A prospective study of laboratory and clinical measures of postural stability to predict community-dwelling fallers

Process of dynamic balance recovery after voluntary perturbation: a time-series data analysis of young and older adults

[Purpose] This study investigated differences in the convergence mode of post-step sway between young and older adults using a step-down task to identify fall causes in older adults and assess consecutive postural adjustments. [Participants and Methods] This study included 15 young and 15 older adults (nine females and six males in each group). The participants stepped down from a standing position to a force platform 10 cm lower and maintained a one-leg standing position. The center-of-pressure total trajectory length was assessed using a force plate and regression equations for time and sway were derived from the associated time-series data for both groups. [Results] An inversely proportional aspect was observed for both groups, with significantly different coefficients and constants. The center-of-pressure total trajectory length per second from foot contact was significantly different between 2-3 s and 4-5 s in the older group but not in the younger group. [Conclusion] The results suggest a difference in the convergence mode of dynamic balance between the two groups, with young adults exhibiting a more rapid balance-sway reduction than older adults. The novel computational approach used in this study may be useful for dynamic balance measurements.

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

PURPOSE/AIM

Knee muscles strength is an important factor influencing postural stability in patients with knee osteoarthritis (KOA). However, there is no evidence regarding the relationship between the knee flexor/extensor strength ratio, which is suggested to be a good indicator of knee stability, and postural stability. We aimed to investigate postural stability and its relation to knee flexor and extensor strength and strength symmetry in women with KOA.

MATERIALS AND METHODS

Thirty-five women with unilateral KOA and thirty-five asymptomatic women were assessed with the Prokin system to collect the following parameters during quiet standing with eyes-open and eyes-closed: ellipse area, perimeter, forward-backward standard deviation, mediolateral standard deviation, the average centre of pressure displacement on the x- and y-axises (COPX and COPY), and the limit of stability (LoS) score. Higher scores mean better balance for LoS and poorer balance for other parameters. Knee flexor and extensor strength were assessed bilaterally with the Lafayette hand-held dynamometer.

RESULTS

The COPX during standing with eyes-closed was higher in women with KOA than controls and the LoS score was lower (p < 0.05, Cohens'd = 0.72 and 0.65). Postural stability was correlated with knee muscles strength and the flexor/extensor strength ratios in both groups (r = between 0.395 and 0.456 for LoS, r = between -0.335 and -0.639 for the others, p < 0.05).

CONCLUSIONS

Women with KOA had poorer postural stability in the mediolateral direction during standing with eyes-closed and a worse LoS score than controls. Postural stability was related to knee flexor and extensor strength and the flexor/extensor strength ratio in women.

Influence of aging on the relation between head control and hip joint kinematics during crossover stepping

Falls in older individuals are a serious health issue in super-aged societies. The stepping reaction is an important postural strategy for preventing falls. This study aimed to reveal the characteristics of lateral stepping in response to mechanical disturbance by means of an analysis of the hip joint kinematics in the stepping leg and head stability during crossover steps. The participants included 11 healthy older and 13 younger individuals. An electromagnet-controlled disturbance-loading device induced crossover steps due to lateral disturbance. Responses were measured using a motion capture system and force plates. The righting reaction of the head was quantified by lateral displacement (sway), neck joint kinematics (angle displacement, angular velocity), and neck joint moment during crossover stepping. Moreover, the relationship between the neck lateral bending moment and angular velocity of hip flexion/adduction of the stepping leg was examined. The lateral head sway was significantly larger in the older participants (1.13±0.7 m/s2) than in the younger individuals (0.54±0.3 m/s2); whereas, the angle displacement (older -14.1±7.1 degree, young -8.3±4.5 degree) and angular velocity (older 9.9±6.6 degree/s, 41.2±27.7 degree/s) of the head were significantly lower in the older than in the younger participants. In both groups, the moment of neck lateral bending exhibited a significant negative correlation with the hip flexion angular velocity of the stepping leg. Correlation analysis also showed a significant negative correlation between the neck lateral bending moment and hip adduction angular velocity only in the older group (r = 0.71, p<0.01). In conclusion, older individuals increased instability in the lateral direction of the head and decreased righting angle displacement and angular velocity of the head during crossover steps. The correlation between neck moment and hip flexion/adduction angular velocity suggested a decrease in step speed due to increased neck muscle tone, which could be influenced by vestibulospinal reflexes.

The stepping test, and infrared depth sensor, provide reliable measures of balance in community-dwelling older adults

[Purpose] The purpose was to examine relationships between variables characterizing the 20-second stepping test movement pattern, assessed with an infrared depth sensor (KinectTM), and measurements of dynamic and static balance. [Participants and Methods] A total of 27 independent-living, older adults (7 males and 20 females) participated in this study. For each participant, the stepping test total movement distance, movement displacement, knee movement distance, and step number were calculated from Kinect closed joint-point coordinate data. Dynamic and static balance were assessed using a NeuroCom Balance Master Platform system. [Results] The stepping test total movement distance had a moderate negative correlation with endpoint excursion (r=-0.469) and a moderate positive correlation with total movement distance, corrected for knee movement distance (r=0.557). Step numbers had a moderate negative correlation with stepping test total movement distance (r=-0.667) and total movement distance, corrected for knee movement distance (r=-0.531). Division into high and low-balance sub-groups (based on endpoint excursion or sway velocity scores) revealed that stepping test total movement distances and movement displacements were greater, and step numbers were fewer, in low balance groups. [Conclusion] The stepping test, combined with a KinectTM-assessed movement pattern provides a simple, objective, reliable means for assessing balance in community-dwelling, independent-living older adults.

Advances in mobility aid use reporting: situational context and objective measurement improve understanding of daily aid use in older adults

BACKGROUND

Understanding mobility aid use has implications for falls risk reduction and aid prescription. However, aid use in daily life is understudied and more complex than revealed by commonly used yes/no self-reporting.

AIMS

To advance approaches for evaluating mobility aid use among older adults using a situational (context-driven) questionnaire and wearable sensors.

METHODS

Data from two cross-sectional observational studies of older adults were used: (1) 190 participants (86 ± 5 years) completed tests of standing, sit-to-stand, walking, grip strength, and self-reported fear of falling and (2) 20 participants (90 ± 4 years) wore two body-worn and one aid-mounted sensors continuously for seven days to objectively quantify aid use during walking. Situational and traditional binary reporting stratified participants into aid dependency levels (0-4) and aid-user groups, respectively. Physical performance and fear of falling were compared between aid users, and dependency levels and sensor-derived walking behaviors were compared to reported aid use.

RESULTS

Physical performance and fear of falling differed between aid-user groups (P < 0.05). Sensor-derived outputs revealed differences in walking behaviors and aid use when categorized by dependency level and walking bout length (P < 0.05). Walking bout frequency (rho(18) = - 0.47, P = 0.038) and aid use time (rho(13) = .72, P = 0.002) were associated with dependency level.

DISCUSSION

Comparisons of situational aid dependency revealed heterogeneity between aid users suggesting binary aid use reporting fails to identify individual differences in walking and aid use behaviors.

CONCLUSIONS

Enhanced subjective aid use reporting and objective measurements of walking and aid use may improve aid prescription and inform intervention to support safe and effective mobility in older adults.

Accuracy of the Fullerton Advanced Balance (FAB) scale and a modified FAB model for predicting falls in older adults: A prospective study

BACKGROUND

This study aimed to determine the accuracy of the FAB scale and the accuracy of combining certain FAB scale items into a model for predicting falls in older adults.

METHODS

Eighty older adults were evaluated at baseline using all FAB scale items. A 6-month follow-up period was used to determine fall incidence. The Receiver Operation Characteristic (ROC) curve was used to assess the predictive capability of the total FAB scale for falls in older adults. A model comprising some FAB items was constructed using logistic regression analysis and a forward stepwise method. ROC curve analysis was used to assess the accuracy of the new model.

RESULTS

The accuracy of the total FAB scale for predicting falls was excellent (AUC = 0.95). The cut-off score for the FAB scale was 25 points, with a sensitivity of 96.5% and a specificity of 80%. Among the ten FAB items, a regression model was identified by combining four items: step up onto and over a 6-inch bench; tandem walk; standing on foam with eyes closed; and reactive postural control. The new model achieved an excellent level of accuracy (AUC = 0.98) with a cut-off score of 11 out of 16 points, a sensitivity of 100%, and a specificity of 87%.

CONCLUSIONS

Both the total FAB score and the new FAB model were highly accurate for predicting falls in older adults.

Comparative Analysis of Fall Risk Assessment Features in Community-Elderly and Stroke Survivors: Insights from Sensor-Based Data

Fall-risk assessment studies generally focus on identifying characteristics that affect postural balance in a specific group of subjects. However, falls affect a multitude of individuals. Among the groups with the most recurrent fallers are the community-dwelling elderly and stroke survivors. Thus, this study focuses on identifying a set of features that can explain fall risk for these two groups of subjects. Sixty-five community dwelling elderly (forty-nine female, sixteen male) and thirty-five stroke-survivors (twenty-two male, thirteen male) participated in our study. With the use of an inertial sensor, some features are extracted from the acceleration data of a Timed Up and Go (TUG) test performed by both groups of individuals. A short-form berg balance scale (SFBBS) score and the TUG test score were used for labeling the data. With the use of a 100-fold cross-validation approach, Relief-F and Extra Trees Classifier algorithms were used to extract sets of the top 5, 10, 15, 20, 25, and 30 features. Random Forest classifiers were trained for each set of features. The best models were selected, and the repeated features for each group of subjects were analyzed and discussed. The results show that only the stand duration was an important feature for the prediction of fall risk across all clinical tests and both groups of individuals.

Differing postural control patterns in individuals with bilateral and unilateral hearing loss

OBJECTIVES

Hearing loss (HL) is associated with imbalance and increased fall risk. The mechanism underlying this relationship and differences across types of hearing loss remains unclear. Head mounted displays (HMD) can shed light on postural control mechanisms via an analysis of head sway.

PURPOSE

The purpose of this study was to evaluate head sway in response to sensory perturbations in individuals with bilateral (BHL) or unilateral hearing loss (UHL) and compare them to controls.

MATERIALS AND METHODS

We recruited 36 controls, 23 individuals with UHL and 14 with BHL. An HMD (HTC Vive) measured head sway while participants stood on the floor, hips-width apart. Stimuli included two levels of visuals and sound. Root Mean Square Velocity (RMSV) and Power Spectral Density (PSD) were used to quantify head sway.

RESULTS

Adjusting for age, individuals with BHL had significantly higher anterior-posterior and medio-lateral RMSV than controls and individuals with UHL. Individuals with UHL demonstrated significantly lower response to visual perturbations in RMSV AP and in all 3 frequency segments of PSD compared to controls. Individuals with UHL showed significantly lower movements at high frequencies compared to controls. Sounds or severity of HL did not impact head sway.

CONCLUSIONS

Individuals with BHL demonstrated increased sway with visual perturbations and should be clinically assessed for balance performance and fall risk. Individuals with UHL exhibited reduced responses to visual stimuli compared with controls, which may reflect conscious movement processing. Additional studies are needed to further understand the mechanistic relationship between hearing loss and imbalance.

Effects of Visual Input Absence on Balance Recovery Responses to Lateral Standing Surface Perturbations in Older and Younger Adults

Although the ability to recover balance in the lateral direction has important implications with regard to fall risk in older adults, the effect of visual input on balance recovery in response to lateral perturbation and the effect of age are not well studied. We investigated the effect of visual input on balance recovery response to unpredictable lateral surface perturbations and its age-related changes. Ten younger and 10 older healthy adults were compared during balance recovery trials performed with the eyes open and eyes closed (EC). Compared with younger adults, older adults showed increased electromyography (EMG) peak amplitude of the soleus and gluteus medius, reduced EMG burst duration of the gluteus maximus and medius, and increased body sway (SD of the body's center of mass acceleration) in EC. In addition, older adults exhibited a smaller % increase (EC-eyes open) of the ankle eversion angle, hip abduction torque, EMG burst duration of the fibularis longus, and a greater % increase of body sway. All kinematics, kinetics, and EMG variables were greater in EC compared with eyes open in both groups. In conclusion, the absence of visual input negatively affects the balance recovery mechanism more in older adults compared with younger adults.

IMOVE: Protocol for a randomized, controlled 2x2 factorial trial of improvisational movement and social engagement interventions in older adults with early Alzheimer's disease

Background

In addition to cognitive impairment, people with Alzheimer's disease (PWAD) experience neuropsychiatric symptoms (e.g., apathy, depression), altered gait, and poor balance that further diminish their quality of life (QoL). Here, we describe a unique, randomized, controlled trial to test the hypothesis that both movement and social engagement aspects of a group dance intervention alter the connectivity of key brain networks involved in motor and social-emotional functioning and lead to improved QoL in PWAD.

Methods

IMOVE (NCT03333837) was a single-center, randomized, controlled 2x2 factorial trial that assigned PWAD/caregiver dyads to one of 4 study conditions (Movement Group, Movement Alone, Social Group, or Usual Care control). The Movement Group participated in twice-weekly group improvisational dance (IMPROVment® Method) classes for 12 weeks. The Movement Alone intervention captured the same dance movement and auditory stimuli as the group class without social interaction, and the Social Group used improvisational party games to recapitulate the fun and playfulness of the Movement Group without the movement. The primary outcome was change in QoL among PWAD. Key secondary outcomes were functional brain network measures assessed using graph-theory analysis of resting-state functional magnetic resonance imaging scans, as well as neuropsychiatric symptoms, gait, and balance.

Results

A total of 111 dyads were randomized; 89 completed the study, despite interruption and modification of the protocol due to COVID-19 restrictions (see companion paper by Fanning et al.). The data are being analyzed and will be submitted for publication in 2023.

Assessment of gait and posture characteristics using a smartphone wearable system for persons with osteoporosis with and without falls

We used smartphone technology to differentiate the gait characteristics of older adults with osteoporosis with falls from those without falls. We assessed gait mannerism and obtained activities of daily living (ADLs) with wearable sensor systems (smartphones and inertial measurement units [IMUs]) to identify fall-risk characteristics. We recruited 49 persons with osteoporosis: 14 who had a fall within a year before recruitment and 35 without falls. IMU sensor signals were sampled at 50 Hz using a customized smartphone app (Lockhart Monitor) attached at the pelvic region. Longitudinal data was collected using MoveMonitor+ (DynaPort) IMU over three consecutive days. Given the close association between serum calcium, albumin, PTH, Vitamin D, and musculoskeletal health, we compared these markers in individuals with history of falls as compared to nonfallers. For the biochemical parameters fall group had significantly lower calcium (P = 0.01*) and albumin (P = 0.05*) and higher parathyroid hormone levels (P = 0.002**) than nonfall group. In addition, persons with falls had higher sway area (P = 0.031*), lower dynamic stability (P < 0.001***), gait velocity (P = 0.012*), and were less able to perform ADLs (P = 0.002**). Thus, persons with osteoporosis with a history of falls can be differentiated by using dynamic real-time measurements that can be easily captured by a smartphone app, thus avoiding traditional postural sway and gait measures that require individuals to be tested in a laboratory setting.

Reliability, validity, and minimal detectable change of the Step Test in patients with total knee arthroplasty

BACKGROUND

Step Test (ST) is frequently used to assess dynamic balance and locomotor function in clinical practice.

AIMS

This study aimed to determine the concurrent validity, reliability, and minimal detectable change (MDC) of the ST in patients with total knee arthroplasty (TKA).

METHODS

The study included 56 patients with TKA. The intraclass correlation coefficient (ICC) was used to assess the test-retest reliability of the ST. The correlations of the ST with timed up and go (TUG) and 10-m walk test (10MWT) were assessed for concurrent validity.

RESULTS

Test-retest (ICC 0.90) reliability of the ST was determined to be excellent. The SEM and MDC95 values of test-retest reliability were 0.76 and 2.11, respectively. A significantly moderate correlation was found between the ST and TUG (p < 0.05, r: - 0.69), and 10MWT (p < 0.05, r: - 0.67).

CONCLUSION

The ST is a valid and reliable method in the assessment of dynamic balance ability and locomotor function in patients with TKA. The ST can be used to quantify changes in dynamic balance level and locomotor function in patients with TKA.

Limits of stability and falls during a multicomponent exercise program in faller older adults: A retrospective cohort study

BACKGROUND/OBJETIVES

Multicomponent exercise programs have been demonstrated to prevent falls in older adults. However, the underlying responsible mechanisms are not clear. We aimed to analyze the association between changes in the limits of stability (LOS) as a relevant balance component, and falls occurrence during a multicomponent physical exercise program.

METHODS

Retrospective study, including ninety-one participants who had experienced a fall in the previous year, and were attended in a falls unit. All of them were included in a twice-a-week multicomponent exercise program during 16 weeks. Pre- and post-program measurements were collected for leg press, gait speed, the short physical performance battery (SPPB), and LOS (point of excursion [POE] and maximal excursion [MEX]) with posturography. Falls occurrence was assessed between the beginning and the completion of the exercise program (16 week).

RESULTS

The mean age was 77.2 years, and 72 were female. Thirty-two participants fell at least once during the exercise period. The global baseline POE was 47.6 %, and the MEX was 64.7 %, and there were no differences between fallers and nonfallers. Nonfallers presented greater improvements in POE (6.3 % versus 1.3 %; p < .05) and MEX (9.2 % versus 3.0 %; p < .01) than fallers. The POE and MEX were independently associated with a reduced probability of having had a fall, OR: 0.95 (95 % CI: 0.91 to 0.99) and 0.94 (95 % CI: 0.90 to 0.99), respectively. Changes in SPPB results or leg press strength were not associated with decreased falls. Adjusted probability of fall occurrence decreased by 5 % and 6 % per 1 % improvement in absolute values in POE and MEX, respectively.

CONCLUSIONS

Improvements in LOS after a multicomponent physical exercise program in older adults with previous falls may be associated with a decreased occurrence of falls.

Age-related differences in stepping stability following a sudden gait perturbation are associated with lower limb eccentric control of the perturbed limb

INTRODUCTION

Falls are a leading cause of severe injuries and a major threat to quality of life in older adults. Elderly fallers demonstrate insufficient eccentric quadriceps control during the weight acceptance phase of initial single limb stance. However, the functional role of eccentric control of the perturbed (leading) leg during walking balance recovery and its age-related differences have not yet been studied; thus we investigated age-related differences in eccentric control at the knee of the perturbed leg and its influence on the postural sway and stability of the trailing leg during balance recovery following unexpected surface drop perturbations.

METHODS

Ten younger and ten older healthy adults were compared during balance recovery following an 8 cm unexpected surface drop perturbation at gait initiation. Outcomes related to perturbed leg included 1) eccentric knee extensor work; 2) electromyography (EMG) peak amplitude, peak latency, and eccentric EMG burst duration of the rectus femoris (RF); and 3) knee flexion angle during the single limb support. Outcomes related to stability of the trailing leg included 4) margin of stability (MoS) at first compensatory step touchdown after the perturbation. 5) Postural sway (standard deviation of center of mass acceleration) was measured in the anterior-posterior (A-P), medio-lateral (M-L), vertical directions during the single limb support.

RESULTS

Compared to younger adults, older adults demonstrated lower eccentric knee extensor work (p = 0.034), shorter RF EMG burst duration (p < 0.01), delayed RF EMG peak latency (p = 0.01), smaller knee flexion angle (p = 0.01) and MoS (p = 0.04), and higher postural sway (M-L (p = 0.02), vertical (p < 0.01)). There was a positive correlation between eccentric work and MoS (p = 0.03) and a negative correlation between M-L postural sway and 1) RF eccentric EMG burst duration (p = 0.04), and 2) eccentric work (p = 0.01).

CONCLUSIONS

Older adults demonstrated deficits in eccentric knee extensor control in the perturbed leg during single limb support, which contributed to reduced stability of the trailing leg compensatory step and greater postural sway during balance recovery. This finding provides insight into mechanisms of fall recovery from an unexpected unilateral postural perturbation and directions for lower limb strengthening exercises for aging populations.

Age-related asymmetry in anticipatory postural movements during unilateral arm movement and imagery

Reaching movements of the arms are accompanied by anticipatory (APM) and compensatory postural motion (CPM) that counteract the resulting perturbations to body stability. Recent research has shown that these postural actions are also observable in the context of imagined arm movements. As motor imagery (MI) shares many neurophysiological and behavioral characteristics with physical movements, and MI training can affect subsequent performance, MI tasks provide a good setting for studying the anticipatory aspects of postural control. This study investigated APMs and CPMs of the head and hip of healthy young and older adults in the temporal vicinity of physical and imagined forward raises of the dominant and non-dominant arm. When MI of the dominant arm was self-initiated, both age groups showed APM in the anteroposterior plane. When the self-initiated MI was of the non-dominant arm, only the older group showed anteroposterior APM. The older group did not show APM when an expected arm movement (or MI) was made to an external signal. This suggests an age-related deficit in coordinating postural preparation with external events. Only the older group showed mediolateral APM, and only for dominant arm MI, indicating sensitivity to potential perturbation to the weaker, non-dominant side of the body. Overall, the older group showed more anticipatory postural motion at the head. Systematic APM for manual MI suggests that MI training may be an effective intervention for anticipatory postural control. An integrated model of postural support for executed and imagined limb movements is suggested.

Nonlinear Dynamic Measures of Walking in Healthy Older Adults: A Systematic Scoping Review

BACKGROUND

Maintaining a healthy gait into old age is key to preserving the quality of life and reducing the risk of falling. Nonlinear dynamic analyses (NDAs) are a promising method of identifying characteristics of people who are at risk of falling based on their movement patterns. However, there is a range of NDA measures reported in the literature. The aim of this review was to summarise the variety, characteristics and range of the nonlinear dynamic measurements used to distinguish the gait kinematics of healthy older adults and older adults at risk of falling.

METHODS

Medline Ovid and Web of Science databases were searched. Forty-six papers were included for full-text review. Data extracted included participant and study design characteristics, fall risk assessment tools, analytical protocols and key results.

RESULTS

Among all nonlinear dynamic measures, Lyapunov Exponent (LyE) was most common, followed by entropy and then Fouquet Multipliers (FMs) measures. LyE and Multiscale Entropy (MSE) measures distinguished between older and younger adults and fall-prone versus non-fall-prone older adults. FMs were a less sensitive measure for studying changes in older adults' gait. Methodology and data analysis procedures for estimating nonlinear dynamic measures differed greatly between studies and are a potential source of variability in cross-study comparisons and in generating reference values.

CONCLUSION

Future studies should develop a standard procedure to apply and estimate LyE and entropy to quantify gait characteristics. This will enable the development of reference values in estimating the risk of falling.

Relationship between hip abductor strength, rate of torque development scaling factor and medio-lateral stability in older adults

BACKGROUND

Recently, the rate of torque development scaling factor (RTD-SF) has been proposed as a useful tool that could contribute to a more comprehensive insight into muscular capacity. While lower RTD-SF is associated with ageing and certain neuromuscular diseases, it remains unknown whether this novel measure is associated with the postural control in the older adults.

RESEARCH QUESTION

Are hip abductor muscle strength, RTD and RTD-SF associated with responses to external postural perturbations in medio-lateral direction in older adults?

METHODS

Twenty healthy older adults (14 females, 6 males) were assessed for hip abductor muscle strength, RTD and RTD-SF, using a custom-built dynamometer. Perturbations were applied at waist level (4 perturbation intensities, 15 repetitions each) using a wire-pull paradigm, with centre-of-pressure (CoP) being recorded with force plates. For each condition (i.e. perturbation intensity), medio-lateral displacement and velocity of the CoP were computed. For both parameters, within-individual variation (representing consistency of the responses), expressed by the standard deviation (SD) of CoP parameters was also considered. Pearson correlation coefficients were computed between parameters of hip muscle capacity and CoP responses and SD values of CoP responses.

RESULTS

RTD-SF was moderately positively related to the consistency of the responses of both CoP displacement and velocity (r = 0.53-0.56; p = 0.011-0.016) at the lowest level of the perturbation magnitude (15 N). No other statistically significant relationships were found (all r < 0.35).

SIGNIFICANCE

RTD-SF could play a role in preserving postural balance in older adults when low-intensity perturbations are applied. RTD-SF is a novel outcome measure that could represent an important alternative clinical tool to traditional strength assessments. It could represent a supplementary tool to assess the risk of falls, however, several limitations and ambiguities need to be resolved by future research before it can be utilized in practice.

Risk of falls using the Biodex Balance System in non-faller patients with Parkinson Disease

PURPOSE

Biodex Balance System (BBS) is a low-cost platform used to assess balance in different populations. However, no study has used this tool to evaluate the risk of falls related to balance changes in non-faller individuals with Parkinson Disease (PD).

OBJECTIVE

The aim of this study was to determine the changes in the balance in non-faller individuals with mild to moderate PD compared to healthy elders.

METHODS

Forty-six PD patients at stages 2 and 3 were assessed in the 'on' state (fully medicated) as well as 31 age-matched healthy controls. They were submitted to the fall risk protocol of BBS and performed three 20-s trials and a 60-s rest interval between the trials.

RESULTS

Non-faller PD patients had an increased instability when compared to the healthy controls in the anteroposterior (controls: 1.54 ± 1.00 vs. PD patients: 2.91 ± 0.93) and mediolateral directions (controls: 1.21 ± 0.57 vs. PD patients: 1.42 ± 0.46), resulting in a great overall instability in the PD patients (controls: 1.28 ± 0.61 vs. PD patients: 4.09 ± 1.22). A significant correlation between overall instability and UPDRS-III (motor symptoms) in individuals with PD was observed.

CONCLUSION

BBS was able to identify the risk of falls in non-fallers, showing that PD patients have a greater risk of falls in unstable conditions than age-matched healthy elders, mainly due to the large sway in the anteroposterior direction. Furthermore, the severity of motor symptoms was related to overall instability which can increase the risk of falls in PD patients.

AGE-RELATED DIFFERENCES IN STATIC POSTURAL BALANCE IN KOREAN ELDERLY ADULTS

Poor postural balance has been related to falls in older people. Although fall rates increase with age, age-related declines in postural balance of older people are still unclear. The goal of this study was to investigate age-related changes in the static postural balance ability of Korean elderly adults. Three hundred and eighty-nine normal elderly adults with ages ranging from 57 years to 87 years participated in this study. All elderly adults were instructed to stand in their preferred natural stance on a self-developed force platform. As postural sway variables, peak frequency, mean frequency, mean velocity, and mean distance were calculated from the center of pressure (COP) trajectories in both the medio-lateral (ML) and antero-posterior (AP) directions. The mean velocity in the older-elderly was significantly faster compared to those of the other age groups particularly in the AP direction ([Formula: see text]). In both the ML and AP directions, the older-elderly group showed a greater mean distance compared to the other age groups ([Formula: see text]). Conversely, no significant age group differences were found in mean frequency and peak frequency ([Formula: see text]). Our results mean that the older-elderly group showed postural balance with faster AP sway speed and overall sway size. The results of our study help in the understanding of age-related declines in postural balance for the prevention of falls and the development of a regression model for normative postural balance ability in Korean elderly adults.

A review of center of pressure (COP) variables to quantify standing balance in elderly people: Algorithms and open-access code

Postural control is often quantified by recording the trajectory of the center of pressure (COP)-also called stabilogram-during human quiet standing. This quantification has many important applications, such as the early detection of balance degradation to prevent falls, a crucial task whose relevance increases with the aging of the population. Due to the complexity of the quantification process, the analyses of sway patterns have been performed empirically using a number of variables, such as ellipse confidence area or mean velocity. This study reviews and compares a wide range of state-of-the-art variables that are used to assess the risk of fall in elderly from a stabilogram. When appropriate, we discuss the hypothesis and mathematical assumptions that underlie these variables, and we propose a reproducible method to compute each of them. Additionally, we provide a statistical description of their behavior on two datasets recorded in two elderly populations and with different protocols, to hint at typical values of these variables. First, the balance of 133 elderly individuals, including 32 fallers, was measured on a relatively inexpensive, portable force platform (Wii Balance Board, Nintendo) with a 25-s open-eyes protocol. Second, the recordings of 76 elderly individuals, from an open access database commonly used to test static balance analyses, were used to compute the values of the variables on 60-s eyes-open recordings with a research laboratory standard force platform.

Reliability and Fall-Risk Predictability of the Short Form of the Fullerton Advanced Balance Scale in Iranian Older Adults

Recently, a short form of the Fullerton Advanced Balance (SF-FAB) scale was reported as a good predictor of falls in older adults. However, we found no evidence regarding its reliability in non-American older adults. Therefore, we aimed to analyze the reliability and homogeneity of the SF-FAB scale to measure postural balance in Iranian older adults. Eighty-five community-dwelling older adults (70.75 ± 4.97 years) performed the SF-FAB test on two occasions 1 week apart. In both instances, four raters assessed the performance on the test. The SF-FAB scale (mean total score: 12.46 ± 3.53) revealed acceptable internal consistency (Cronbach's α = .77), excellent intrarater reliability (intraclass correlation coefficient = .94-.99), and excellent interrater reliability (intraclass correlation coefficient = .92-.99). The overall prediction success rate was 83.5% with correctly classifying 95.6% of nonfallers and 35.3% of fallers. The SF-FAB scale can provide a quick screen of balance status in older adults to trigger referral to clinicians for a more comprehensive assessment.

Hip muscle strength, dynamic balance and functional capacity of community-dwelling older adults aged 60 and older: A cross-sectional study

The objective of the present study was to evaluate the association of hip muscle strength, dynamic balance and functional capacity in the older adults aged 60 to 79 years and older adults aged 80 years and older. A total of 191 community-dwelling older adults participated in this study. Isometric muscle strength was quantified as the peak torque (PT), measured using an isokinetic dynamometer. Functional capacity was determined by the forward step test (ST) and the dynamic balance by the tandem gait (TG) test. The hip flexor, extensor, abductor and adductor PT in the older adults aged 60 to 79 years had a positive influence on the execution of the step test (p < 0.05). The peak adductor torque did not show a significant association with tandem gait (p = 0.649). In older adults aged 80 years and older, the peak adductor torque was the only one that showed an association with the performance of the ST (p = 0.001) and TG (p = 0.024) tests. The hip adductors may have a higher contribution in adults aged 80 years and older during the execution of clinical tests. These findings are relevant to clinical practice as they can help in the development of appropriate physical exercise programs targeting older adults of different age groups.

Development of postural stability in children with autism spectrum disorder: a cross-sectional study

The purpose was to investigate the effects of age on postural stability for children with autism spectrum disorder (ASD). Twenty-nine children with mild ASD were assigned into one of the three groups: 6–8 years (U8), 9–11 years (U11) and 12–14 years (U14). Participants stood barefoot with both feet on a force platform and maintained stationary for 15 seconds during eyes-open and eyes-closed conditions. Center of pressure data were collected and variables were calculated, including displacements, total distances, sway areas, and sample entropy. The variables were compared among the three groups using a mixed-model ANOVA. The age group effect was significant for mediolateral center of pressure displacement (p = 0.04) and sway distance (p = 0.02). Post-hoc comparisons revealed that U8 exhibited greater mediolateral displacement and total distance compared to U14, regardless of test conditions. The U14 group exhibited improved mediolateral postural stability compared to U8, whereas no differences were found between U8 and U11 or between U11 and U14. This may suggest that children with ASD could slowly develop postural stability but only demonstrate significant changes over a long period of time. Early intervention programs aimed to improve complexity of postural control could be beneficial.

Predicting falls in community-dwelling older adults: a systematic review of prognostic models

OBJECTIVE

To systematically review and critically appraise prognostic models for falls in community-dwelling older adults.

ELIGIBILITY CRITERIA

Prospective cohort studies with any follow-up period. Studies had to develop or validate multifactorial prognostic models for falls in community-dwelling older adults (60+ years). Models had to be applicable for screening in a general population setting.

INFORMATION SOURCE

MEDLINE, EMBASE, CINAHL, The Cochrane Library, PsycINFO and Web of Science for studies published in English, Danish, Norwegian or Swedish until January 2020. Sources also included trial registries, clinical guidelines, reference lists of included papers, along with contacting clinical experts to locate published studies.

DATA EXTRACTION AND RISK OF BIAS

Two authors performed all review stages independently. Data extraction followed the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist. Risk of bias assessments on participants, predictors, outcomes and analysis methods followed Prediction study Risk Of Bias Assessment Tool.

RESULTS

After screening 11 789 studies, 30 were eligible for inclusion (n=86 369 participants). Median age of participants ranged from 67.5 to 83.0 years. Falls incidences varied from 5.9% to 59%. Included studies reported 69 developed and three validated prediction models. Most frequent falls predictors were prior falls, age, sex, measures of gait, balance and strength, along with vision and disability. The area under the curve was available for 40 (55.6%) models, ranging from 0.49 to 0.87. Validated models' The area under the curve ranged from 0.62 to 0.69. All models had a high risk of bias, mostly due to limitations in statistical methods, outcome assessments and restrictive eligibility criteria.

CONCLUSIONS

An abundance of prognostic models on falls risk have been developed, but with a wide range in discriminatory performance. All models exhibited a high risk of bias rendering them unreliable for prediction in clinical practice. Future prognostic prediction models should comply with recent recommendations such as Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis.

PROSPERO REGISTRATION NUMBER

CRD42019124021.

Short-term balance training and acute effects on postural sway in balance-deficient older adults: a randomized controlled trial

BACKGROUND

We aimed to determine the effectiveness of 4 weeks of balance exercise compared with no intervention on objectively measured postural sway.

METHODS

This was a single-center parallel randomized controlled, open label, trial. A six-sided dice was used for allocation at a 1:1-ratio between exercise and control. The trial was performed at a university hospital clinic in Sweden and recruited community-dwelling older adults with documented postural instability. The intervention consisted of progressively challenging balance exercise three times per week, during 4 weeks, with follow-up at week five. Main outcome measures were objective postural sway length during eyes open and eyes closed conditions.

RESULTS

Sixty-five participants aged 70 years (balance exercise n = 32; no intervention n = 33) were randomized. 14 participants were excluded from analysis because of early dropout before follow-up at week five, leaving 51 (n = 22; n = 29) participants for analysis. No significant differences were detected between the groups in any of the postural sway outcomes. Within-group analyses showed significant improvements in hand grip strength for the intervention group, while Timed Up & Go improvements were comparable between groups but only statistically significant in the control group.

CONCLUSIONS

Performing balance exercise over a four-week intervention period did not acutely improve postural sway in balance-deficient older adults. The lower limit in duration and frequency to achieve positive effects remains unclear.

TRIAL REGISTRATION

Clinical trials NCT03227666 , July 24, 2017, retrospectively registered.

Stepping impairment and falls in older adults: A systematic review and meta-analysis of volitional and reactive step tests

OBJECTIVE

To systematically examine stepping performance as a risk factor for falls. More specifically, we examined (i) if step tests can distinguish fallers from non-fallers and (ii) the type of step test (e.g. volitional vs reactive stepping) that is required to distinguish fallers from non-fallers.

DATA SOURCE

PubMed, EMBASE, CINAHL, Cochrane Database of Systematic Reviews and reference lists of included articles.

STUDY SELECTION

Cross-sectional and cohort studies that assessed the association between at least one step test and falls in older people (age ≥ 60 and/or mean age of 65).

RESULTS

A meta-analysis of 61 studies (n = 9536) showed stepping performance was significantly worse in fallers compared to non-fallers (Cohen'sd 0.56, 95 % CI 0.48 to 0.64, p < 0.001, I² 66 %). This was the case for both volitional and reactive step tests. Twenty-three studies (n = 3615) were included in a diagnostic meta-analysis that showed that step tests have moderate sensitivity (0.70, 95 % CI 0.62 to 0.77), specificity (0.68, 95 % CI 0.58 to 0.77) and area under the receiver operating characteristics curve (AUC) (0.75, 95 % CI 0.59 to 0.86) in discriminating fallers from non-fallers.

CONCLUSIONS

This large systematic review demonstrated that both volitional and reactive stepping impairments are significant fall risk factors among older adults. Step tests can identify fallers from non-fallers with moderate accuracy.

Risk-of-falling related outcomes improved in community-dwelling older adults after a 6-week sideways walking intervention: a feasibility and pilot study

BACKGROUND

Aging increases fall risk and alters gait mechanics and control. Our previous work has identified sideways walking as a potential training regimen to decrease fall risk by improving frontal plane control in older adults' gait. The purposes of this pilot study were to test the feasibility of sideways walking as an exercise intervention and to explore its preliminary effects on risk-of-falling related outcomes.

METHODS

We conducted a 6-week single-arm intervention pilot study. Participants were community-dwelling older adults ≥ 65 years old with walking ability. Key exclusion criteria were neuromusculoskeletal and cardiovascular disorders that affect gait. Because initial recruitment rate through University of Nebraska at Omaha and Omaha community was slower than expected (3 participants∙week- 1), we expanded the recruitment pool through the Mind & Brain Health Labs registry of the University of Nebraska Medical Center. Individualized sideways walking intervention carried out under close supervision in a 200 m indoor walking track (3 days∙week- 1). Recruitment and retention capability, safety, and fidelity of intervention delivery were recorded. We also collected (open-label) walking speed, gait variability, self-reported and performance-based functional measures to assess participants' risk-of-falling at baseline and post-intervention: immediate, and 6 weeks after the completion of the intervention.

RESULTS

Over a 7-month period, 42 individuals expressed interest, 21 assessed for eligibility (21/42), and 15 consented to participate (15/21). Most of the potential participants were reluctant to commit to a 6-week intervention. Desired recruitment rate was achieved after revising the recruitment strategy. One participant dropped out (1/15). Remaining participants demonstrated excellent adherence to the protocol. Participants improved on most outcomes and the effects remained at follow-up. No serious adverse events were recorded during the intervention.

CONCLUSIONS

Our 6-week sideways walking training was feasible to deliver and demonstrated strong potential as an exercise intervention to improve risk-of-falling outcomes in community-dwelling older adults. In a future trial, alternative clinical tools should be considered to minimize the presence of ceiling/floor effects. A future large trial is needed to confirm sideways walking as a fall prevention intervention.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04505527 . Retrospectively registered 10 August 2020.

Effects of 6-Month Multimodal Physical Exercise Program on Bone Mineral Density, Fall Risk, Balance, and Gait in Patients with Alzheimer's Disease: A Controlled Clinical Trial

We aimed to determine the short- and medium-term effects of a multimodal physical exercise program (MPEP) on bone health status, fall risk, balance, and gait in patients with Alzheimer’s disease. A single-blinded, controlled clinical trial was performed where 72 subjects were allocated in a 3:1 ratio to an intervention group (IG; n = 53) and control group (CG; n = 19), where the IG’s subjects were admitted to live in a State Reference Center of Alzheimer’s disease, which offers the targeted exercise program, while the CG’s subjects resided in independent living. A multidisciplinary health team assessed all patients before allocation, and dependent outcomes were again assessed at one, three, and six months. During the study, falls were recorded, and in all evaluations, bone mineral density was measured using a calcaneal quantitative ultrasound densitometer; balance and gait were measured using the performance-oriented mobility assessment (POMA), the timed up and go test (TUG), the one-leg balance test (OLB), and the functional reach test (FR). There were no differences between groups at baseline for all outcome measures. The prevalence of falls was significantly lower in the IG (15.09%) than in the CG (42.11%) (χ² = 5.904; p = 0.015). We also found that there was a significant time*group interaction, with a post hoc Šidák test finding significant differences of improved physical function, especially in gait, for the IG, as assessed by POMA-Total, POMA-Gait, and TUG with a large effect size (ƞ²p = 0.185–0.201). In balance, we found significant differences between groups, regardless of time, and a medium effect size as assessed by POMA-Balance and the OLB (ƞ²p = 0.091–0.104). Clinically relevant effects were observed, although without significant differences in bone health, with a slowing of bone loss. These results show that a multimodal physical exercise program reduces fall risk and produces an improvement in gait, balance, and bone mineral density in the short and medium term in institutionalized patients with Alzheimer’s disease.

Immediate Effects of Aquatic Therapy on Balance in Older Adults with Upper Limb Dysfunction: An Exploratory Study

Background: Aquatic physiotherapy has been shown to be effective in developing balance, strength, and functional reach over time. When dealing with immediate effects, the literature has concentrated more on the body’s physiological response to the physical and mechanical properties of water during passive immersion. The purpose of this study was to evaluate the effects of a single 45-min active aquatic physiotherapy session on standing balance and strength, and its relationship with functional reach in persons 55 years and older with upper limb dysfunction. Methods: The intervention group (n = 12) was assessed before and after a single aquatic physiotherapy session, while the control group (n = 10) was evaluated before and after 45 min of sitting rest. Functional assessment was made using the visual analogue pain scale (points), step test (repetitions), functional reach test (cm), and global balance-standing test on a force platform (% time). A two-way repeated-measures ANOVA was applied (p < 0.05). Results: The intervention group showed non-significant improvements between measurement before and after the intervention: Pain: 6.2 ± 1.9 vs. 5.2 ± 2.3 cm, steps: 7.0 ± 2.0 vs. 7.4 ± 1.8 repetitions, reach: 9.1 ± 2.8 vs. 10.4 ± 3.8 cm, and balance: 61.7 ± 5.9 vs. 71.3 ± 18.2% time in balance on the platform. The control group showed fewer changes but had better baseline values. A comparison between groups with time showed no significant differences in these changes. Conclusions: No significant immediate effects were found for one session of aquatic physiotherapy applied to patients older than 55 years with upper limb dysfunction.

The Postural Stability Measures Most Related to Aging, Physical Performance, and Cognitive Function in Healthy Adults

Background

Different measures have been used to quantify body balance; some of which use technology to measure postural sway, others are physical performance or self-reported. However, there is little information on the best postural sway measures associated with aging, physical performance, and cognitive function measures.

Objective

To evaluate the relationship between postural sway measures and aging, physical performance, and cognitive function measures.

Methods

A total of 51 subjects (53% female, mean age 53.2 ± 21 years) participated in this cross-sectional study. The participants completed the Activities-specific Balance Confidence (ABC) Scale questionnaire, the Functional Gait Assessment (FGA), the Montreal Cognitive Assessment (MoCA) test, and gait speed. Afterward, the participants performed 8 balance exercises, and their postural sway was measured using a force plate. Spearman's rank correlation coefficient was used to examine the relationship between the study variables.

Results

Age was negatively associated with cognitive function, gait speed, ABC scores, and FGA scores. In addition, cognitive ability was associated positively with ABC scores (r = 0.38, p ≤ 0.01). Age, FGA scores, and gait speed were significantly associated with the postural sway of the AP direction in some exercises and in all exercises in the ML directions (p < 0.05). The cognitive function and ABC scores were significantly associated with only postural sway measures in the ML direction (p < 0.05).

Conclusion

The postural sway measures in the lateral direction had more and stronger associations with age, physical performance, and cognitive function measures compared to those in the AP direction.

Lower-Limb Factors Associated with Balance and Falls in Older Adults: A Systematic Review and Clinical Synthesis

BACKGROUND

Despite sufficient evidence to suggest that lower-limb-related factors may contribute to fall risk in older adults, lower-limb and footwear influences on fall risk have not been systematically summarized for readers and clinicians. The purpose of this study was to systematically review and synethesize the literature related to lower-limb, foot, and footwear factors that may increase the risk of falling among community-dwelling older adults.

METHODS

We searched PubMed, Embase, PsycINFO, CINAHL, Web of Science, Cochrane Library, and AgeLine. To describe the trajectory toward increasing risk of falls, we examined those articles that linked age-related changes in the lower limb or footwear to prospective falls or linked them to evidenced-based fall risk factors, such as gait and balance impairment.

RESULTS

This systematic review consisted of 81 articles that met the review criteria, and the results reflect a narrative review of the appraised literature for eight pathways of lower-limb-related influences on fall risk in older adults. Six of the eight pathways support a direct link to fall risk. Two other pathways link to the intermediate factors but lack studies that provide evidence of a direct link.

CONCLUSIONS

This review provides strong guidance to advance understanding and assist with managing the link between lower-limb factors and falls in older adults. Due to the lack of literature in specific areas, some recommendations were based on observational studies and should be applied with caution until further research can be completed.

Center of pressure displacement characteristics differentiate fall risk in older people: A systematic review with meta-analysis

Falling is the second most prevalent cause of accidental death in the world. Currently available clinical tests to assess balance in older people are insufficiently sensitive to screen for fall risk in this population. Laboratory tests that record the center of pressure (COP) trajectory could overcome this problem but despite their widespread use, the choice of COP trajectory features for use as a biomarker of fall risk lacks consensus. This systematic review and meta-analysis aimed at identifying the best COP characteristics to predict risk of falling in older adults. More than 4000 articles were screened; 44 (7176 older adults) were included in this study. Several COP parameters emerged as good indices to discriminate fallers from non-fallers. From sensitivity analysis, Sway area per unit time, anteroposterior mean velocity, and radial mean velocity were the best traditional features. In this study, identification of older people with a high fall risk was demonstrated using quiet-standing recordings. Such screening would also be useful for routine follow-up of balance changes in older fallers in clinical practice.

Association between Statin Use and Balance in Older Adults

Background: Several medications have been associated with an increased risk of balance deficits and greater likelihood to sustain a fall, representing a large health and economic issue. Statins are regularly prescribed to prevent strokes and heart attacks, but their impact on balance is unknown. The aim of this paper was to determine whether statin use is associated with poorer balance performances in older adults. Methods: All participants, one group taking statins (n = 34), and the other group not taking statins (n = 31), completed a balance assessment with their eyes closed and their eyes opened on a MatScan Pressure Sensing Mat. Center of Pressure (CoP) velocity, peak-to-peak distance, and standard deviation were collected in both anteroposterior (AP) and mediolateral (ML) directions. Multiple linear regression analyses were performed for each balance outcome, testing the statin use status as a predictor and controlling for appropriate factors including participants characteristics, lipid profile, and cardiovascular disease. Results: After controlling for confounding factors, statin use significantly predicted both CoP ML-Amplitude (β = 0.638, p = 0.004) and ML-Velocity (β = 0.653, p = 0.002) in the eyes-opened condition. Conclusions: The present study detected a negative association between statin use and balance control in the ML direction, suggesting that caution should be taken when prescribing statins in older adults, as this could decrease ML stability and ultimately increase fall and fracture risks.

Lateral Perturbation-Induced and Voluntary Stepping in Fallers and Nonfallers After Stroke

OBJECTIVE

A loss of balance poststroke from externally induced perturbations or during voluntary movements is often recovered by stepping. The purpose of this study was to characterize stepping behavior during lateral induced waist-pull perturbations and voluntary steps in community-dwelling fallers and nonfallers with chronic stroke.

METHODS

This study used a cohort design. Thirty participants >6 months poststroke were exposed to 24 externally triggered lateral waist-pull perturbations and 20 voluntary steps. Balance tolerance limit (BTL) (transition from single to multiple steps) and first step type were determined for the waist-pull perturbations. Step parameters of initiation time, velocity, first step length, and clearance were calculated at and above BTL and for the voluntary steps. Hip abductor/adductor torque, foot cutaneous sensation, and self-reported falls that occurred 6 months prior were evaluated.

RESULTS

Twelve participants were classified retrospectively as fallers and 18 as nonfallers. Fallers had a reduced BTL and took more medial first steps than nonfallers. Above BTL, no between-group differences were found in medial steps. At BTL, the nonparetic step clearance was reduced in fallers. Above BTL, fallers took longer to initiate a paretic and nonparetic step and had a reduced nonparetic step length and clearance compared with nonfallers. There was a between-group difference in step initiation time for voluntary stepping with the paretic leg (P < .05). Fallers had a reduced paretic abductor torque and impaired paretic foot cutaneous sensation.

CONCLUSION

A high fall rate poststroke necessitates effective fall prevention strategies. Given that more differences were found during perturbation-induced stepping between fallers and nonfallers, further research assessing perturbation-induced training on reducing falls is needed.

IMPACT

Falls assessments should include both externally induced perturbations along with voluntary movements in determining the fall risk.

Comparison of Treadmill Trip-Like Training Versus Tai Chi to Improve Reactive Balance Among Independent Older Adult Residents of Senior Housing: A Pilot Controlled Trial

BACKGROUND

There is growing interest in using perturbation-based balance training to improve the reactive response to common perturbations (eg, tripping and slipping). The goal of this study was to compare the efficacy of treadmill-based reactive balance training versus Tai Chi performed at, and among independent residents of, older adult senior housing.

METHODS

Thirty-five residents from five senior housing facilities were allocated to either treadmill-based reactive balance training or Tai Chi training. Both interventions were performed three times per week for 4 weeks, with each session lasting approximately 30 minutes. A battery of balance tests was performed at baseline, and again 1 week, 1 month, 3 months, and 6 months post-training. The battery included six standard clinical tests of balance and mobility, and a test of reactive balance performance.

RESULTS

At baseline, no significant between-group differences were found for any balance tests. After training, reactive balance training participants had better reactive balance than Tai Chi participants. Maximum trunk angle was 13.5° smaller among reactive balance training participants 1 week after training (p = .01), and a reactive balance rating was 24%-31% higher among reactive balance training participants 1 week to 6 months after training (p < .03). Clinical tests showed minimal differences between groups at any time point after training.

CONCLUSION

Trip-like reactive balance training performed at senior housing facilities resulted in better rapid balance responses compared with Tai Chi training.

The Characteristics of Feet Center of Pressure Trajectory during Quiet Standing

To investigate the level of bilateral symmetry or asymmetry between right and left foot center of pressure (COP) trajectory in the mediolateral and anteroposterior directions, this study involved 102 participants (54 females and 48 males). Ground reaction forces were measured using two Kistler force plates during two 45-s quiet standing trials. Comparisons of COP trajectory were performed by correlation and scatter plot analysis. Strong and very strong positive correlations (from 0.6 to 1.0) were observed between right and left foot anteroposterior COP displacement trajectory in 91 participants; 11 individuals presented weak or negative correlations. In the mediolateral direction, moderate and strong negative correlations (from −0.5 to −1.0) were observed in 69 participants, weak negative or weak positive correlations in 30 individuals, and three showed strong positive correlations (0.6 to 1.0). Additional investigation is warranted to compare COP trajectories between asymptotic individuals as assessed herein (to determine normative data) and those with foot or leg symptoms to better understand the causes of COP asymmetry and aid clinicians with the diagnosis of posture-related pathologies.

Subclinical Peroneal Neuropathy Affects Ambulatory, Community-Dwelling Adults and Is Associated with Falling

BACKGROUND

Peroneal neuropathy with an overt foot drop is a known risk factor for falling. Subclinical peroneal neuropathy caused by compression at the fibular neck is subtler and does not have foot drop. A previous study found subclinical peroneal neuropathy in 31 percent of hospitalized patients. This was associated with having fallen. The purpose of this study was to determine the prevalence of subclinical peroneal neuropathy in ambulatory adults and investigate if it is associated with falling.

METHODS

A cross-sectional study of 397 ambulatory adults presenting to outpatient clinics at a large academic hospital was conducted from 2016 to 2017. Patients were examined for dorsiflexion weakness and signs of localizing peroneal nerve compression to the fibular neck. Fall risk was assessed with the Activities-Specific Balance Confidence Scale and self-reported history of falling. Multivariate logistic regression was used to correlate subclinical peroneal neuropathy with fall risk and a history of falls.

RESULTS

The mean patient age was 54 ± 15 years and 248 patients (62 percent) were women. Thirteen patients (3.3 percent) were found to have subclinical peroneal neuropathy. After controlling for various factors known to increase fall risk, patients with subclinical peroneal neuropathy were 3.74 times (95 percent CI, 1.06 to 13.14) (p = 0.04) more likely to report having fallen multiple times in the past year than patients without subclinical peroneal neuropathy. Similarly, patients with subclinical peroneal neuropathy were 7.22 times (95 percent CI, 1.48 to 35.30) (p = 0.02) more likely to have an elevated fall risk on the Activities-Specific Balance Confidence fall risk scale.

CONCLUSION

Subclinical peroneal neuropathy affects 3.3 percent of adult outpatients and may predispose them to falling.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Step width variability as a discriminator of age-related gait changes

BACKGROUND

There is scientific evidence that older adults aged 65 and over walk with increased step width variability which has been associated with risk of falling. However, there are presently no threshold levels that define the optimal reference range of step width variability. Thus, the purpose of our study was to estimate the optimal reference range for identifying older adults with normative and excessive step width variability.

METHODS

We searched systematically the BMC, Cochrane Library, EBSCO, Frontiers, IEEE, PubMed, Scopus, SpringerLink, Web of Science, Wiley, and PROQUEST databases until September 2018, and included the studies that measured step width variability in both younger and older adults during walking at self-selected speed. Data were pooled in meta-analysis, and standardized mean differences (SMD) with 95% confidence intervals (CI) were calculated. A single-decision threshold method based on the Youden index, and a two-decision threshold method based on the uncertain interval method were used to identify the optimal threshold levels (PROSPERO registration: CRD42018107079).

RESULTS

Ten studies were retrieved (older adults = 304; younger adults = 219). Step width variability was higher in older than in younger adults (SMD = 1.15, 95% CI = 0.60; 1.70; t = 4.72, p = 0.001). The single-decision method set the threshold level for excessive step width variability at 2.14 cm. For the two-decision method, step width variability values above the upper threshold level of 2.50 cm were considered excessive, while step width variability values below the lower threshold level of 1.97 cm were considered within the optimal reference range.

CONCLUSION

Step width variability is higher in older adults than in younger adults, with step width variability values above the upper threshold level of 2.50 cm to be considered as excessive. This information could potentially impact rehabilitation technology design for devices targeting lateral stability during walking.

Study of Postural Stability Features by Using Kinect Depth Sensors to Assess Body Joint Coordination Patterns

A stable posture requires the coordination of multiple joints of the body. This coordination of the multiple joints of the human body to maintain a stable posture is a subject of research. The number of degrees of freedom (DOFs) of the human motor system is considerably larger than the DOFs required for posture balance. The manner of managing this redundancy by the central nervous system remains unclear. To understand this phenomenon, in this study, three local inter-joint coordination pattern (IJCP) features were introduced to characterize the strength, changing velocity, and complexity of the inter-joint couplings by computing the correlation coefficients between joint velocity signal pairs. In addition, for quantifying the complexity of IJCPs from a global perspective, another set of IJCP features was introduced by performing principal component analysis on all joint velocity signals. A Microsoft Kinect depth sensor was used to acquire the motion of 15 joints of the body. The efficacy of the proposed features was tested using the captured motions of two age groups (18-24 and 65-73 years) when standing still. With regard to the redundant DOFs of the joints of the body, the experimental results suggested that an inter-joint coordination strategy intermediate to that of the two extreme coordination modes of total joint dependence and independence is used by the body. In addition, comparative statistical results of the proposed features proved that aging increases the coupling strength, decreases the changing velocity, and reduces the complexity of the IJCPs. These results also suggested that with aging, the balance strategy tends to be more joint dependent. Because of the simplicity of the proposed features and the affordability of the easy-to-use Kinect depth sensor, such an assembly can be used to collect large amounts of data to explore the potential of the proposed features in assessing the performance of the human balance control system.

Wearable inertial sensors to measure gait and posture characteristic differences in older adult fallers and non-fallers: A scoping review

BACKGROUND

Wearable inertial sensors have grown in popularity as a means of objectively assessing fall risk. This review aimed to identify gait and posture differences among older adult fallers and non-fallers which can be measured with the use of wearable inertial sensors. In addition to describing the number of sensors used to obtain measures, the concurrent anatomical locations, how these measures compare to current forms of clinical fall risk assessment tests and the setting of tests.

METHODS

Following the development of a rigorous search strategy, MEDLINE, Web of Science, Cochrane, EMBASE, PEDro, and CINAHL were systematically searched for studies involving the use of wearable inertial sensors, to determine gait and postural based differences among fallers or those at high fall risk compared with non-fallers and low fall risk adults aged 60 years and older.

RESULTS

Thirty five papers met the inclusion criteria. One hundred and forty nine gait and posture characteristic differences were identified using wearable inertial sensors. There were sensor derived measures which significantly and strongly correlated with traditional clinical tests. The use of a single wearable inertial sensor located at the lower posterior trunk, was most the most effective location and enough to ascertain multiple pertinent fall risk factors.

CONCLUSION

This review identified the capabilities of identifying fall risk factors among older adults with the use of wearable inertial sensors. The lightweight portable nature makes inertial sensors an effective tool to be implemented into clinical fall risk assessment and continuous unsupervised home monitoring, in addition to, outdoor testing.

Does variability in motor output at individual joints predict stride time variability in gait? Influences of age, sex, and plane of motion

Old age is associated with variability in gait motor output, particularly in females, and is linked to fall risk. However, little is known about how older age and sex affect variability in the outputs of individual joints, and how these variabilities contribute to the collective gait output. Healthy adults aged 18-99 years (N = 102, 57 females) completed six trials of straight walking at self-selected speed. Stride time variability (coefficient of variation) and variabilities of lower limb tridimensional joint angles (standard deviations: SD) were calculated. Age * Sex (A * S) mixed models were conducted on all measures and year-by-year rates of change were subsequently estimated. Correlations and stepwise linear regression analyses were computed between joint angular variabilities and stride time variability. Each year of age was associated with 0.022% higher stride time variability (A: p = .002), 0.07° lower variability in peak ankle dorsiflexion (A: p = .004), 0.002-0.098° higher variability in mean ankle inversion/eversion, mean pelvic obliquity, and pelvic rotation range of motion (A: p < .05), and 0.024° higher variability in knee flexion/extension range of motion in males (A * S: p = .003). Higher variability in mean ankle and hip flexion/extension and in mean ankle inversion/eversion correlated with (ρ = 0.211-0.336; ps < 0.05) and independently predicted higher stride time variability (ps < 0.05), together explaining 21.9% of variance. Results suggest that higher stride time variability with older age may be produced by a shift from sagittal plane variability to frontal plane variability at the ankle.

Effects of a 6-Week Faroese Chain Dance Programme on Postural Balance, Physical Function, and Health Profile in Elderly Subjects: A Pilot Study

The present pilot study investigates the impact of a Faroese chain dance intervention on health profile, mobility, and postural balance in elderly subjects. Healthy elderly subjects (n=27; age 75 ± 5 yrs) were randomised into an intervention group (IG) and a control group (CG). IG performed twice-weekly sessions of Faroese chain dance over 6 weeks. Dancing sessions lasted 30 min in the initial 3 weeks and 45 min in the final 3 weeks. Health profile was determined before and after intervention by measuring blood pressure, resting heart rate, muscle mass, and body fat content. Postural balance was evaluated using the Berg Balance Scale (BBS) and Fullerton Advanced Balance Scale (FAB) tests, while mobility was assessed using the Short Physical Performance Battery (SPPB), the Timed Up & Go (TUG) test, the 6-min walk test, and the 30-s sit-to-stand test. Systolic and diastolic blood pressure were lowered (9 ± 6 and 6 ± 3 mmHg, respectively) in IG, with a tendency (P=0.07) for a greater change score than in CG. Mean arterial pressure declined (P<0.05) by 7 ± 3 mmHg in IG, which tended (P=0.09) to be greater than in CG. IG improved (P<0.05) on BBS and FAB scores by 3.6 ± 2.1% and 15.8 ± 8.3%, with the change score for FAB being greater (P<0.05) than in CG (0.3 ± 1.6). Moreover, the postintervention SPPB score was improved (P<0.05) more in IG (13.9 ± 7.4%) compared to CG, while performance in the 30-s sit-to-stand, 6-min walk, and TUG tests improved (4–15%; P<0.05) in IG only. Body fat content was reduced (P<0.05) from 36.3 ± 2.8% to 34.8 ± 2.8% in IG, with no between-group differences and no change in CG (34.1 ± 2.8% to 33.7 ± 3.1%). In conclusion, a 6-week Faroese chain dance programme lowers blood pressure and improves postural balance and physical function in elderly.

Performance-based clinical tests of balance and muscle strength used in young seniors: a systematic literature review

BACKGROUND

Many balance and strength tests exist that have been designed for older seniors, often aged ≥70 years. To guide strategies for preventing functional decline, valid and reliable tests are needed to detect early signs of functional decline in young seniors. Currently, little is known about which tests are being used in young seniors and their methodological quality. This two-step review aims to 1) identify commonly used tests of balance and strength, and 2) evaluate their measurement properties in young seniors.

METHODS

First, a systematic literature search was conducted in MEDLINE to identify primary studies that employed performance-based tests of balance and muscle strength, and which aspects of balance and strength these tests assess in young seniors aged 60-70. Subsequently, for tests used in ≥3 studies, a second search was performed to identify method studies evaluating their measurement properties. The quality of included method studies was evaluated using the Consensus-based Standards for selection of health Measurement Instruments (COSMIN) checklist.

RESULTS

Of 3454 articles identified, 295 met the inclusion criteria. For the first objective, 69 balance and 51 muscle strength tests were identified, with variations in administration mode and outcome reporting. Twenty-six balance tests and 15 muscle strength tests were used in ≥3 studies, with proactive balance tests and functional muscle power tests used most often. For the second objective, the search revealed 1880 method studies, of which nine studies (using 5 balance tests and 1 strength test) were included for quality assessment. The Timed Up and Go test was evaluated the most (4 studies), while the Community Balance and Mobility (CBM) scale was the second most assessed test (3 studies). For strength, one study assessed the reliability of the Five times sit-to-stand.

CONCLUSION

Commonly used balance and muscle strength tests in young seniors vary greatly with regards to administration mode and outcome reporting. Few studies have evaluated measurement properties of these tests when used in young seniors. There is a need for standardisation of existing tests to improve their informative value and comparability. For measuring balance, the CBM is a new and promising tool to detect even small balance deficits in balance in young seniors.

The Berg Balance Scale as a clinical screening tool to predict fall risk in older adults: a systematic review

BACKGROUND

The Berg Balance Scale (BBS) is often used in clinical practice to predict falls in the older adults. However, there is no consensus in research regarding its ability to predict falls.

OBJECTIVE

To verify whether the BBS can predict falls risk in older adults.

DATA SOURCE

Manual and electronic searches (Medline, EMBASE, CINAHL, Ageline, Lilacs, Web of Science, Cochrane Library and PEDro) were conducted using blocks of words (older adults, falls, BBS, study design) and their synonyms, with no language restrictions and published since 1989.

STUDY SELECTION CRITERIA

Prognostic studies or clinical trials were used to assess the BBS and falls history.

DATA EXTRACTION AND DATA SYNTHESIS

In this narrative synthesis, two independent assessors extracted data from articles and a third reviewer provided consensus, in case of disagreement. The methodological quality was assessed using the Quality In Prognosis Studies tool.

RESULTS

1047 studies were found and 8 studies were included in this review. The mean BBS score was high, regardless of the history of falls. Three studies presented cut-off scores for BBS, ranging from 45 to 51 points. Two studies reported a difference in the BBS score between fallers and non-fallers. Studies presented low to moderate risk of bias.

LIMITATIONS

Unfeasible to conduct a meta-analysis due the heterogeneity of included studies.

CONCLUSION

The evidence to support the use of BBS to predict falls is insufficient, and should not be used alone to determine the risk of falling in older adults.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42016032309.