Age-associated declines in complex walking task performance: the Walking InCHIANTI toolkit

Towards a comprehensive framework for complex walking tasks: Characterization, behavioral adaptations, and clinical implications in ageing and neurological populations

Complex walking tasks, including change of direction, patterns and rhythms, require more attentional resources than simple walking and significantly impact walking performance, especially among ageing and neurological populations. More studies have been focusing on complex walking situations, with or without the addition of cognitive tasks, creating a multitude of walking situations. Given the lack of a clear and extensive definition of complex walking, this narrative review aims to identify and more precisely characterize situations and related tests, improve understanding of behavioral adaptations in ageing and neurological populations, and report the clinical applications of complex walking. Based on the studies collected, we are proposing a framework that categorizes the different forms of complex walking, considering whether a cognitive task is added or not, as well as the number of distinct objectives within a given situation. We observed that combining complex walking tasks with a cognitive assignment places even greater strain on attentional resources, resulting in a more pronounced decline in walking and/or cognitive performance. This work highlights the relevance of complex walking as a simple tool for early detection of cognitive impairments and risk of falls, and its potential value in cognitive-motor rehabilitation. Future studies should explore various complex walking tasks in ageing and neurological populations, under varied conditions in real-life or in extended virtual environments.

Amplify Gait to Improve Locomotor Engagement in Spinal Cord Injury (AGILE SCI) trial: study protocol for an assessor blinded randomized controlled trial

BACKGROUND

Among ambulatory people with incomplete spinal cord injury (iSCI), balance deficits are a primary factor limiting participation in walking activities. There is broad recognition that effective interventions are needed to enhance walking balance following iSCI. Interventions that amplify self-generated movements (e.g., error augmentation) can accelerate motor learning by intensifying sensorimotor feedback and facilitating exploration of motor control strategies. These features may be beneficial for retraining walking balance after iSCI. We have developed a cable-driven robot that creates a movement amplification environment during treadmill walking. The robot applies a continuous, laterally-directed, force to the pelvis that is proportional in magnitude to real-time lateral velocity. Our purpose is to investigate the effects of locomotor training in this movement amplification environment on walking balance. We hypothesize that for ambulatory people with iSCI, locomotor training in a movement amplification environment will be more effective for improving walking balance and participation in walking activities than locomotor training in a natural environment (no applied external forces).

METHODS

We are conducting a two-arm parallel-assignment intervention. We will enroll 36 ambulatory participants with chronic iSCI. Participants will be randomized into either a control or experimental group. Each group will receive 20 locomotor training sessions. Training will be performed in either a traditional treadmill environment (control) or in a movement amplification environment (experimental). We will assess changes using measures that span the International Classification of Functioning, Disability and Health (ICF) framework including 1) clinical outcome measures of gait, balance, and quality of life, 2) biomechanical assessments of walking balance, and 3) participation in walking activities quantified by number of steps taken per day.

DISCUSSION

Training walking balance in people with iSCI by amplifying the individual's own movement during walking is a radical departure from current practice and may result in new strategies for addressing balance impairments. Knowledge gained from this study will expand our understanding of how people with iSCI improve walking balance and how an intervention targeting walking balance affects participation in walking activities. Successful outcomes could motivate development of clinically feasible tools to replicate the movement amplification environment within clinical settings.

TRIAL REGISTRATION

NCT04340063.

Nonlinear and threshold effects of built environment on older adults' walking duration: do age and retirement status matter?

Introduction

Walking plays a crucial role in promoting physical activity among older adults. Understanding how the built environment influences older adults' walking behavior is vital for promoting physical activity and healthy aging. Among voluminous literature investigating the environmental correlates of walking behaviors of older adults, few have focused on walking duration across different age groups and life stages, let alone examined the potential nonlinearities and thresholds of the built environment.

Methods

This study employs travel diary from Zhongshan, China and the gradient boosting decision trees (GBDT) approach to disentangle the age and retirement status differences in the nonlinear and threshold effects of the built environment on older adults' walking duration.

Results

The results showed built environment attributes collectively contribute 57.37% for predicting older adults' walking duration, with a higher predicting power for the old-old (70+ years) or the retired. The most influencing built environment attribute for the young-old (60-70 years) is bus stop density, whereas the relative importance of population density, bus stop density, and accessibility to green space or commercial facilities is close for the old-old. The retired tend to walk longer in denser-populated neighborhoods with better bus service, but the non-retired are more active in walking in mixed-developed environments with accessible commercial facilities. The thresholds of bus stop density to encourage walking among the young-old is 7.8 counts/km2, comparing to 6 counts/km2 among the old-old. Regarding the green space accessibility, the effective range for the non-retired (4 to 30%) is smaller than that of the retired (12 to 45%).

Discussion

Overall, the findings provide nuanced and diverse interventions for creating walking-friendly neighborhoods to promote walking across different sub-groups of older adults.

Relationship between lower limb muscle activity and cortical activation among elderly people during walking: Effects of fast speed and cognitive dual task

Objective

Gait is a complex behavior that involves not only the musculoskeletal system, but also higher-order brain functions, including cognition. This study was performed to investigate the correlation between lower limb muscle activity and cortical activation during treadmill walking in two groups of elderly people: the young-old (aged 65-74 years) and the old-old (aged 75-84 years).

Methods

Thirty-one young-old and 31 old-old people participated in this study. All participants were sequentially subjected to three gait conditions on a treadmill: (1) comfortable walking, (2) fast walking, and (3) cognitive dual-task walking. During treadmill walking, the activity of the lower limb muscles was measured using a surface electromyography system, and cortical activation was measured using a functional near-infrared spectroscopy system. The correlation between muscle activity and cortical activation during treadmill walking was analyzed and compared between the two groups.

Results

During comfortable walking, lower extremity muscle activity had a strong correlation with cortical activation, especially in the swing phase; this was significantly stronger in the young-old than the old-old. During fast walking, the correlations between lower limb muscle activity and cortical activation were stronger than those during comfortable walking in both groups. In cognitive dual-task walking, cortical activation in the frontal region and motor area was increased, although the correlation between muscle activity and cortical activation was weaker than that during comfortable walking in both groups.

Conclusion

The corticomotor correlation differed significantly between the old-old and the young-old. These results suggest that gait function is compensated by regulating corticomotor correlation as well as brain activity during walking in the elderly. These results could serve as a basis for developing gait training and fall prevention programs for the elderly.

Visuospatial working memory and obstacle crossing in young and older people

Obstacle crossing requires visuospatial working memory to guide the trailing leg trajectory when vision in unavailable. Visuospatial working memory, as assessed with neuropsychological tests, declines with age, however, this remains to be investigated functionally in obstacle crossing. There is also evidence that visuospatial encoding during a secondary task interferes with balance control during stepping and walking in older people. Here, we studied the interaction effects of age by delay (study 1) and age by secondary visuospatial task (study 2) conditions on obstacle clearance in a visuospatial working memory -guided obstacle crossing task. Healthy young adults aged 19 to 36 years (n = 20 in study 1 and n = 17 in study 2) and healthy older adults aged 66 to 83 years (n = 29 in study 1 and n = 21 in study 2) were instructed to step over an obstacle with their leading leg and straddle it for a delay period before completing the crossing with their trailing leg. In study 1, two obstacle height conditions (12 cm, 18 cm) and two delay durations (20 s, 60 s) were presented in random order. In study 2, participants were required to attend to either no secondary task (control), a visuospatial secondary (star movement) task, or a nonspatial secondary (arithmetic) task, while straddling the obstacle for a delay duration of 20 s, at obstacle heights of 12 cm and 18 cm, randomly presented. Trailing leg kinematics (mean and variability of maximum toe clearance over the obstacle) were determined via motion capture. There were no statistically significant age by delay or age by secondary task interactions. In study 1, toe clearance variability was significantly greater in young adults and increased with increasing delay duration in both groups. In study 2, compared with the control condition, toe clearance variability was significantly greater in the non-spatial secondary task condition but not in the visuospatial condition. Contrary to our hypotheses, these findings suggest that young and older adults alike can store an obstacle representation via visuospatial working memory for durations of at least 60 s and use this information to safely scale their trailing leg over an obstacle. However, the increase in trailing leg toe clearance variability with delay duration suggests that obstacle representation starts to deteriorate even within the first 20 s regardless of age. The finding that undertaking a concurrent arithmetic task impaired visuospatial working memory-guided obstacle clearance suggests a potential increased risk of tripping during obstacle crossing while dual-tasking in both young and older people.

Kinematic analysis of speed transitions within walking in younger and older adults

The ability to adapt to environmental and task demands while walking is critical to independent mobility outside the home and this ability wanes with age. Such adaptability requires individuals to acutely change their walking speed. Regardless of age, changes between walking speeds are common in daily life, and are a frequent type of walking adaptability. Here, we report on older and younger adults when transitioning from preferred walking speed overground to either slower or faster walking. Specifically, we evaluated biomechanical parameters prior to, during, and post transition. Individuals approached the walking speed transition similarly, independent of whether the transition was to slower or faster walking. Regardless of age or walking speed, the step during which a walking speed transition occurred was distinct from those prior- and post- transition, with on average 0.15 m shorter step lengths, 3.6° more hip flexion, and 3.3° more dorsiflexion during stance. We also found that peak hip flexion occurred 22% later, and peak hip extension (39%), knee flexion (26%), and dorsiflexion (44%) occurred earlier in stance for both typical to slower and typical to faster walking. Older adults had altered timing of peak joint angles compared with younger adults across both acceleration and deceleration conditions, indicating age-dependent responses to changing walking speed. Our findings are an important first step in establishing values for kinematics during walking speed transitions in younger and typical older adults.

Changes in Cortical Activity during Preferred and Fast Speed Walking under Single- and Dual-Tasks in the Young-Old and Old-Old Elderly

In the elderly, walking while simultaneously engaging in other activities becomes more difficult. This study aimed to examine the changes in cortical activity during walking with aging. We try to reveal the effects of an additional task and increased walking speed on cortical activation in the young-old and the old-old elderly. Twenty-seven young-old (70.2 ± 3.0 years) and 23 old-old (78.0 ± 2.3 years) participated in this study. Each subject completed four walking tasks on the treadmill, a 2 × 2 design; two single-task (ST) walking conditions with self-selected walking speed (SSWS) and fast walking speed (FWS), and two dual-task (DT) walking conditions with SSWS and FWS. Functional near-infrared spectroscopy was applied for measurement of cerebral oxyhemoglobin (oxyHb) concentration during walking. Cortical activities were increased during DT conditions compared with ST conditions but decreased during the FWS compared with the SSWS on the primary leg motor cortex, supplementary motor area, and dorsolateral prefrontal cortex in both the young-old and the old-old. These oxyHb concentration changes were significantly less prominent in the old-old than in the young-old. This study demonstrated that changes in cortical activity during dual-task walking are lower in the old-old than in the young-old, reflecting the reduced adaptive plasticity with severe aging.

Associations Between Physical and Executive Functions Among Community-Dwelling Older Men and Women

Walking is a complex task requiring the interplay of neuromuscular, sensory, and cognitive functions. Owing to the age-related decline in cognitive and physical functions, walking may be compromised in older adults, for cognitive functions, especially poor performance in executive functions, is associated with slow walking speed. Hence, the aim of this study was to investigate the associations between different subdomains of executive functions and physical functions and whether the associations found differ between men and women. Multiple linear regression analysis was performed on data collected from 314 community-dwelling older adults who did not meet physical activity guidelines but had intact cognition. Our results showed that, while executive functions were associated with gait and lower extremity functioning, the associations depended partly on the executive process measured and the nature of the physical task. Moreover, the associations did not differ between the sexes.

Association Between Visual Field Damage and Gait Dysfunction in Patients With Glaucoma

Importance

Gait dysfunction is common in older people with visual impairment and is a major cause of falls.

Objective

To compare 3-year longitudinal changes in gait measures across the spectrum of baseline visual field (VF) damage in glaucoma.

Design, Setting, and Participants

A post hoc analysis was designed on September 1, 2018, following a prospective cohort study, which enrolled older adults with glaucoma or suspected glaucoma from September 2013 to March 2015 and followed up for up to 3 years. Baseline VF damage was defined by integrated VF (IVF) sensitivity and categorized as normal/mild (IVF >28 dB), moderate (IVF, 23-28 dB), and severe (IVF, <23 dB). Each participant walked on an electronic walkway back and forth twice at normal pace each study year. Linear mixed-effects models evaluated longitudinal change in gait outcomes (1) stratified within each VF severity category and (2) across the range of IVF sensitivity. Analysis took place from October 2019 to October 2020.

Main Outcomes and Measures

Three-year changes in 7 gait assessments under usual-pace walking, including base support and its coefficient of variation, stride length and its coefficient of variation, stride velocity and its coefficient of variation, and cadence.

Results

Of 241 participants, the mean (SD) age was 70.8 (7.7) years, 116 (48.2%) were women, and 70 (29.0%) were African American. When comparing longitudinal gait changes over 3 years across the spectrum of IVF sensitivity, each 5-unit (dB) decrement was associated with more rapid declines in stride velocity (-0.05 z score unit/y; 95% CI, -0.09 to -0.01; P = .01) and cadence (-0.07 z score unit/y; 95% CI, -0.10 to -0.03; P < .001). When evaluating gait changes within each glaucoma severity group, shorter stride length was associated with persons with normal/mild (-0.06 z score unit/y; 95% CI, -0.10 to -0.03; P = .001), moderate (-0.08 z score unit/y; 95% CI, -0.12 to -0.04; P < .001), and severe VF damage (-0.16 z score unit/y; 95% CI, -0.24 to -0.07; P < .001), while stride velocity (-0.18 z score unit; 95% CI, -0.28 to -0.07; P = .002) and slower cadence (-0.15 z score unit; 95% CI, -0.25 to -0.04; P = .006) were associated with those with severe VF damage.

Conclusions and Relevance

At worse levels of baseline VF damage, patients with glaucoma in this study demonstrated an exacerbated decline in walking speeds (ie, stride velocity and cadence), indicating that mobility speeds decrease faster over time in older adults with glaucoma.

Metabolic syndrome and the benefit of a physical activity intervention on lower-extremity function: Results from a randomized clinical trial

BACKGROUND

In older adults, increases in physical activity may prevent decline in lower-extremity function, but whether the benefit differs according to metabolic syndrome (MetS) status is uncertain. We aim to investigate whether structured physical activity is associated with less decline in lower-extremity function among older adults with versus without MetS.

METHODS

We used data from the multicenter Lifestyle Interventions and Independence for Elders (LIFE) study to analyze 1535 sedentary functionally-vulnerable women and men, aged 70 to 89 years old, assessed every 6 months (February 2010-December 2013) for an average of 2.7 years. Participants were randomized to a structured, moderate-intensity physical activity intervention (PA; n = 766) or health education program (HE; n = 769). MetS was defined according to the 2009 multi-agency harmonized criteria. Lower-extremity function was assessed by 400-m walking speed and the Short Physical Performance Battery (SPPB) score.

RESULTS

763 (49.7%) participants met criteria for MetS at baseline. Relative to HE, PA was associated with faster 400-m walking speed among participants with MetS (P < 0.001) but not among those without MetS (P = 0.91), although the test for statistical interaction was marginally non-significant (P = 0.07). In contrast, no benefit of PA versus HE was observed on the SPPB score in either MetS subgroup.

CONCLUSIONS

Among older adults at high risk for mobility disability, moderate-intensity physical activity conveys significant benefits in 400-m walking speed but not SPPB in those with, but not without, MetS. The LIFE physical activity program may be an effective strategy for maintaining or improving walking speed among vulnerable older adults with MetS.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01072500.

Regional Gray Matter Density Associated With Fast-Paced Walking in Older Adults: A Voxel-Based Morphometry Study

BACKGROUND

Walking speed during fast-paced walking task has been associated with cognitive function. It is unclear what underlying brain structures are related to fast-paced walking. We investigated the association of gray matter (GM) density with fast-paced walking speed and usual-paced walking speed.

METHODS

We collected data from 284 older adults from a subset of the Health, Aging, and Body composition study (mean age = 83 [SD = 2.8], 58% women, 41% black). Voxel-wise analyses on magnetic resonance imaging data identified regions of the brain where GM density was associated with fast-paced walking speed. We then extracted GM density for all identified regions and modeled the association with fast-paced walking speed after adjusting for demographic factors, clinical factors, and cognitive function. Analyses were repeated for usual-paced walking. Regions with beta coefficients ≥0.3 m/s were considered to be meaningfully correlated.

RESULTS

GM density of clusters from cortical regions in the right middle and superior frontal gyrus, right postcentral gyrus, and left superior temporal gyrus were positively correlated with fast-paced walking speed in adjusted models. Adjustment for cognitive function had little impact on the findings. Caudate was correlated with usual paced walking speed at coefficient ≥0.3 m/s after adjustment of demographic factors and clinical factors, but not after further adjustment of cognitive function.

CONCLUSIONS

Fast-paced walking speed was correlated with GM density of right middle and superior frontal gyrus, right postcentral gyrus, and left superior temporal gyrus, and could potentially provide evidence about subclinical structural change of brain related to aging.

Does dual-tasking provide additional value in timed "up and go" test for predicting the occurrence of falls? A longitudinal observation study by age group (young-older or old-older adults)

BACKGROUND

Previous studies using relatively large samples and longitudinal observational designs reported dual-tasking had additional value in timed "up and go" test (TUG) for falls assessment among well-functioning older adults.

AIM

To elucidate the additional value of dual-tasking in TUG for predicting the occurrence of falls among community-dwelling older adults by age group using a predictive model.

METHODS

This longitudinal observation study included 987 community-dwelling older adults at baseline. A TUG without performing another task (single-TUG) and a TUG while counting aloud backward from 100 were conducted at baseline. We computed the dual-task cost (DTC) value, which is used to quantify trends in subjects' execution of motor tests under dual-task conditions. Data on fall history were obtained using a self-administered questionnaire at the 1-year follow-up. The final analysis included 649 individuals divided into a young-older adult group (aged 60-74 years) and an old-older adult group (aged ≥ 75 years). Associations between the occurrence of falls and TUG-related values were analyzed by age group using multivariate logistic regression models.

RESULTS

For old-older adults, there were significant associations between the occurrence of falls and single-TUG time (odds ratio [OR] 1.143, 95% confidence interval [CI] 1.018-1.285) and DTC value (OR 0.981, 95% CI 0.963-0.999). No significant associations were observed for young-older adults.

CONCLUSIONS

Slower single-TUG time and lower DTC value are associated with the occurrence of falls among old-older adults but not among young-older adults. Dual tasking may provide an additional value in TUG for predicting falls among old-older adults.

Cognitive Motor Dual Task Costs in Older Adults with Motoric Cognitive Risk Syndrome

The purpose of this study was to characterize Cognitive Motor Dual Task (CMDT) costs for a community-based sample of older adults with Motoric Cognitive Risk Syndrome (MCR), as well as investigate associations between CMDT costs and cognitive performance. Twenty-five community-dwelling older adults (ages 60-89 years) with MCR performed single and dual task complex walking scenarios, as well as a computerized cognitive testing battery. Participants with lower CMDT costs had higher scores on composite measures of Working Memory, Processing Speed, and Shifting, as well as an overall cognitive composite measure. In addition, participants with faster single task gait velocity had higher scores on composite measures of Working Memory, Processing Speed, and overall cognition. Taken together, these results suggest that CMDT paradigms can help to elucidate the interplay between cognitive and motor abilities for older adults with MCR.

Effect of an Enriched Protein Drink on Muscle Mass and Glycemic Control during Combined Lifestyle Intervention in Older Adults with Obesity and Type 2 Diabetes: A Double-Blind RCT

Background: Weight loss is key to treatment of older adults with obesity and type 2 diabetes, but also a risk for muscle mass loss. This study investigated whether a whey protein drink enriched with leucine and vitamin D could preserve muscle mass and improve glycemic control during combined lifestyle intervention in this population. Methods: 123 older adults with obesity and type 2 diabetes were randomized into a 13-week lifestyle intervention with dietary advice and exercise, receiving either the enriched protein drink (test) or an isocaloric control (control). Muscle mass was assessed with dual-energy X-ray absorptiometry and glycemic control by oral glucose tolerance test. Statistical analyses were performed using a linear mixed model. Results: There was a nonsignificant increase in leg muscle mass (+0.28 kg; 95% CI, −0.01 to 0.56) and a significant increase in appendicular muscle mass (+0.36 kg; 95% CI, 0.005 to 0.71) and total lean mass (+0.92 kg; 95% CI, 0.19 to 1.65) in test vs. control. Insulin sensitivity (Matsuda index) also increased in test vs. control (+0.52; 95% CI, 0.07 to 0.97). Conclusions: Use of an enriched protein drink during combined lifestyle intervention shows beneficial effects on muscle mass and glycemic control in older adults with obesity and type 2 diabetes.

Effects of a 4-month judo program on gait performance in older adults

BACKGROUND

Falls prevention is a critical goal of training program for older individuals. This study explored the effects of a judo program on gait performance in older adults.

METHODS

Pre- and post-intervention (15 weeks, 1-hr session, twice a week) step length (cm), gait cycle time (s), speed (m·s-1) and cadence (step·min-1) mean values (AVG) and coefficients of variation (CV) were assessed in a judo (JG: N.=16 novice judoka; age=69.3±3.9 years) and a control (CG: N.=14 healthy older adults; age=70.1±4.5 years) group. Two 3 (motor complexity: flat, corridor, hurdling) ×2 (group: JG, CG) ×2 (time: pre, post) MANOVAs with repeated measures were applied to ascertain differences in gait parameters.

RESULTS

A significant Time×Motor Complexity×Group interaction was found for AVG and CV. For AVG, JG showed improvements for flat and hurdling conditions in step length (flat: ∆=+2.6%, d=0.4; hurdling: ∆=+3.2%, d=0.4), gait cycle (flat: ∆=-4.3%, d=0.4; hurdling: ∆=-4.0%, d=0.5), speed (flat: ∆=+6.6%, d=0.7; hurdling: ∆=+6.7%, d=0.6) and cadence (flat: ∆=4.3%, d=0.4; hurdling: ∆=3.9%, d=0.5). For CV, JG improved step length for flat (∆=-20.9%, d=0.6) and hurdling (∆=-16.3%, d=0.8) conditions, whereas CG showed a deterioration in the step length for the corridor condition (∆=+22.3%, d=0.7).

CONCLUSIONS

The findings demonstrated the effectiveness of an adapted judo program for improving gait performance in older individuals, suggesting a potential protective effect for fall risk.

Obstacle Negotiation in Older Adults: Prefrontal Activation Interpreted Through Conceptual Models of Brain Aging

Background and Objectives

The influence of interindividual differences on brain activation during obstacle negotiation and the implications for walking performance are poorly understood in older adults. This study investigated the extent to which prefrontal recruitment during obstacle negotiation is explained by differences in age, executive function, and sex. These data were interpreted according to the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH) framework of brain aging. We also tested the association between prefrontal recruitment and walking performance.

Research Design and Methods

Prefrontal oxygenated hemoglobin concentration (O₂Hb) was measured during typical walking (Typical) and obstacle negotiation (Obstacles) tasks in 50 adults aged 65 years and older using functional near-infrared spectroscopy. The primary outcome was the change in prefrontal recruitment (∆PFR), measured as Obstacles ∆O₂Hb minus Typical ∆O₂Hb. Multiple regression was used to test the relationship between ∆PFR and age, executive function measured by the Trail Making Test, and sex. Pearson's correlation coefficient was used to investigate the association between ∆PFR and the cost of Obstacles walking speed relative to Typical walking.

Results

Age, executive function, and their interaction significantly predicted greater ∆PFR (R ² = 0.34, p = .01). Participants were subgrouped according to age and executive function to examine the interaction effects. Adults of lower age and with lower executive function exhibited greater ∆PFR during Obstacles compared to their peers with higher executive function (p = .03). Adults of advanced age exhibited a ceiling of prefrontal recruitment during obstacle negotiation, regardless of executive function level (p = .87). Greater ∆PFR was significantly associated with a smaller cost of Obstacles (r = 0.3, p = .03).

Discussion and Implications

These findings are consistent with the CRUNCH framework: neural inefficiency where a greater amount of brain activation is needed for task performance at a similar level, compensatory overactivation to prevent a steeper decline in task performance, and capacity limitation with a recruitment ceiling effect.

Comparison of the characteristics of work-related injuries between older workers and the workers of the conventional working-age in the Republic of Korea, 2010-2014

OBJECTIVE

With population ageing, the number of older workers is increasing and the number of work-related injuries in older people is also increasing. Occupational patterns and work-related injury patterns vary with age. This study aimed to compare the incidence and characteristics of work-related injuries in older and younger workers in Korea.

METHODS

We conducted a retrospective review of the characteristics of workers hospitalised with work-related injuries from January 2010 to December 2014, using data from the National Hospital Discharge In-Depth Injury Survey in South Korea. The analysis was stratified by age into older (aged ≥65 years) and younger (aged 20-64 years) workers.

RESULTS

The hospitalisation rate in older workers was double that of younger workers (2014 IRR: 2.06, 95% CI 1.53 to 2.76). Compared with workers of conventional working-age, a higher proportion of injured older workers were female (33.1% vs 13.6%, p<0.001), injured due to falls (40.8% vs 28.5%) and injured while working on a farm (46.5% vs 6.3%, p<0.001). In older workers, work-related injuries were seasonal and peaked during summer, but there was little seasonality in injuries among younger workers.

CONCLUSION

Older workers are more vulnerable to work-related injuries and have a different profile of work-related injuries from younger workers. Age-related differences in the injury profile need to be considered when developing workplace injury prevention policies and programmes, and the specific vulnerabilities of older workers need to be addressed.

Biomechanical influences of gait patterns on knee joint: Kinematic & EMG analysis

Background

As lumbar spinal stenosis commonly occurs between the L2 and L5 segments, hip abductors are easily affected. However, studies regarding the gait pattern in these patients from the coronal plane have not yet been conducted.

Purpose

To determine the effects of lumbar spinal stenosis on the gait pattern (stride width and femorotibial angle) and hip abductor surface electromyography in varied stride widths compared with healthy individuals.

Study design

Prospective case-control study.

Methods

Seventeen patients and 20 healthy individuals were enrolled. Each participant completed three gait assessments in their normal gait, adducted gait and abducted gait. The femorotibial angle and surface electromyography signals were measured. Pain scores was used to quantify the degree of discomfort in the gluteal area and medial side of the knee.

Results

When the hip abductors’ surface electromyography signals were normalized by quadriceps femoris, patients group showed significantly higher activation ratios throughout all gait patterns. Generally, surface electromyography signals and ratios were significantly higher during abducted gait compared with a normal gait. Femorotibial angle became significantly closer to the varus in healthy individuals during abducted gait. When femorotibial angle during normal gait was compared between the two groups, patients group exhibited slightly wider stride width and FTA significantly closer to the varus. Pain scores were significantly higher in the patient group and during abducted gait.

Conclusion

Wider stride widths indicated increased relative activation of the hip abductors, closer proximity between femorotibial angle and varus, and increased pain scores for discomfort. The same tendency was observed in patients group when compared with healthy individuals. Widening of stride width in patients group despite abductor weakness suggests that additional muscle recruitment may be needed to maintain balance. Furthermore, such a distinctive gait pattern exerts increased loading on the medial knee, relating to the escalated risk of degenerative knee osteoarthritis.

Effect of Group Counseling Plus Tailored Exercise on Mobility Function in Multiple Sclerosis

Background

Multiple sclerosis (MS) impairs muscular function and limits individuals' ability to perform everyday activities requiring mobility. People with MS frequently exhibit mobility problems (ie, slower walking speed, shorter strides). General exercise training (eg, resistance, aerobic) provides modest physiological and walking mobility benefits. However, researchers suggest tailoring of interventions to address mobility specifically. We conducted a phase 2a pre-post intervention development study (Obesity-Related Behavioral Intervention Trials [ORBIT] intervention development model) of mobility exercise plus cognitive behavioral counseling to improve function and social cognitions known to encourage exercise.

Methods

The intervention was conducted twice per week for 8 weeks followed by 1 month of self-managed mobility exercise. Participants (N = 29; mean ± SD age = 52.24 ± 11.36 years, mean time since MS diagnosis ≥11 years) were assessed at baseline and after follow-up for mobility function, social cognitions, and intervention fidelity indicators.

Results

Results indicated significant improvements in a variety of valid measures of mobility function (eg, 400-m walk), self-regulatory efficacy for mobility exercise and symptom control, and fidelity measures with small to medium effect sizes.

Conclusions

Positive findings suggest that the intervention seems to merit testing as a randomized pilot study following the ORBIT model.

Assessing gait efficacy in older adults: An analysis using item response theory

BACKGROUND

Assessing confidence in walking in older adults is important, as mobility is a critical aspect of independence and function, and self-report provides complementary information to performance-based measures. The modified Gait Efficacy Scale (mGES) is a self-report measure used to examine confidence in walking.

RESEARCH QUESTION

What are the psychometric properties of the mGES at the item level? Are there opportunities for improvement?

METHODS

We performed a secondary analysis of baseline data from a cluster randomized trial of 424 community-dwelling older adults and reliability data from 123 participants. We fitted a graded response model to dissect the mGES to the item and individual response level and examined opportunities to improve and possible shorten the mGES. We examined psychometric characteristics such as internal consistency, test-retest reliability and construct validity with respect to other relevant measures.

RESULTS

Mobility tasks such as navigating stairs and curbs with separate items for going up and down largely provide the same information on confidence, with downward direction providing slightly more. It may be reasonable to consider removal of walking 1/2 mile, stepping down and/or stair tasks with railings items due to little or duplicate information contributed compared to other items. The shortened scales proposed by removing the above items had similar psychometric properties to mGES.

SIGNIFICANCE

The mGES has good psychometric properties, but can be potentially shortened to substantially reduce responder burden. The upward direction curb and stairs items can be removed to result in a 7-item scale with virtually no loss of desirable psychometrics. An alternative 3-item version, level surface walking, stepping down curb and climbing up stairs without a railing items, entails only a minimal loss in psychometric properties.

The Effect of Age on Gait Speed When Texting

Texting while walking exerts a high cognitive load, and may be a sensitive test of the integrity of the cognitive–motor interface. We aimed to investigate the association between chronological age and gait speed while texting. A convenience sample of 308 community-dwellers was recruited: n ≥ 50 in each age group (20–29, 30–39, 40–49, 50–59) and n = 100 aged ≥60 years. Gait speed was measured over 10 metres under two experimental conditions: 1) walking at usual pace; 2) walking at usual pace while texting the message “Good morning Harry” on their smartphone. Both median gait speed with and without texting decreased with increasing age (p < 0.001). The differences between single- and dual-task gait speed were substantial for each age group and increased after the age of 50 years (p < 0.001). Median gait speeds while texting in people aged 50–59 (1.07 m/s) and ≥60 years (1.00 m/s) were below the recommended minimum for safely crossing roads (1.20 m/s). Texting while walking currently exposes people aged 50 and over to considerable environmental hazards. The significant slowing of gait speed while texting from middle age may be a marker of neurodegeneration, a cohort effect, or an appropriate compensatory response to reduce the risk of injury.

Multimodal Imaging of Brain Activity to Investigate Walking and Mobility Decline in Older Adults (Mind in Motion Study): Hypothesis, Theory, and Methods

Age-related brain changes likely contribute to mobility impairments, but the specific mechanisms are poorly understood. Current brain measurement approaches (e.g., functional magnetic resonance imaging (fMRI), functional near infrared spectroscopy (fNIRS), PET) are limited by inability to measure activity from the whole brain during walking. The Mind in Motion Study will use cutting edge, mobile, high-density electroencephalography (EEG). This approach relies upon innovative hardware and software to deliver three-dimensional localization of active cortical and subcortical regions with good spatial and temporal resolution during walking. Our overarching objective is to determine age-related changes in the central neural control of walking and correlate these findings with a comprehensive set of mobility outcomes (clinic-based, complex walking, and community mobility measures). Our hypothesis is that age-related walking deficits are explained in part by the Compensation Related Utilization of Neural Circuits Hypothesis (CRUNCH). CRUNCH is a well-supported model that describes the over-recruitment of brain regions exhibited by older adults in comparison to young adults, even at low levels of task complexity. CRUNCH also describes the limited brain reserve resources available with aging. These factors cause older adults to quickly reach a ceiling in brain resources when performing tasks of increasing complexity, leading to poor performance. Two hundred older adults and twenty young adults will undergo extensive baseline neuroimaging and walking assessments. Older adults will subsequently be followed for up to 3 years. Aim 1 will evaluate whether brain activity during actual walking explains mobility decline. Cross sectional and longitudinal designs will be used to study whether poorer walking performance and steeper trajectories of decline are associated with CRUNCH indices. Aim 2 is to harmonize high-density EEG during walking with fNIRS (during actual and imagined walking) and fMRI (during imagined walking). This will allow integration of CRUNCH-related hallmarks of brain activity across neuroimaging modalities, which is expected to lead to more widespread application of study findings. Aim 3 will study central and peripheral mechanisms (e.g., cerebral blood flow, brain regional volumes, and connectivity, sensory function) to explain differences in CRUNCH indices during walking. Research performed in the Mind in Motion Study will comprehensively characterize the aging brain during walking for developing new intervention targets.

Assessing physical performance and physical activity in large population-based aging studies: home-based assessments or visits to the research center?

Background

The current study aims to compare correlations between a range of measures of physical performance and physical activity assessing the same underlying construct in different settings, that is, in a home versus a highly standardized setting of the research center or accelerometer recording. We also evaluated the selective attrition of participants related to these different settings and how selective attrition affects the associations between variables and indicators of health, functioning and overall activity.

Methods

Cross-sectional analyses comprising population-based samples of people aged 75, 80, and 85 years living independently in Jyväskylä, Finland. The AGNES study protocol involved the following phases: 1) phone interview (n = 1886), 2) face-to-face at-home interview (n = 1018), 3) assessments in the research center (n = 910), and 4) accelerometry (n = 496). Phase 2 and 3 included walking and handgrip strength tests, and phase 4 a chest-worn and thigh-worn accelerometer estimating physical activity and assessing posture, respectively, for 3–10 days in free-living conditions.

Results

Older people with poorer health and functioning more likely refrained from subsequent study phases, each requiring more effort or commitment from participants. Paired measures of walking speed (R = 0.69), handgrip strength (R = 0.85), time in physical activity of at least moderate intensity (R = 0.42), and time in upright posture (R = 0.30) assessed in different settings correlated with each other, and they correlated with indicators of health, functioning and overall activity. Associations were robust regardless of limitations in health and functioning, and low overall activity.

Conclusions

Correlational analyses did not clearly reveal one superior setting for assessing physical performance or physical activity. Inclusion of older people with early declines in health, functioning and overall activity in studies on physical performance and physical activity is feasible in terms of study outcomes, but challenging for recruitment.

Development of a clinical prediction model for the onset of functional decline in people aged 65-75 years: pooled analysis of four European cohort studies

BACKGROUND

Identifying those people at increased risk of early functional decline in activities of daily living (ADL) is essential for initiating preventive interventions. The aim of this study is to develop and validate a clinical prediction model for onset of functional decline in ADL in three years of follow-up in older people of 65-75 years old.

METHODS

Four population-based cohort studies were pooled for the analysis: ActiFE-ULM (Germany), ELSA (United Kingdom), InCHIANTI (Italy), LASA (Netherlands). Included participants were 65-75 years old at baseline and reported no limitations in functional ability in ADL at baseline. Functional decline was assessed with two items on basic ADL and three items on instrumental ADL. Participants who reported at least some limitations at three-year follow-up on any of the five items were classified as experiencing functional decline. Multiple logistic regression analysis was used to develop a prediction model, with subsequent bootstrapping for optimism-correction. We applied internal-external cross-validation by alternating the data from the four cohort studies to assess the discrimination and calibration across the cohorts.

RESULTS

Two thousand five hundred sixty community-dwelling people were included in the analyses (mean age 69.7 ± 3.0 years old, 47.4% female) of whom 572 (22.3%) reported functional decline at three-year follow-up. The final prediction model included 10 out of 22 predictors: age, handgrip strength, gait speed, five-repeated chair stands time (non-linear association), body mass index, cardiovascular disease, diabetes, chronic obstructive pulmonary disease, arthritis, and depressive symptoms. The optimism-corrected model showed good discrimination with a C statistic of 0.72. The calibration intercept was 0.06 and the calibration slope was 1.05. Internal-external cross-validation showed consistent performance of the model across the four cohorts.

CONCLUSIONS

Based on pooled cohort data analyses we were able to show that the onset of functional decline in ADL in three years in older people aged 65-75 years can be predicted by specific physical performance measures, age, body mass index, presence of depressive symptoms, and chronic conditions. The prediction model showed good discrimination and calibration, which remained stable across the four cohorts, supporting external validity of our findings.

Effectiveness of a muticomponent workout program integrated in an evidence based multimodal program in hyperfrail elderly patients: POWERAGING randomized clinical trial protocol

BACKGROUND

Short-term and mid-term comparison of the efficacy of a multimodal program that incorporates a therapeutic workout program, medication review, diet adjustment and health education, in comparison to the standard medical practice in the improvement of the neuromuscular and physiological condition. Furthermore, it is intended to analyse the maintenance of these effects in a long-term follow-up (12 months) from the onset of the intervention.

METHODS

A randomized clinical trial of elderly frail patients drawn from the Clinical Management Unit "Tiro de Pichón", Health District of Malaga, will be included in the study (after meeting the inclusion / exclusion criteria) will be randomized in two groups: a control group that will undergo an intervention consistent of medication review + diet adjustment + health education (regular workout recommendations within a complete advice on healthy lifestyles) and an experimental group whose intervention will consist of a multimodal treatment: therapeutic workout program+ medication review+ diet adjustment + health education. The sociodemographic, clinical and tracing variables will be reflected at the beginning of the study. In addition, the follow-up variables will be gathered at the second and sixth months after the beginning of the treatment and at the third and sixth months after the treatment (follow-up). The follow-up variables that will be measured are: body mass index, general health condition, fatigue, frailty, motor control, attention- concentration- memory, motor memory, spatial orientation, grip strength, balance (static, semi-dynamic), gait speed and metabolomics. A descriptive analysis of the sociodemographic variables of the participants will be conducted. One-Factor ANOVA will be used for the Within-Subject analysis and as for the Between-Subject analysis, the outcome variables between both the groups in each moment of the data collection will be compared.

DISCUSSION

A multimodal program that incorporates a therapeutic workout program, medication review, diet adjustment and health education may be effective treatment to reduce the functional decline in elderly. The results of the study will provide information on the possible strengths and benefits in multimodal program in elderly.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02772952 registered May 2017.

Moderate Increase in Protein Intake Promotes a Small Additional Improvement in Functional Capacity, But Not in Muscle Strength and Lean Mass Quality, in Postmenopausal Women Following Resistance Exercise: A Randomized Clinical Trial

The aim of this study was to evaluate the effect of a moderate increase in protein intake on muscle strength, functional capacity and lean mass quality improvements in postmenopausal women following resistance exercise. Forty-seven postmenopausal women were randomized in two groups: Normal protein (NP, n = 25), who received a dietary plan containing ~0.8 g protein·kg^-1·d^-1 (recommended dietary allowance-RDA recommendations); and higher protein (HP, n = 22), which a moderate increase in protein intake was recommended (~1.2 g protein·kg^-1·d^-1). Resistance training was performed for 10 weeks, three times/week. Muscle strength (handgrip strength and one repetition maximum test-1-RM), functional capacity and lean mass (LM) quality (muscle strength to lean mass ratio) were evaluated. Dietary intake was assessed by nine 24 h food recalls. After intervention, both groups increased similarly the leg extension 1-RM and handgrip strength. Regarding functional capacity tests, both groups increased the balance test score (SPPB) and 10 m walk test speed, with no differences between the groups. In addition, an increase in speed to perform the 6 min and 400 m walk tests was observed over the time, with an additional improvement in the HP group (time × group interaction; p = 0.007 and p = 0.004, respectively). About LM quality, leg extension 1-RM/leg LM improved over the time in both groups (p = 0.050), with no time × group interaction. All these significant changes had a low effect size. In conclusion, a moderate increase in protein intake promoted a small additional improvement in functional capacity, but it did not induce a greater increase in strength and LM quality after 10 weeks of resistance exercise in postmenopausal women. This trial was registered at ClinicalTrials.gov as NCT03024125.

Contribution of vision and its age-related changes to postural stability in obstacle crossing during locomotion

BACKGROUND

Obstacle crossing requires sufficient toe clearance for trip and fall prevention for which postural stability is a prerequisite. It is thought that the upper visual field plays an important role in the maintenance of postural stability, but its influence and age-dependence have not been investigated yet.

RESEARCH QUESTION

What is the role of the visual fields in maintaining postural stability during crossing an obstacle in young and older adults?.

METHODS

This study included 14 young adults and 14 older adults. The participants, wearing an accelerometer and liquid crystal shutter goggles, were asked to cross an obstacle under the following three conditions (i) full vision; (ii) total visual field occlusion at two steps before the obstacle, and (iii) lower visual field occlusion at two steps before the obstacle. The root mean square ratio in the mediolateral direction (RMSR_ML) for the three sections (i.e., approach to the obstacle, lead limb crossing, and trail limb crossing), as well as the root mean square in the mediolateral direction (RMS_ML) for each section were calculated.

RESULTS

RMS_ML during lead limb crossing was significantly increased in older adults compared to young adults (p < 0.01). There was no significant main effect of visual condition and age group on RMSR_ML for the three steps.

SIGNIFICANCE

The study results suggest postural lateral instability in older adults with poor balance ability during lead limb crossing. Regardless of age, the peripheral visual information appears to contribute minimally to the maintenance of postural lateral stability at least from two steps before the obstacle, when the participants perceived the surrounding environment and the size of the obstacle while approaching it.

Changes in step time variability, not changes in step length and width, are associated with lower-trunk sway during dual-task gait in older adults

Individuals are exposed to repetitive dual-task-like situations in daily life, particularly while walking, and falls among community-dwelling older adults typically occur in such situations. Thus, understanding how individuals adapt their walking-related motion under dual-task conditions is of clinical importance. The present study was conducted to investigate the association between dual-task-related changes (DT-changes) in lower-limb gait parameters and DT-changes in lower-trunk sway. We hypothesized that DT-changes in both spatial- and temporal-lower-limb gait parameters would be associated with DT-changes in lower-trunk sway. Participants were older adults aged > 60 years who lived independently in communities (n = 43, 73.7 [6.1] years old), and younger adults (n = 28, 22.7 [5.1] years old). Participants were asked to walk while performing an additional cognitive task, or with no additional task. During walking, lower-limb gait parameters (step time, step length and width) and lower-trunk sway were measured using a photoelectric cell system and inertial sensors. In older adults, DT-changes in step time variability was significantly associated with DT-changes in lower-trunk sway (standard beta = 0.683, p = 0.003), and DT-changes in lower-trunk sway variability (standard beta = 0.493, p = 0.029). In younger adults, DT-changes in step width were significantly associated with DT-changes in lower-trunk sway (standard beta = 0.395, p = 0.041). The current results partially supported our hypotheses. The association between DT-changes in lower limb and DT-changes in lower-trunk sway varied according to age group.

Middle-Aged Men With HIV Have Diminished Accelerometry-Based Activity Profiles Despite Similar Lab-Measured Gait Speed: Pilot Study

BACKGROUND

People aging with HIV are living with increased risk for functional decline compared with uninfected adults of the same age. Early preclinical changes in biomarkers in middle-aged individuals at risk for mobility and functional decline are needed.

OBJECTIVE

This pilot study aims to compare measures of free-living activity with lab-based measures. In addition, we aim to examine differences in the activity level and patterns by HIV status.

METHODS

Forty-six men (23 HIV+, 23 HIV-) currently in the MATCH (Muscle and Aging Treated Chronic HIV) cohort study wore a consumer-grade wristband accelerometer continuously for 3 weeks. We used free-living activity to calculate the gait speed and time spent at different activity intensities. Accelerometer data were compared with lab-based gait speed using the 6-minute walk test (6-MWT). Plasma biomarkers were measured and biobehavioral questionnaires were administered.

RESULTS

HIV+ men more often lived alone (P=.02), reported more pain (P=.02), and fatigue (P=.048). In addition, HIV+ men had lower blood CD4/CD8 ratios (P<.001) and higher Veterans Aging Cohort Study Index scores (P=.04) and T-cell activation (P<.001) but did not differ in levels of inflammation (P=.30) or testosterone (P=.83). For all participants, accelerometer-based gait speed was significantly lower than the lab-based 6-MWT gait speed (P<.001). Moreover, accelerometer-based gait speed was significantly lower in HIV+ participants (P=.04) despite the absence of differences in the lab-based 6-MWT (P=.39). HIV+ participants spent more time in the lowest quartile of activity compared with uninfected (P=.01), who spent more time in the middle quartiles of activity (P=.02).

CONCLUSIONS

Accelerometer-based assessment of gait speed and activity patterns are lower for asymptomatic men living with HIV compared with uninfected controls and may be useful as preclinical digital biomarkers that precede differences captured in lab-based measures.

Intraclass Correlation Coefficients for Planning Cluster Randomized Trials in Community-Dwelling Older Adults

Objectives: With the emerging trends, more cluster randomized trials will be conducted in older adults, where facilities are randomized rather than individuals. Similarity of individuals from a facility (intraclass correlation coefficient/ICC) plays a critical role, but not readily available. We document ICCs for measures commonly used in community-dwelling older adults and discuss implications. Method: Secondary analysis of a range of baseline measures from the On the Move cluster randomized trial, whose ICCs were computed using a linear mixed model. Results: Self-reported disability measures related to facility characteristics and sense of community had the greatest ICCs (>0.10), while mobility performance measures had 0.05 to 0.10, and cognitive measure 0.11. Discussion: The ICCs for measures commonly used in older adults are of a sufficient magnitude to have a substantial impact on planned sample size of a study and credibility of results, and should be taken into consideration in study planning and data analysis.

Walking while talking: Young adults flexibly allocate resources between speech and gait

BACKGROUND

Walking while talking is an ideal multitask behavior to assess how young healthy adults manage concurrent tasks as it is well-practiced, cognitively demanding, and has real consequences for impaired performance in either task. Since the association between cognitive tasks and gait appears stronger when the gait task is more challenging, gait challenge was systematically manipulated in this study.

OBJECTIVE

To understand how young adults accomplish the multitask behavior of walking while talking as the gait challenge was systematically manipulated.

METHODS

Sixteen young adults (21 ± 1.6 years, 9 males) performed three gait tasks with and without speech: unobstructed gait (easy), obstacle crossing (moderate), obstacle crossing and tray carrying (difficult). Participants also provided a speech sample while seated for a baseline indicator of speech. The speech task was to speak extemporaneously about a topic (e.g. first car). Gait speed and the duration of silent pauses during speaking were determined. Silent pauses reflect cognitive processes involved in speech production and language planning.

RESULTS

When speaking and walking without obstacles, gait speed decreased (relative to walking without speaking) but silent pause duration did not change (relative to seated speech). These changes are consistent with the idea that, in the easy gait task, participants placed greater value on speech pauses than on gait speed, likely due to the negative social consequences of impaired speech. In the moderate and difficult gait tasks both parameters changed: gait speed decreased and silent pauses increased.

CONCLUSION

Walking while talking is a cognitively demanding task for healthy young adults, despite being a well-practiced habitual activity. These findings are consistent with the integrated model of task prioritization from Yogev-Seligmann et al., [1].

The Role of Ethnic and Racial Disparities in Mobility and Physical Function in Older Adults

Objective: To compare estimates of the prevalence of mobility and physical function limitations by race and ethnicity using data from the Medical Expenditure Panel Survey (MEPS). Method: The sample comprised of 28,854 adults aged ≥60 from the MEPS (2004-2013). Physical function (limitations in basic and instrumental activities of daily living [ADL/IADL]) and mobility limitations were assessed by self-report. Results: Non-Hispanic Whites (NHWs) represented the majority of the sample followed by non-Hispanic Blacks (NHBs), Hispanic and non-Hispanic Other (Other). For mobility limitation, NHBs had the highest prevalence followed by NHWs and Hispanics (33.3%, 28.6%, and 26.2%, respectively). Multivariable logistic regression analyses were performed for the primary outcome of mobility limitation. In the adjusted model, Hispanics had lower odds of mobility limitations (prevalence odds ratio [POR]: 0.78; 95% confidence interval [CI] = [0.67,0.91]) compared with NHWs. For ADL limitations, NHBs had higher odds of having ADLs (POR: 1.87; 95% CI = [1.44, 2.44]) when compared with NHWs. Conclusion: This article evaluated the influence of race and ethnicity, on the prevalence of mobility and functional limitations that are not always consistent with expected racial and ethnic differences.

[Cognition and mobility : The influence of the brain on gait]

Cognitive abilities and gait with its physical parameters are important for mobility. There is clinically sound evidence that a reduction of gait speed can be seen as an early subclinical indicator of cognitive decline of even higher risk of onset of dementia. The dual-task paradigm is a method in which the older person has to simultaneously solve two different task. It is of utmost importance to identify older persons at risk of falls or onset of dementia. The dual-task paradigm seems to be an important method in this process.

Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke

BACKGROUND

Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke.

METHODS

Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist scoring of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities-specific Balance Confidence Scale, respectively.

RESULTS

There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks.

CONCLUSION

This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke.

The incidence of sarcopenia among hospitalized older patients: results from the Glisten study

BACKGROUND

New evidence is emerging on the importance of lean body mass during periods of illness and recovery. The preservation of lean body mass during such periods of intense stress impacts both patient and treatment outcomes. However, data concerning the incidence of sarcopenia among older people during hospitalization are scarce. The objective of this study was to evaluate the development of sarcopenia in a sample of hospitalized older subjects.

METHODS

We used data of 394 participants from the multicentre Italian Study conducted by the Gruppo Lavoro Italiano Sarcopenia-Trattamento e Nutrizione (GLISTEN) in 12 Acute Care Wards (Internal Medicine and Geriatrics) of University Hospitals across Italy. This study was designed to determine the prevalence of sarcopenia at hospital admission and the change in muscle mass and strength during hospitalization. Sarcopenia was defined as low skeletal mass index (kg/m² ) along with either low handgrip strength or slow walking speed [European Working Groups on Sarcopenia in Older People (EWGSOP) criteria]. Estimation of skeletal muscle mass was performed by bioelectrical impedance analysis (BIA).

RESULTS

The mean age of the 394 enrolled patients (including 211 females who accounted for 53% of the sample) was 79.6 ± 6.4 years. Among those without sarcopenia at hospital admission, 14.7% of the study sample met the EWGSOP sarcopenia diagnostic criteria at discharge. The incidence of sarcopenia during hospitalization was significantly associated with the number of days spent in bed but was not correlated with the total length of hospital stay. In particular, patients who developed sarcopenia spent an average of 5.1 days in bed compared with 3.2 days for those with no sarcopenia at discharge (P = 0.02). Patients with sarcopenia showed a significantly lower body mass index compared with non-sarcopenic peers (25.0 ± 3.8 kg/m² vs. 27.6 ± 4.9 kg/m² , respectively; P < 0.001). Similarly, the skeletal mass index at admission was significantly lower among patients who developed sarcopenia during hospital stay.

CONCLUSIONS

Incident sarcopenia during hospital stay is relatively common and is associated with nutritional status and the number of days of bed rest.

Effectiveness of a Timing and Coordination Group Exercise Program to Improve Mobility in Community-Dwelling Older Adults: A Randomized Clinical Trial

IMPORTANCE

Timing and coordination exercises may be an important addition to community-based health promotion exercise programs to improve walking in older adults.

OBJECTIVE

To compare the effectiveness of the On the Move group exercise program, which focuses on the timing and coordination of movement, with a seated strength, endurance, and flexibility program (usual care) at improving function, disability, and walking ability of older adults.

DESIGN, SETTING, AND PARTICIPANTS

Cluster-randomized, single-blind intervention trial. Thirty-two independent living facilities, senior apartment buildings, and senior community centers were randomized to On the Move (16 sites; 152 participants) or usual care (16 sites; 146 participants). Participants were 65 years or older, able to ambulate independently with a gait speed of at least 0.60 m/s, able to follow 2-step commands, and were medically stable.

INTERVENTIONS

Exercise classes were 50 minutes, twice a week for 12 weeks and had 10 or fewer participants per class. On the Move consisted of warm-up, timing and coordination (stepping and walking patterns), strengthening, and stretching exercises. The usual-care program consisted of warm-up, strength, endurance, and stretching exercises.

MAIN OUTCOMES AND MEASURES

The primary outcomes were self-report of function and disability (Late Life Function and Disability Instrument) and mobility (6-minute walk distance and gait speed) assessed by blinded individuals.

RESULTS

Participants (mean [SD] age, 80.0 [8.1] years) were mostly female (251 [84.2%]) and white (249 [83.6%]) and had a mean (SD) of 2.8 (1.4) chronic conditions. Intervention groups were similar on baseline characteristics. Postintervention, 142 (93.4%) participants in On the Move and 139 (95.2%) participants in usual care completed testing. On the Move had greater mean (SD) improvements than the usual-care group in gait speed (0.05 [0.13] vs -0.01 [0.11] m/s; adjusted difference = 0.05 [0.02] m/s; P = .002) and 6-minute walk distance (20.6 [57.1] vs 4.1 [55.6] m; adjusted difference = 16.7 [7.4] m; P = .03). Attendance was greater in the usual-care program compared with On the Move (95 [65.1%] vs 76 [50.0%] attended ≥20 classes; P = .03). There were no significant differences in any of the other primary or secondary outcomes.

CONCLUSIONS AND RELEVANCE

The On the Move group exercise program was more effective at improving mobility than a usual-care exercise program, despite lower attendance. Additional research examining the impact of the intervention on long-term disability outcomes is needed before recommending routine implementation into clinical practice.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01986647.

The effects of object height and visual information on the control of obstacle crossing during locomotion in healthy older adults

In order to safely avoid obstacles, humans must rely on visual information regarding the position and shape of the object obtained in advance. The present study aimed to reveal the duration of obstacle visibility necessary for appropriate visuomotor control during obstacle avoidance in healthy older adults. Participants included 13 healthy young women (mean age: 21.5±1.4years) and 15 healthy older women (mean age: 68.5±3.5years) who were instructed to cross over an obstacle along a pressure-sensitive pathway at a self-selected pace while wearing liquid crystal shutter goggles. Participants were evaluated during three visual occlusion conditions: (i) full visibility, (ii) occlusion at T-1 step (T: time of obstacle crossing), and (iii) occlusion at T-2 steps. Toe clearances of both the lead and trail limb (LTC and TTC) were calculated. LTC in the occlusion at T-2 steps condition was significantly greater than that in other conditions. Furthermore, a significant correlation was observed between LTC and TTC in both groups, regardless of the condition or obstacle height. In the older adult group alone, step width in the occlusion at T-2 steps condition increased relative to that in full visibility conditions. The results of the present study suggest that there is no difference in the characteristics of visuomotor control for appropriate obstacle crossing based on age. However, older adults may exhibit increased dependence on visual information for postural stability; they may also need an increased step width when lacking information regarding their positional relationship to obstacles.

Cognitive status, fast walking speed and walking speed reserve-the Gait and Alzheimer Interactions Tracking (GAIT) study

The aims of this study were to (1) determine if older people at their fast walking speed (FWS) are able to reach the speed required at pedestrian crossings (>1.2 m/s) and (2) determine the role of cognitive impairment on the ability to alter speed and walk quickly. Participants were recruited from the Angers Memory Clinic, France. Gait speed was assessed at preferred and FWS using a GAITRite walkway. Walking speed reserve (WSR) was calculated as the difference between FWS and preferred speeds. Participants were classified into cognitive stages (cognitively healthy, mild cognitive impairment, mild and moderate dementia) based on neuropsychological evaluations. The proportion of participants with a FWS of <1.2 m/s was reported. The association between cognitive stage and preferred, fast and walking speed reserve was assessed using multivariable regression, adjusting for covariates. The mean age of the sample (n = 681) was 73.3 (SD 5.8) years. At preferred speed 73.7%, and at FWS 12.8%, of participants had speeds less than 1.2 m/s. Poorer cognitive stage was associated with slower preferred speed (β -0.08, 95% CI -0.10, -0.06), FWS (β -0.13, 95% CI -0.16, -0.10) and also with smaller WSR (m/s) (β -0.05, 95% CI -0.07, -0.03), but not WSR (%) (β -1.73, 95% CI -4.38, 0.93). In older people, worse stages of cognitive impairment were associated with poorer ability to increase speed and walk quickly. Such limitations may result in reduced ability to access the community.

Computerized Dual-Task Testing of Gait and Visuospatial Cognitive Functions; Test-Retest Reliability and Validity

The common occurrence of age decline in mobility and cognition does cause a decrease in the level of physical activity and an increased falls risk. Consequently, dual -task (DT) assessment that simultaneously addresses both mobility skills and cognitive functions are important because, continued difficulties and fall injuries will have a sizable impact in this population. The first objective of the present study was to assess test-retest reliability of a computerized DT treadmill walking protocol and concurrent outcome measures of gait and visuospatial executive function in a group of healthy older adults. Secondly, discriminative validity was evaluated by examining the effect of DT conditions (single task vs. dual-task) on; (a) spatiotemporal gait measures (average and coefficient of variation) and (b) visuomotor and visuospatial executive performance measures. Twenty-five community-dwelling individuals median age 65 (range 61-67) were recruited from a Fitness Facility. Participants performed a computerized visuomotor tracking task and a visuospatial executive game task in standing and while treadmill walking. Testing was conducted on two occasions, 1 week apart. Moderate to high test-retest reliability (ICC values of 0.65-0.88) were observed for spatiotemporal gait variables. No significant differences between the group means were observed between test periods in any gait variable. Moderate test-retest reliability (ICC values of 0.6-0.65) was observed for measures of visuomotor and visuospatial executive performance during treadmill walking. Significant DT effects were observed for both spatiotemporal gait variables and visuospatial executive performance measures. This study demonstrates the reliability and reproducibility of the computer-based assessment tool for dual task treadmill walking. The high to moderate ICC values and the lack of systematic errors in the measures indicate that this tool has the ability to repeatedly record reliable data from community-dwelling older adults. The present computerized dual-task protocols broaden the types of standardized visuomotor and visuospatial executive activities for use with DT treadmill walking that has previously been reported.

Vitamin B12 and Homocysteine Associations with Gait Speed in Older Adults: The Baltimore Longitudinal Study of Aging

OBJECTIVES

This study aimed to assess the independent associations of serum levels of vitamin B12 and plasma concentrations of homocysteine with gait speed decline.

DESIGN, SETTING, PARTICIPANTS

This study utilized longitudinal analysis of participants 50 years or older from The Baltimore Longitudinal Study of Aging, N=774.

MEASUREMENTS

Gait speed (m/s) was assessed using the 6-meter usual pace test. Vitamin B12 and homocysteine concentrations were collected using standard clinical protocols. Linear mixed effects regression was stratified by baseline age category (50-69, 70-79, and ≥80 years old).

RESULTS

Mean follow-up time for the total study sample was 5.4 ± 2.0 years. No association between vitamin B12 and gait speed decline over the follow-up time for any age group was found. Elevated homocysteine concentrations were associated with decline in gait speed after adjustment for covariates (50-69: β= -0.005, p=.057; 70-79: β= -0.013, p<.001, ≥80: β= -0.007, p=.054).

CONCLUSION

Homocysteine and vitamin B12 are inversely related, yet only homocysteine was associated with gait speed decline in this population of healthy older adults. Given these results, future research should be directed towards investigating the relationship in populations with greater variation in vitamin B12 concentrations and other mechanisms influencing homocysteine concentrations.

Effects of Physical-Cognitive Dual Task Training on Executive Function and Gait Performance in Older Adults: A Randomized Controlled Trial

Physical and cognitive training seem to counteract age-related decline in physical and mental function. Recently, the possibility of integrating cognitive demands into physical training has attracted attention. The purpose of this study was to evaluate the effects of twelve weeks of designed physical-cognitive training on executive cognitive function and gait performance in older adults. Thirty-six healthy, active individuals aged 72.30 ± 5.84 years were assigned to two types of physical training with major focus on physical single task (ST) training (n = 16) and physical-cognitive dual task (DT) training (n = 20), respectively. They were tested before and after the intervention for executive function (inhibition, working memory) through Random Number Generation and for gait (walking with/without negotiating hurdles) under both single and dual task (ST, DT) conditions. Gait performance improved in both groups, while inhibitory performance decreased after exercise training with ST focus but tended to increase after training with physical-cognitive DT focus. Changes in inhibition performance were correlated with changes in DT walking performance with group differences as a function of motor task complexity (with/without hurdling). The study supports the effectiveness of group exercise classes for older individuals to improve gait performance, with physical-cognitive DT training selectively counteracting the age-related decline in a core executive function essential for daily living.

Age-Related Differences in Locomotor Strategies During Adaptive Walking

Simultaneous control of lower limb stepping movements and trunk motion is important for skilled walking; adapting gait to environmental constraints requires frequent alternations in stepping and trunk motion. These alterations provide a window into the locomotor strategies adopted by the walker. The authors examined gait strategies in young and healthy older adults when manipulating step width. Anteroposterior (AP) and mediolateral (ML) smoothness (quantified by harmonic ratios) and stepping consistency (quantified by gait variability) were analyzed during narrow and wide walking while controlling cadence to preferred pace. Results indicated older adults preserved ML smoothness at the expense of AP smoothness, shortened their steps, and exhibited reduced stepping consistency. The authors conclude that older adults prioritized ML control over forward progression during adaptive walking challenges.

Different cognitive functions discriminate gait performance in younger and older women: A pilot study

AIM

Cognitive dysfunction is associated with slower gait speed in older women, but whether cognitive function affects gait performance earlier in life has yet to be investigated. Thus, the objective of this study was to test the hypothesis that cognitive function will discriminate gait performance in healthy younger women.

METHODS

Fast-pace and dual-task gait speed were measured in 30 young to middle-aged (30-45y) and 26 older (61-80y) women without mild cognitive impairment. Visuoperceptual ability, working memory, executive function, and learning ability were assessed using neuropsychological tests. Within each age group, women were divided by the median into lower and higher cognitive function groups to compare gait performance.

RESULTS

Younger women with higher visuoperceptual ability had faster fast-pace (2.25±0.30 vs. 1.98±0.18m/s, p≤0.01) and dual-task gait speed (2.02±0.27 vs. 1.69±0.25m/s, p≤0.01) than women with lower visuoperceptual ability. The difference in dual-task gait speed remained significant (p=0.02) after adjusting for age, years of education, and other covariates. Dividing younger women based on other cognitive domains showed no difference in gait performance. In contrast, working memory and executive function discriminated dual-task gait speed (p<0.05) in older women after adjusting for age and education.

CONCLUSION

To our knowledge, this is the first study to show that poorer cognitive function even at a relatively young age can negatively impact mobility. Different cognitive functions discriminated gait performance based on age, highlighting a possible influence of aging in the relationship between cognitive function and mobility in women.

Age-Related Change in Mobility: Perspectives From Life Course Epidemiology and Geroscience

Mobility is the most studied and most relevant physical ability affecting quality of life with strong prognostic value for disability and survival. Natural selection has built the "engine" of mobility with great robustness, redundancy, and functional reserve. Efficient patterns of mobility can be acquired during development even by children affected by severe impairments. Analogously, age-associated impairments in mobility-related physiological systems are compensated and overt limitations of mobility only occur when the severity can no longer be compensated. Mobility loss in older persons usually results from multiple impairments in the central nervous system, muscles, joints, and energetic and sensory physiological systems. Early preclinical changes in these physiological systems that precede mobility loss have been poorly studied. Peak performance, rate of decline, compensatory behaviors, or subclinical deterioration of physiological resources may cumulatively influence both timing of mobility loss and chances of recovery, but their role as risk factors has not been adequately characterized. Understanding the natural history of these early changes and intervening on them would likely be the most effective strategy to reduce the burden of disability in the population. For example, young women with low bone peak mass could be counseled to start strength resistance exercise to reduce their high risk of developing osteoporosis and fracture later in life. Expanding this approach to other physiological domains requires collecting and interpreting data from life course epidemiological studies, establishing normative measures of mobility, physical function, and physical activity, and connecting them with life course trajectories of the mobility-relevant physiological domains.

Impacts of small vestibular schwannoma on community ambulation, postural, and ocular control

OBJECTIVES/HYPOTHESIS

To investigate balance, community mobility, gaze instability, and dizziness handicap and assess falls risk in people who are conservatively managed with small vestibular schwannoma (VS).

STUDY DESIGN

Cross-sectional study with controls.

METHODS

The study involved 18 people (mean age 58.7 ± 12.2 years) diagnosed with VS (<12 mm) and 22 age-matched controls (mean age 56.9 ± 8.0 years). Measures included standing on firm and foam surfaces with feet apart, then together with eyes open and closed, Timed Up and Go (TUG) test and dual TUG test, Dynamic Gait Index, 6-Minute Walk Test, Halmagyi Impulse Test, Dynamic Visual Acuity Test, and the Dizziness Handicap Inventory.

RESULTS

The clinical group failed more trials standing feet together on foam with eyes closed (P < .05); had inferior mobility and walked more slowly with divided attention (P < .05); had more difficulty walking with head movement, negotiating obstacles, and using stairs (P < .01); and walked shorter distances (P < .001) than controls. Reduced gaze stability (P < .01) and higher total (P = .007) and subcategory dizziness handicap scores (P < .05) were revealed compared to age-matched controls.

CONCLUSIONS

Although outcomes for the clinical group are inferior to the control group across all measures and the dizziness impact is higher, the results fall in the low-risk category for falls. Preliminary data (level 4 evidence) support using a suite of clinical measures to monitor people with VS during conservative management.

LEVEL OF EVIDENCE

4 Laryngoscope, 127:1147-1152, 2017.

Assessing Daily Physical Activity in Older Adults: Unraveling the Complexity of Monitors, Measures, and Methods

At the 67th Gerontological Society of America Annual Meeting, a preconference workshop was convened to discuss the challenges of accurately assessing physical activity in older populations. The advent of wearable technology (eg, accelerometers) to monitor physical activity has created unprecedented opportunities to observe, quantify, and define physical activity in the real-world setting. These devices enable researchers to better understand the associations of physical activity with aging, and subsequent health outcomes. However, a consensus on proper methodological use of these devices in older populations has not been established. To date, much of the validation research regarding device type, placement, and data interpretation has been performed in younger, healthier populations, and translation of these methods to older populations remains problematic. A better understanding of these devices, their measurement properties, and the data generated is imperative to furthering our understanding of daily physical activity, its effects on the aging process, and vice versa. The purpose of this article is to provide an overview of the highlights of the preconference workshop, including properties of the different types of accelerometers, the methodological challenges of employing accelerometers in older study populations, a brief summary of ongoing aging-related research projects that utilize different types of accelerometers, and recommendations for future research directions.

Collaborative Evaluation of the Healthy Habits Program: An Effective Community Intervention to Improve Mobility and Cognition of Chinese Older Adults Living in the U.S

OBJECTIVES

There is a growing demand to reduce ethnic health disparities. The Healthy Habits Program (HHP) was implemented to provide a community-based physical activity and education intervention for Chinese older adults living in Boston, Massachusetts. This study evaluated the HHP by assessing outcomes that are critical for maintaining independence of older persons.

DESIGN, SETTING AND PARTICIPANTS

Quantitative evaluation was performed on 50 Chinese older adults enrolled in the HHP. The community members were trained in data collection and management.

MEASUREMENTS

Cognition (Mini Mental State Examination (MMSE), Trail Making Test and Complex Walking Task), mobility (Short Physical Performance Battery (SPPB) and maximal gait speed), depressive symptoms (Patient Health Questionnaire-9), perceived disability (World Health Organization Disability Assessment 2.0), nutritional status (Mini Nutrition Assessment®), and strength (grip and leg strength) were assessed at baseline and at 6 months. All tests were translated into Chinese.

RESULTS

Of the 50 participants (mean age 68.4 years; 68% female), 78% achieved the goal of performing exercise ≥3 times/week. After 6 months, clinically meaningful improvements were observed in mobility (mean SPPB score changed from 10.3 to 11.1 points; p=0.01) and cognition (mean MMSE score changed from 26.0 to 27.8 points; p=0.001). There were also statistically significant improvements in executive function, depressive symptoms and perceived disability (p<0.05).

CONCLUSION

Culturally sensitive community interventions, such as the HHP, are effective for improving mobility and cognition of Chinese older adults. This reveals the potential of promoting successful aging in minority populations through community settings, and should be advocated to reduce ethnic health disparities in the U.S.