To identify the shared neuroimaging signature of gait slowing and cognitive impairment.
We assessed a cohort of older adults (n = 175, mean age 73 years, 57% female, 65% white) with repeated measures ...of gait speed over 14 years, MRI for gray matter volume (GMV) at year 10 or 11, and adjudicated cognitive status at year 14. Gait slowing was calculated by bayesian slopes corrected for intercepts, with higher values indicating faster decline. GMV was normalized to intracranial volume, with lower values indicating greater atrophy for 10 regions of interest (hippocampus, anterior and posterior cingulate, primary and supplementary motor cortices, posterior parietal lobe, middle frontal lobe, caudate, putamen, pallidum). Nonparametric correlations adjusted for demographics, comorbidities, muscle strength, and knee pain assessed associations of time to walk with GMV. Logistic regression models calculated odds ratios (ORs) of gait slowing with dementia or mild cognitive impairment with and without adjustment for GMV.
Gait slowing was associated with cognitive impairment at year 14 (OR per 0.1 s/y slowing 1.47; 95% confidence interval 1.04-2.07). The right hippocampus was the only region that was related to both gait slowing (ρ = -0.16,
= 0.03) and cognitive impairment (OR 0.17,
= 0.009). Adjustment for right hippocampal volume attenuated the association of gait slowing with cognitive impairment by 23%.
The association between gait slowing and cognitive impairment is supported by a shared neural substrate that includes a smaller right hippocampus. This finding underscores the value of long-term gait slowing as an early indicator of dementia risk.
Objective: To examine cross sectional associations between mobility with or without disability and social engagement in a community-based sample of older adults. Methods: Social engagement of ...participants (n = 676) was outside the home (participation in organizations and use of senior centers) and in home (talking by phone and use of Internet). Logistic or proportional odds models evaluated the association between social engagement and position in the disablement process (no mobility limitations, mobility limitations/no disability, and mobility limitations/disability). Results: Low mobility was associated with lower level of social engagement of all forms (Odds ratio (OR) = 0.59, confidence intervals (CI): 0.41-0.85 for organizations; OR = 0.67, CI: 0.42-1.06 for senior center; OR = 0.47, CI: 0.32-0.70 for phone; OR = 0.38, CI: 0.23-0.65 for Internet). For social engagement outside the home, odds of engagement were further reduced for individuals with disability. Discussion: Low mobility is associated with low social engagement even in the absence of disability; associations with disability differed by type of social engagement.
Abstract
Background
Age-related limitations in mobility and decreased physical activity appear to be linked cross-sectionally; however, large-scale, longitudinal analyses of the associations between ...age-related changes in mobility and engagement in physical activity are lacking. In this longitudinal study, we hypothesized that early mobility limitations would contribute to later decreases in physical activity to a larger degree than the reciprocal association of early decreases in physical activity to later mobility limitations.
Methods
Participants were 2,876 initially well-functioning community-dwelling older adults (aged 70–79 years at baseline; 52% women; 39% black) studied over a 9-year period. Usual walking speed and self-reported physical activity (based on minutes per week of walking) were assessed at Years 0 (ie, baseline), 4, and 9. A cross-lagged, longitudinal model assessed the bidirectional associations between walking speed and physical activity over time.
Results
Early change in walking speed between Years 0 and 4 predicted late change in physical activity between Years 4 and 9 (β = .13 p < .001). However, early change in physical activity did not predict late change in walking speed (β = −.01, p = .79). The difference between these two predictive associations was highly significant (p < .001). Associations were independent of baseline demographic and physical health variables, as well as longitudinal changes in grip and quadriceps strength.
Conclusions
The results suggest declining walking speed as a precursor to declining engagement in physical activity, but the converse association was not evident. Improving walking speed may be a method to increase physical activity among elderly individuals.
•Explicit definitions for selected regions of interest are important for replication.•For clinical groups, describe brain lesions and their proximity to fNIRS channels.•Describe software and specific ...processing pipelines used, to ensure reproducibility.•Report on the test-retest reliability of fNIRS data during balance and walking tasks.
Functional near-infrared spectroscopy (fNIRS) is increasingly used in the field of posture and gait to investigate patterns of cortical brain activation while people move freely. fNIRS methods, analysis and reporting of data vary greatly across studies which in turn can limit the replication of research, interpretation of findings and comparison across works.
Considering these issues, we propose a set of practical recommendations for the conduct and reporting of fNIRS studies in posture and gait, acknowledging specific challenges related to clinical groups with posture and gait disorders.
Our paper is organized around three main sections: 1) hardware set up and study protocols, 2) artefact removal and data processing and, 3) outcome measures, validity and reliability; it is supplemented with a detailed checklist.
This paper was written by a core group of members of the International Society for Posture and Gait Research and posture and gait researchers, all experienced in fNIRS research, with the intent of assisting the research community to lead innovative and impactful fNIRS studies in the field of posture and gait, whilst ensuring standardization of research.
It is important to understand the factors associated with life space mobility so that mobility disability can be prevented/treated. The purpose of this study was to identify the association between ...mobility determinants and life space among older adults.
This study was a cross-sectional analysis of 249 community-dwelling older adults (mean age=77.4 years, 65.5% female, 88% white) who were recruited for a randomized, controlled, clinical intervention trial. Associations between cognitive, physical, psychosocial, financial, and environmental mobility determinants and the Life Space Assessment (LSA) at baseline were determined using Spearman's correlation coefficients and one-way analysis of variance. Multivariate analysis was performed using multivariable linear regression models.
The mean LSA score for the sample was 75.3 (SD=17.8). Personal factors (age, gender, education, comorbidities), cognitive (Trail Making Test A and B), physical (gait speed, lower extremity power, Six Minute Walk Test, Figure of 8 Walk Test, tandem stance, energy cost of walking, and Late Life Function and Disability Function Scale), psychosocial (Modified Gait Efficacy Scale), and financial (neighborhood socio-economic status) domains of mobility were significantly associated with LSA score. In the final regression model, age (β=-0.43), lower extremity power (β=0.03), gait efficacy (β=0.19), and energy cost of walking (β=-57.41) were associated with life space (R 2=0.238).
Younger age, greater lower extremity power, more confidence in walking, and lower energy cost of walking were associated with greater life space. Clinicians treating individuals with mobility disability should consider personal, physical, and psychosocial factors assessing barriers to life space mobility.
Background
The fast‐growing population of older Chinese immigrants and their segregated residences highlight the importance of understanding the role of neighborhood context in cognitive health. The ...segregation‐cognition association is equivocal based on a limited number of studies among Hispanic and Asian Americans. To close the knowledge gap, this study examined the associations of neighborhood segregation and socioeconomic status (NSES) with cognitive functioning among older Chinese immigrants.
Methods
Four waves of cognitive performance tests were conducted in the Population Study of Chinese Elderly in Chicago (2011–2019) and linked to the 2010 to 2014 American Community Survey estimates of neighborhood contexts. NSES was a summary z‐score of six census variables of education, income/wealth, and occupation. Neighborhood segregation was measured by the Index of Concentrations at the Extremes (ICE), which simultaneously assesses Chinese and English language use within a given census tract. There were 170 census tracts in the present sample of 2044 participants. Latent growth curve models with adjusted cluster robust standard errors were estimated.
Results
On average, cognitive functioning declined over time (B = −0.07, p < 0.001). After adjusting for individual‐level predictors, living in high‐NSES neighborhoods was associated with slower cognitive decline (B = 0.003, p = 0.04). ICE was not associated with cognitive functioning, but boosted the protective effect of high NSES on cognitive decline (B = 0.006, p = 0.05).
Conclusions
Neighborhood socioeconomic advantage was related to slower cognitive decline among older Chinese immigrants, especially among those living in neighborhoods with more English speakers or less segregation. This finding suggests complex associations between neighborhood context and cognitive health among Chinese immigrants.
Abstract
Background
Objective measures of community mobility are advantageous for capturing movement outside the home. Compared with subjective, self-reported techniques, global positioning system ...(GPS) technologies leverage passive, real-time location data to reduce recall bias and increase measurement precision. We developed methods to quantify community mobility among community-dwelling older adults and assessed how GPS-derived indicators relate to clinical measures of physical and cognitive performance.
Methods
Participants (n = 149; M ± standard deviation SD = 77.1 ± 6.5 years) from the program to improve mobility in aging (PRIMA) study, a physical therapy intervention to improve walking ability, carried a GPS device for 7 days. Community mobility was characterized by assessing activity space, shape, duration, and distance. Associations between GPS-derived indicators and cognition and physical function were evaluated using Spearman correlations.
Results
In adjusted models, a larger activity space, greater duration (eg, time out-of-home), and greater distance traveled from home were correlated with better 6-Minute Walk Test performance (ρ = 0.17–0.23, p’s < .05). A more circular activity shape was related to poorer performance on the Trail Making Test, Part A (ρ = 0.18, p < .05). More time out-of-home and a larger activity space were correlated with faster times on the Trail Making Test, Part B (ρ = −0.18 to −0.24, p’s < .05). Community mobility measures were not associated with global cognition, skilled walking, or usual gait speed.
Conclusion
GPS-derived community mobility indicators capture real-world activity among older adults and were correlated with clinical measures of executive function and walking endurance. These findings will guide the design of future interventions to promote community mobility.
Abstract
Objective
Parkinsonian motor signs are common and disabling in older adults without Parkinson’s disease (PD), but its risk factors are not completely understood. We assessed the influence of ...striatal dopamine levels, cerebral small vessel disease, and other factors on age-related parkinsonian motor signs in non-PD adults.
Methods
Striatal dopamine transporter (DAT) binding was quantified via 11C-CFT positron emission tomography in 87 neurologically intact adults (20–85 years, 57.47% female) with concurrent data on: Unified Parkinson’s Disease Rating Scale motor (UPDRSm), white matter hyperintensities (WMH), and other risk factors (grip strength, vibratory sensitivity, cardio- and cerebro-vascular comorbidities). Sex-adjusted nonparametric models first estimated the associations of age, DAT, WMH, and other factors with UPDRSm; next, interactions of age by DAT, WMH, or other factors were tested. To quantify the influence of DAT, WMH, and other risk factors on the main association of age with UPDRSm, multivariable mediation models with bootstrapped confidence intervals (CI) were used.
Results
Older age, lower DAT, higher WMH, and worse risk factors significantly predicted worse UPDRSm (sex-adjusted p < .04 for all). DAT, but not WMH or other factors, positively and significantly interacted with age (p = .02). DAT significantly reduced the age-UPDRSm association by 30% (results of fully adjusted mediation model: indirect effect: 0.027; bootstrapped 95% CI: 0.0007, 0.074).
Conclusions
Striatal dopamine appears to influence to some extent the relationship between age and parkinsonian signs. However, much of the variance of parkinsonian signs appears unexplained. Longitudinal studies to elucidate the multifactorial causes of this common condition of older age are warranted.
PDF
