Maximum step length as a potential screening tool for falls in non-disabled older adults living in the community

Evaluating the Prognostic and Clinical Validity of the Fall Risk Score Derived From an AI-Based mHealth App for Fall Prevention: Retrospective Real-World Data Analysis

Background

Falls pose a significant public health concern, with increasing occurrence due to the aging population, and they are associated with high mortality rates and risks such as multimorbidity and frailty. Falls not only lead to physical injuries but also have detrimental psychological and social consequences, negatively impacting quality of life. Identifying individuals at high risk for falls is crucial, particularly for those aged ≥60 years and living in residential care settings; current professional guidelines favor personalized, multifactorial fall risk assessment approaches for effective fall prevention.

Objective

This study aimed to explore the prognostic validity of the Fall Risk Score (FRS), a multifactorial-based metric to assess fall risk (using longitudinal real-world data), and establish the clinical relevance of the FRS by identifying threshold values and the minimum clinically important differences.

Methods

This retrospective cohort study involved 617 older adults (857 observations: 615 of women, 242 of men; mean age 83.3, SD 8.7 years; mean gait speed 0.49, SD 0.19 m/s; 622 using walking aids) residing in German residential care facilities and used the LINDERA mobile health app for fall risk assessment. The study focused on the association between FRS at the initial assessment (T1) and the normalized number of falls at follow-up (T2). A quadratic regression model and Spearman correlation analysis were utilized to analyze the data, supported by descriptive statistics and subgroup analyses.

Results

The quadratic model exhibited the lowest root mean square error (0.015), and Spearman correlation analysis revealed that a higher FRS at T1 was linked to an increased number of falls at T2 (ρ=0.960, P<.001). Subgroups revealed significant strong correlations between FRS at T1 and falls at T2, particularly for older adults with slower gait speeds (ρ=0.954, P<.001) and those using walking aids (ρ=0.955, P<.001). Threshold values revealed that an FRS of 45%, 32%, and 24% corresponded to the expectation of a fall within 6, 12, and 24 months, respectively. Distribution-based minimum clinically important difference values were established, providing ranges for small, medium, and large effect sizes for FRS changes.

Conclusions

The FRS exhibits good prognostic validity for predicting future falls, particularly in specific subgroups. The findings support a stratified fall risk assessment approach and emphasize the significance of early and personalized intervention. This study contributes to the knowledge base on fall risk, despite limitations such as demographic focus and potential assessment interval variability.

Relationship between respiratory muscle strength and dynamic balance in older persons requiring care or support: Focusing on the maximal single step length test and maximal double step length test as dynamic balance indices

BACKGROUND

Falls are a major health problem. The relationship between dynamic balance related to falls and respiratory muscle strength related to sarcopenia and frailty is poorly understood.

RESEARCH QUESTION

How do dynamic balance measures, such as maximal single step length test (MSL) and maximal double step length test (MDST), and respiratory muscle strength measures, such as maximal inspiratory (PImax) and maximal expiratory (PEmax), related to the requirement for long-term care or support in older people who live in the community?

METHODS

This was a cross-sectional study of 39 older people (17 men, 22 women) aged ≥ 65 years community-dwelling who were certified as requiring long-term care or support under the Japanese system. The participants' PImax, PEmax, MSL, and MDST results were recorded. The measurement data were evaluated using Pearson's correlation coefficients and multiple regression analysis.

RESULTS

MDST showed a positive correlation with PImax (r = 0.430, p = 0.006) but no correlation with PEmax. MSL showed no correlation with PImax or PEmax. A positive correlation was found between MDST and MSL (r = 0.851, p < 0.001), and multiple regression analysis with MDST as the dependent variable and PImax and MST as independent variables showed significant differences for MSL (p < 0.001) and PImax (p = 0.027).

SIGNIFICANCE

In older people requiring long-term care or support, MDST had a greater association with inspiratory muscle strength compared with MSL. These results suggest the importance of inspiratory muscle strength training and MDST assessment in the prevention of falls in older people requiring long-term care or support.

Predictability of Fall Risk Assessments in Community-Dwelling Older Adults: A Scoping Review

Fall risk increases with age, and one-third of adults over 65 years old experience a fall annually. Due to the aging population, the number of falls and related medical costs will progressively increase. Correct prediction of who will fall in the future is necessary to timely intervene in order to prevent falls. Therefore, the aim of this scoping review is to determine the predictive value of fall risk assessments in community-dwelling older adults using prospective studies. A total of 37 studies were included that evaluated clinical assessments (questionnaires, physical assessments, or a combination), sensor-based clinical assessments, or sensor- based daily life assessments using prospective study designs. The posttest probability of falling or not falling was calculated. In general, fallers were better classified than non-fallers. Questionnaires had a lower predictive capability compared to the other assessment types. Contrary to conclusions drawn in reviews that include retrospective studies, the predictive value of physical tests evaluated in prospective studies varies largely, with only smaller-sampled studies showing good predictive capabilities. Sensor-based fall risk assessments are promising and improve with task complexity, although they have only been evaluated in relatively small samples. In conclusion, fall risk prediction using sensor data seems to outperform conventional tests, but the method's validity needs to be confirmed by large prospective studies.

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.

Practical and validated tool to assess falls risk in the primary care setting: a systematic review

OBJECTIVE

Although several falls risk assessment tools are available, it is unclear which have been validated and which would be most suitable for primary care practices. This systematic review aims to identify the most suitable falls risk assessment tool for the primary care setting (ie, requires limited time, no expensive equipment and no additional space) and that has good predictive performance in the assessment of falls risk among older people living independently.

DESIGN

A systematic review based on prospective studies.

METHODS

An extensive search was conducted in the following databases: PubMed, Embase, CINAHL, Cochrane and PsycINFO. Tools were excluded if they required expensive and/or advanced software that is not usually available in primary care units and if they had not been validated in at least three different studies. Of 2492 articles published between January 2000 and July 2020, 27 were included.

RESULTS

Six falls risk assessment tools were identified: Timed Up and Go (TUG) test, Gait Speed test, Berg Balance Scale, Performance Oriented Mobility Assessment, Functional Reach test and falls history. Most articles reported area under the curve (AUC) values ranging from 0.5 to 0.7 for these tools. Sensitivity and specificity varied substantially across studies (eg, TUG, sensitivity:10%-83.3%, specificity:28.4%-96.6%).

CONCLUSIONS

Given that none of the falls risk assessment tools had sufficient predictive performance (AUC <0.7), other ways of assessing high falls risk among independently living older people in primary care should be investigated. For now, the most suitable way to assess falls risk in the primary care setting appears to involve asking patients about their falls history. Compared with the other five tools, the falls history requires the least amount of time, no expensive equipment, no training and no spatial adjustments. The clinical judgement of healthcare professionals continues to be most important, as it enables the identification of high falls risk even for patients with no falls history.

TRIAL REGISTRAION NUMBER

The Netherlands Trial Register, NL7917; Pre-results.

Falls prevention at GP practices: a description of daily practice

BACKGROUND

General practitioners (GPs) can be considered the designated professionals to identify high fall risk and to guide older people to fall preventive care. Currently it is not exactly known how GPs treat this risk. This study aims to investigate GPs' daily practice regarding fall preventive care for frail older patients.

METHODS

Sixty-five GPs from 32 Dutch practices participated in this study for a period of 12 months. When a GP entered specific International Classification of Primary Care-codes related to frailty and/or high fall risk in their Electronic Health Records, a pop-up appeared asking "Is this patient frail?". If the GP confirmed this, the GP completed a short questionnaire about patient's fall history and fear of falling (FOF), and the fall preventive care provided.

RESULTS

The GPs completed questionnaires regarding 1394 frail older patients aged ≥75. Of 20% of these patients, the GPs did not know whether they had experienced a fall or not. The GPs did not know whether a FOF existed in even more patients (29%). Of the patients with a fall history and/or a FOF (N = 726), 37% (N = 271) received fall preventive care. Two main reasons for not offering fall preventive care to these patients were: I) the patient finds treatment too intensive or too much of a hassle (37%), and II) the GP identified a high fall risk but the patient did not acknowledge this (14%). When patients were treated for high fall risk, the GP and the physiotherapist were the most frequently involved health care providers. The involved health care providers most often treated mobility limitations, cardiovascular risk factors, and FOF.

CONCLUSIONS

The results from this study show that GPs were frequently not aware of their frail patient's fall history and/or FOF and that the majority of the frail older patients with a fall history and/or FOF did not receive fall preventive care. Developing systematic screening strategies for the primary care setting enhancing the identification of high fall risk and the provision of fall preventive care may improve patients' quality of life and reduce health care costs.

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.

Evaluation of Concurrent Validity between a Smartphone Self-Test Prototype and Clinical Instruments for Balance and Leg Strength

The evolving use of sensors to objectively assess movements is a potentially valuable addition to clinical assessments. We have developed a new self-test application prototype, MyBalance, in the context of fall prevention aimed for use by older adults in order to independently assess balance and functional leg strength. The objective of this study was to investigate the new self-test application for concurrent validity between clinical instruments and variables collected with a smartphone. The prototype has two test procedures: static standing balance test in two positions, and leg strength test performed as a sit-to-stand test. Thirty-one older adults were assessed for balance and functional leg strength, in an outpatient physiotherapy setting, using seven different clinical assessments and three sensor-tests. The results show that clinical instruments and sensor measurements correlate to a higher degree for the smartphone leg strength test. For balance tests, only a few moderate correlations were seen in the Feet Together position and no significant correlations for the Semi Tandem Stance. This study served as a first step to develop a smartphone self-test application for older adults to assess functional balance at home. Further research is needed to test validity, reliability, and user-experience of this new self-test application.

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.

Do Older People Accurately Estimate the Length of Their First Step during Gait Initiation?

Background/Study Context: Advancing age is associated with a decrease in step length. In line with previous studies showing that older adults often overestimate their motor abilities, we investigate whether older adults overestimate the length of their first step during gait initiation. The underlying effect could be a failure to update the internal model of motor action as a function of age-related motor decline. Methods: Without taking a step, community-dwelling older women (n = 22, age range: 68-87 years) and younger women (n = 19, age range: 19-33 years) estimated the length of their first step for both preferred step length and largest step length, which were performed without endangerment. Thereafter, the participants performed real gait initiation for both types of steps. The estimated step lengths were compared to the actual step lengths. Results: Older adults judged their first step as larger than it was (mean error: 30% for the preferred step and 9% for the largest step). A fine-grained analysis showed that this effect mainly concerned those for whom an increased risk of falling was suspected. These older adults were also among those who performed the shortest steps, and they presented with a slight decrease in cognitive functioning. Younger participants underestimated their preferred step length. Overall, the estimates were more accurate for the largest steps than for the preferred-length steps. Conclusion: Step length estimation revealed powerful evidence for overestimation in older adults. Those who overestimated step length presented with more signs of motor decline. While this result sustains the idea of an insufficient actualization of the motor-action model, the explanation also refers to more global appraisal processes. Further research should explore the relevance of this task as a clinical laboratory tool for assessing gait capacity and the risk of falling.

Differences in Cognitive-Motor Interference in Older Adults While Walking and Performing a Visual-Verbal Stroop Task

Objectives: Studies using the dual-task (DT) paradigm to explain age-related performance decline due to cognitive-motor interference (CMI) which causes DT costs (DTCs) revealed contradictory results for performances under DT conditions. This cross-sectional study analyzed whether differences in demographics, physical functioning, concerns of falling (CoF), and other mental factors can explain positive and negative DTCs in older adults while walking in DT situations.

Methodology: N = 222 participants (57–89 years) performed a single task (ST) and a DT walking condition (visual-verbal Stroop task) in randomized order on a treadmill. Gait parameters (step length, step width) were measured at a constant self-selected walking speed. Demographics [age, Mini Mental Status Examination (MMSE)], physical functioning (hand grip strength), CoF [Falls Efficacy Scale International (FES-I)], and mental factors [Short Form-12 (SF-12)] were assessed. An analysis of variance (ANOVA) was used to reveal subgroup differences. A four-step hierarchical regression analysis was conducted to identify which variables determine the DTC.

Results: Three subgroups were identified: (1) participants (n = 53) with positive DTCs (improvements under DT conditions); (2) participants with negative DTCs (n = 60) in all gait parameters; and (3) participants (n = 109) who revealed non-uniform DTCs. Baseline characteristics between the subgroups showed differences in age (F_(2,215) = 4.953; p = 0.008; η² = 0.044). The regression analysis revealed that physical functioning was associated with positive DTC and CoF with negative DTC.

Conclusion: The results confirmed a huge inter-individual variability in older adults. They lead us to suggest that factors causing performance differences in DTCs needs to be reassessed. Functional age seems to determine DTCs rather than calendric age. Psychological variables particularly seem to negatively influence DT performance.

Estimation of reduced walking speed using simple measurements of physical and psychophysiological function in community-dwelling elderly people: a cross-sectional and longitudinal study

BACKGROUND

Early detection of reduced mobility function is important in elderly people. Usual walking speed is useful to assess mobility function, but is often not feasible in a community setting.

AIMS

This study aimed to explore a simple surrogate indicator of usual walking speed in elderly people.

METHODS

The participants were 516 community-dwelling elderly people. As a baseline survey, the usual walking speed and candidates of surrogate indicators including physical function and psychophysiological function were measured. After 2 years, the occurrence of mobility limitation was assessed.

RESULTS

In cross-sectional analysis, a linear regression model with maximum step length, age, and sex presented the most favourable adjusted R² of 0.426 for estimating usual walking speed. Maximum step length (MSL) also showed good predictive accuracy for usual walking speed < 0.8 m/s {area under the curve [AUC] 0.908 [95% confidence interval (CI) 0.811, 1.000]} and < 1.0 m/s [AUC 0.883 (95% CI) 0.832, 0.933)] in receiver-operating characteristic (ROC) analysis. In longitudinal analysis, the predictive accuracy of MSL for mobility limitation [AUC 0.813 (95% CI 0.752, 0.874)] was similar to that of usual walking speed [AUC 0.808 (95% CI 0.747, 0.869)] in ROC analysis.

CONCLUSIONS AND DISCUSSION

The results of this study suggest that MSL may serve as a simple surrogate indicator of UWS in elderly people.

Determining Risk of Falls in Community Dwelling Older Adults: A Systematic Review and Meta-analysis Using Posttest Probability

BACKGROUND

Falls and their consequences are significant concerns for older adults, caregivers, and health care providers. Identification of fall risk is crucial for appropriate referral to preventive interventions. Falls are multifactorial; no single measure is an accurate diagnostic tool. There is limited information on which history question, self-report measure, or performance-based measure, or combination of measures, best predicts future falls.

PURPOSE

First, to evaluate the predictive ability of history questions, self-report measures, and performance-based measures for assessing fall risk of community-dwelling older adults by calculating and comparing posttest probability (PoTP) values for individual test/measures. Second, to evaluate usefulness of cumulative PoTP for measures in combination.

DATA SOURCES

To be included, a study must have used fall status as an outcome or classification variable, have a sample size of at least 30 ambulatory community-living older adults (≥65 years), and track falls occurrence for a minimum of 6 months. Studies in acute or long-term care settings, as well as those including participants with significant cognitive or neuromuscular conditions related to increased fall risk, were excluded. Searches of Medline/PubMED and Cumulative Index of Nursing and Allied Health (CINAHL) from January 1990 through September 2013 identified 2294 abstracts concerned with fall risk assessment in community-dwelling older adults.

STUDY SELECTION

Because the number of prospective studies of fall risk assessment was limited, retrospective studies that classified participants (faller/nonfallers) were also included. Ninety-five full-text articles met inclusion criteria; 59 contained necessary data for calculation of PoTP. The Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS) was used to assess each study's methodological quality.

DATA EXTRACTION

Study design and QUADAS score determined the level of evidence. Data for calculation of sensitivity (Sn), specificity (Sp), likelihood ratios (LR), and PoTP values were available for 21 of 46 measures used as search terms. An additional 73 history questions, self-report measures, and performance-based measures were used in included articles; PoTP values could be calculated for 35.

DATA SYNTHESIS

Evidence tables including PoTP values were constructed for 15 history questions, 15 self-report measures, and 26 performance-based measures. Recommendations for clinical practice were based on consensus.

LIMITATIONS

Variations in study quality, procedures, and statistical analyses challenged data extraction, interpretation, and synthesis. There was insufficient data for calculation of PoTP values for 63 of 119 tests.

CONCLUSIONS

No single test/measure demonstrated strong PoTP values. Five history questions, 2 self-report measures, and 5 performance-based measures may have clinical usefulness in assessing risk of falling on the basis of cumulative PoTP. Berg Balance Scale score (≤50 points), Timed Up and Go times (≥12 seconds), and 5 times sit-to-stand times (≥12) seconds are currently the most evidence-supported functional measures to determine individual risk of future falls. Shortfalls identified during review will direct researchers to address knowledge gaps.

Comparison of intraobserver single-task reliabilities of the Interactive Balance System (IBS) and Vertiguard in asymptomatic subjects

The intraobserver reliabilities of the Interactive Balance System (IBS) and Vertiguard were compared in 30 asymptomatic volunteers. Relative reliability for all IBS single tasks and parameters in the IBS was excellent (intraclass correlation coefficient, ICC ≥0.75). The ICC values ranged from 0.78 to 0.89. The ICC values of the Vertiguard system ranged from 0 to 0.75. The cumulative measure of injury risk of the Vertiguard system was highly reliable.

Feasibility of repeated self-measurements of maximum step length and gait speed by community-dwelling older persons

OBJECTIVES

Self-management of mobility and fall risk can be important in fall prevention; however, it remains unstudied. Therefore, the current study assessed whether community-dwelling older persons were able to repeatedly self-assess maximum step length (MSL) and gait speed (GS) in their own home for a 6-month period, how these tests changed during this period and if these changes were related to falling.

DESIGN

This is a prospective study.

SETTING

This study was conducted at home.

PARTICIPANTS

A total of 56 community-dwelling older adults (24 women (43%), mean age 76.2 (SD 3.9) years) entered the study; of which, 45 completed the study.

METHODS

Participants performed MSL and GS once a week in their own home during a 6-month period.

PRIMARY AND SECONDARY OUTCOMES

Repeated MSL and GS measurements were the primary outcomes. Falls, self-management and mobility were the secondary outcomes.

RESULTS

Self-assessment of MSL and GS by older persons is feasible. Compliance of repeatedly self-measuring MSL and GS was good; the median number of weekly measurements was 23.0 (88%) and 21.0 (81%) for MSL and GS, respectively. Drop-outs showed less self-management abilities compared to the participants who completed the study (p=0.049). Linear mixed models showed a small significant improvement in MSL and GS over time (p<0.001), without an influence on falling.

CONCLUSIONS

Most community-dwelling older persons are able and willing to repeatedly assess their MSL and GS. Self-managing mobility and fall risk did not increase fall occurrence. The fact that older persons can be actively involved in their own healthcare is clinically relevant. Further studies are needed to examine the (cost-)effectiveness of self-management in fall prevention interventions.

Locomotive Syndrome: Definition and Management

Locomotive syndrome is a condition of reduced mobility due to impairment of locomotive organs. Since upright bipedal walking involves minutely controlled movement patterns, impairment of any aspect of the locomotive organs has the potential to adversely affect it. In addition to trauma, chronic diseases of the locomotive organs, which progress with repeated bouts of acute exacerbations, are common causes of the locomotive syndrome. In Japan's super-aging society, many people are likely to experience locomotive syndrome in the later part of their lives. Exercise intervention is effective in improving motor function, but because the subjects are elderly people with significant degenerative diseases of the locomotor organs, caution should be taken in choosing the type and intensity of exercise. The present review discusses the definition, current burden, diagnosis and interventions pertaining to the locomotive syndrome. The concept and measures are spreading throughout Japan as one of the national health policy targets.

Performance on a test of rapid stepping in community-dwelling older adults: validity, relative and absolute reliability and minimum detectable change

Reduced stepping speed is associated with balance deficits and falls in older adults. We evaluated psychometric properties of a test of rapid stepping, the Thirty-Rapid-Step test (30-RST) in 37 community-dwelling older adults. Participants performed the 30-RST, dynamic (step execution time, five-times-sit-to-stand test, gait speed, maximum step length and four-square-step test) and static (single-leg-stance-time and postural sway) performance-based tests. Relationships between 30-RST and performance-based tests were evaluated with Spearman's rho. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), 95% limits of agreement and minimum detectable change at the 95% confidence level (MDC95) were computed for the 30-RST. Relationships between 30-RST and dynamic measures were moderate to very good (r = -0.35-0.73, p < 0.05); however, relationships between 30-RST and static balance were weak (r = 0.04-0.19, p > 0.05). The ICC2,1 was 0.85 for 30-RST indicating excellent test-retest reliability. SEM expressed as a percent of mean 30-RST was 8.2%, indicating low measurement error. The MDC95 was 9.4 s, and MDC95 expressed as a percent of mean 30-RST was moderately low at 22.6%. The 30-RST is a valid measure of dynamic balance and mobility with excellent relative and absolute reliability, and may be a useful measure in geriatric clinical settings and studies investigating balance in healthy community-dwelling older adults.

Effects of age and step length on joint kinetics during stepping task

Following a balance perturbation, a stepping response is commonly used to regain support, and the distance of the recovery step can vary. To date, no other studies have examined joint kinetics in young and old adults during increasing step distances, when participants are required to bring their rear foot forward. Therefore, the purpose of this study was to examine age-related differences in joint kinetics with increasing step distance. Twenty young and 20 old adults completed the study. Participants completed a step starting from double support, at an initial distance equal to the individual's average step length. The distance was increased by 10% body height until an unsuccessful attempt. A one-way, repeated measures ANOVA was used to determine the effects of age on joint kinetics during the maximum step distance. A two-way, repeated measures, mixed model ANOVA was used to determine the effects of age, step distance, and their interaction on joint kinetics during the first three step distances for all participants. Young adults completed a significantly longer step than old adults. During the maximum step, in general, kinetic measures were greater in the young than in the old. As step distance increased, all but one kinetic measure increased for both young and old adults. This study has shown the ability to discriminate between young and old adults, and could potentially be used in the future to distinguish between fallers and non-fallers.

The predictive value of gait speed and maximum step length for falling in community-dwelling older persons

BACKGROUND

Falling is a major health problem.

OBJECTIVE

To investigate the predictive value for falls of the maximum step length and gait speed.

DESIGN

A prospective cohort study.

SETTING

Geriatric outpatient clinic.

SUBJECTS

Three hundred and fifty-two community-dwelling older persons screened by their general practitioner.

METHODS

Maximum step length and gait speed were recorded as part of a comprehensive geriatric assessment. One-year follow-up was performed using the fall telephone system.

RESULTS

One hundred and thirty-six (39%) of all subjects (mean age: 76.2 years, standard deviation: 4.3, 55% female), fell at least once, of whom 96 were injured. Predictive values for any falls of both maximum step length and gait speed were low (area under the curve (AUC): 0.53 and 0.50) and slightly better for recurrent falls (maximum step length AUC: 0.64 and gait speed AUC: 0.59). After adding age, gender and fall history to the prediction model, the AUC was 0.63 for maximum step length and 0.64 for gait speed, and for recurrent falls, the AUC was 0.69 both for maximum step length and gait speed. The prediction of fall-related injuries showed similar results. A higher maximum step length score indicated a lower likelihood for falls (hazards ratio 0.36; 95% confidence interval 0.17-0.78).

CONCLUSIONS

Maximum step length and gait speed as single-item tools do not have sufficient power to predict future falls in community-dwelling older persons.

Reference values and age and sex differences in physical performance measures for community-dwelling older Japanese: a pooled analysis of six cohort studies

Objectives

To determine age- and sex-specific reference values for six physical performance measures, i.e. hand-grip strength, one-legged stance, and gait speed and step length at both usual and maximum paces, and to investigate age and sex differences in these measures among community-dwelling older Japanese adults.

Methods

We conducted a pooled analysis of data from six cohort studies collected between 2002 and 2011 as part of the Tokyo Metropolitan Institute of Gerontology-Longitudinal Interdisciplinary Study on Aging. The pooled analysis included cross-sectional data from 4683 nondisabled, community-dwelling adults aged 65 years or older (2168 men, 2515 women; mean age: 74.0 years in men and 73.9 years in women).

Results

Unweighted simple mean (standard deviation) hand-grip strength, one-legged stance, usual gait speed, usual gait step length, maximum gait speed, and maximum gait step length were 31.7 (6.7) kg, 39.3 (23.0) s, 1.29 (0.25) m/s, 67.7 (10.0) cm, 1.94 (0.38) m/s, and 82.3 (11.6) cm, respectively, in men and 20.4 (5.0) kg, 36.8 (23.4) s, 1.25 (0.27) m/s, 60.8 (10.0) cm, 1.73 (0.36) m/s, and 69.7 (10.8) cm, respectively, in women. All physical performance measures showed significant decreasing trends with advancing age in both sexes (all P<0.001 for trend). We also constructed age- and sex-specific appraisal standards according to quintiles. With increasing age, the sex difference in hand-grip strength decreased significantly (P<0.001 for age and sex interaction). In contrast, sex differences significantly increased in all other measures (all P<0.05 for interactions) except step length at maximum pace.

Conclusion

Our pooled analysis yielded inclusive age- and sex-specific reference values and appraisal standards for major physical performance measures in nondisabled, community-dwelling, older Japanese adults. The characteristics of age-related decline in physical performance measures differed between sexes.

Analytical review: focus on fall screening assessments

BACKGROUND

Falls and their associated injuries profoundly impact health outcomes, functional independence, and health care expenses, particularly for the ever-increasing elderly population. This systematic search and review assessed the current evidence for the role of fall screening assessments.

OBJECTIVE

To review the current evidence for fall risk screening assessments in community-dwelling (outpatient), inpatient medical and surgical wards, inpatient rehabilitation centers, and postrehabilitation outpatient settings.

DATA SOURCES

MEDLINE and Embase (January 1980 to December 2012).

STUDY SELECTION

Prospective validation studies of acute medical or surgical inpatients, acute rehabilitation inpatients, outpatients who completed acute inpatient rehabilitation, or community-dwelling elderly.

DATA EXTRACTION

Sensitivity, specificity, positive predictive value, negative predictive value, receiver operating characteristics with area under the curve.

RESULTS

We summarized key findings from 6 literature reviews. We then identified 31 articles: 12 studies in community setting, 13 in the acute medical inpatient or surgical inpatient setting, and 6 studies in the rehabilitation setting. Twenty-two studies not previously reviewed were included, and 9 studies previously reviewed were considered relevant and were included to allow comparison with data from the studies not previously reviewed.

CONCLUSION

We recommend consideration of 7 assessment tools to be used in conjunction with overall clinical evaluation to assess falls risk: the Timed Up and Go Test with a cutoff of >12.34 seconds and Functional Gait Assessment among community-dwelling elderly; St Thomas Risk Assessment Tool in medical inpatients <65 years old and surgical inpatients; Hendrich fall risk model II in medical inpatients; 10-Minute Walk Test in patients in poststroke rehabilitation; and Berg Balance Scale or the Step Test in patients in poststroke rehabilitation who had fallen during their inpatient stay.

Effects of step length, age, and fall history on hip and knee kinetics and knee co-contraction during the maximum step length test

BACKGROUND

Maximum step length is a brief clinical test involving stepping out and back as far as possible with the arms folded across the chest. This test has been shown to predict fall risk, but the biomechanics of this test are not fully understood. Knee and hip kinetics (moments and powers) are greater for longer steps and for younger subjects, but younger subjects also step farther.

METHODS

To separate the effects of step length, age, and fall history on joint kinetics; healthy younger (age=27(5), N=14), older non-fallers (age=72(5), N=14), and older fallers (age=75(6), N=11) all stepped to the same relative target distances of 20-80% of their height. Knee and hip kinetics and knee co-contraction were calculated.

FINDINGS

Hip and knee kinetics and knee co-contraction all increased with step length, but older non-fallers and fallers utilized greater stepping hip and less stepping knee extensor kinetics. Fallers had greater stepping knee co-contraction than non-fallers. Stance knee co-contraction of non-fallers was similar to young for shorter steps and similar to fallers for longer steps.

INTERPRETATION

Age had minimal effects and fall history had no effects on joint kinetics of steps to similar distances. Effects of age and fall history on knee co-contraction may contribute to age-related kinetic differences and shorter maximal step lengths of older non-fallers and fallers, but step length correlated with every variable tested. Thus, declines in maximum step length could indicate declines in hip and knee extensor kinetics and impaired performance on similar tasks like recovering from a trip.

A novel infrared laser device that measures multilateral parameters of stepping performance for assessment of fall risk in elderly individuals [corrected]

BACKGROUND AND AIMS

Avoiding falls requires fast and appropriate step responses in real-life situations. We developed a step-tracking device that uses an infrared laser sensor for convenient assessment of stepping performance, including concurrent assessment of temporal and spatial parameters. In the present study, we created a new index for assessment of fall risk that uses step speed and accuracy measurements. The purpose of this study was to determine whether the new index could discriminate between elderly individuals with different risks of falling.

METHODS

One hundred and fifty-two community-dwelling elderly individuals (73.9 ± 4.6 years) participated and performed stepping tasks as quickly as possible on a plus-shaped mat in response to optical cues. The step-tracking device with the infrared sensor detected the motion and position of both legs in the step field. The device recorded temporal and spatial parameters, foot-off and foot-contact time, step length, and the percentage of correctly executed steps. We used the coefficients of a logistic regression model to develop "stepping-response score" based on the weighted sum of these temporal and spatial parameters.

RESULTS

The faller group had significantly worse stepping-response score than the non-faller group (p < 0.001). A stepwise logistic regression analysis demonstrated that stepping-response score was independently associated with falling (odds ratio = 0.15; p < 0.001). The ROC curve had a moderate AUC (0.73) for stepping-response score (sensitivity 73.0 %; specificity 69.7 %).

CONCLUSIONS

This study indicates that the stepping-response score calculated from measurements obtained using the new step-tracking device can identify elderly individuals who are at a risk of falling.

Development of measurement system for task oriented step tracking using laser range finder

BACKGROUND

Avoiding a fall requires fast and appropriate step responses, stepping speed as a fall risk indicator has only been assessed in older adults. We have developed a new measurement system that applies a laser range finder to assess temporal and spatial parameters of stepping performance such as step speed, length, and accuracy. This measurement system has higher portability, lower cost, and can analyze a larger number of temporal and spatial parameters than existing measurement systems. The aim of this study was to quantify the system for measuring reaction time and stride duration by compared to that obtained using a force platform.

METHODS

Ten healthy young adults performed steps in response to visual cues. The measurement system applied a laser range finder to measure the position and velocity of the center of each leg and of both legs.We applied the developed measurement system to the rhythmic stepping exercise and measured reaction time and stride duration. In addition, the foot-off time and foot-contact time were quantified using the measurement system, and compared to the foot-off time and foot-contact time quantified using a force platform.

RESULTS

We confirmed that the measurement system can detect where a participant stood and measured reaction time and stride duration.Remarkable consistency was observed in the test-retest reliability of the foot-off time and foot-contact time quantified by the measurement system (p < 0.001). The foot-off time and foot-contact time quantified by the measurement system were highly correlated with the foot-off time and foot-contact time quantified by the force platform (reaction time: r = 0.997, stride duration: r = 0.879; p < 0.001).

CONCLUSIONS

The new measurement system provided a valid measure of temporal step parameters in young healthy adults.The validity of the system to measure reaction time and stride duration was evaluated, and confirmed by applying to the rhythmic stepping exercise.

Validity, reliability and minimum detectable change of the maximum step length test in people with stroke

Stroke is a significant cause of deficits in balance, mobility and disability. Although tests of stepping speed are associated with balance performance after stroke, relationships between clinical tests of stepping distance and balance performance have not been investigated in people with stroke. A validated test of stepping distance and balance in older adults (the maximum step length [MSL] test), and two clinical measures associated with balance in people with stroke (the five-times-sit-to-stand test [FTSST] and gait speed) were evaluated in nineteen independent community-dwelling people with chronic stroke. There were strong relationships between MSL and performance on the clinical balance measures (Pearson's r 0.69 to -0.88), suggesting that MSL is a valid measure of balance after stroke. Test-retest reliability coefficients were excellent for the MSL tests (ICC both limbs; 0.98). Standard error of measurement expressed as a percentage of mean MSL was computed as 5.6% (hemiparetic leg) and 5.4% (unaffected leg), indicative of low levels of measurement error and excellent absolute reliability of the MSL test in people with stroke. Minimum detectable change expressed as a percentage of mean MSL was low (14.9% to 15.4%), suggesting that MSL may be sensitive to detecting change in physical performance in people with stroke. Advantages of the MSL test are that it is easy to administer, requiring minimal training, equipment, time or space. These advantages, together with the validity of the MSL test, its excellent test-retest and absolute reliability, and its low minimum change percent value suggest that MSL may be a useful measure of balance capabilities in people with stroke.

Can falls be predicted with gait analytical and posturographic measurement systems? A prospective follow-up study in a nursing home population

OBJECTIVE

To validate previously proposed findings and to develop an objective, feasible and efficient bifactorial (risk factors: gait impairment and balance disorders) fall risk assessment.

DESIGN

Prospective follow-up study Setting: Nursing homes (Halle/Saale, Germany).

SUBJECTS

One hundred and forty-six nursing home residents (aged 62-101 years) were recruited.

METHODS

Gait data were collected using a mobile inertial sensor-based system (RehaWatch). Postural regulation data were measured with the Interactive Balance System. Falls were recorded in standardized protocols over a follow-up period of 12 months.

MAIN MEASURES

Gait parameters (e.g. spatial-temporal parameters), posturographic parameters (e.g. postural subsystems), number of falls.

RESULTS

Seventeen (12%) of the participants had more than two falls per year. The predictive validity of the previously selected posturographic parameters was inadequate (sensitivity: 47%). The new measurement tool defined 67 participants showing an increased risk of falls. In reality, only 8 participants actually fell more than twice during the follow-up period (positive predictive value (PPV): 12%). The negative predictive value (NPV) was 88%. The posturographic frequency range F2-4 (peripheral-vestibular system), stride time and standard deviation of landing phase were the most powerful parameters for fall prediction. Gait and postural variability were larger in the high-risk group (e.g. gait speed; confidence interval (CI)(high): 0.57-0.79 vs. CI(low): 0.72-0.81 m/s).

CONCLUSION

RehaWatch and the Interactive Balance System are able to measure two of the most important fall risk factors, but their current predictive ability is not satisfactory yet. The correlation with physiological mechanisms is only shown by the Interactive Balance System.

The maximal double step length test can evaluate more adequately the decrease of physical function with age, than the maximal single step length test

The maximal double step length (MDSL) test is a modified version of the maximal step length (MSL) test used to evaluate the dynamic balance related to falls in the elderly. Although this test can evaluate their physical function using movements similar to daily activities as compared to MSL, it has not been clarified whether it can adequately evaluate the activities of daily living (ADL) abilities of the elderly, as they decrease with age. This study aimed to examine the relationship between both MSL and MDSL on age and ADL in elderly subjects. Fifty-seven elderly females who live independently (age 74.8±5.6 years) were recruited. MSL and MDSL were conducted twice after completing an ADL questionnaire. Intra-class correlation coefficients (ICCs) of both tests were high (for MSL: ICC=0.95, for MDSL: ICC=0.81-0.82). Age and ADL significantly correlated to MDSL (age: r=-0.32-0.41, ADL: r=0.28-0.48), but not to MSL (age: r=-0.19, ADL: r=0.15). MDSL has high reliability as it relates to age and ADL. It may be more useful to evaluate ADL required for independent living and prevent falls in the elderly better than MSL.

Do voluntary step reactions in dual task conditions have an added value over single task for fall prediction? A prospective study

BACKGROUND AND AIMS

Stepping reactions play a critical role in responding to balance perturbations, whether they are a consequence of external perturbation or self-induced in nature. The aim of the present study was to determine prospectively the capacity of voluntary stepping performance in singleand dual-task conditions, to predict future falls among older community-dwelling persons. We also aimed to assess whether dual task conditions have an added value over single tasks for fall prediction.

METHODS

A total of 100 healthy old volunteers (mean age 78.4±5.7 yrs), from two self-care protected retirement homes for older adults, performed the Voluntary Step Execution Test in single- and dual-task conditions as a reaction time task while standing on a single force platform. Step initiation, preparatory and swing phases, and foot-contact time were extracted from data on center of pressure and ground reaction force. One-year fall incidences were monitored.

RESULTS

Ninety-eight subjects completed the one-year follow-up, 49 non-fallers, 32 one-time fallers, and 17 recurrent fallers (two or more falls). Recurrent fallers had significantly slower voluntary step execution times in both single- and dual-task conditions, especially due to a slower preparation phase. Two stepwise (backward) logistic regression models showed that longer step execution times have strong predictive value for falls in both single- and dual-task conditions (odds ratio (OR) 8.7 and 5.4, respectively, p<0.05).

CONCLUSIONS

Voluntary Step Execution Test in both single- and dual-task conditions is a simple and safe examination which can potentially and effectively predict future falls, with no added value to dual- over single-task condition.