Gait symmetry in the dual task condition as a predictor of future falls among independent older adults: a 2-year longitudinal study

Comparative analysis of gait domains in middle-aged and older adults under single- and dual-task conditions

BACKGROUND

Dual-task gaits are linked to falls in older individuals, but their underlying structure is unknown compared to single-task gaits. We employed principal component analysis (PCA) to discover independent domains underlying single- and dual-task gaits in cognitively healthy community-dwelling people over 45.

METHODS

One hundred eighty-nine independent individuals (aged 45-80) completed health surveys, physical and cognitive tests, and walking evaluations under single-task, motor dual-task, and cognitive dual-task conditions. We applied PCA to 17 spatiotemporal gait parameters to identify independent domains for each gait. Logistic regression analyses were conducted to determine demographic, physical, and cognitive characteristics associated with domain scores.

RESULTS

The results revealed six independent domains consistent across all three gait types: rhythm, variability, phase, pace, base of support (BOS), and asymmetry. These domains accounted for 77.2-83.8 % of the overall gait variance. Rhythm, variability, and phase were the top three domains for all three gait types. Pace was the fourth domain for single- and motor dual-task gaits, while asymmetry held this position for the cognitive dual-task gait. In all three gaits, male sex and heavier weight were associated with greater BOS scores. Taller height and shorter five-times-sit-to-stand test (5XSST) time were associated with greater pace scores, while heavier weight was additionally linked to greater phase scores (p < 0.05). Notably, greater variability domain scores in the cognitive dual-task gait were uniquely associated with poorer executive function, balance, and shorter 5XSST time (p < 0.05).

SIGNIFICANCE

PCA results revealed consistent gait domains across single-, dual-, and cognitive dual-task conditions in older adults. These findings support the feasibility of using standardized, streamlined assessments focusing on these core domains in geriatric gait assessments. Findings of the unique cognitive dual-task gait characteristics highlight the importance of assessing gait variability and asymmetry of this gait for fall risk screening and prevention interventions.

An Exploration of the Effects of Gait Speed and Joint Movements on Minimum Toe Clearance Across the Lifespan: A Cross-Sectional Study

The effect of gait speed on minimum toe clearance (MTC) amount may vary across the lifespan due to changes in joint relationships, potentially affecting trip-related fall risk in older adults. We evaluated whether age influences the relationship between gait speed and MTC amount, as well as between joint movements and MTC amount. Optical motion capture data was collected on 62 participants between the ages of 20 and 83 years during 25 gait trials at self-selected normal, fast, and slow speeds. Multilevel models were used for data analysis. Gait speed was associated with a 0.13 cm increase in MTC amount for every meter per second increase in gait speed with other factors constant and was unaffected by age. Ankle dorsi-plantarflexion, knee and hip flexion-extension, and stance hip abduction-adduction changed the MTC amount by 0.05, 0.02, 0.04, and 0.04 cm, respectively, for each degree of joint movement, with other factors constant, and was unaffected by age. Age did not affect the relationship between gait speed and MTC amount, nor the relationship of joint moments with MTC, indicating that these factors may not be associated with trip-related fall risk with healthy aging.

Distinguishing retrospective fallers from nonfallers in people who use a unilateral lower-limb prosthesis

BACKGROUND

Over 52% of people who use a lower-limb prosthesis fall once every year, but fall risk is still not effectively screened. Few studies have identified clinical outcome measures that could help screen fall risk. Gait asymmetries between the intact and prosthetic limbs could also potentially help identify fall risk, based on findings in people with stroke. However, no studies have examined the relationship between gait asymmetries and falls in people who use a lower-limb prosthesis. Therefore, we sought to determine if any gait asymmetry parameters could significantly distinguish 12-month retrospective fallers from nonfallers.

METHODS

People were recruited from private practice and the Amputee Coalition National Conference. Participants completed a 12-month retrospective fall history and 7 clinical outcome measures, as well as level-ground walking at self-selected pace with wearable sensors that collected kinematic (sagittal plane: hip, knee, and ankle range of motion) and kinetic (peak braking and propulsion ground reaction force) data.

RESULTS

Twenty-two individuals who use a unilateral prosthesis participated (age 57.6 ± 14.2 years; 15 transtibial, 7 transfemoral). No gait asymmetry parameters significantly distinguished 12-month retrospective fallers from nonfallers. However, the Four Square Step Test did significantly distinguish fallers from nonfallers (P = 0.040, Hedge g = -0.739, area under the curve = 0.725, CI = 50-95%, cutoff time = 13.14 s), irrespective of level of prosthesis use. No parameters significantly distinguished fallers from nonfallers by level of prosthesis use (transtibial, transfemoral).

CONCLUSIONS

The Four Square Step Test cutoff time may be useful to distinguish fallers from nonfallers in unilateral lower-limb prosthesis users.

Gait Spatio-Temporal Parameters Vary Significantly Between Indoor, Outdoor and Different Surfaces

Human gait is usually studied in clinical environments, but wearable devices have extended gait analysis beyond traditional assessments. Older adults tend to walk differently indoors and outdoors; however, most gait assessments are conducted on indoor surfaces. It is therefore important to evaluate gait in various outdoor environments. Insights gained from these assessments significantly enhance our understanding of the impact of environmental factors on gait performance and ensure that clinical evaluations are effectively aligned with everyday locomotion. A total of 100 participants with foot pain, 38 young (18-45 years) and 62 older adults (65-80 years), completed a 10-Metre Walk Test (10MWT) in three randomised conditions at their typical, comfortable walking pace, including (1) 10MWT of indoor walking, (2) 10MWT of outdoor walking on grass and (3) 10MWT of outdoor walking on a sidewalk. Wearable inertial sensors recorded gait data and the magnitudes of the following gait measures: gait speed, cadence, stride length, stride duration and asymmetry. A statistical analysis using ANOVA and post hoc comparisons revealed a significantly lower gait speed (p < 0.001), lower stride length (p < 0.001) and lower asymmetry (p < 0.001) indoors compared to outdoors, demonstrating that environmental factors significantly affect spatio-temporal gait parameters. Wearable sensor-based gait analysis performed in controlled clinical settings may underestimate real-life conditions. Some important spatio-temporal parameters, useful in detecting people with gait impairment and at risk of falling, are significantly affected by environment and individual postural ability more than demographic factors.

Toward Convenient and Accurate IMU-Based Gait Analysis

While inertial measurement unit (IMU)-based systems have shown their potential in quantifying medically significant gait parameters, it remains to be determined whether they can provide accurate and reliable parameters both across various walking conditions and in healthcare settings. Using an IMU-based system we previously developed, with one IMU module on each subject's heel, we quantify the gait parameters of 55 men and 46 women, all healthy and aged 40-65, in normal, dual-task, and fast walking conditions. We evaluate their intra-session reliability, and we establish a new reference database of such parameters showing good to excellent reliability. ICC(2,1) assesses relative reliability, while SEM% and MDC% assess absolute reliability. The reliability is excellent for all spatiotemporal gait parameters and the stride length (SL) symmetry ratio (ICC ≥ 0.90, SEM% ≤ 4.5%, MDC% ≤ 12.4%) across all conditions. It is good to excellent for the fast walking performance (FWP) indices of stride (Sr), stance (Sa), double-support (DS), and step (St) times; gait speed (GS); and the GS normalized to leg length (GSn1) and body height (GSn2) (ICC ≥ 0.91, |SEM%| ≤ 10.0%, |MDC%| ≤ 27.6%). Men have a higher swing time (Sw) and SL across all conditions. The following parameters are gender-independent: (1) Sa, DS, GSn1, GSn2; (2) the symmetry ratios of SL and GS, as well as Sa% and Sw% (representing Sa and Sw as percentages of Sr); and (3) the FWPs of Sr, Sa, Sw, DS, St, cadence, Sa% and Sw%. Our results provide reference values with new insights into gender FWP comparisons rarely reported in the literature. The advantages and reliability of our IMU-based system make it suitable in medical applications such as prosthetic evaluation, fall risk assessment, and rehabilitation.

Females Present Reduced Minimum Toe Clearance During Walking As Compared to Males in Active Older Adults

BACKGROUND

Physical decline due to aging has been associated with the risk of falls. Minimum toe clearance (MTC) is a gait parameter that might play a role in the mechanism of tripping and falling. However, it is unclear if there are any sex-related effects regarding MTC as people age. The present study investigated if there are sex-related differences in MTC in older active adults.

METHODS

Twenty-three females and 23 males (F: 65.5 ± 4.8 years; M: 61.9 ± 5.2 years) walked on a treadmill at a preferred walking speed, while kinematic data were obtained at a sampling frequency of 100 Hz and up-sampled to 120 and 240 Hz. MTC was calculated from the kinematics data and evaluated concerning its magnitude (ie, MTC and MTC/leg length), the time between left/right MTC (ie, T-MTC), amount of variability (ie, coefficient of variation [CV] and coefficient of variation modified [CVm]), and temporal structure of variability, that is, the complexity of the time series (ie, MTC α, T-MTC α).

RESULTS

No sex effects were found for MTC/leg length, for the amount of variability (ie, CV and CVm), and for the complexity of the time series (MTC α, T-MTC α). However, females exhibited significantly lower MTC and T-MTC after adjusting for walking speed, mass, and age as covariates.

CONCLUSIONS

The reduced MTC in females suggests a potential sex-related disparity in the risk of tripping and falling among active older adults.

Influence of Physical Characteristics of Obstacles on the Locomotor Pattern of Older Adults at Higher Risk of Falling

OBJECTIVE

This study aimed to investigate the locomotor behavior of older adults with and without a history of falls as they avoided obstacles with different physical characteristics.

METHODS

Twenty-one older adults participated in this study. The group was divided into higher risk of falling (n = 10) and lower risk of falling (n = 11). The following conditions were carried out: (1) walking and avoiding a solid obstacle and (2) walking and avoiding a fragile obstacle.

RESULTS

Older adults at higher risk of falling had worse performance during the obstacle approach phase. Both groups performed worse when avoiding the fragile obstacle than when avoiding the solid obstacle. Older adults at higher risk of falling had their feet closer when avoiding the obstacle, and both groups raised their limbs higher to avoid a fragile obstacle. Older adults at higher risk of falling were closer to obstacles after avoiding them.

CONCLUSION

For the participants in this study, the physical characteristics of the obstacle did not interfere with the locomotor performance of older adults during obstacle avoidance. This study found that older adults at higher risk of falls modulated their locomotor pattern before avoiding the obstacles, presenting lower velocity, shorter step length, and greater step width compared with older adults at lower risk of falling.

Performance of Regression-Based Models for Real-Time Estimation of Anterior Ground Reaction Forces during Walking

Diminished limb propulsive forces correlate with increased fall risk and reduced mobility. Gait biofeedback retraining, focusing on anteriorly directed ground reaction forces, holds promise for improving limb propulsive forces. However, the current reliance on bulky and expensive instrumented treadmills restricts its applicability beyond the laboratory. Inertial measurement units (IMUs), cost-effective alternatives to treadmills, have shown potential in offline estimation of ground reaction forces. Nevertheless, real-time estimation of anterior-posterior ground reaction forces (AGRFs) using IMUs remains unexplored. This study assessed the real-time efficacy of regression-based models for AGRF estimation during walking. Ten participants walked at varying speeds, while IMU and force plate data were recorded. Using 75% of the data for training, participant-specific models were generated and tested on the remaining 25% of trials without altering temporal parameters. Two regression models were created: an unweighted model and a weighted model. Model efficacy for braking and propulsion was evaluated using intraclass correlation coefficients, absolute error, minimal detectable change (MDC), and 95% confidence intervals. Model estimates of the AGRF times series were evaluated using R2 and normalized root mean squared error (NRMSE) values. While both models aligned well with collected data, they fell short in predicting peak propulsion force, surpassing the MDC. Model estimates of the AGRF time series also generated relatively low R2 values and relatively high NRMSE values. This performance was slightly inferior to real-time regression models for vertical ground reaction forces. These findings suggest leveraging deep learning-based approaches which may be better suited for handling time series data.

The Influence of Multiple Pregnancies on Gait Asymmetry: A Case Study

Gait asymmetry is a predictor of fall risk and may contribute to increased falls during pregnancy. Previous work indicates that pregnant women experience asymmetric joint laxity and pelvic tilt during standing and asymmetric joint moments and angles during walking. How these changes translate to other measures of gait asymmetry remains unclear. Thus, the purpose of this case study was to determine the relationships between pregnancy progression, subsequent pregnancies, and gait asymmetry. Walking data were collected from an individual during 2 consecutive pregnancies during the second and third trimesters and 6 months postpartum of her first pregnancy and the first, second, and third trimesters and 6 months postpartum of her second pregnancy. Existing asymmetries in step length, anterior-posterior (AP) impulses, AP peak ground reaction forces, lateral impulses, and joint work systematically increased as her pregnancy progressed. These changes in asymmetry may be attributed to pelvic asymmetry, leading to asymmetric hip flexor and extensor length, or due to asymmetric plantar flexor strength, as suggested by her ankle work asymmetry. Relative to her first pregnancy, she had greater asymmetry in step length, step width, braking AP impulse, propulsive AP impulse, and peak braking AP ground reaction force during her second pregnancy, which may have resulted from increased joint laxity.

Altered coordination strategies during upright stance and gait in teachers of the Alexander Technique

Deterioration in movement and posture often occurs with aging. Yet there may be approaches to movement training that can maintain posture and movement coordination patterns as we age. The Alexander Technique is a non-exercise-based approach that aims to improve everyday movement and posture by increasing awareness and modulating whole-body postural muscle activity. This study assessed whether nineteen 55-72-year-old Alexander Technique teachers showed different posture and movement coordination patterns than twenty age-matched controls during a standing and walking protocol using 3D inertial sensors. During upright stance, Alexander Technique teachers showed lower centroidal sway frequency at the ankle (p = .04) and lower normalized jerk at the sternum (p = .05) than controls. During gait, Alexander Technique teachers had more symmetrical gait cycles (p = .04), more symmetrical arm swing velocity (p = .01), greater arm swing velocity (p < .01), greater arm swing range of motion (p = .02), and lower range of acceleration of the torso in the frontal plane (p = .03) than controls. Smoother control of upright posture, more stable torso motion, and less restrained arm mobility suggest that Alexander Technique training may counter movement degradation that is found with aging. Results highlight the important balance between mobility and stability within the torso and limbs.

The Effects of 12-Week Dual-Task Physical-Cognitive Training on Gait, Balance, Lower Extremity Muscle Strength, and Cognition in Older Adult Women: A Randomized Study

This study aims to investigate the effects of dual-task physical-cognitive the training on body balance (BB), gait performance (GP), lower limb muscle strength (LEMS), and cognitive performance (CP) in a group of cognitively normal older adult women (n = 44; 66.20 ± 4.05 years). Of these, 22 were randomly allocated to the dual-task training (DT) group, and 22 participated in the control group (CG). Assessments were performed at baseline, after 12 weeks of intervention, and at the end of 12 weeks of follow-up, using the following instruments: Timed Up & Go (TUG), Timed Up & Go manual (TUGm), Timed Up & Go cognitive (TUGc), Balance Test (TEC), sit-to-stand test (STS), and verbal fluency test (VF). After 12 weeks of DT training, participants showed a significant time × group interaction in all motor assessments (BB, GP, LEMS), as well as in three cognitive tests (VF-grouping, VF-exchange, VF-total). No time-group interaction effect was indicated for the VF-category test. At all evaluation times, CG members maintained constant physical and cognitive performance. We conclude that 12 weeks of physical-cognitive DT training was effective in promoting BB, GP, and LEMS, as well as CP in cognitively normal older adult women, with lasting effects up to 12 weeks after the intervention.

Muscular and Prefrontal Cortex Activity during Dual-Task Performing in Young Adults

Postural control depends on attentional resources besides automatic processes. The dual-task paradigm is a possible approach to analyzing the interference and performance between motor and/or cognitive tasks. Various studies showed that, when individuals simultaneously perform two tasks, the postural stability can decline during a dual-task compared with a single-task due to the attentional resources required performing the tasks. However, little is known about the cortical and muscular activity pattern during dual-task performance. Therefore, this study aims to analyze the muscular and prefrontal activity under dual-task performance in healthy young adults. Thirty-four healthy young adults (mean age ± SD = 22.74 ± 3.74 years) were recruited to perform a postural task (standing posture) and a dual-task (maintaining standing posture while performing a cognitive task). Lower-limb muscle activity was bilaterally collected from five muscles using surface electromyography (sEMG), and the co-contraction index (CCI) was also calculated for selected muscle pairings. The oxy- and deoxyhemoglobin concentrations (prefrontal cortex activity) were recorded using functional near-infrared spectroscopy (fNIRS). Data were compared between single- and dual-task performance. Prefrontal activity increased (p < 0.05), and muscle activity decreased in most analyzed muscles (p < 0.05), from the single-task to cognitive dual-task performing. The co-contraction index patterns changed from single- to dual-task conditions in most selected muscle pairs (p < 0.05). We conclude that the cognitive task negatively interfered with motor performance once the muscle activity decreased and the prefrontal cortex activity increased under a dual-task, suggesting that young adults prioritized cognitive task performance, and they allocated more attentional resources to the cognitive task over the motor performance. Understanding the neuromotor changes can help adopt a better clinical practice to prevent injuries. However, future studies are recommended to assess and monitor muscular and cortical activity during the dual-task performance to provide additional information about the cortical and muscular activity patterns in postural control while performing a dual-task.

Effects of wearable visual cueing on gait pattern and stability in patients with Parkinson’s disease

The present study examined the effects of wearable visual cues, provided by a wearable laser device, on the gait pattern and stability in patients with Parkinson’s disease (PD). In total, 18 patients with a clinical diagnosis of idiopathic PD (Hoehn and Yahr stage II-III) and 18 healthy controls were included. The main outcome measures included spatiotemporal parameters, sagittal plane kinematic parameters of joints in lower limbs, and dynamic center of pressure (COP) parameters. Significant intra-group improvement in gait parameters was observed in PD patients. Compared with that at baseline, the gait pattern improved in PD patients under the cued condition, with longer stride length and higher toe clearance, as well as shortening of double stance phase, especially the stride length, double stance phase and toe clearance were not significantly different between cued condition and healthy control groups. In kinematics, the ankle peak dorsiflexion in swing phase and the hip range of motion (ROM) in gait cycle was significantly improved in PD patients with visual cues and close to healthy controls. Decreased anteroposterior (AP) position of COP improved gait stability in patients with PD under the cued condition. Multiple linear regression analysis showed that the AP position has a negative correlation with ankle peak dorsiflexion in swing phase. Pearson’s correlation coefficients showed that the minimum toe clearance (Mini TC) was positively correlated with the ankle peak dorsiflexion in swing phase. The immediate effect of wearable visual cues improved the gait pattern and stability in PD patients, suggesting that it may be effective when applied as an alternative technique in rehabilitation training for PD patients.

The Nebulous Association between Cognitive Impairment and Falls in Older Adults: A Systematic Review of the Literature

BACKGROUND

In older people, dementia is a well-established risk factor for falls. However, the association and the causal relationship between falls and the earlier stages of cognitive impairment remains unclear. The purpose of the study was to review the literature data on the association between falls and cognitive impairment, no dementia, including Mild Cognitive Impairment.

METHODS

According to PRISMA guidelines, we searched five electronic databases (EMBASE, Web of Science, Medline, CINAHL, and PsychINFO) for articles published between January 2011 and August 2022 on observational studies of older people with a cognitive assessment and/or cognitive impairment diagnosis and a recording of falls. Their quality was reviewed according to the STROBE checklist.

RESULTS

We selected 42 of the 4934 initially retrieved publications. In 24 retrospective studies, a statistically significant association between falls and cognitive status was found in only 15 of the 32 comparisons (47%). Of the 27 cross-sectional analyses in prospective studies, only eight (30%) were positive and significant. We counted four longitudinal analyses, half of which suggested a causal relationship between falls and cognitive impairment. The investigational methods varied markedly from one study to another.

CONCLUSION

It is still not clear whether falls are associated with cognitive impairment, no dementia. Data in favor of a causal relationship are scarce. Further studies are needed to clarify their relationship.

Intelligent Fall-Risk Assessment Based on Gait Stability and Symmetry Among Older Adults Using Tri-Axial Accelerometry

This study aimed to use the k-nearest neighbor (kNN) algorithm, which combines gait stability and symmetry derived from a normalized cross-correlation (NCC) analysis of acceleration signals from the bilateral ankles of older adults, to assess fall risk. Fifteen non-fallers and 12 recurrent fallers without clinically significant musculoskeletal and neurological diseases participated in the study. Sex, body mass index, previous falls, and the results of the 10 m walking test (10 MWT) were recorded. The acceleration of the five gait cycles from the midsection of each 10 MWT was used to calculate the unilateral NCC coefficients for gait stability and bilateral NCC coefficients for gait symmetry, and then kNN was applied for classifying non-fallers and recurrent fallers. The duration of the 10 MWT was longer among recurrent fallers than it was among non-fallers (p &lt; 0.05). Since the gait signals were acquired from tri-axial accelerometry, the kNN F1 scores with the x-axis components were 92% for non-fallers and 89% for recurrent fallers, and the root sum of squares (RSS) of the signals was 95% for non-fallers and 94% for recurrent fallers. The kNN classification on gait stability and symmetry revealed good accuracy in terms of distinguishing non-fallers and recurrent fallers. Specifically, it was concluded that the RSS-based NCC coefficients can serve as effective gait features to assess the risk of falls.

The Performance Index Identifies Changes Across the Dual Task Timed Up and Go Test Phases and Impacts Task-Cost Estimation in the Oldest-Old

Introduction: Dual tasking is common in activities of daily living (ADLs) and the ability to perform them usually declines with age. While cognitive aspects influence dual task (DT) performance, most DT-cost (DT-C) related metrics include only time- or speed- delta without weighting the accuracy of cognitive replies involved in the task.

Objectives: The primary study goal was to weight the accuracy of cognitive replies as a contributing factor when estimating DT-C using a new index of DT-C that considers the accuracy of cognitive replies (P-index) in the instrumented timed up and go test (iTUG). Secondarily, to correlate the novel P-index with domains of the Mini-Mental State Examination (MMSE).

Methods: Sixty-three participants (≥85 years old) took part in this study. The single task (ST) and DT iTUG tests were performed in a semi-random order. Both the time taken to complete the task measured utilizing an inertial measurement unit (IMU), and the accuracy of the cognitive replies were used to create the novel P-index. Clinical and sociodemographic data were collected.

Results: The accuracy of the cognitive replies changed across the iTUG phases, particularly between the walk 1 and walk 2 phases. Moreover, weighting 0.6 for delta-time (W₁) and 0.4 for cognitive replies (W₂) into the P-index enhanced the prediction of the MMSE score. The novel P-index was able to explain 37% of the scores obtained by the fallers in the “spatial orientation” and “attention” domains of the MMSE. The ability of the P-index to predict MMSE scores was not significantly influenced by age, schooling, and number of medicines in use. The Bland-Altman analysis indicated a substantial difference between the time-delta-based DT-C and P-index methods, which was within the limits of agreement.

Conclusions: The P-index incorporates the accuracy of cognitive replies when calculating the DT-C and better reflects the variance of the MMSE in comparison with the traditional time- or speed-delta approaches, thus providing an improved method to estimate the DT-C.

Stride Length Predicts Adverse Clinical Events in Older Adults: A Systematic Review and Meta-Analysis

Background: This meta-analysis aims to estimate the power of walking stride length as a predictor of adverse clinical events in older adults. Methods: We searched all electronic databases until April 2021 for studies reporting stride length and other spatial gait parameters, including stride velocity, stride width, step width and stride variability, and compared them with clinical outcomes in the elderly. Meta-analyses of odds ratios (ORs) of effects of stride length on clinical outcomes used the generic inverse variance method and random model effects. Clinical outcomes were major adverse events (MAEs), physical disability and mortality. Results: Eleven cohort studies with 14,167 patients (mean age 75.4 ± 5.6 years, 55.8% female) were included in the analysis. At 33.05 months follow up, 3839 (27%) patients had clinical adverse events. Baseline stride length was shorter, WMD −0.15 (−0.19 to −0.11, p < 0.001), and stride length variability was higher, WMD 0.67 (0.33 to 1.01, p < 0.001), in fallers compared to non-fallers. Other gait parameters were not different between the two groups (p > 0.05 for all). Short stride length predicted MAE OR 1.36 (95% CI; 1.19 to 1.55, p < 0.001), physical disability OR 1.26 (95% CI; 1.11 to 1.44, p = 0.004) and mortality OR 1.69 (95% CI; 1.41 to 2.02, p < 0.001). A baseline normalized stride length ≤ 0.64 m was more accurate in predicting adverse clinical events, with summary sensitivity 65% (58–71%), specificity 72% (69–75%) and accuracy 75.5% (74.2–76.7%) compared to stride length variability 5.7%, with summary sensitivity 66% (61–70%), specificity 56% (54–58%) and accuracy 57.1% (55.5–58.6%). Conclusion: The results of this meta-analyses support the significant value of stride length for predicting life-threatening clinical events in older adults. A short stride length of ≤0.64 m accurately predicted clinical events, over and above other gait measures.

An Evaluation of Symmetries in Ground Reaction Forces during Self-Paced Single- and Dual-Task Treadmill Walking in the Able-Bodied Men

Gait is a complex autonomous activity that has long been viewed as a symmetrical locomotion, even when it adapts to secondary concurrent attention-demanding tasks. This study aimed to evaluate the symmetry of the three ground reaction forces (GRFs) in able-bodied individuals during self-paced treadmill walking with and without concurrent cognitive demands. Twenty-five male participants (age: 34.00 ± 4.44 years) completed two gait assessment sessions, each of whom were familiarized with the walking trials during their first session. Both sessions involved six-minute self-paced treadmill walking under three conditions: single-task walking and walking while concurrently responding to auditory 1-back and 2-back memory tasks. The symmetry of the GRFs was estimated using a nonlinear approach. Changes in the symmetry and walking speed across conditions in both sessions were assessed using inferential statistics. Results demonstrated that the three GRFs deviated from perfect symmetry by ≥10%. Engaging working memory during walking significantly reduced the symmetry of the vertical GRF (p = 0.003), and its detrimental effects on walking speed were significantly reduced in the second session with respect to the first session (p < 0.05). The findings indicate imperfect gait symmetry in able-bodied individuals, suggesting that common perceptions of gait symmetry should be reconsidered to reflect its objective importance in clinical settings.

Can dual-task paradigms predict Falls better than single task? - A systematic literature review

With about one third of adults aged 65 years and older being reported worldwide to fall each year, and an even higher prevalence with advancing age, aged-related falls and the associated disabilities and mortality are a major public health concern. In this context, identification of fall risk in healthy older adults is a key component of fall prevention. Since dual-task outcomes rely on the interaction between cognition and motor control, some studies have demonstrated the role of dual-task walking performance or costs in predicting future fallers. However, based on previous reviews on the topic, (1) discriminative and (2) predictive powers of dual tasks involving gait and a concurrent task are still a matter of debate, as is (3) their superiority over single tasks in terms of fall-risk prediction. Moreover, less attention has been paid to dual tasks involving postural control and transfers (such as gait initiation and turns) as motor tasks. In the present paper, we therefore systematically reviewed recent literature over the last 7 years in order to answer the three above mentioned questions regarding the future of lab-based dual tasks (involving posture, gait initiation, gait and turning) as easily applicable tests for identifying healthy older adult fallers. Despite great heterogeneity among included studies, we emphasized, among other things, the promising added value of dual tasks including turns and other transfers, such as in the Timed Up and Go test, for prediction of falls. Further investigation of these is thus warranted.

Using supervised learning machine algorithm to identify future fallers based on gait patterns: A two-year longitudinal study

INTRODUCTION

Given their major health consequences in the elderly, identifying people at risk of fall is a major challenge faced by clinicians. A lot of studies have confirmed the relationships between gait parameters and falls incidence. However, accurate tools to predict individual risk among independent older adults without a history of falls are lacking.

OBJECTIVE

This study aimed to apply a supervised learning algorithm to a data set recorded in a two-year longitudinal study, in order to build a classification tree that could discern subsequent fallers based on their gait patterns.

METHODS

A total of 105 adults aged >65 years, living independently at home and without a recent fall history were included in a two-year longitudinal study. All underwent physical and functional assessment. Gait speed, stride length, frequency, symmetry and regularity, and minimum toe clearance were recorded in comfortable, fast and dual task walking conditions in a standardized laboratory environment. Fall events were recorded using personal falls diaries. A supervised machine learning algorithm (J48) has been applied to the data recorded at inclusion in order to obtain a classification tree able to identify future fallers.

RESULTS

Based on fall information from 96 volunteers, a classification tree correctly identifying 80% of future fallers based on gait patterns, gender, and stiffness, was obtained, with accuracy of 84%, sensitivity of 80%, specificity of 87%, a positive predictive value of 78%, and a negative predictive value of 88%.

DISCUSSION

While the performances of the classification tree warrant further confirmation, it is the first predictive tool based on gait parameters that are identified (not clustered) allowing its use by other research teams.

CONCLUSION

This original longitudinal pilot study using a supervised machine learning algorithm, shows that gait parameters and clinical data can be used to identify future fallers among independent older adults.