Predisability and gait patterns in older adults

Simple Mobility Tests Predict Use of Assistive Devices in Older Adults

BACKGROUND

Assistive devices (ADs) for ambulation are commonly provided to improve safety and independence in older adults. Despite the common use of these devices, there are no standard prescribing guidelines, and non-health care providers, including caregivers and family members, often make decisions about the need for ADs. Identifying factors or a single screening test associated with AD use would benefit clinicians and non-health care caregivers in making decisions to adopt an AD for patients, clients, and family members.

PURPOSE/OBJECTIVES

The purpose of this cross-sectional study was to identify the test that best predicts ADs for ambulation and non-AD use among community-dwelling individuals.

METHODS

Eighty-five older adults (81.6 ± 8.2 years old) who underwent outpatient physical therapy participated in this study. They participated in a series of tests, including the Timed Up and Go, handgrip and quadriceps strength, the 30-second chair-rise test, the 5-m fast gait speed, the Functional Independence Measure, the locomotive syndrome tests (stand-up test, 2-step test [2ST], and the Locomo-5 Checklist), and numeric pain scales. Mann-Whitney U tests were used to identify differences between those who did and did not use an AD for ambulation. Logistic regression analyses were used to examine which test best predicted AD use.

RESULTS

80% of participants (n = 68) used an AD for ambulation. There were significant differences in all test variables between users and nonusers (P = .033 to P < .001), except for quadriceps strength, age, and pain (all P > .05). Only the 2ST was a significant predictor of AD use, with a cutoff distance of the toe-to-toe stride shorter than 93% of body height (sensitivity: 72%, and specificity: 82%, P = .048).

DISCUSSION

Simple functional measures differed between those who did and did not use ADs for ambulation; however, only the 2ST predicted AD status. Individuals who cannot step 93% of their body height may be appropriate for an AD.

CONCLUSIONS

If comprehensive clinical evaluations are not available to make decisions about AD use, the 2ST can be used to make clinical recommendations for an AD for ambulation.

Defining and Measuring Preclinical Mobility Limitation: An Expert Consensus Exercise Informed by a Scoping Review

BACKGROUND

Early change in function in older adults has been termed preclinical disability (PCD). PCD has been understudied compared to other stages of disability because it is unlikely to receive comparative priority in clinical settings. It has major implications for prevention and population health as it may be the optimal time to intervene to prevent further decline. A standardized approach to research in PCD, including a common definition and measurement approaches, is needed to advance this work.

METHODS

The process to establish how PCD should be defined and measured was undertaken in 2 stages: (1) a scoping review of the literature, which was used to inform (2) a web-enabled consensus meeting with content experts.

RESULTS

The scoping review and the consensus meeting support the use of the term preclinical mobility limitation (PCML) and that it should be measured using both patient-reported and performance-based measures. It was agreed that the definition of PCML should include modification of frequency and/or method of task completion, without overt disability, and that requisite mobility tasks include walking (distance and speed), stairs, and transfers.

CONCLUSIONS

Currently, there are few standardized assessments that can identify PCML. PCML is the term that most clearly describes the stage where people experience a change in routine mobility tasks, without a perception of disability. Further evaluation into the reliability, validity, and responsiveness of outcome measures is needed to advance research on PCML.

Visual-somatosensory integration (VSI) as a novel marker of Alzheimer’s disease: A comprehensive overview of the VSI study

Identification of novel, non-invasive, non-cognitive based markers of Alzheimer’s disease (AD) and related dementias are a global priority. Growing evidence suggests that Alzheimer’s pathology manifests in sensory association areas well before appearing in neural regions involved in higher-order cognitive functions, such as memory. Previous investigations have not comprehensively examined the interplay of sensory, cognitive, and motor dysfunction with relation to AD progression. The ability to successfully integrate multisensory information across multiple sensory modalities is a vital aspect of everyday functioning and mobility. Our research suggests that multisensory integration, specifically visual-somatosensory integration (VSI), could be used as a novel marker for preclinical AD given previously reported associations with important motor (balance, gait, and falls) and cognitive (attention) outcomes in aging. While the adverse effect of dementia and cognitive impairment on the relationship between multisensory functioning and motor outcomes has been highlighted, the underlying functional and neuroanatomical networks are still unknown. In what follows we detail the protocol for our study, named The VSI Study, which is strategically designed to determine whether preclinical AD is associated with neural disruptions in subcortical and cortical areas that concurrently modulate multisensory, cognitive, and motor functions resulting in mobility decline. In this longitudinal observational study, a total of 208 community-dwelling older adults with and without preclinical AD will be recruited and monitored yearly. Our experimental design affords assessment of multisensory integration as a new behavioral marker for preclinical AD; identification of functional neural networks involved in the intersection of sensory, motor, and cognitive functioning; and determination of the impact of early AD on future mobility declines, including incident falls. Results of The VSI Study will guide future development of innovative multisensory-based interventions aimed at preventing disability and optimizing independence in pathological aging.

Real-Time Step Length Estimation in Indoor and Outdoor Scenarios

In this paper, human step length is estimated based on the wireless channel properties and the received signal strength indicator (RSSI) method. The path loss between two ankles, called the on-ankle path loss, is converted from the RSSI, which is measured by our developed wearable hardware in indoor and outdoor ambulation scenarios. The human walking step length is estimated by a reliable range of RSSI values. The upper threshold and the lower threshold of this range are determined experimentally. This paper advances our previous step length measurement technique by proposing a novel exponential weighted moving average (EWMA) algorithm to update the upper and lower thresholds, and thus the step length estimation, recursively. The EWMA algorithm allows our measurement technique to process each shorter subset of the dataset, called a time window, and estimate the step length, rather than having to process the whole dataset at a time. The step length is periodically updated on the fly when the time window is "sliding" forwards. Thus, the EWMA algorithm facilitates the step length estimation in real-time. The impact of the EWMA parameter is analysed, and the optimal parameter is discovered for different experimental scenarios. Our experiments show that the EWMA algorithm could achieve comparable accuracy as our previously proposed technique with errors as small as 3.02% and 0.30% for the indoor and outdoor scenarios, respectively, while the processing time required to output an estimation of the step length could be significantly shortened by 53.96% and 60% for the indoor walking and outdoor walking, respectively.

Standard Error of the Mean and Minimal Detectable Change of Gait Speed in Older Adults Using Japanese Long-Term Care Insurance System

Evaluation of motor function, such as gait ability, can accurately predict the subsequent occurrence of disability in older adults. There are no reports of standard error of the mean (SEM) or minimal detectable change (MDC) with respect to gait in Japanese long-term care insurance-certified individuals. The purpose of this study was to investigate the values of preferred gait, fast gait, and the timed up and go (TUG) test. This study included 46 participants using the Japanese long-term care insurance system. (age 86.5 ± 6.6 years, 12 men, 34 women). The duration of three gait were measured twice using a stopwatch. The SEM was 0.07 for preferred gait, 0.09 for fast gait and 2.59 for TUG. The MDC was 0.19 for preferred gait, 0.26 for fast gait, and 7.17 for TUG. The SEM and MDC values of preferred gait, fast gait, and TUG in this study corroborated with those of previous studies, whereas others were different. Considering that gait speed differs with the country, it may be difficult to compare it among different population groups. We obtained the results of gait speed of Japanese long-term care insurance-certified individuals, which is a new finding

The effects of mobile phone use on walking: a dual task study

OBJECTIVES

The aim of this study was to examine the effects of walking at different speeds while using a mobile phone on spatiotemporal stride parameters among young adults. Ten participants (7 male, 3 female; age = 24.7 ± 4.4 years, mean ± 1SD) completed 12 walking trials. Trials consisted of tasks performed at both normal and fast walking speeds-walking only, walking while texting, and walking while talking on a mobile phone. Gait velocity, stride length, cadence, and double support time were computed using data from accelerometers on either shoe.

RESULTS

The effects of distracted walking were not significantly larger when performed at a self-selected fast walking speed compared with a normal walking speed. However, walking while texting produced significant decreases in gait velocity, stride length, and cadence, with a significant increase in double support time at both walking speeds. Moreover texting increased the size of the relative variability of walking, observed through a significant increase in the coefficient of variation of cadence, stride length, and double support time. The observed changes may be suggestive of compromised balance when walking while texting regardless of walking speed. This may place the individual at a greater risk of, slips, trips and falls.

Neural control of postural sway: Relationship to strength measures in young and elderly adults

Age-related changes in postural sway are well-established, and studied from a control perspective using an inverted pendulum model. The purpose of the present work was to expand previous research in this area by investigating relationships between sway-related control parameters and musculoskeletal measures of muscle function and health. Eleven female older adults and eight female young adults completed blood draw, grip, leg extension, and balance tests. Serum levels of skeletal muscle-specific troponin T (sTnT), a biomarker for muscle health, were obtained from blood samples. Maximal grip force and leg extension torque were obtained from dynamometer tests. Center of pressure parameters were derived from force platform records obtained during eyes open and eyes closed balance tests. Sway control parameters were derived from an inverted pendulum model with PID-feedback control. Regression analyses were used to quantify the relationship between model parameters and grip strength, leg strength, and sTnT. Model integral gain (K_i) was observed to significantly predict grip strength in the eyes open condition. In the eyes closed condition, model derivative gain (K_d) was observed to significantly predict sTnT, and both proportional (K_p) and noise (K_n) model gains were observed to significantly predict grip and leg strength measures. Collectively, the relationship between control (K_i, K_d, K_p) and musculoskeletal health (strength, sTnT) parameters suggests a compensation mechanism, which may have served to minimize effects of reduced muscle function on sway amplitude, overshoot, and accuracy. Most associations were observed during eyes closed conditions, suggesting that visual input plays a larger role in regulating balance than the proposed compensation mechanisms. This work highlights the potential use for both strength and sTnT tests as biomarkers for postural control and balance impairment in older adults.

Effect of multimorbidity on gait speed in well-functioning older people: A population-based study in Peru

AIM

To determine the association between multimorbidity and gait speed in a population-based sample of older people without functional dependency.

METHODS

Data were obtained from a previously made cross-sectional population-based study of individuals aged >60 years carried out in San Martin de Porres, the second most populous district in Lima, Peru. We included well-functioning, independent older people. Exclusion criteria emphasized removing conditions that would impair gait. The exposure of interest was non-communicable chronic disease multimorbidity, and the outcome was gait speed determined by the time required for the participant to walk a distance of 8 m out of a total distance of 10 m. Generalized linear models were used to estimate adjusted gait speed by multimorbidity status.

RESULTS

Data from 265 older adults with a median age of 68 years (IQR 63-75 years) and 54% women were analyzed. The median gait speed was 1.06 m/s (SD 0.27) and the mean number of chronic conditions per adult was 1.1 (SD ±1). The difference in mean gait speed between older adults without a chronic condition and those with ≥3 chronic conditions was 0.24 m/s. In crude models, coefficients decreased by a significant exponential factor for every increase in the number of chronic conditions. Further adjustment attenuated these estimates.

CONCLUSIONS

Slower speed gaits are observed across the spectrum of multimorbidity in older adults without functional dependency. The role of gait speed as a simple indicator to evaluate and monitor general health status in older populations is expanded to include older adults without dependency. Geriatr Gerontol Int 2018; 18: 293-300.

Gait disorders in the elderly and dual task gait analysis: a new approach for identifying motor phenotypes

BACKGROUND

Gait disorders and gait analysis under single and dual-task conditions are topics of great interest, but very few studies have looked for the relevance of gait analysis under dual-task conditions in elderly people on the basis of a clinical approach.

METHODS

An observational study including 103 patients (mean age 76.3 ± 7.2, women 56%) suffering from gait disorders or memory impairment was conducted. Gait analysis under dual-task conditions was carried out for all patients. Brain MRI was performed in the absence of contra-indications. Three main gait variables were measured: walking speed, stride frequency, and stride regularity. For each gait variable, the dual task cost was computed and a quartile analysis was obtained. Nonparametric tests were used for all the comparisons (Wilcoxon, Kruskal-Wallis, Fisher or Chi2 tests).

RESULTS

Four clinical subgroups were identified: gait instability (45%), recurrent falls (29%), memory impairment (18%), and cautious gait (8%). The biomechanical severity of these subgroups was ordered according to walking speed and stride regularity under both conditions, from least to most serious as follows: memory impairment, gait instability, recurrent falls, cautious gait (p < 0.01 for walking speed, p = 0.05 for stride regularity). According to the established diagnoses of gait disorders, 5 main pathological subgroups were identified (musculoskeletal diseases (n = 11), vestibular diseases (n = 6), mild cognitive impairment (n = 24), central nervous system pathologies, (n = 51), and without diagnosis (n = 8)). The dual task cost for walking speed, stride frequency and stride regularity were different among these subgroups (p < 0.01). The subgroups mild cognitive impairment and central nervous system pathologies both showed together a higher dual task cost for each variable compared to the other subgroups combined (p = 0.01). The quartile analysis of dual task cost for stride frequency and stride regularity allowed the identification of 3 motor phenotypes (p < 0.01), without any difference for white matter hyperintensities, but with an increased Scheltens score from the first to the third motor phenotype (p = 0.05).

CONCLUSIONS

Gait analysis under dual-task conditions in elderly people suffering from gait disorders or memory impairment is of great value in assessing the severity of gait disorders, differentiating between peripheral pathologies and central nervous system pathologies, and identifying motor phenotypes. Correlations between motor phenotypes and brain imaging require further studies.

Gait shows a sex-specific pattern of associations with daily functioning in a community-dwelling population of older people

BACKGROUND

Gait is increasingly considered an important indicator of health. Yet, little is known on the relation of gait with established health indicators, e.g. daily functioning. Although gait differs by sex, it is unknown whether different gait domains provide different health indicators in men or women. We investigated how gait associates with basic and instrumental activities of daily living (BADL and IADL) in community-dwelling persons.

METHODS

In 2500 participants of the population-based Rotterdam Study (aged ≥ 50 yrs), gait was assessed by electronic walkway and summarized into seven independent gait domains: Pace, Rhythm, Phases, Tandem, Turning, Variability, Base of Support, which were averaged into Global Gait. We assessed BADL with the disability index of the Stanford Health Assessment Questionnaire and IADL with the Instrumental Activities of Daily Living scale. BADL and IADL were analyzed as continuous scores, and dichotomised: with impairment defined as moderate to very severe disability.

RESULTS

In men, Global Gait, Pace, and Rhythm associated with BADL in linear analyses. In contrast, all domains except Base of Support associated with BADL or IADL in women. Associations of Global Gait and Phases with BADL were significantly stronger in women (p-interaction < 0.05). Similarly, associations of Global Gait, Rhythm, and Phases with IADL were stronger in women (p-interaction < 0.05). For dichotomised analyses, higher Global Gait, Pace, and Rhythm associated with less BADL-impairment in men, while Global Gait associated with less BADL and IADL-impairment in women.

CONCLUSIONS

In men, Pace and Rhythm may suffice as health indicators, while women may require comprehensive gait assessment to better estimate their health status.

Age-related decline in divided-attention: from theoretical lab research to practical real-life situations

The purpose of this advanced review is to provide readers with an up-to-date synopsis of age-related changes in divided-attention abilities. An interdisciplinary approach is taken, supplying readers with evidence from very structured laboratory studies and findings from more ecological research studies that target real-life divided-attention situations (i.e., walking and talking). The review goes beyond the reported age-related declines in divided-attention abilities and offers the reader an overview of current cognitive (dual-task) training findings which suggest that these declines can be diminished with training. The contents of this review and the future directions proposed demonstrate that divided-attention research and its recent application to aging and mobility has become a major and fast growing scientific field of investigation. WIREs Cogn Sci 2013, 4:623-640. doi: 10.1002/wcs.1252 CONFLICT OF INTEREST: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.

Role of APOE genotype in gait decline and disability in aging

OBJECTIVES

Although apolipoprotein E (APOE) genetic variation may influence risk of gait decline and disability in aging through multiple mechanisms, a systematic examination of this relationship has been lacking. Our objective was to quantify the risk of gait decline and disability associated with the APOE ε4 allele in aging.

METHODS

We evaluated 627 community-dwelling adults aged 70 and older (white 67.8%) with APOE genotype and quantitative gait measurements participating in the Einstein Aging Study over a median follow-up of 3.0 years. Main outcomes were gait speed decline (cm/s/year) and incident disability.

RESULTS

APOE ε4 allele frequency was 24.1%. Presence of APOE ε4 was not significantly associated with gait speed decline overall (p = .37) but was associated with faster gait speed decline in older men (estimate: -1.16, 95% CI: -2.31 to -0.01, p = .04). The interaction between the ε4 allele and male sex predicted gait speed decline (estimate: -1.70, 95% CI: -3.33 to -0.07, p = .04). Presence of the APOE ε4 allele was associated with increased risk of disability in older men (HR 3.72, 95% CI: 1.44-9.59, p = .007). Associations of the ε4 allele with study outcomes remained significant even after accounting for several potential confounders including vascular and cognitive status. The strength of the associations was stronger in the white subgroup.

CONCLUSION

This preliminary report suggests that the APOE ε4 allele is associated with increased risk of gait speed decline and disability in older men.

Using a body-fixed sensor to identify subclinical gait difficulties in older adults with IADL disability: maximizing the output of the timed up and go

Objective

The identification and documentation of subclinical gait impairments in older adults may facilitate the appropriate use of interventions for preventing or delaying mobility disability. We tested whether measures derived from a single body-fixed sensor worn during traditional Timed Up and Go (TUG) testing could identify subclinical gait impairments in community dwelling older adults without mobility disability.

Methods

We used data from 432 older adults without dementia (mean age 83.30±7.04 yrs, 76.62% female) participating in the Rush Memory and Aging Project. The traditional TUG was conducted while subjects wore a body-fixed sensor. We derived measures of overall TUG performance and different subtasks including transitions (sit-to-stand, stand-to-sit), walking, and turning. Multivariate analysis was used to compare persons with and without mobility disability and to compare individuals with and without Instrumental Activities of Daily Living disability (IADL-disability), all of whom did not have mobility disability.

Results

As expected, individuals with mobility disability performed worse on all TUG subtasks (p<0.03), compared to those who had no mobility disability. Individuals without mobility disability but with IADL disability had difficulties with turns, had lower yaw amplitude (p<0.004) during turns, were slower (p<0.001), and had less consistent gait (p<0.02).

Conclusions

A single body-worn sensor can be employed in the community-setting to complement conventional gait testing. It provides a wide range of quantitative gait measures that appear to help to identify subclinical gait impairments in older adults.

A velocidade da marcha pode identificar idosos com medo de cair?

OBJETIVO: Este estudo teve como propósito analisar a capacidade da velocidade da marcha em identificar idosos com medo de cair. METODOLOGIA: Trata-se de estudo transversal analítico, realizado com amostra de 60 idosos da comunidade. Os dados foram obtidos por meio de questionário estruturado, análise da velocidade da marcha para percorrer a distância de 4,6 m e do medo de cair, avaliado pela escala de Autoeficácia de Quedas. A capacidade da velocidade da marcha em identificar idosos com medo de cair foi determinada por meio de regressão linear múltipla, com nível de significância p<0,05 e IC 95%. RESULTADOS: Em relação à velocidade da marcha, a média foi de 0,71 (± 0,21) m/s, enquanto que para a escala de Autoeficácia de Quedas a média do escore foi de 24,85 (± 6,68). Na análise de regressão linear múltipla, o escore total da escala de Autoeficácia de Quedas permaneceu significativamente associado (R²= 0,35) com a depressão autorrelatada, a limitação funcional para atividades básicas da vida diária e a velocidade da marcha. CONCLUSÃO: A velocidade da marcha, além da depressão autorrelatada e limitação funcional para atividades básicas da vida diária, têm capacidade de identificar idosos com medo de cair. Desta forma, a investigação das condições de saúde nessa população pode ser útil para detectar o medo de cair e identificar que cuidados e intervenções seriam prioritários para melhorar a funcionalidade e qualidade de vida desses idosos.

High-sensitivity C-reactive protein and mobility disability in older adults

OBJECTIVE

to determine the association of high sensitivity C-reactive protein (HsCRP) levels with a risk of mobility disability and decline in older adults with and without vascular disease.

DESIGN

prospective cohort.

SETTING

community-residing population.

SUBJECTS

six hundred and twenty-four adults age 70 and older (62% women) with gait and HsCRP assessments.

MAIN OUTCOME MEASURES

incident mobility disability (velocity <70 cm/s) and annual rates of decline on gait velocity.

RESULTS

elevated HsCRP levels (≥ 3 mg/l) at baseline present in 224 of the 624 eligible subjects was associated with a faster annual decline in gait velocity of 0.91 cm/s (P=0.02). Subjects with elevated HsCRP levels had increased risk of mobility disability (hazard ratio: 1.85, 95% CI: 1.09-3.14). Each one-unit increase in log HsCRP levels in the 406 subjects without prevalent mobility disability was associated with increased risk of mobility disability (hazard ratio: 1.33, 95% CI: 1.05-1.68). The association of baseline HsCRP levels with mobility disability and decline was stronger in the 224 individuals without vascular disease. The associations were not significant in the 400 subjects with vascular disease.

CONCLUSIONS

HsCRP levels predict mobility disability and accelerated decline in walking speed in older adults. These associations were stronger in those without vascular disease.

Effect of treadmill training on specific gait parameters in older adults with frailty: case series

BACKGROUND AND PURPOSE

Treadmill-walking training (TWT) as an intervention to improve the gait of frail older adults has not been well studied. In this pilot study, we describe the feasibility, tolerance, and effect of TWT on specific gait parameters during overground walking in 4 frail older adults as a prelude to developing larger-scale exercise intervention trials in this high-risk population.

CASE DESCRIPTION

Four community-residing frail older individuals (age > 70 years) with Mini-Mental State Examination score of 26 or higher and no activity limitations. Frailty was defined as the presence of at least 3 of the following 5 attributes: slow gait (<1 m/s); unintentional weight loss (>10 lb in prior year); self-report of poor grip strength; exhaustion; and low level of physical activity.

INTERVENTION

The TWT consisted of 24 sessions (3 times per week for 8 weeks). Five quantitative gait parameters (velocity, stride length, swing time, percentage of double support phase, and coefficient of variation [COV] of stride length) during overground walking were measured at baseline, weekly during training, and immediately post-TWT.

OUTCOME

All participants tolerated TWT without significant complications. Following TWT, gait velocity increased in all participants by 6.4 to 26.8 cm/s, which was larger than the reported value for meaningful change in gait velocity (4 cm/s). Stride length and double support phase also showed improvement in all participants (mean percentage increase of 10.8% for stride length and 17.1% reduction for double support phase posttraining compared with baseline). Swing time improved in 3 participants (mean reduction of 4.5%). The COV of stride length did not show consistent improvement.

DISCUSSION

This case series shows that TWT is feasible and well tolerated by frail older adults and may improve most gait parameters in this high-risk population.

Inflammatory markers and gait speed decline in older adults

BACKGROUND

Increased inflammatory activity and gait speed decline are common with aging, but the association between the two is not well established. The objective of this study was to determine the influence of inflammatory markers, interleukin-6 (IL-6), and tumor necrosis factor alpha, on gait speed performance and decline in older adults.

METHODS

We conducted cross-sectional and longitudinal analyses of 333 adults aged 70 and older (61% women) with gait and biomarker assessments identified from participants in the Einstein Aging Study, a community-based aging study. Gait velocity measured at baseline and annual follow-up visits (median follow-up 2.3 years) was the main outcome.

RESULTS

At baseline, higher interleukin-6 levels were associated with slower gait velocity (estimate -4.90 cm/s, p = .008). Adjusted for age, gender, education, and medical illnesses, a one-unit increase in baseline log IL-6 levels was associated with a 0.98 cm/s faster gait speed decline per year (p = .002). The results remained significant after adjustments for additional potential confounders such as physical activity levels, body mass index, and medications. Participants in the highest IL-6 quartile had a 1.75 cm/s/year faster decline in gait velocity compared with those in the lowest quartile (p = .002). Tumor necrosis factor alpha was not associated with gait velocity at cross-section or with gait speed decline.

CONCLUSIONS

IL-6 levels are associated with gait performance in community residing seniors and predicts risk of gait speed decline in aging.