Elderly fall risk prediction using static posturography

Relationships between balance performance and connectivity of motor cortex with primary somatosensory cortex and cerebellum in middle aged and older adults

Connectivity of somatosensory cortex (S1) and cerebellum with the motor cortex (M1) is critical for balance control. While both S1-M1 and cerebellar-M1 connections are affected with aging, the implications of altered connectivity for balance control are not known. We investigated the relationship between S1-M1 and cerebellar-M1 connectivity and standing balance in middle-aged and older adults. Our secondary objective was to investigate how cognition affected the relationship between connectivity and balance. Our results show that greater S1-M1 and cerebellar-M1 connectivity was related to greater postural sway during standing. This may be indicative of an increase in functional recruitment of additional brain networks to maintain upright balance despite differences in network connectivity. Also, cognition moderated the relationship between S1-M1 connectivity and balance, such that those with lower cognition had a stronger relationship between connectivity and balance performance. It may be that individuals with poor cognition need increased recruitment of brain regions (compensation for cognitive declines) and in turn, higher wiring costs, which would be associated with increased functional connectivity.

Repeated exposure to virtual reality decreases reliance on visual inputs for balance control in healthy adults

Postural control may encounter acute challenges when individuals are immersed in a virtual reality (VR) environment, making VR a potential pertinent tool for enhancing balance capacity. Nonetheless, the effects of repeated exposure to VR on balance control remain to be fully elucidated. Fifty-five healthy participants stood upright for six bouts of 90 s each in an immersive virtual reality (VR) environment using a head-mounted display (repeated VR exposure). During these bouts, participants experienced simulated forward and backward displacements. Before and after the repeated VR exposure, the center of pressure mean velocity (VELCOP) was measured in response to simulated forward and backward displacement in VR, as well as during quiet upright standing with eyes open (EO) and closed (EC) in the real environment. The results revealed a significant decrease in VELCOP for forward and backward simulated displacements in both antero-posterior and medio-lateral directions (p < 0.01) after compared to before repeated VR exposure. Furthermore, VELCOP significantly decreased when participants stood upright in EC (-5%; p = 0.004), but not EO (+3%; p > 0.05) in the real environment after repeated VR exposure. The Romberg ratio (EC/EO) was reduced in both antero-posterior and medio-lateral directions (p < 0.05) after VR exposure. This study indicates that repeated exposure to VR induces changes in balance control in both virtual and real environments. These changes may be attributed, in part, to a reduction in the weighting of visual inputs in the multisensory integration process occurring during upright standing. Accordingly, these findings highlight VR as a potentially effective tool for balance rehabilitation. SIGNIFICANCE STATEMENT: This study indicates that repeated exposure to VR induces changes in balance control in both virtual and real environments that can rely, in part, on a reduction in the weighting of visual inputs in the multisensory integration process occurring during upright standing.

Changes in postural stability after cerebrospinal fluid tap test in patients with idiopathic normal pressure hydrocephalus

Introduction

In patients with idiopathic normal pressure hydrocephalus (iNPH), the characteristics of balance disturbance are not as well understood as those related to gait. This study examined changes in postural stability in quiet standing after the cerebrospinal fluid tap test (CSFTT) in these patients. Furthermore, the study explored the relationship between the amount of spontaneous body sway and both gait and executive function.

Materials and methods

All patients diagnosed with iNPH underwent CSFTT. We evaluated their center of pressure (COP) measurements on a force plate during quiet standing, both pre- and post-CSFTT. Following the COP measurements, we calculated COP parameters using time and frequency domain analysis and assessed changes in these parameters after CSFTT. At pre-CSFTT, we assessed the Timed Up and Go (TUG) and the Frontal Assessment Battery (FAB). We investigated the relationship between COP parameters and the TUG and FAB scores at pre-CSFTT.

Results

A total of 72 patients with iNPH were initially enrolled, and 56 patients who responded positively to CSFTT were finally included. Post-CSFTT, significant improvements were observed in COP parameters through time domain analysis. These included the velocity of COP (vCOP), root-mean-square of COP (rmsCOP), turn index, torque, and base of support (BOS), compared to the pre-CSFTT values (p < 0.05). In the frequency domain analysis of COP parameters post-CSFTT, there was a decrease in both the peak and average of power spectral density (PSD) values in both the anteroposterior (AP) and mediolateral (ML) directions below 0.5 Hz (p < 0.05). In addition, the TUG scores showed a positive correlation with vCOP, rmsCOP, turn index, torque, BOS, and both the peak and average PSD values in the AP and ML directions below 0.5 Hz (p < 0.05). The FAB scores demonstrated a negative correlation with vCOP, rmsCOP, turns index, BOS, and both peak and average PSD values in the AP direction below 0.5 Hz (p < 0.05).

Conclusion

In patients with iNPH who responded to CSFTT, there was an improvement in spontaneous body sway during quiet standing after CSFTT. Increased spontaneous sway is associated with impaired gait and frontal lobe function. This may be linked to impaired cortico-cortical and cortico-subcortical circuits in patients with iNPH.

Fall prediction in a quiet standing balance test via machine learning: Is it possible?

The elderly population is growing rapidly in the world and falls are becoming a big problem for society. Currently, clinical assessments of gait and posture include functional evaluations, objective, and subjective scales. They are considered the gold standard to indicate optimal mobility and performance individually, but their sensitivity and specificity are not good enough to predict who is at higher risk of falling. An innovative approach for fall prediction is the machine learning. Machine learning is a computer-science area that uses statistics and optimization methods in a large amount of data to make outcome predictions. Thus, to assess the performance of machine learning algorithms in classify participants by age, number of falls and falls frequency based on features extracted from a public database of stabilometric assessments. 163 participants (116 women and 47 men) between 18 and 85 years old, 44.0 to 75.9 kg mass, 140.0 to 189.8 cm tall, and 17.2 to 31.9 kg/m2 body mass index. Six different machine learning algorithms were tested for this classification, which included Logistic Regression, Linear Discriminant Analysis, K Nearest-neighbours, Decision Tree Classifier, Gaussian Naive Bayes and C-Support Vector Classification. The machine learning algorithms were applied in this database which has sociocultural, demographic, and health status information about participants. All algorithm models were able to classify the participants into young or old, but our main goal was not achieved, no model identified participants at high risk of falling. Our conclusion corroborates other works in the biomechanics field, arguing the static posturography, probably due to the low daily living activities specificity, does not have the desired effects in predicting the risk of falling. Further studies should focus on dynamic posturography to assess the risk of falls.

The effect of Tai Chi lower extremity exercise on the balance control of older adults in assistant living communities

BACKGROUND

Although Tai Chi (TC) is an evidence-based fall prevention training for older adults, its effective movements remain unclear, which may limit the practice of TC. The purpose of this study was to compare the effectiveness of TC lower extremity exercise (TC LEE), the 8-form Tai Chi (8-form TC), and a stretching control intervention for improving balance and functional mobility among older adults.

METHODS

This was a randomized controlled trial. A total of 102 participants (79 ± 6 years old) were recruited from assisted living facilities. All participants were randomly assigned to the TC LEE (n = 40), 8-form TC (n = 31), and stretching (n = 31) groups in which they received the respective interventions for 16 weeks. The Berg Balance Scale (BBS), Timed Up and Go (TUG) test, and center of pressure (COP) measurements during quiet stance were collected prior to and following the 16-week interventions. Comparisons on all measurements were conducted among all groups.

RESULTS

Significant improvements were found in BBS (P = 0.002), TUG test (P = 0.001), root mean square amplitude of COP displacement in the anterior-posterior (P = 0.001) and medial-lateral (P = 0.001) directions, and average COP speed in the anterior-posterior (P = 0.001) and medial-lateral (P = 0.001) directions after training in the TC intervention groups compared with the stretching group. The upper limit of the 95% confidence interval (CI) of differences in change scores on the BBS (-0.8 - 1.3 points) between the TC LEE group and the 8-form TC group was within equivalence margins (1.8 points), while the upper limit of the 95% CI of differences in change scores on the TUG test (0.1 - 2.1 s) exceeded the equivalence margin (0.7 s) with the TC LEE group having the larger change scores.

CONCLUSION

TC LEE can improve balance and functional mobility in older adults, and may have greater effect than the 8-form TC on improving functional mobility as measured by the TUG test.

TRIAL REGISTRATION

ChiCTR2300070600 retrospectively registered.

Fall risk classification with posturographic parameters in community-dwelling older adults: a machine learning and explainable artificial intelligence approach

BACKGROUND

Computerized posturography obtained in standing conditions has been applied to classify fall risk for older adults or disease groups. Combining machine learning (ML) approaches is superior to traditional regression analysis for its ability to handle complex data regarding its characteristics of being high-dimensional, non-linear, and highly correlated. The study goal was to use ML algorithms to classify fall risks in community-dwelling older adults with the aid of an explainable artificial intelligence (XAI) approach to increase interpretability.

METHODS

A total of 215 participants were included for analysis. The input information included personal metrics and posturographic parameters obtained from a tracker-based posturography of four standing postures. Two classification criteria were used: with a previous history of falls and the timed-up-and-go (TUG) test. We used three meta-heuristic methods for feature selection to handle the large numbers of parameters and improve efficacy, and the SHapley Additive exPlanations (SHAP) method was used to display the weights of the selected features on the model.

RESULTS

The results showed that posturographic parameters could classify the participants with TUG scores higher or lower than 10 s but were less effective in classifying fall risk according to previous fall history. Feature selections improved the accuracy with the TUG as the classification label, and the Slime Mould Algorithm had the best performance (accuracy: 0.72 to 0.77, area under the curve: 0.80 to 0.90). In contrast, feature selection did not improve the model performance significantly with the previous fall history as a classification label. The SHAP values also helped to display the importance of different features in the model.

CONCLUSION

Posturographic parameters in standing can be used to classify fall risks with high accuracy based on the TUG scores in community-dwelling older adults. Using feature selection improves the model's performance. The results highlight the potential utility of ML algorithms and XAI to provide guidance for developing more robust and accurate fall classification models. Trial registration Not applicable.

The effects of virtual reality training on postural sway and physical function performance on older women with chronic low back pain: A double-blind randomized clinical trial

BACKGROUND

Chronic low back pain (CLBP) is known as an important debilitating health condition among older women.

OBJECTIVE

This study aimed to evaluate the effects of eight-week virtual reality training (VRT) exercises on postural sway and physical function performance (PFP) among older women suffering from CLBP.

METHODS

Twenty-seven older women presenting with CLBP were randomized into experimental and control groups. The experimental group was instructed to perform 30-minute VRT exercises three times a week for eight weeks. Plantar pressure variables [sway velocity (SV) and anterior-posterior (AP) and medial-lateral (ML) fluctuations of the center of pressure (CoP)], 30-second chair stand test (30CST), and timed up and go (TUG) test were recorded.

RESULTS

The VRT group exhibited significant decreases in SV (p= 0.002), AP (p= 0.008), and ML (p= 0.02) fluctuations. Also, the performance of the VRT group in the 30CST and TUG tests significantly improved after the exercises (P< 0.001).

CONCLUSION

According to the results, VRT and the program used in this study should be used to enhance balance and PFP in older women with CLBP who mostly prefer activities that are accessible and feasible in low-risk environments.

Clinical Static Balance Assessment: A Narrative Review of Traditional and IMU-Based Posturography in Older Adults and Individuals with Incomplete Spinal Cord Injury

Maintaining a stable upright posture is essential for performing activities of daily living, and impaired standing balance may impact an individual's quality of life. Therefore, accurate and sensitive methods for assessing static balance are crucial for identifying balance impairments, understanding the underlying mechanisms of the balance deficiencies, and developing targeted interventions to improve standing balance and prevent falls. This review paper first explores the methods to quantify standing balance. Then, it reviews traditional posturography and recent advancements in using wearable inertial measurement units (IMUs) to assess static balance in two populations: older adults and those with incomplete spinal cord injury (iSCI). The inclusion of these two groups is supported by their large representation among individuals with balance impairments. Also, each group exhibits distinct aspects in balance assessment due to diverse underlying causes associated with aging and neurological impairment. Given the high vulnerability of both demographics to balance impairments and falls, the significance of targeted interventions to improve standing balance and mitigate fall risk becomes apparent. Overall, this review highlights the importance of static balance assessment and the potential of emerging methods and technologies to improve our understanding of postural control in different populations.

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.

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.

Predicting use of a gait-stabilizing device using a Wii Balance Board

Gait-stabilizing devices (GSDs) are effective at preventing falls, but people are often reluctant to use them until after experiencing a fall. Inexpensive, convenient, and effective methods for predicting which patients need GSDs could help improve adoption. The purpose of this study was to determine if a Wii Balance Board (WBB) can be used to determine whether or not patients use a GSD. We prospectively recruited participants ages 70-100, some who used GSDs and some who did not. Participants first answered questions from the Modified Vulnerable Elders Survey, and then completed a grip-strength test using a handgrip dynamometer. Finally, they were asked to complete a series of four 30-second balance tests on a WBB in random order: (1) eyes open, feet apart; (2) eyes open, feet together; (3) eyes closed, feet apart; and (4) eyes closed, feet together. The four-test series was repeated a second time in the same random order. The resulting data, represented as 25 features extracted from the questionnaires and the grip test, and data from the eight balance tests, were used to predict a subject's GSD use using generalized functional linear models based on the Bernoulli distribution. 268 participants were consented; 62 were missing data elements and were removed from analysis; 109 were not GSD users and 97 were GSD users. The use of velocity and acceleration information from the WBB improved upon predictions based solely on grip strength, demographic, and survey variables. The WBB is a convenient, inexpensive, and easy-to-use device that can be used to recommend whether or not patients should be using a GSD.

Influence of age on static postural control in adults with type 2 diabetes mellitus: a cross-sectional study

Aim

It was the aim of this study to assess static postural control characteristics in people with type 2 diabetes mellitus (T2D) of different ages using a force platform. A relationship was also established between static postural control parameters and age in this study.

Methods

A total of 706 participants with T2D were included in this study. The participants were stratified into three age groups: Group 1 (<60 years old), Group 2 (60-70 years old), and Group 3 (>70 years old). Static postural control assessment during two-leg stance was performed on a force platform by all participants. The center of pressure (CoP)-related parameters were measured under two stance conditions (eyes open and closed). Kruskal-Wallis tests were applied to explore the difference among the different age groups. Multivariate regression analysis was performed to determine the relation between age and static postural control parameters.

Results

Group 1 (<60 years old) had significantly less CoP total tracking length (TTL), sway area (SA), and CoP velocity along the Y direction (V-Y) under both eyes-open and eyes-closed conditions compared with Group 2 (60-70 years old) and Group 3 (>70 years old). Group 1 (<60 years old) had significantly less CoP maximum sway length along the X direction (MSL_X) and longer tracking length each area unit (TTL/SA) under the eyes-open condition compared with Group 2 (60-70 years old) and Group 3 (>70 years old). There was a significantly positive correlation between age and the most static postural parameters such as CoP TTL, SA, MSL-X, MSL-Y, and V-Y. There was a significantly negative correlation between age and TTL/SA.

Conclusion

This study suggested that older T2D participants had worse static postural control ability than younger ones. Most static postural parameters presented a significant correlation with age; the higher the age, the worse the static postural control.

Sport dependent effects on the sensory control of balance during upright posture: a comparison between professional horseback riders, judokas and non-athletes

Introduction

Compared to judokas (JU) and non-athletes (NA), horseback riders (HR) may develop specific changes in their sensory control of balance.

Methods

Thirty-four international-level JU, twenty-seven international-level HR and twenty-one NA participated. Participants stood upright on a plateform (static condition) or on a seesaw device with an instability along the mediolateral (ML) or the anteroposterior (AP) direction (dynamic conditions). These conditions were carried out with eyes opened (EO) or closed (EC), and with (wF) or without a foam (nF). Experimental variables included conventional (linear), non-linear center-of-pressure (COP) parameters, Romberg Quotient (RQ) and Plantar Quotient (PQ).

Results

Group effects. COP Surface (COPS) and standard deviation of COP along AP (SDY) were lower in HR than in JU in Static. SD Y was lower in HR than in JU in Dynamic AP. COP velocity (COPV) was lower in both HR and JU than in NA in Static and Dynamic. Sample entropy along AP and ML (SampEnY and SampEnX) were higher in HR than in JU in Static. SampEnY was higher in HR than in JU in Dynamic ML. Sensory effects. In EC, COPV was lower in JU than in NA in Dynamic AP, and lower in JU than in both HR and NA in Dynamic ML. In EO, COPV was lower in both JU and HR than in NA in Dynamic ML. RQ applied to COPS was lower in JU than in both HR and NA in Dynamic AP, and lower in JU than in HR in Dynamic ML. RQ applied to COPV was lower in JU than in both HR and NA in Static and Dynamic. PQ applied to COPS was higher in JU than in both HR and NA in Dynamic ML.

Conclusion

Results showed that the effects of sport expertise on postural control could only be revealed with specific COP variables and were directionally oriented and sport-dependant. HR seem to rely more on vision than JU, thus revealing that the contribution of the sensory inputs to balance control is also sport-dependent. Results open up new knowledge on the specificity of sport practice on multisensory balance information during upright posture.

Yoga as a balance intervention for middle-age and older adults with history of lateral ankle sprain: An exploratory study

INTRODUCTION

Balance deficiencies are common among aging adults. Musculoskeletal injuries such as lateral ankle sprains (LAS) also contribute to compromised balance; potentially amplifying the postural insufficiencies in these age groups with a history of LAS. Yoga has emerged as an effective balance training intervention for aging adults; but limited application exists in these age cohorts with LAS history. This study may provide important guidance for the implementation of this intervention in these populations.

METHODS

In this cohort design study, middle-age and older adults with a history of LAS completed an 8-week beginner-level yoga class. Balance was measured before and after the yoga intervention statically (force plate) and dynamically (star excursion balance test [SEBT]) using single-limb balance tasks.

RESULTS

Following the yoga intervention, older adults improved static postural control in the anterior-posterior direction, as well as dynamic postural control in selected reach directions of the SEBT relative to the middle-age adults.

CONCLUSION

This is an important step in exploring how to help the aging population that likely has amplifications in balance deficiencies due to a common musculoskeletal injury, LAS. While more work is needed to determine how to optimize and document balance improvements in aging adults with LAS history, yoga appears to be a promising form of intervention, particularly for older adults.

Characterization of Balance Control and Postural Stability in Patients With Alzheimer Disease

Balance in Alzheimer disease (AD) patients is not rigorously understood. In this study, we characterize balance using qualitative [Berg Balance Scale (BBS)] and quantitative measures (posturography) and assess relationships between qualitative and quantitative balance measures in AD. Patients with mild-moderate AD (n=48) were recruited. BBS scores and posturography metrics, including medial-lateral sway range, anterior-posterior sway range, sway area, and sway velocity, were assessed in eyes-open and eyes-closed conditions. Adjusted linear regressions were used to assess relationships between posturography and BBS score. Mean BBS score was 50.4±5.3. In eyes-open conditions, posturography and BBS score were not significantly associated. In eyes-closed conditions, better BBS score was significantly associated with lower sway area (β=-0.91; P =0.006). Better scores of BBS items involving turning and reduced base of support were associated with greater eyes-closed sway area. Posturography in the more challenging eyes-closed condition may predict functional balance deficits in AD patients.

Accuracy and repeatability of the Microsoft Azure Kinect for clinical measurement of motor function

Quantitative assessment of motor function is increasingly applied in fall risk stratification, diagnosis, and disease monitoring of neuro-geriatric disorders of balance and gait. Its broad application, however, demands for low-cost and easy to use solutions that facilitate high-quality assessment outside laboratory settings. In this study, we validated in 30 healthy adults (12 female, age: 32.5 [22 - 62] years) the performance and accuracy of the latest generation of the Microsoft RGB-D camera, i.e., Azure Kinect (AK), in tracking body motion and providing estimates of clinical measures that characterise static posture, postural transitions, and locomotor function. The accuracy and repeatability of AK recordings was validated with a clinical reference standard multi-camera motion capture system (Qualisys) and compared to its predecessor Kinect version 2 (K2). Motion signal quality was evaluated by Pearson's correlation and signal-to-noise ratios while the accuracy of estimated clinical parameters was described by absolute and relative agreement based on intraclass correlation coefficients. The accuracy of AK-based body motion signals was moderate to excellent (RMSE 89 to 20 mm) and depended on the dimension of motion (highest for anterior-posterior dimension), the body region (highest for wrists and elbows, lowest for ankles and feet), and the specific motor task (highest for stand up and sit down, lowest for quiet standing). Most derived clinical parameters showed good to excellent accuracy (r .84 to .99) and repeatability (ICC(1,1) .55 to .94). The overall performance and limitations of body tracking by AK were comparable to its predecessor K2 in a cohort of young healthy adults. The observed accuracy and repeatability of AK-based evaluation of motor function indicate the potential for a broad application of high-quality and long-term monitoring of balance and gait in different non-specialised environments such as medical practices, nursing homes or community centres.

Systematic Review on the Applicability of Principal Component Analysis for the Study of Movement in the Older Adult Population

Principal component analysis (PCA) is a dimensionality reduction method that has identified significant differences in older adults' motion analysis previously not detected by the discrete exploration of biomechanical variables. This systematic review aims to synthesize the current evidence regarding PCA use in the study of movement in older adults (kinematics and kinetics), summarizing the tasks and biomechanical variables studied. From the search results, 1685 studies were retrieved, and 19 studies were included for review. Most of the included studies evaluated gait or quiet standing. The main variables considered included spatiotemporal parameters, range of motion, and ground reaction forces. A limited number of studies analyzed other tasks. Further research should focus on the PCA application in tasks other than gait to understand older adults' movement characteristics that have not been identified by discrete analysis.

Older adults with a history of falling exhibit altered cortical oscillatory mechanisms during continuous postural maintenance

Background and Aim

The significant risk of falling in older adults 65 years or older presents a substantial problem for these individuals, their caretakers, and the health-care system at large. As the proportion of older adults in the United States is only expected to grow over the next few decades, a better understanding of physiological and cortical changes that make an older adult more susceptible to a fall is crucial. Prior studies have displayed differences in postural dynamics and stability in older adults with a fall history (FH) and those who are non-fallers (NF), suggesting surplus alterations that occur in some older adults (i.e., FH group) in addition to the natural aging process.

Methods

The present study measured postural dynamics while the FH, NF, and young adult (YA) groups performed continuous postural maintenance. In addition, electroencephalography activity was recorded while participants performed upright postural stance to examine any group differences in cortical areas involved in postural control.

Results

As expected, older participants (FH and NF) exhibited worse postural stability, as evidenced by increased excursion, compared to the YA group. Further, while NF and YA show increased alpha activity in occipital areas during the most demanding postural task (eyes closed), the FH group did not show any differences in occipital alpha power between postural tasks.

Conclusions

As alpha activity reflects suppression of bottom-up processing and thus diversion of cognitive resources toward postural centers during more demanding postural maintenance, deficits in this regulatory function in the FH group are a possible impaired cortical mechanism putting these individuals at greater fall risk.

Relevance for Patients

Impaired inhibitory function in older adults may impact postural control and increase their risk of falling. Interventions that aim at addressing cortical processing deficits may improve postural stability and facilitate independent living in this population.

Reliability and Usability Analysis of an Embedded System Capable of Evaluating Balance in Elderly Populations Based on a Modified Wii Balance Board

This paper analyzes the reliability and usability of a portable electronic instrument that measures balance and balance impairment in older adults. The center of pressure (CoP) metrics are measured with a modified Wii Balance Board (mWBB) platform. In the intra- and inter-rater testing, 16 and 43 volunteers (mean 75.66 and standard deviation (SD) of 7.86 years and 72.61 (SD 7.86) years, respectively) collaborated. Five volunteer raters (5.1 (SD 3.69) years of experience) answered the System Usability Scale (SUS). The most reliable CoP index in the intra-examiner tests was the 95% power frequency in the medial-lateral displacement of the CoP with closed-eyes. It had excellent reliability with an intraclass correlation coefficient ICC = 0.948 (C.I. 0.862-0.982) and a Pearson's correlation coefficient PCC = 0.966 (p < 0.001). The best index for the inter-rater reliability was the centroidal frequency in the anterior-posterior direction closed-eyes, which had an ICC (2,1) = 0.825. The mWBB also obtained a high usability score. These results support the mWBB as a reliable complementary tool for measuring balance in older adults. Additionally, it does not have the limitations of laboratory-grade systems and clinical screening instruments.

Changes in postural sway during upright stance after short-term lower limb physical inactivity: A prospective study

Previous studies have reported that motor behavior is affected by short-term physical inactivity using cast immobilization; however, the effects of inactivity on postural sway are not well-understood. This study aimed to investigate the effects of short-term lower limb disuse on postural sway in the upright position after cast removal. Twenty-two healthy young adults were enrolled, and each participant’s lower limb on one side was fixed with a soft bandage and medical splint made from metal and soft urethane for 10 h. Fluctuations in the center of pressure (COP) were measured before and after immobilization; the total trajectory length, mean velocity, COP root mean square (RMS) area, mean medial-lateral (M-L) COP, and mean anterior-posterior (A-P) COP were selected as evaluation parameters. Compared with the postural sway before cast application, we noted an increase and shift (from the fixed to the nonfixed side) in the postural sway after cast removal. Our results therefore suggest that short-term disuse may cause acute changes in COP movements during quiet standing. Moreover, patients may maintain their standing posture by adopting a compensatory strategy involving lateral control, similar to individuals with stroke and patients who have undergone total knee arthroplasty.

Incongruity of Geometric and Spectral Markers in the Assessment of Body Sway

Different measurements of body oscillations in the time or frequency domain are being employed as markers of gait and balance abnormalities. This study investigates basic relationships within and between geometric and spectral measures in a population of young adult subjects. Twenty healthy subjects stood with parallel feet on a force platform with and without a foam pad. Adaptation effects to prolonged stance were assessed by comparing the first and last of a series of eight successive trials. Centre of Foot Pressure (CoP) excursions were recorded with Eyes Closed (EC) and Open (EO) for 90s. Geometric measures (Sway Area, Path Length), standard deviation (SD) of the excursions, and spectral measure (mean power Spectrum Level and Median Frequency), along the medio-lateral (ML) and antero-posterior (AP) direction were computed. Sway Area was more strongly associated than Path Length with CoP SD and, consequently, with mean Spectrum Level for both ML and AP, and both visual and surface conditions. The squared-SD directly specified the mean power Spectrum Level of CoP excursions (ML and AP) in all conditions. Median Frequency was hardly related to Spectrum Level. Adaptation had a confounding effect, whereby equal values of Sway Area, Path Length, and Spectrum Level corresponded to different Median Frequency values. Mean Spectrum Level and SDs of the time series of CoP ML and AP excursions convey the same meaning and bear an acceptable correspondence with Sway Area values. Shifts in Median Frequency values represent important indications of neuromuscular control of stance and of the effects of vision, support conditions, and adaptation. The Romberg Quotient EC/EO for a given variable is contingent on the compliance of the base of support and adaptation, and different between Sway Area and Path Length, but similar between Sway Area and Spectrum Level (AP and ML). These measures must be taken with caution in clinical studies, and considered together in order to get a reliable indication of overall body sway, of modifications by sensory and standing condition, and of changes with ageing, medical conditions and rehabilitation treatment. However, distinct measures shed light on the discrete mechanisms and complex processes underpinning the maintenance of stance.

Dysfunction in dynamic, but not static balance is associated with risk of accidental falls in hemodialysis patients: a prospective cohort study

Background

Patients with chronic kidney disease undergoing hemodialysis (HD) have a high incidence of falls. Impairment of balance function is a risk factor for falls in the general elderly, and no report examining the association between balance dysfunction and fall incidence in HD patients exists.

Methods

This prospective cohort study was conducted at a single center. The timed-up-and-go test (TUG) as a dynamic balance function was performed and length of the center of pressure (CoP) as a static balance function was measured before and after the HD session at baseline. Data of the number and detailed information of accidental falls for 1 year were collected. Multiple regression analyses were performed to assess the relationships between the number of falls and balance function.

Results

Forty-three patients undergoing HD were enrolled in the study. During 1 year of observation, 24 (55.8%) patients experienced accidental falls. TUG time was longer, and CoP was shorter in the post-HD session than in the pre-HD session. Adjusted multiple regression analyses showed that the number of accidental falls was independently associated with TUG time in the pre-HD session (B 0.267, p < 0.001, R² 0.413) and that in the post-HD session (B 0.257, p < 0.001, R² 0.530), but not with CoP.

Conclusions

Dynamic balance was associated with fall incidence in maintenance HD patients. The evaluation and intervention of dynamic balance function might reduce the risk of falls in HD patients.

Trial registration

This study was carried out with the approval of the Niigata Rinko Hospital Ethics Committee (approval number 2005–92) (Registered on December 11, 2019) and registered in The University Hospital Medical Information Network (registration number 000040618).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02877-6.

Brain and muscle activation patterns during postural control affect static postural control

BACKGROUND

Previous studies have reported existence of coordinated brain and muscle activity patterns that affect postural control. However, differences in these activity patterns that affect postural control are still unclear. The purpose of this study was to clarify brain and muscle activity pattern affecting postural control.

RESEARCH QUESTION

Does the difference in brain and muscle activity patterns during postural control affect postural control ability?

METHOD

Nineteen healthy men (mean age: 24.8 ± 4.1 years, height: 171.8 ± 5.5 cm, and weight: 63.5 ± 12.5 kg) performed a postural control task on a balance board, and their brain and muscle activities and body sway during the task were measured using functional near-infrared spectroscopy, surface electromyography, and three-dimensional accelerometry. Hierarchical cluster analysis was conducted to extract subgroups based on brain and muscle activities and postural control, and correlation analysis was performed to investigate the relationship between brain activity, muscle activity, and postural control.

RESULTS

Two subgroups were found. Subgroup 1 (n = 9) showed higher brain activity in the supplementary motor area (p = 0.04), primary motor cortex (p = 0.04) and stable postural control in the mediolateral (p < 0.01) planes, and subgroup 2 (n = 10) showed higher muscle activity in the tibialis anterior (p < 0.01), a higher shank muscles co-contraction (p = 0.02) and unstable postural control. Furthermore, the supplementary motor area activity is negatively correlated with body sway of mediolateral plane (r = -0.51, p = 0.02), and tibialis anterior activity is positively correlated with body sway on the mediolateral plane (r = 0.62, p = 0.004).

SIGNIFICANCE

Higher brain activity in motor-related areas, lower activity in the lower limb muscles and lower co-contraction of shank muscles were observed in stable postural control. These results will facilitate the planning of new rehabilitation methods for improving postural control ability.

Increased 18F-FDG Uptake in the Axillary Lymph Nodes of the Vaccinated Side Associated with COVID-19 Vaccination

A 50-year-old female patient underwent (¹⁸fluorine-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) following modified radical mastectomy for cancer of the left breast. Ten days before the PET/CT, the coronavirus disease-2019 (COVID-19) vaccine was injected intramuscularly into the right deltoid muscle. Increased (¹⁸F-FDG uptake of maximum standardized uptake value (11.0) was observed in the lymph nodes of the right axilla, which had not been observed in the previous PET/CT. The size of the oval-shaped lymph nodes was up to approximately 11×9 mm; however, it was larger than that observed on the previous PET/CT. We contemplate that the increased (¹⁸F-FDG uptake was a reactive change in the lymph nodes associated with the COVID-19 vaccine.

The Use of Static Posturography Cut-Off Scores to Identify the Risk of Falling in Older Adults

BACKGROUND

Falling is the most common accident that occurs in daily living and the second leading cause of unintentional injury death worldwide. The complexity of the risk factors associated with falling makes older people at risk of falling difficult to identify. The aim of the study was to identify the cut-off scores of standing posturography measures that can be used to predict the risk of falling in older adults.

METHODS

This observational study involved 267 elderly people aged 65 to 85 years (73.99 SD 7.51) living in south-eastern Poland. The subjects were divided into two groups: a group with a high risk of falling and a group with a low risk of falling, based on their timed up-and-go test. Postural stability was assessed during eyes-open and eyes-closed trials using the two-plate stability platform CQ Stab 2P.

RESULTS

The best accuracy, sensitivity, and specificity were observed for the sway path, anterior-posterior sway path, and medial-lateral sway path with open and closed eyes. The clinical cut-off score to predict the risk of falling was 350.63 for the sway path with open eyes, 272.64 for the anterior-posterior sway path, and 159.63 for the medial-lateral sway path. The clinical cut-off score for sway path with closed eyes was 436.11.

CONCLUSIONS

Static posturography screenings in clinical practice may also be useful for detecting typical balance changes in older adults.

Acoustic Environmental Conditions (Do Not?) Affect the Static Posturography Diagnostic Accuracy: A Test-Retest Reliability Study

Static posturography assessed with force platforms is a procedure used to obtain objective estimates related to postural adjustments. However, controlling multiple intrinsic and extrinsic factors influencing the diagnostic accuracy is essential to obtain reliable measurements and recommend its use with clinical or research purposes. We aimed to analyze how different environmental acoustic conditions affect the test−retest reliability and to analyze the most appropriate number of trials to calculate a valid mean average score. A diagnostic accuracy study was conducted enrolling 27 healthy volunteers. All procedures were taken considering consistent device settings, posture, feet position, recording time, and illumination of the room. Three trials were recorded in a silent environment (35−40 dB) and three trials were recorded in a noisy environment (85−90 dB). Results showed comparable reliability estimates for both acoustic conditions (ICC = 0.453−0.962 and 0.621−0.952), but silent conditions demonstrated better sensitivity to changes (MDC = 13.6−76%). Mean average calculations from 2 and 3 trials showed no statistically significant differences (p > 0.05). Cross-sectional studies can be conducted under noisy or silent conditions as no significantly different scores were obtained (p > 0.05) and ICC were comparable (except oscillation area). However, longitudinal studies should consider silent conditions as they demonstrated better sensitivity to real changes not derived from measurement errors.

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.

Instrumented Functional Test for Objective Outcome Evaluation of Balance Rehabilitation in Elderly Fallers: A Clinical Study

<b><i>Introduction:</i></b> Observational tests, e.g., the Berg Balance Scale (BBS) are widely used for balance evaluation in the elderly fallers. However, they do not allow objective outcome evaluation of rehabilitative interventions. This study aimed to investigate, in a clinical setting, the use of inertial measurement units (IMUs) integrated into the BBS test for objective outcome evaluation of balance rehabilitation in elderly fallers compared to conventional BBS scores. <b><i>Methods:</i></b> Thirty-six elderly fallers were recruited from the in-patient population of a geriatrics Clinic. Participants performed the BBS test while wearing 3 IMUs placed on the sternum, sacrum, and tibia of the dominant leg following admission to the clinic. Subsequently, they completed a rehabilitation program for 2–4 weeks. They performed a similar test before their discharge. The physical therapist recorded the BBS scores at both sessions, and the sensor data of the 2-min quiet standing task (BBS task 2) were extracted for objective balance evaluation. Moreover, eleven young adults were recruited to perform a 2-min quiet standing test while wearing the same IMUs. Center-of-pressure (COP) and segmental center-of-mass (COM) accelerations were calculated to estimate time-domain, frequency-domain, and intersegment coordination biomarkers of balance. <b><i>Results:</i></b> COP time- and frequency-domain measures, COM acceleration time-domain measures, and intersegment coordination measures could identify age-related changes in balance of seniors compared to young adults (<i>p</i> &#x3c; 0.05). Moreover, balance biomarkers of senior adults exhibited a reduced sway acceleration and jerkiness in the medial-lateral direction post-rehabilitation (<i>p</i> &#x3c; 0.05). Although the total BBS scores increased post-rehabilitation, sway displacement and velocity did not significantly improve. We observed a significant association between pelvis-leg coordination at high sway oscillations and the total BBS scores pre- and post-rehabilitation. <b><i>Conclusion:</i></b> IMUs enable not only the characterization of underlying causes of impaired balance but also the identification of improved and yet impaired aspects of balance post-rehabilitation. Hence, IMUs allow us to characterize risk factors post-rehabilitation in elderly fallers, whereas the BBS scores only show changes in overall balance. It is crucial to objectively evaluate the effectiveness of such interventions to reduce future falls and their adverse consequences. Therefore, instrumented balance assessment is recommended since it can provide quantitative and objective measures for clinical outcome evaluations.

Standing, Transition, and Walking Ability in Older Adults: The Case for Independently Evaluating Different Domains of Mobility Function

BACKGROUND

Independent mobility is a complex behavior that relies on the ability to walk, maintain stability, and transition between postures. However, guidelines for assessment that details what elements of mobility to evaluate and how they should be measured remain unclear.

METHODS

Performance on tests of standing, sit-to-stand, and walking were evaluated in a cohort of 135 complex, comorbid, and older adults (mean age 87 ± 5.5 years). Correlational analysis was conducted to examine the degree of association for measures within and between mobility domains on a subset of participants (n = 83) able to complete all tasks unaided. Participants were also grouped by the presence of risk markers for frailty (gait speed and grip strength) to determine if the level of overall impairment impacted performance scores and if among those with risk markers, the degree of association was greater.

RESULTS

Within-domain relationships for sit-to-stand and walking were modest (rho = 0.01-0.60). Associations either did not exist or relationships were weak for measures reflecting different domains (rho = -0.35 to 0.25, p > 0.05). As expected, gait speed differed between those with and without frailty risk markers (p < 0.001); however, balance and sit-to-stand measures did not (p ≥ 0.05).

CONCLUSIONS

This study highlights the need to independently evaluate different mobility domains within an individual as a standard assessment approach. Modest within-domain relationships emphasize the need to account for multiple, unique control challenges within more complex domains. These findings have important implications for standardized mobility assessment and targeted rehabilitation strategies for older adults.

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.

Classification of Older and Fall-Experienced Subjects by Postural Sway Data using Mass Spring Damper Model

The quiet standing test is used to detect diseases of the postural control system. The descriptive statistics of the center of pressure (COP) of older people during the test tend to be larger than those of healthy young people, but they cannot indicate structural problems in postural control. COP trajectories can be mathematically modeled with structural parameters such as viscosity, stiffness, and stochastic terms; however, the classification accuracy of older and fall-experienced people using such parameters has not been sufficiently verified. In this study, six structural parameters of a mass-spring-damper (MSD) model were estimated using two datasets, in which a total of 212 subjects performed quiet standing tests under four conditions. The estimated parameters were used for classification with a random forest algorithm to examine the differences in classification accuracy compared to seven conventional descriptive statistics methods. For the classification of older subjects, the classification accuracy of the MSD parameter method was the highest in foam condition, with positive likelihood ratios approximately 8.0. For the classification of fall-experienced subjects, the positive likelihood ratio of the MSD parameter method was 5.0, which is better than conventional descriptive statistics. Various MSD parameters revealed that aging and changing the floor surface and visual conditions cause oscillations in the COP behavior. While the MSD parameters were confirmed to help classify older subjects more accurately than the conventional descriptive statistics, there was room for further improvement in the classification accuracy of fall-experienced subjects.

Evaluation of vestibular function in children with purulent media otitis by computer stabilometry

The aim of the research – assessment of vestibular function in children with acute purulent otitis media by computer static stabilometry compared with typically developed children of the same age. Materials and methods: 22 children with purulent otitis media aged 4 to 7 years and 30 practically healthy peers were examined by static stabilometry on the device “MPFI stabilograph 1” (Kharkiv, Ukraine). Indicators of variation and shape of the pressure center distribution, spectral-correlation indicators of stabilograms, as well as integral indicators of stability (length, velocity and angle of postural oscillations) were taken into account and the equilibrium functions of the two sensory states (open and closed eyes) are calculated in the StabiliS software. Results: purulent otitis media causes posterior displacement of the absolute coordinates of the pressure center. In the state with closed eyes, children with purulent otitis differ from their healthy coevals by 14 of 24 stabilometric parameters, including stabilogram length, speed, angle and amplitude of oscillations, giving way to them in the stability of equilibrium. Children with purulent otitis media are more sensitive to the visual canal of postural control than their coevals. Involvement of visual afferents in postural control significantly improves balance maintenance in children with purulent otitis by reducing deviations of postural oscillations, which is reflected in the probable changes of 9 out of 24 stabilometric parameters compared to control. Conclusions: In preschool age, purulent otitis media leads to latent vestibular dysfunction, which is manifested by a violation of the stability of the vertical posture in a state with closed eyes and is compensated by visual-vestibulo-proprioceptive integration in the process of postural control.

An Assessment of Balance through Posturography in Healthy about Women: An Observational Study

The incidence of falls in adults constitutes a public health problem, and the alteration in balance is the most important factor. It is necessary to evaluate this through objective tools in order to quantify alterations and prevent falls. This study aims to determine the existence of alteration of balance and the influence of age in a population of healthy women. Static posturography was performed on 49 healthy adult women with no history of falls in four different situations using the Romberg test with the NedSVE/IBV^® platform. The variables studied were the body sway area and the anteroposterior and mediolateral displacements. The situation of maximum instability occurred in RGC (p = 0.001), with a significant increase in anteroposterior oscillations regarding the ML (p < 0.001), with no correlation to age. Age alone does not influence the balance in the sample studied, other factors must come together to alter it. The joint cancellation of visual and somatosensory afferents could facilitate the appearance of falls, given that it is a situation of maximum instability. Proprioceptive training is interesting as a preventive strategy for falls.

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.

Videoconference-Based Adapted Physical Exercise Training Is a Good and Safe Option for Seniors

Videoconference-based adapted physical exercise combines the benefits of supervised exercise training with staying at home, when conventional training is inaccessible. However, exercising with the use of a screen can be considered an optokinetic stimulation, and could therefore induce changes in sensory processing, affecting postural stability. The objectives of this study were to compare the effectiveness of the training delivered Face-to-Face and by Videoconferencing in improving physical capacities of older adults, and to evaluate the possible effects of the Videoconference mode on the processing of sensory information that could affect postural control. Twenty eight older adults underwent the supervised exercise program for sixteen weeks either Face-to-Face or by Videoconference. Muscular strength of knee and ankle flexors and extensors, maximum oxygen uptake, postural stability and horizontal rotational vestibulo-ocular reflex were evaluated before and after the training. Both modes of training similarly increased the VO₂ peak and strength of the motor muscles of lower limbs in all participants. The use of the Videoconference did not modify the vestibulo-ocular reflex in subjects or the importance of vision for postural control. Therefore, the Videoconference-based exercise training can be considered a safe and effective way to maintain good functional capacity in seniors.

Relationship of proprioception, cutaneous sensitivity, and muscle strength with the balance control among older adults

BACKGROUND

Balance impairment is one of the strongest risk factors for falls. Proprioception, cutaneous sensitivity, and muscle strength are 3 important contributors to balance control in older adults. The relationship that dynamic and static balance control has to proprioception, cutaneous sensitivity, and muscle strength is still unclear. This study was performed to investigate the relationship these contributors have to dynamic and static balance control.

METHODS

A total of 164 older adults (female = 89, left dominant = 15, age: 73.5 ± 7.8 years, height: 161.6 ± 7.1 cm, weight: 63.7 ± 8.9 kg, mean ± SD) participated in this study. It tested the proprioception of their knee flexion/extension and ankle dorsi/plantarflexion, along with cutaneous sensitivity at the great toe, first and fifth metatarsals, arch, and heel, and the muscle strength of their ankle dorsi/plantarflexion and hip abduction. The Berg Balance Scale (BBS) and the root mean square (RMS) of the center of pressure (CoP) were collected as indications of dynamic and static balance control. A partial correlation was used to determine the relationship between the measured outcomes variables (BBS and CoP-RMS) and the proprioception, cutaneous sensitivity, and muscle strength variables.

RESULTS

Proprioception of ankle plantarflexion (r = -0.306, p = 0.002) and dorsiflexion (r = -0.217, p = 0.030), and muscle strength of ankle plantarflexion (r = 0.275, p = 0.004), dorsiflexion (r = 0.369, p < 0.001), and hip abduction (r = 0.342, p < 0.001) were weakly to moderately correlated with BBS. Proprioception of ankle dorsiflexion (r = 0.218, p = 0.020) and cutaneous sensitivity at the great toe (r = 0.231, p = 0.041) and arch (r = 0.285, p = 0.002) were weakly correlated with CoP-RMS in the anteroposterior direction. Proprioception of ankle dorsiflexion (r = 0.220, p = 0.035), knee flexion (r = 0.308, p = 0.001) and extension (r = 0.193, p = 0.040), and cutaneous sensitivity at the arch (r = 0.206, p = 0.028) were weakly to moderately correlated with CoP-RMS in the mediolateral direction.

CONCLUSION

There is a weak-to-moderate relationship between proprioception and dynamic and static balance control, a weak relationship between cutaneous sensitivity and static balance control, and a weak-to-moderate relationship between muscle strength and dynamic balance control.

A novel model to quantify balance alterations in older adults based on the center of pressure (CoP) measurements with a cross-sectional study

Background

The timely detection of fall risk or balance impairment in older adults is transcendental because, based on a reliable diagnosis, clinical actions can be taken to prevent accidents. This study presents a statistical model to estimate the fall risk from the center of pressure (CoP) data.

Methods

This study is a cross-sectional analysis from a cohort of community-dwelling older adults aged 60 and over living in Mexico City. CoP balance assessments were conducted in 414 older adults (72.2% females) with a mean age of 70.23 ± 6.68, using a modified and previously validated Wii Balance Board (MWBB) platform. From this information, 78 CoP indexes were calculated and analyzed. Multiple logistic regression models were fitted in order to estimate the relationship between balance alteration and the CoP indexes and other covariables.

Results

The CoP velocity index in the Antero-Posterior direction with open eyes (MVELAPOE) had the best value of area under the curve (AUC) to identify a balance alteration (0.714), and in the adjusted model, AUC was increased to 0.827. Older adults with their mean velocity higher than 14.24 mm/s had more risk of presenting a balance alteration than those below this value (OR (Odd Ratio) = 2.94, p<0.001, 95% C.I.(Confidence Interval) 1.68–5.15). Individuals with increased age and BMI were more likely to present a balance alteration (OR 1.17, p<0.001, 95% C.I. 1.12–1.23; OR 1.17, p<0.001, 95% C.I. 1.10–1.25). Contrary to what is reported in the literature, sex was not associated with presenting a balance alteration (p = 0.441, 95% C.I. 0.70–2.27).

Significance

The proposed model had a discriminatory capacity higher than those estimated by similar means and resources to this research and was implemented in an embedded standalone system which is low-cost, portable, and easy-to-use, ideal for non-laboratory environments. The authors recommend using this technology to support and complement the clinical tools to attend to the serious public health problem represented by falls in older adults.

Is Fall Risk Systematically Evaluated in Memory Clinics? A National Survey of Practice in France

BACKGROUND

Falls are a major health problem in older persons but are still under-diagnosed and challenging to prevent. Current guidelines do not target high-risk populations, especially people living with dementia. In France, people with neurocognitive disorders are mainly referred to memory clinics (MCs).

OBJECTIVE

We aimed to survey the routine practice of physicians working in MCs regarding fall risk assessment.

METHODS

We conducted a cross-sectional survey in France from January to May 2019 among physicians working in MCs, through an anonymous online questionnaire: twenty-seven questions about the physician's background and their practice of fall risk assessment, especially use of clinical and paraclinical tools. We compared the results according to the age and the specialty of the physician.

RESULTS

We obtained 171 responses with a majority of women (60%) and geriatricians (78%). All age classes and all French regions were represented. Most of respondents (98.8%) stated that they address gait and/or falls in outpatient clinic and 95.9%in day hospitals. When asked about how they assess fall risk, fall history (83%) and gait examination (68.4%) were the most widely used, while orthostatic hypotension (24%) and clinical standardized tests (25.7%) were less common. Among standardized tests, One-leg Balance, Timed Up and Go Test, and gait speed measurements were the most used. Geriatricians had more complete fall risk assessment than neurologists (e.g., 56%versus 13%for use of standardized tests, p < 0.0001).

CONCLUSION

Almost all physicians addressed the question of fall in MC, but practices are widely heterogeneous. Further investigations are needed to standardize fall risk assessment in MCs.

The effects of mechanical noise bandwidth on balance across flat and compliant surfaces

Although the application of sub-sensory mechanical noise to the soles of the feet has been shown to enhance balance, there has been no study on how the bandwidth of the noise affects balance. Here, we report a single-blind randomized controlled study on the effects of a narrow and wide bandwidth mechanical noise on healthy young subjects’ sway during quiet standing on firm and compliant surfaces. For the firm surface, there was no improvement in balance for both bandwidths—this may be because the young subjects could already balance near-optimally or optimally on the surface by themselves. For the compliant surface, balance improved with the introduction of wide but not narrow bandwidth noise, and balance is improved for wide compared to narrow bandwidth noise. This could be explained using a simple model, which suggests that adding noise to a sub-threshold pressure stimulus results in markedly different frequency of nerve impulse transmitted to the brain for the narrow and wide bandwidth noise—the frequency is negligible for the former but significantly higher for the latter. Our results suggest that if a person’s standing balance is not optimal (for example, due to aging), it could be improved by applying a wide bandwidth noise to the feet.

A Systematic Review of Interventions for Balance Dysfunction in Patients With Vestibular Schwannoma

OBJECTIVE

Dizziness is a major contributing factor to poor quality of life for patients with vestibular schwannoma (acoustic neuroma). We wished to review the literature on interventions for balance dysfunction in these patients.

DATA SOURCES

A systematic literature review was performed identifying studies that measured balance function before and after treatment for vestibular schwannoma. Data sources include Medline (1950-present), EMBASE (1974-present), Cochrane Library (issue 3, 2008), NHS Centre of reviews and dissemination, Clinical Evidence, Cochrane central register of controlled trial, and CINAHL.

STUDY SELECTION

A minimum follow-up of 6 months was required, to estimate long-term balance function. Eight articles were identified, including five studies with surgical intervention, two studies with stereotactic radiotherapy, and one comparing the two. Study design was generally poor with a high risk of bias. These studies all utilized the Dizziness Handicap Inventory (DHI) as a measure of pre- and postintervention balance function.

DATA EXTRACTION

Results showed that overall DHI scores are not statistically affected by intervention irrespective of modality (surgery or stereotactic radiotherapy). Patients selected with severe dizziness, who undergo surgery, improved postoperatively. No other studies for severe dizziness were noted for comparison.

CONCLUSIONS

Age, sex, and tumor size have no statistically significant effect on DHI outcomes, and no evidence to suggest which treatment modality has better dizziness related outcomes.No specific treatment modality was superior in terms of long-term balance function. Patients with severe dizziness may benefit from surgery, although no comparator studies were identified.

Fatigue-Induced Inter-Limb Asymmetries in Strength of the Hip Stabilizers, Postural Control and Gait Following a Unilateral Countermovement Vertical Jump Protocol

It is generally accepted that neuromuscular overload and fatigue of one lower limb can affect the functional ability of the ipsilateral limb, and possibly the contralateral limb, increasing the likelihood of injury. The purpose of the current study was to examine the effect of a unilateral countermovement vertical jump (UCVJ) fatigue protocol on the neuromuscular function of the ipsilateral as well as the contralateral lower limb. The isometric strength of the hip stabilizers, postural control via posturographic analysis during the Y-Balance-Test (YBT), and the stance-phase-of-gait were assessed in 24 healthy physical active males and females before and after execution of a UCVJ fatigue protocol. The fatigue protocol included 5 sets of 20 maximum UCVJs performed on the supportive leg, with a 30-s break between sets. Following a 16.8% decline in vertical jump performance and an associated 2.3-fold increase in perceived exertion, our findings revealed significant post-fatigue inter-limb differences regarding postural control. The post-fatigue inter-limb differences regarding the isometric strength of the hip stabilizers and the stance-phase-of-gait parameters were not significant. Our findings showed that a 100 UCVJs session is likely to induce significant inter-limb differences in postural control, possibly increasing the risk of lower limb injury.

Neuroimaging, Behavioral, and Gait Correlates of Fall Profile in Older Adults

Prior research has suggested that measurements of brain functioning and performance on dual tasks (tasks which require simultaneous performance) are promising candidate predictors of fall risk among older adults. However, no prior study has investigated whether brain function measurements during dual task performance could improve prediction of fall risks and whether the type of subtasks used in the dual task paradigm affects the strength of the association between fall characteristics and dual task performance. In this study, 31 cognitively normal, community-dwelling older adults provided a self-reported fall profile (number of falls and fear of falling), completed a gait dual task (spell a word backward while walking on a GaitRite mat), and completed a supine dual task (rhythmic finger tapping with one hand while completing the AX continuous performance task (AX-CPT) with the other hand) during functional magnetic resonance imaging (fMRI). Gait performance, AX-CPT reaction time and accuracy, finger tapping cadence, and brain functioning in finger-tapping-related and AX-CPT-related brain regions all showed declines in the dual task condition compared to the single task condition. Dual-task gait, AX-CPT and finger tapping performance, and brain functioning were all independent predictors of fall profile. No particular measurement domain stood out as being the most strongly associated measure with fall variables. Fall characteristics are determined by multiple factors; brain functioning, motor task, and cognitive task performance in challenging dual-task conditions all contribute to the risk of falling.

Fully Automatic Fall Risk Assessment Based on a Fast Mobility Test

This paper presents a fall risk assessment approach based on a fast mobility test, automatically evaluated using a low-cost, scalable system for the recording and analysis of body movement. This mobility test has never before been investigated as a sole source of data for fall risk assessment. It can be performed in a very limited space and needs only minimal additional equipment, yet provides large amounts of information, as the presented system can obtain much more data than traditional observation by capturing minute details regarding body movement. The readings are provided wirelessly by one to seven low-cost micro-electro-mechanical inertial measurement units attached to the subject's body segments. Combined with a body model, these allow segment rotations and translations to be computed and for body movements to be recreated in software. The subject can then be automatically classified by an artificial neural network based on selected values in the test, and those with an elevated risk of falls can be identified. Results obtained from a group of 40 subjects of various ages, both healthy volunteers and patients with vestibular system impairment, are presented to demonstrate the combined capabilities of the test and system. Labelling of subjects as fallers and non-fallers was performed using an objective and precise sensory organization test; it is an important novelty as this approach to subject labelling has never before been used in the design and evaluation of fall risk assessment systems. The findings show a true-positive ratio of 85% and true-negative ratio of 63% for classifying subjects as fallers or non-fallers using the introduced fast mobility test, which are noticeably better than those obtained for the long-established Timed Up and Go test.

Association of Static Posturography With Severity of White Matter Hyperintensities

Background: Impaired gait and balance are associated with severity of leukoaraiosis. Evaluation of balance is based on neurological examination using Romberg's test with bipedal standing, assessment scale, and posturographic parameters. The goal of this study was to determine the relationship between static equilibrium and grades of white matter hyperintensities (WMHs) using static posturography as a quantitative technical method.

Method: One hundred and eighteen (118) patients with lacunar infarct were recruited and assessed on MRI with Fazekas's grading scale into four groups. On admission, age, gender, height, weight, Berg Balance Scale (BBS), mini-mental state examination (MMSE), and static posturography parameters were recorded, and their correlations with WMHs were determined.

Results: Age was significantly and positively correlated with severity of WMHs (r = 0.39, p < 0.05). WMH score was negatively correlated with BBS score (r = −0.65, p < 0.05) and MMSE score (r = −0.79, p < 0.05). There was a significant positive correlation between track length anteroposterior (AP, with eyes closed) and severity of WMHs (r = 0.70, p < 0.05). Partial correlation analysis and multiple logistic regression analysis indicated that track length AP with eyes closed, was a predictor for the severity of WMHs (p< 0.05).

Conclusion: The severity of WHMs is associated with age, cognitive decline, and impairment in balance. Posturography parameter in track length in AP direction with eyes closed in relation to cognition and balance, may be a potential marker for disease progression in WMHs.

Postadychute-AG, Detection, and Prevention of the Risk of Falling Among Elderly People in Nursing Homes: Protocol of a Multicentre and Prospective Intervention Study

Introduction: While falls among the elderly is a public health issue, because of the social, medical, and economic burden they represent, the tools to predict falls are limited. Posturography has been developed to distinguish fallers from non-fallers, however, there is too little data to show how predictions change as older adults' physical abilities improve. The Postadychute-AG clinical trial aims to evaluate the evolution of posturographic parameters in relation to the improvement of balance through adapted physical activity (APA) programs. Methods: In this prospective, multicentre clinical trial, institutionalized seniors over 65 years of age will be followed for a period of 6 months through computer-assisted posturography and automatic gait analysis. During the entire duration of the follow-up, they will benefit from a monthly measurement of their postural and locomotion capacities through a recording of their static balance and gait thanks to a software developed for this purpose. The data gathered will be correlated with the daily record of falls in the institution. Static and dynamic balance measurements aim to extract biomechanical markers and compare them with functional assessments of motor skills (Berg Balance Scale and Mini Motor Test), expecting their superiority in predicting the number of falls. Participants will be followed for 3 months without APA and 3 months with APA in homogeneous group exercises. An analysis of variance will evaluate the variability of monthly measures of balance in order to record the minimum clinically detectable change (MDC) as participants improve their physical condition through APA. Discussion: Previous studies have stated the MDC through repeated measurements of balance but, to our knowledge, none appear to have implemented monthly measurements of balance and gait. Combined with a reliable measure of the number of falls per person, motor capacities and other precipitating factors, this study aims to provide biomechanical markers predictive of fall risk with their sensitivity to improvement in clinical status over the medium term. This trial could provide the basis for posturographic and gait variable values for these elderly people and provide a solution to distinguish those most at risk to be implemented in current practice in nursing homes. Trial Registration: ID-RCB 2017-A02545-48. Protocol Version: Version 4.2 dated January 8, 2020.

Impact of Body Mass Index on Static Postural Control in Adults With and Without Diabetes: A Cross-Sectional Study

AIM

The objective of this research was to determine the static postural control differences measured from a force platform in Type 2 diabetes mellitus (T2DM) and healthy control groups with different levels of body mass index (BMI), and detect the static postural control difference between T2DM and healthy control groups stratified by different BMI category. This research also explored the relationship of BMI and static postural performance.

METHODS

We recruited 706 participants with T2DM and 692 healthy controls who were sufficiently matched for age, gender, and BMI in this cross-sectional study. The participants were stratified into three groups by BMI: normal weight, overweight, and obesity. All participants performed two-legged static stance postural control assessment on a firm force platform. The Center of Pressure (CoP) parameters were collected under eyes-open and eyes-closed conditions. Mann-Whitney U test was used to compare the static postural control parameters within each BMI category in both groups. The static postural control parameters among different weight groups were compared by Kruskal-Wallis test, post hoc pair-wise comparison were conducted. Generalized linear model was conducted to examine the association between BMI and static postural control parameters while controlling for confounding factors.

RESULTS

Healthy control group had statistical difference in most CoP parameters compared to T2DM group based on all BMI categories. Normal weight participants presented significant difference compared with overweight and/or obesity for total track length (TTL) and velocity of CoP displacements in Y direction (V-Y) under eyes-open condition, and for most CoP parameters under eyes-closed condition in both groups. There were statistically significant correlations between BMI and most static postural control parameters under only eyes-closed condition according to the result of generalized linear model.

CONCLUSION

T2DM patients had impaired static postural control performance compared to healthy controls at all BMI categories. The findings also indicated the association between BMI and static postural control, where higher BMI individuals showed more static postural instability in both T2DM and healthy controls.

Galvanic vestibular stimulation with low intensity improves dynamic balance

Background

Dynamic balance is associated with fall risk. The aim of this study is to explore the effects of galvanic vestibular stimulation with very low intensity direct current (dcGVS) on dynamic balance.

Methodology

We used a rocker force platform for assessing the dynamic balance performance. Center-of-pressure (COP) coordinates were acquired and decomposed to rambling (RA) and trembling (TR). We measured sway parameters, including length, average speed, and average range, affected by dcGVS at 0.01 mA with eyes open (EO) and eyes closed (EC).

Results

We assessed 33 young healthy subjects and found that all sway parameters were shorter in the EO condition, indicating a better dynamic balance performance. dcGVS significantly improved the dynamic balance performance both in EO and EC conditions. All the sway parameters in COP in EO were significantly shorter than those in EC, indicating a better dynamic balance performance in EO. In EO, RA had greater improvement rates than TR. In EC, only average speed had a greater improvement rate in RA, whereas length and average range had greater improvement rates in TR. These results indicate a different modulation model between EO and EC.

Conclusion

These findings indicate that very low intensity dcGVS improved the sway parameters of dynamic balance in young healthy subjects. Moreover, our results suggest different dynamic balance control models between having EO and EC. The mechanisms of these phenomena caused by very low intensity dcGVS require further investigation.