_Vm) during static upright bipedal standing under somatosensory (firm and foam surfaces) and vestibular (head facing forward (HFF), head rotated 90° to the right (HRR), and head rotated 90° to the left (HRL)) perturbations in three auditory conditions (no-music, listening to Jupiter, and listening to their preferred music). We found that CoP_Vm decreased significantly when listening to both Jupiter and preferred music, compared to the no-music condition on both firm (p < .05) and foam (p < .001) surfaces and with the HFF (p < .05), rotated to the right (p < .001) or rotated to the left (p < .001). Moreover, CoP_Vm values increased significantly with somatosensory manipulation (p < .001) in all the auditory conditions and with vestibular manipulation (p < .01) only in the no-music condition. We concluded that listening to both Jupiter and preferred music improved postural balance in visually impaired adolescents, even in challenged postural conditions.

Sex Differences in Falls: The Mediating Role of Gait Stability Ratio and Body Balance in Vulnerable Older Adults

This study, conducted on a large sample of older adults at elevated fall risk (1), aimed to verify statistical differences in gait stability ratio (GSR) and body balance (BB) according to sex, (2) to examine and compare GSR and BB performance between older adult fallers and non-fallers, (3) to determine an association between GSR and BB according to the history of falls, and (4) to explore whether GSR and BB mediate the association between sex and falls. We included 619 individuals (69.8 ± 5.6 years) living in the Autonomous Region of Madeira, Portugal. The frequency of falls was obtained by self-report. BB was determined by the Fullerton Advanced Balance scale, while GSR was established by dividing cadence by gait speed and data collected during the 50-foot walk test. Males indicated a lower prevalence of falls in the last 12 months (23.6%), while females had a higher score (48.7%), as well as a lower balance performance (p < 0.001) and higher GSR scores (p < 0.001). Lower BB control (p < 0.001), as well as higher GSR, were more expressive for fallers (p < 0.001). We found a large, negative and significant correlation between GSR and BB for historical falls (r = −0.560; p < 0.001), and between male and female cohorts (r = −0.507; p < 0.001). The total effect of sex on falls mediated by GSR and BB was 16.4%. Consequently, GSR and BB mediated this association by approximately 74.0% and 22.5%, respectively.

Older adults and stroke survivors are steadier when gazing down

BACKGROUND

Advanced age and brain damage have been reported to increase the propensity to gaze down while walking, a behavior that is thought to enhance stability through anticipatory stepping control. Recently, downward gazing (DWG) has been shown to enhance postural steadiness in healthy adults, suggesting that it can also support stability through a feedback control mechanism. These results have been speculated to be the consequence of the altered visual flow when gazing down. The main objective of this cross-sectional, exploratory study was to investigate whether DWG also enhances postural control in older adults and stroke survivors, and whether such effect is altered with aging and brain damage.

METHODS

Posturography of older adults and stroke survivors, performing a total of 500 trials, was tested under varying gaze conditions and compared with a cohort of healthy young adults (375 trials). To test the involvement of the visual system we performed spectral analysis and compared the changes in the relative power between gaze conditions.

RESULTS

Reduction in postural sway was observed when participants gazed down 1 and 3 meters ahead whereas DWG towards the toes decreased steadiness. These effects were unmodulated by age but were modulated by stroke. The relative power in the spectral band associated with visual feedback was significantly reduced when visual input was unavailable (eyes-closed condition) but was unaffected by the different DWG conditions.

CONCLUSIONS

Like young adults, older adults and stroke survivors better control their postural sway when gazing down a few steps ahead, but extreme DWG can impair this ability, especially in people with stroke.

iPhone Accelerometry Provides a Sensitive In-Home Assessment of Age-Related Changes in Standing Balance

Remote health monitoring has become increasingly important, especially in aging populations. We aimed to identify tasks that are sensitive to age-related changes in balance during fully remote, at-home balance assessment. Participants were 12 healthy young adults (mean age = 26.08 years, range: 18-33) and 12 healthy older adults (mean age = 67.33 years, range: 60-75). Participants performed standing tasks monitored via video conference while their balance was quantified using a custom iPhone application measuring mediolateral center of mass acceleration. We included three stances (feet together, tandem, and single leg) with eyes open or closed, with or without a concurrent cognitive task. Older adults demonstrated significantly more variable center of mass accelerations in tandem (p = .04, ηp2=.25) and significantly higher (p < .01, ηp2=.45) and more variable (p < .01, ηp2=.44) center of mass accelerations in single leg compared with young adults. We also observed that as task challenge increased, balance dual-task cost diminished for older, but not young, adults.

Effect of Increasing Obstacle Distances Task on Postural Stability Variables During Gait Initiation in Older Nonfallers and Fallers

OBJECTIVE

To compare the scaling of the postural stability variables between older nonfallers and fallers during gait initiation (GI) while stepping over increasing obstacle distances.

DESIGN

Cross-sectional study.

SETTING

University research laboratory.

PARTICIPANTS

A sample of participants (N=24) divided into 2 groups: older nonfallers (n=12) and older fallers (n=12). Participants had no known neurologic, musculoskeletal, or cardiovascular conditions that could have affected their walking, and all were independent walkers. All the participants had an adequate cognitive function to participate as indicated by a score of more than 24 on the Mini-Mental State Examination.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The primary dependent variables were peak anterior-posterior (AP) center of mass (CoM)-center of pressure (CoP) separation during anticipatory postural adjustments (APAs), AP CoM-CoP separation at the toe-off, and peak AP CoM-CoP separation during the swing. Secondary dependent variables were AP trunk angle during GI. Within- and between-repeated measures analysis of variance was used to compare means between groups across different task conditions for all the dependent variables.

RESULTS

There was a main effect of group for peak AP CoM-CoP separation during APA (P=.018), an interaction effect between group and condition for AP CoM-CoP separation at toe-off (P=.009), and a main effect of condition for peak AP CoM-CoP separation during the swing (P<.001). We also found a main effect of group for peak AP trunk angle during the swing (P=.028).

CONCLUSIONS

For GI while stepping over increasing obstacle distances, older fallers adopt a more conservative strategy of AP CoM-CoP separation than nonfallers prior to toe-off and demonstrate increased peak AP trunk lean during the swing. AP CoM-CoP separation prior to toe-off during the GI task may be a critical marker to identify fallers and warrants additional investigation.

Associations of Gait Speed, Cadence, Gait Stability Ratio, and Body Balance with Falls in Older Adults

To investigate the association between gait speed (GS), cadence (CAD), gait stability ratio (GSR), and body balance (BB) with falls in a large sample of older adults. The analysis included 619 individuals-305 men and 314 women (69.50 ± 5.62 years)-residing in the Autonomous Region of Madeira, Portugal. Mobility in GS, CAD, and GSR was assessed using the 50-foot walk test and BB by the Fullerton Advanced Balance scale. The frequency of falls was obtained by self-report. Linear regression analysis showed that higher performance in GS and BB was able to reduce the risk of falling by up to 0.34 and 0.44 times, respectively. An increase in the GSR value enhanced the risk of falling by up to 0.10 times. Multinomial analysis indicated that, in relation to the highest tertile (reference), older adults classified with GS and BB performance in the lowest tertile (lowest) had an increased chance (OR) of falling by up to 149.3% and 48.8%, respectively. Moreover, in relation to the highest tertile, the performance of the GSR classified in the lowest and medium tercile showed an increase in the chance of falling by up to 57.4% and 56.4%, respectively.

Balance Therapy With Hands-Free Mobile Robotic Feedback for At-Home Training Across the Lifespan

Providing aging adults with engaging, at-home balance therapy is essential to promote long-term adherence to unsupervised training and to foster independence. We developed a portable interactive balance training system that provides real-world visual cues on balance performance using wobble board tilt angles to control the speed of a robotic car platform in a three-dimensional environment. The goal of this study was to validate this mobile balance therapy system for home use across the lifespan. Twenty younger (18-39 years) and nineteen older (58-74 years) healthy adults performed balance training with and without visual feedback while standing on a wobble board instrumented with a consumer-grade inertial measurement unit (IMU) and optical motion tracking markers. Participants performed feedback trials based on either the robotic car's movements or a commercially-available virtual game. Wobble board tilt measurements were highly correlated between IMU and optical measurement systems ( [Formula: see text]), with high agreement in outcome metrics ( [Formula: see text]) and small bias ( [Formula: see text]). Both measurement systems identified similar aging, feedback, and stance type effects including (1) altered movement control when older adults performed tilting trials with either robotic or virtual feedback compared to without feedback, (2) two-fold greater wobble board oscillations in older vs. younger adults during steady standing, (3) no difference in board oscillations during steady standing in narrow vs. wide double support, and (4) greater wobble board oscillations for single compared to double support. These findings demonstrate the feasibility of implementing goal-directed robotic balance training with mobile tracking of balance performance in home environments.

Effects of Modified-Otago Exercise Program on Four Components of Actual Balance and Perceived Balance in Healthy Older Adults

Falls are a serious problem for older adults, leading to adverse injuries and decreased quality of life. Balance impairment is a key factor in falls. The Otago Exercise Program (OEP) is a promising intervention for preventing falls, thereby improving balance and gait. Previous studies reported improved effects on balance using the OEP conducted in a group setting, and recommended additional walking. Walking is a feasible exercise that benefits both fall-related physical and physiological functions. This study aims to investigate the effects of a modified-Otago Exercise Program (modified-OEP) on four components of actual balance (static, dynamic, proactive, and reactive balance) and perceived balance in healthy older adults, by conducting the modified-OEP in a groupsetting, and including additional walking in one session to gain better efficacy. Participants aged 60–85 years old were randomly assigned to the modified-OEP group or the control group (CT). The modified-OEP consisted of 60 min sessions made up of 30 min of OEP and 30 min of walking, three times a week for 12 weeks, while no intervention was assigned to the control group. The modified-OEP group showed significant improvement in the four components of actual balance and in perceived balance. Furthermore, the modified-OEP group outperformed the control group in all parameters except for dynamic balance, after 12 weeks. The present study highlights the beneficial effects of a modified-OEP on all balance components. Additionally, this study is the first to demonstrate the measurement of all actual balance components as well as perceived balance.

Less Vibrotactile Feedback Is Effective to Improve Human Balance Control during Sensory Cues Alteration

For individuals with altered sensory cues, vibrotactile feedback improves their balance control. However, should vibrotactile feedback be provided every time balance control is compromised, or only one-third of the time their balance is compromised? We hypothesized that vibrotactile feedback would improve balance control more when provided every time their balance is compromised. Healthy young adults were randomly assigned to two groups: group 33% feedback (6 males and 6 females) and group 100% feedback (6 males and 6 females). Vibrotactile feedbacks related to the body's sway angle amplitude and direction were provided, while participants stood upright on a foam surface with their eyes closed. Then, we assessed if balance control improvement lasted when the vibrotactile feedback was removed (i.e., post-vibration condition). Finally, we verified whether or not vibrotactile feedback unrelated to the body's sway angle and direction (sham condition) altered balance control. The results revealed no significant group difference in balance control improvement during vibrotactile feedback. Immediately following vibrotactile feedback, both groups reduced their balance control commands; body sway velocity and the ground reaction forces variability decreased. For both groups, unrelated vibrotactile feedback worsened balance control. These results confirmed that participants processed and implemented vibrotactile feedback to control their body sways. Less vibrotactile feedback was effective in improving balance control.

Impact of Sensory Afferences in Postural Control Quantified by Force Platform: A Protocol for Systematic Review

Older adults’ postural balance is a critical domain of research as balance deficit is an important risk factor for falls that can lead to severe injuries and death. Considering the effects of ageing on sensory systems, we propose that posturographic evaluation with a force platform exploring the effect of sensory deprivation or perturbation on balance could help understand postural control alterations in the elderly. The aim of the future systematic review and meta-analysis described in this protocol is to explore the capacity of older adults to maintain their balance during sensory perturbations, and compare the effect of perturbation between the sensory channels contributing to balance. Seven databases will be searched for studies evaluating older adults’ balance under various sensory conditions. After evaluating the studies’ risk of bias, results from similar studies (i.e., similar experimental conditions and posturographic markers) will be aggregated. This protocol describes a future review that is expected to provide a better understanding of changes in sensory systems of balance due to ageing, and therefore perspectives on fall assessment, prevention, and rehabilitation.

Proprioceptive Neuromuscular Facilitation Improves Symptoms Among Older Adults With Knee Osteoarthritis During Stair Ascending: A Randomized Controlled Trial

OBJECTIVE

This study aimed to investigate the effects of a 6-wk proprioceptive neuromuscular facilitation stretching on pain, proprioception, joint range of motion, and joint moments during stair ascending among older adults with knee osteoarthritis.

DESIGN

This study is a randomized, controlled, and assessor-blinded trial. Thirty-six older adults with knee osteoarthritis were randomly assigned to the proprioceptive neuromuscular facilitation and the control groups. They received proprioceptive neuromuscular facilitation stretching and health lecture series, respectively, for 6 wks. Final data analysis included 14 participants of the proprioceptive neuromuscular facilitation group and 13 of the control group. Pain score, joint proprioception, range of motion, and joint moments during stair ascending were measured before and after the stretching. Two-way (group by time) analysis of variance with repeated measures was used to evaluate stretching effects.

RESULTS

Significant interactions were detected in pain score, joint proprioception, external knee adduction moment, and external knee extension moment. Compared with week 0, the pain score, joint proprioception threshold, and external knee adduction moment decreased, whereas the external knee extension moment increased among older adults in the proprioceptive neuromuscular facilitation group at week 7.

CONCLUSIONS

Proprioceptive neuromuscular facilitation could be recommended as one of the clinical treatments for knee osteoarthritis to relieve pain, improve proprioception, and balance load distribution between medial and lateral compartments at the knee.

Postural Sway and Muscle Activity Dynamics of Upright Standing on Sloped Surfaces

During upright standing, individuals often use co-contraction muscle activity at the ankle joint when encountering increased postural difficulty; however, this strategy has been shown to be maladaptive. The purpose of the current investigation was to examine the effect of sloped standing on postural sway and muscle co-contraction at the ankle joint as a function of postural difficulty. Twelve young (21.67 ± 1.11 years) adults performed upright standing on flat, declined, and inclined support surfaces. Center of pressure displacements indexed postural sway while electromyography data were collected for the tibialis anterior and gastrocnemius medialis muscles. A co-contraction index and a nonlinear coupling metric (cross-approximate entropy) were computed between ankle dorsiflexor and plantar flexor muscles (tibialis anterior/gastrocnemius medialis) activity. The results showed that higher degrees of postural difficulty led to increased amounts of sway as well as increased sway regularity. Lower co-contraction index was observed for higher degrees of postural difficulty; however, increased dynamic coupling occurred with deviations from the flat standing condition. Overall, increased postural difficulty as manipulated by sloped standing (in either inclined or declined conditions) resulted in individuals adopting a more regular sway trajectory that may be due, in part, to a stronger dynamic coupling strategy occurring at the neuromuscular level.

Balance and prospective falls in patients with rheumatoid arthritis

Background

Postural control is associated with fall risk. Patients with rheumatoid arthritis (RA) have a higher risk to fall than healthy subjects. The objective of this study was to identify associations between variables of postural control with prospective falls in patients with RA.

Methods

For the baseline, the balance performance of 289 men and women with RA, ages 24–85 years, was evaluated by SPPB, FICSIT-4 and Romberg tests. Postural sway for Romberg, semitandem, tandem and one-leg stands were measured with the Leonardo Mechanograph®. Self-reported disability was assessed using the Health Assessment Questionnaire (HAQ) and the Activity-specific Balance Confidence Scale (ABC-scale). Falls were reported in quarterly reports over a year. Univariate and multiple logistic regression analysis were used to explore any associations with falling. Receiver-operating characteristics were determined, and the area under the curve is reported.

Results

A total of 238 subjects completed the 1-year follow-up, 48 (20.2%) experienced at least one fall during the observational period. Age (OR = 1.04, CI 1.01–1.07), HAQ (OR = 1.62, 1.1–2.38), FICSIT-4 scoring 0–4 (OR = 2.38, 1.13–5.0), and one-leg standing (OR = 2.14, 1.06–4.31) showed significant associations with falls. With regard to the SPPB and ABC-scale, no statistically significant associations with falls were found. The quartiles containing the worst results of medio-lateral sway of Romberg (OR = 2.63, CI 1.03–6.69), total sway of semitandem (OR = 3.07, CI 1.10–8.57) and tandem (OR = 2.86, CI 1.06–7.69), and area of sway of semitandem (OR = 2.80, CI 1.11–7.08) stands were associated with falls.

Conclusions

The assessment of a one-leg stand seems to be a good screening tool to discriminate between high and low risk of falls in RA patients in clinical practice. A low FICSIT-4 score and several sway parameters are important predictors of falls.

Trial registration

The study has been registered at the German Clinical Trials Register and the WHO International Clinical Trials Registry Platform (ICTRP) since 16 March 2017 (DRKS00011873).

Influence of serial subtraction tasks on transient characteristics of postural control

We sought to better understand the influence of cognitive perturbations on transient aspects of postural control. Twenty healthy, younger adults had their postural control assessed during eyes open quiet stance. Participants completed three different conditions that either had no cognitive perturbation present, an easy cognitive perturbation (i.e., serial subtraction by ones), or a more difficult cognitive perturbation (i.e., serial subtraction by sevens). All trials finished with 60 s of undisturbed eyes open quiet stance, which was the focus of the balance assessment. 95% confidence ellipse area (EA) was calculated for 5-s epochs throughout the trial. The difference in EA from the first epoch after participants started (onset) or stopped (offset) the cognitive task to the last epoch of the trial (i.e., 55-60 s after perturbation) was used to characterize transient postural control behavior. Functional near-infrared spectroscopy was also used to quantify changes in prefrontal cortex activation during the counting tasks to support interpretation of the transient balance findings. There was a significant effect of condition for transient balance characteristics following a cognitive perturbation (P < 0.001), with greater transient increases in postural sway for both difficult (Cohen's d = 0.40, P < 0.001) and easier (Cohen's d = 0.29, P = 0.013) cognitive perturbations relative to no cognitive perturbation. The onset of cognitive tasks was also associated with greater transient increases in postural sway than the offset of the cognitive tasks (Cohen's d = 0.24, P = 0.019). The functional near-infrared spectroscopy data indicated that a significant decrease in deoxygenated hemoglobin was observed for left Brodmann area 46 for both the subtraction by ones (T = -3.97; Benjamini-Hochberg significance value (q) = 0.008) and subtraction by sevens (T = -3.11; q = 0.036) conditions relative to the baseline condition. The subtraction by sevens condition was also associated with a relative increase in deoxygenated hemoglobin for the right Brodmann area 9 (T = 3.36; q = 0.026) compared to the subtraction by ones condition. In conclusion, serial subtraction can elicit transient increases in postural sway, with more difficult tasks and the onset of the cognitive-motor challenge exhibiting magnified effects. Additionally, even the cessation of a cognitive task (i.e., serial subtraction) can be associated with lingering perturbing effects on balance control.

Characteristics of step responses following varying magnitudes of unexpected lateral perturbations during standing among older people - a cross-sectional laboratory-based study

INTRODUCTION

The inability to recover from unexpected lateral loss of balance may be particularly relevant to the problem of falling.

AIM

We aimed to explore whether different kinematic patterns and strategies occur in the first recovery step in single-step trials in which a single step was required to recover from a fall, and in multiple-step trials in which more than one step was required to recover from a fall. In addition, in the multiple-step trials, we examined kinematic patterns of balance recovery where extra steps were needed to recover balance.

METHODS

Eighty-four older adults (79.3 ± 5.2 years) were exposed to unannounced right/left perturbations in standing that were gradually increased to trigger a recovery stepping response. We performed a kinematic analysis of the first recovery step of all single-step and multiple-step trials for each participant and of total balance recovery in the multiple-step trial.

RESULTS

Kinematic patterns and strategies of the first recovery step in the single-step trials were significantly dependent on the perturbation magnitude. It took a small, yet significantly longer time to initiate a recovery step and a significantly longer time to complete the recovery step as the magnitude increased. However, the first recovery step in the multiple-step trials showed no significant differences between different perturbation magnitudes; while, in total balance recovery of these trials, we observed a small, yet significant difference as the magnitude increased.

CONCLUSIONS

At relatively low perturbation magnitudes, i.e., single-step trials, older adults selected different first stepping strategies and kinematics as perturbation magnitudes increased, suggesting that this population activated pre-planned programs based on the perturbation magnitude. However, in the first recovery step of the multiple-step trials, i.e., high perturbation magnitudes, similar kinematic movement patterns were used at different magnitudes, suggesting a more rigid, automatic behavior, while the extra-steps were scaled to the perturbation magnitude. This suggest that older adults activate pre-planned programs based on the magnitude of the perturbation, even before the first step is completed..

The Foulage Test: Proof of Concept of a Novel Stepping Test Using a Stabilometer

Objective

In this article, we aimed to describe the Foulage test (FT) and investigate the test-retest reliability of parameters recorded during stepping execution in healthy adults.

Materials and methods

This was a single-center prospective cohort study conducted at an outpatient clinic. It included five healthy male participants [mean age ± standard deviation (SD): 27 ± 5.4 years]. The FT was performed first with the participants’ eyes open and again with their eyes closed. If the heel height was not within 2-6 cm, the participant was asked to restart. The FT value and variance of steps were automatically calculated. To verify the influence of heel height, measurements were taken at different heel heights. We also evaluated the Romberg ratio (calculated from the parameters with eyes open and closed) and defined it as the dynamic Romberg ratio. Correlations between parameters were also assessed.

Results

The parameters’ FT value (front-back width of the band of locus shape) and variance of steps plateaued under stable conditions within a heel height of 2-6 cm. FT values and variance of steps were strongly correlated. The dynamic Romberg ratios by FT value and by the variance of steps were also strongly correlated.

Conclusions

The FT is a dynamic and reproducible equilibrium function test that can quantify agitation with the eyes open or closed in general outpatient clinics, and it may be employed as a clinically useful method for the observation of clinical courses in patients with vestibular disorders.

Does the time of day differently impact the effects of an exercise program on postural control in older subjects? A pilot study

Background

The time of day that people exercise can potentially influence the efficiency of exercises for fall prevention in older adults. The present pilot study was conducted to explore the feasibility and effects of morning versus afternoon exercising on postural control in institutionalized older adults.

Methods

Nine older adults completed a 3-month multimodal exercise program in its entirety (14 participants were recruited at the beginning and were initially randomly separated into two groups). One group exercised in the morning (ME; n = 4) and the other in the afternoon (AE; n = 5). Postural control was assessed with a force platform at pre and post-intervention at the following times: 8 a.m., 11 a.m., 2 p.m. and 5 p.m.

Results

Postural control significantly improved only in the AE group post-intervention. Improvements in postural control in the AE group were mainly observed in the morning.

Conclusions

The afternoon would be the best period to implement exercise sessions dedicated to improve postural control in older subjects with benefits mainly observed in the morning. Further studies are needed with a larger sample in order to confirm these results.

Balance Differences between North and South American Older Adults: A Cross-Sectional, Age and Sex Matched Study

This study aimed to characterize the risk of falling in low-, moderate- and high-risk participants from two different geographical locations using a portable force-plate. A sample of 390 older adults from South and North America were matched for age, sex, height and weight. All participants performed a standardized balance assessment using a force plate. Participants were classified in low, moderate and high risk of falling. No differences were observed between South and North American men, nor comparing North American men and women. South American women showed the significantly shorter center of pressure path length compared to other groups. The majority of the sample was categorized as having low risk of falling (male: 65.69% and female: 61.87%), with no differences between men and women. Moreover, no differences were found between North vs. South Americans, nor between male and female groups compared separately. In conclusion, South American women had better balance compatible with the status of the 50–59 years’ normative age-range. The prevalence of low falls risk was~61–65%; the prevalence of moderate to high risk was~16–19%. The frequency of fall risk did not differ significantly between North and South Americans, nor between males and females.

Changes in postural balance associated with a woman's aging process

CONTEXT

Aging causes a progressive worsening in postural balance, affecting functional independence and increasing the risk of falls.

OBJECTIVE

The aim of the study was to evaluate the effect of aging on the static balance in women from 50-years to 89-years of age.

DESIGN

This was a cross-sectional study, with 400 irregularly active women were evaluated and grouped by age: Group 6^th decade (age 50 to 59) ‒ 58 participants; Group 7^th decade (age 60 to 69) ‒ 214 participants; Group 8^th decade (age 70 to 79) ‒ 92 participants; Group 9^th decade (age 80 to 89) ‒ 36 participants. Postural balance was evaluated using a portable force platform in a standard standing position, with Eyes Open (EO) and Eyes Closed (EC).

RESULTS

In the two measurement conditions, the elderly women in Group 9^th decade presented mediolateral displacement and range, and mean velocity greater than the women's values in Groups 6^th and 7^th decade. In the EO e EC situation, the displacement was higher in the elderly Group 9^th decade compared to younger groups. Group 8^th has a mean velocity greater than Group 6^th decade in the EO situation.

CONCLUSIONS

Posturography showed a decline in postural balance with advancing age, suggesting that the 9^th decade of life is a borderline age to this detriment due to an increase in postural instability.

The impact of two weeks of traditional therapy supplemented with virtual reality on balance control in neurologically-impaired children and adolescents

BACKGROUND

The aim of the study was to assess whether two weeks of therapy (traditional and VR) may improve balance in children and adolescents with neurological problems of different origins and whether the deterioration in gait dynamic balance showed by patient's ground reaction forces (GRF) determinates therapy effectiveness.

METHODS

29 participants aged 9-17 attended traditional therapy supplemented by tailor-made games. Therapy comprised exercises improving balance, range of motion, posture control, proprioception, muscle strength. Biodex Balance System was used for main assessment before and after therapy in tests: Postural Stability, modified Clinical Test of Sensory Integration and Balance, and Limits of Stability. Participants underwent gait analysis before the therapy to determine GRF. An increased maximal lateral component or decreased maximal anterior component in the push-off phase taking place in both legs were regarded as deterioration. This enabled the division into two groups with and without such a deterioration. Results were compared between the groups before and within groups before and after therapy.

RESULTS

The precision of forward-backwards body sway improved most significantly in the group with decreased GRF and reached the level of the second group, who worsened antero-posterior repeatability during stance on an unstable surface with eyes open.

CONCLUSION

Two weeks of combined traditional and VR therapy tailored to patients' functional weakness positively influenced the balance of neurologically impaired children. The group with decreased gait dynamic balance improved the tasks, which were intensively trained in the games. The second group remained more spontaneous in the trained direction.

Plantar sensation, plantar pressure, and postural stability alterations and effects of visual status in older adults

PURPOSE

Ageing leads to plantar sensation and pressure alterations and poor postural control. The aim of this study was to compare the plantar sensation and static plantar pressure distribution between young and older adults. A secondary aim was to investigate the effect of ageing and visual status on postural stability.

MATERIALS AND METHODS

Forty older subjects and 43 young adult individuals participated in the study. Plantar light touch sensation was evaluated using Semmes-Weinstein monofilaments. Static plantar pressure and postural stability were assessed with the WinTrack^® Pedobarography device.

RESULTS

Plantar sensation thresholds of the older individuals were higher compared to the young in all plantar regions (p < 0.001). The plantar contact area was greater in older individuals (p < 0.001). Maximum plantar pressure of midfoot was higher and maximum plantar pressure of the rearfoot and whole foot was less in older individuals during quiet stance (p < 0.05). The main effects of group and visual condition were significant for mean latero-lateral and antero-posterior sway speed with large effect sizes (p < 0.05).

CONCLUSIONS

The sensation of all plantar regions reduced, the rearfoot plantar pressure decreased, and the midfoot plantar pressure increased in older individuals compared to young. Postural stability was reduced in the older individuals, and their postural control was more affected by the eliminated visual information compared to the young. Increased plantar contact area and midfoot plantar pressure may be related to decreased MLA height in older individuals. Older individuals may need visual information more to maintain postural control because of reduced plantar sensation.

Chronic Effects of Breaching Blast Exposure on Sensory Organization and Postural Limits of Stability

OBJECTIVE

The goal of this effort to investigate if experienced breachers, professionals with a career history of exposure to repeated low-level blasts, exhibited postural instability.

METHODS

Postural data were examined using traditional tests of means and compared to normative data.

RESULTS

Breachers had significantly lower NeuroCom Sensory Organization Test (SOT) visual scores (within normative limits), prolonged Limits of Stability (LOS) test reaction time (30% of breachers and 7% of controls testing abnormal), and slower LOS movement velocity (21% of breachers and 0% of controls testing abnormal) compared to controls.

CONCLUSION

Our LOS test findings are like those previously reported for students in the military breacher training course and seem to indicate that while acute effects of blasts on sensory control of balance fade away, effects on postural LOS persist over time.

Sensor-Based Fall Risk Assessment: A Survey

Fall is a major problem leading to serious injuries in geriatric populations. Sensor-based fall risk assessment is one of the emerging technologies to identify people with high fall risk by sensors, so as to implement fall prevention measures. Research on this domain has recently made great progress, attracting the growing attention of researchers from medicine and engineering. However, there is a lack of studies on this topic which elaborate the state of the art. This paper presents a comprehensive survey to discuss the development and current status of various aspects of sensor-based fall risk assessment. Firstly, we present the principles of fall risk assessment. Secondly, we show knowledge of fall risk monitoring techniques, including wearable sensor based and non-wearable sensor based. After that we discuss features which are extracted from sensors in fall risk assessment. Then we review the major methods of fall risk modeling and assessment. We also discuss some challenges and promising directions in this field at last.

Adaptations in Reactive Balance Strategies in Healthy Older Adults After a 3-Week Perturbation Training Program and After a 12-Week Resistance Training Program

Both resistance training (RT) and perturbation-based training (PBT) have been proposed and applied as interventions to improve reactive balance performance in older adults. PBT is a promising approach but the adaptations in underlying balance-correcting mechanisms through which PBT improves reactive balance performance are not well-understood. Besides it is unclear whether PBT induces adaptations that generalize to movement tasks that were not part of the training and whether those potential improvements would be larger than improvements induced by RT. We performed two training interventions with two groups of healthy older adults: a traditional 12-week RT program and a 3-week PBT program consisting of support-surface perturbations of standing balance. Reactive balance performance during standing and walking as well as a set of neuro-muscular properties to quantify muscle strength, sensory and motor acuity, were assessed pre- and post-intervention. We found that both PBT and RT induced training specific improvements, i.e., standing PBT improved reactive balance during perturbed standing and RT increased strength, but neither intervention affected reactive balance performance during perturbed treadmill walking. Analysis of the reliance on different balance-correcting strategies indicated that specific improvements in the PBT group during reactive standing balance were due to adaptations in the stepping threshold. Our findings indicate that the strong specificity of PBT can present a challenge to transfer improvements to fall prevention and should be considered in the design of an intervention. Next, we found that lack of improvement in muscle strength did not limit improving reactive balance in healthy older adults. For improving our understanding of generalizability of specific PBT in future research, we suggest performing an analysis of the reliance on the different balance-correcting strategies during both the training and assessment tasks.