The aim of this study was to develop alternate forms of the walking while talking (WWT) dual task, and to determine whether beginning the WWT in mid-alphabet vs. at the beginning of the alphabet, affects task outcomes. Alternate test forms help reduce practice effects leading to more precise estimates of change over time. We conducted a cross-sectional study in 145 community-residing older adults (mean age, 79.2 ± 6.8 y) without dementia or depression. Subjects performed four WWT trials with a different initial letter (a, b, m or n). There were no differences in velocity, correct letters, or errors on WWT trials beginning at shared points in the alphabet (`a' compared to `b' and `m' compared to `n'). However, trials initiating with letters from the beginning of the alphabet compared to mid-alphabet showed significant differences (with higher number of correct letters and fewer errors for `a' and `b' trials) but not for velocity. Thus, starting WWT in mid-alphabet is different from starting at the beginning of the alphabet. Alternate forms of the WWT with two separate initial letters from a shared point of the alphabet (specifically `a' and `b' or `m' and `n') may be used upon repeated administration to reduce practice effects.
Dual task; Alternate forms; Practice effects; Elderly; Walking
The current study critically assessed the relationship between cognitive functions and gait in nondemented older adults. Quantitative measures of gait (velocity, cadence, and a coefficient of variance in stride length) were assessed in single and dual-task conditions. Three cognitive factors captured the domains of Executive Attention, Verbal IQ, and Memory. Linear regressions showed that Executive Attention was related to velocity in both walking conditions. However, Memory and Verbal IQ were also related to velocity. Memory was related to Cadence in both walking conditions. Executive Attention was related to the coefficient of variance in stride length in both walking conditions. Linear mixed effects models showed that dual-task costs were largest in velocity followed by cadence and the coefficient of variance in stride length. The relationship between cognitive functions and gait depends, in part, on the analytic approach used, gait parameters assessed, and walking condition.
gerontology; motor control; aging
Stimuli are processed concurrently and across multiple sensory inputs. Here we directly compared the effect of multisensory integration (MSI) on reaction time across three paired sensory inputs in eighteen young (M=19.17 yrs) and eighteen old (M=76.44 yrs) individuals. Participants were determined to be non-demented and without any medical or psychiatric conditions that would affect their performance. Participants responded to randomly presented unisensory (auditory, visual, somatosensory) stimuli and three paired sensory inputs consisting of auditory-somatosensory (AS) auditory-visual (AV) and visual-somatosensory (VS) stimuli. Results revealed that reaction time (RT) to all multisensory pairings was significantly faster than those elicited to the constituent unisensory conditions across age groups; findings that could not be accounted for by simple probability summation. Both young and old participants responded the fastest to multisensory pairings containing somatosensory input. Compared to younger adults, older adults demonstrated a significantly greater RT benefit when processing concurrent VS information. In terms of co-activation, older adults demonstrated a significant increase in the magnitude of visual-somatosensory co-activation (i.e., multisensory integration), while younger adults demonstrated a significant increase in the magnitude of auditory-visual and auditory-somatosensory co-activation. This study provides first evidence in support of the facilitative effect of pairing somatosensory with visual stimuli in older adults.
Multisensory Integration; Cross-Modal; Sensory Processing; Aging
To establish reference values for stair ascent and descent times in community dwelling ambulatory older adults, and to examine their predictive validity for functional decline.
Longitudinal cohort study. Mean follow-up time was 1.8 year (maximum 3.2 y, total 857.9 person-years).
Older adults age 70 and older (N=513; mean age, 80.8±5.1y), without disability or dementia.
Main Outcome Measures
Time to ascend and descend 3 steps measured at baseline. 14 point Disability scale assessed functional status at baseline and at follow-up interviews every 2–3 months. Functional decline was defined as an increase in the disability score by 1-point during the follow-up period.
The mean ± standard deviation (SD) stair ascent and descent time for three steps was 2.78 ±1.49 and 2.83 ±1.61 sec respectively. The proportion of self-reported and objective difficulty was higher with longer stair ascent and descent times (P<.001 for trend for both stair ascent and descent). Of the 472 participants with at least one follow-up interview, 315 developed functional decline with a 12-month cumulative incidence of 56.6% (95% confidence interval, CI, 52.1–61.3%). The stair negotiation time was a significant predictor of functional decline after adjusting for covariates including gait velocity (adjusted hazard ratio per one-second increase, aHR 1.12, 95% CI 1.04–1.21 for stair ascent time, aHR 1.15, 95% CI 1.07–1.24 for stair descent time). Stair descent time was a significant predictor of functional decline among relatively high-functioning older adults reporting no difficulty in stair negotiation (P=.001).
The stair ascent and descent times are simple, quick, and valid clinical measures for assessing the risk of functional decline in community dwelling older adults including high-functioning individuals.
Rehabilitation; Activities of daily living; Aged
The current study examined the relationship between cognitive function and falls in elders who did not meet criteria for dementia or Mild Cognitive Impairment (n=172). To address limitations of previous research, associations between cognitive function and falls controlled for the confounding effects of gait measures and other risk factors. A neuropsychological test battery was submitted to factor analysis yielding three orthogonal factors (verbal IQ, Speed/Executive Attention, Memory). Single and recurrent falls within the last 12 months were evaluated. We hypothesized that Speed/Executive Attention would be associated with falls. Additionally, we assessed whether associations between different cognitive functions and falls varied depending on whether single or recurrent falls were examined. Multivariate logistic regressions showed that worse scores on Speed/Executive Attention were associated with increased single and recurrent falls. Worse scores on Verbal IQ were related only to increased recurrent falls. Memory was not associated with either single or recurrent falls. These findings are relevant to risk assessment and prevention of falls, and point to possible shared neural substrate of cognitive and motor function.
cognition; falls; aging
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.
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.
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.
IL-6 levels are associated with gait performance in community residing seniors and predicts risk of gait speed decline in aging.
Mobility; Gait; Inflammation—Interleukin-6
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 four frail older adults as a prelude to developing larger scale exercise intervention trials in this high-risk population.
Four community-residing frail older individuals (age>70) with Mini-Mental Status Examination score of 26 or higher and no activity limitations. Frailty was defined as presence of at least three out of the following five attributes: slow gait (<1 m/sec), unintentional weight loss (>10 lbs in prior year), self-report of poor grip strength, exhaustion, and low level of physical activity.
TWT consisted of 24 sessions (3 times/week for 8 weeks). Five quantitative gait parameters [velocity, stride length, swing time, percentage of double support phase, coefficient of variation (COV) of stride length] during overground walking were measured at baseline, weekly during training, and immediately post-TWT.
All participants tolerated TWT without significant complications. Following TWT, gait velocity increased in all participants by 6.4 to 26.8 cm/sec, which was larger than the reported value for meaningful change in gait velocity (4 cm/sec). 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 post training compared to baseline). Swing time improved in three participants (mean reduction of 4.5 %). The COV of stride length did not show consistent improvement.
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.
gait; exercise; frail older adults; rehabilitation
Evidence suggests that gait is influenced by higher order cognitive and cortical control mechanisms. However, less is known about the functional correlates of cortical control of gait.
Using functional near-infrared spectroscopy, the current study was designed to evaluate whether increased activations in the prefrontal cortex (PFC) were detected in walking while talking (WWT) compared with normal pace walking (NW) in 11 young and 11 old participants. Specifically, the following two hypotheses were evaluated: (a) Activation in the PFC would be increased in WWT compared with NW. (b) The increase in activation in the PFC during WWT as compared with NW would be greater in young than in old participants.
Separate linear mixed effects models with age as the two-level between-subject factor, walking condition (NW vs WWT) as the two-level repeated within-subject factor, and HbO2 levels in each of the 16 functional near-infrared spectroscopy channels as the dependent measure revealed significant task effects in 14 channels, indicating a robust bilateral increased activation in the PFC in WWT compared with NW. Furthermore, the group-by-task interaction was significant in 11 channels with young participants showing greater WWT-related increase in HbO2 levels compared with the old participants.
This study provided the first evidence that oxygenation levels are increased in the PFC during WWT compared with NW in young and old individuals. This effect was modified by age suggesting that older adults may underutilize the PFC in attention-demanding locomotion tasks.
Cognition; Gait; fNIRS
To investigate the incidence of fear of falling (FOF) and the risk factors associated with transient versus persistent FOF in community-dwelling older adults.
Prospective cohort study.
Bronx County, New York.
Three hundred eighty participants without FOF at baseline in the Einstein Aging Study aged 70 and older.
FOF was assessed at baseline and during follow-up interviews at 2- to 3-month intervals for a minimum 2 years. Incident FOF was classified as transient or persistent FOF. Transient FOF was defined as new-onset FOF reported at only one interview, and persistent FOF was FOF reported at two or more interviews over a 2-year period.
Twenty-four-month cumulative incidence of incident FOF was 45.4%, with 60.0% of FOF being persistent. Predictors of incident FOF included female sex (adjusted hazard ratio (aHR) = 1.55, 95% confidence interval (CI) = 1.08–2.23), depressive symptoms (aHR = 1.16, 95% CI = 1.07–1.26), falls (aHR = 1.50, 95% CI = 1.01–2.21), and clinical gait abnormality (aHR = 2.07, 95% CI = 1.42–3.01). The proportion of participants with incident FOF increased linearly with increasing number of risk factors. Predictors for transient and persistent FOF were depressive symptoms and clinical gait abnormality. Female sex and previous falls were predictors of persistent but not transient FOF.
FOF status in older adults may change over time, with shared and distinct risk factors for persistent and transient FOF. Understanding the dynamic nature of FOF and these risk factors will help identify high-risk groups and design future intervention studies.
fear of falling; risk factors; older adults
To examine the ability of clinic based assessments of gait speed to capture limitations in a broad range of home and community based activities.
Community based aging cohort study
655 community residing individuals (61% women) who were age 70 and older (mean 80.4 years).
Main outcome measures
Limitations on three gait related activities of daily living (walking inside home and climbing up and down stairs) and six motor based but gait independent activities (bathing, dressing, getting up from a chair, toileting, shopping, and using public transportation).
Gait speed was associated with presence of self-reported difficulty on all three home based activities that were directly gait related and in 5 out of the 6 motor based activities. Gait speed of ≤1 m/sec was associated with increased risk of limitations on at least one out the nine selected activities (odds ratio 3.21, 95% CI 2.24 to 4.58, p <0.001).
Gait speed measured in clinical settings has ecological validity as a clinical marker of functional status in older adults for use in clinical and research settings.
gait speed; elderly; activities of daily living; screening
Presence of performance inconsistency during repeated assessments of gait may reflect underlying subclinical disease, and help shed light on the earliest stages of disablement. We studied inter-session fluctuations on three selected gait measures (velocity, stride length, and stride length variability) during normal pace walking as well as during a cognitively demanding ‘walking while talking’ condition using a repeated measurement burst design (six sessions within a 2-week period) in 71 nondisabled and nondemented community residing older adults, 40 with predisability (does activities of daily living unassisted but with difficulty). Subjects with predisability had slower gait velocity and shorter stride length on both the normal and walking while talking conditions at baseline compared to nondisabled subjects. However, there was no significant pattern of fluctuations across the six sessions on the three selected gait variables comparing the two groups during normal walking as well as on the walking while talking conditions. Our findings support consistency of gait measurements during the earliest stages of disability.
gait; elderly; measurement; variability; disability
We examined the effect of cognitive fatigue on the Attention Networks Test (ANT). Participants were 228 non-demented older adults. Cognitive fatigue was operationally defined as decline in alerting, orienting, and executive attention performance over the course ANT. Anchored in a theoretical model implicating the frontal basal ganglia circuitry as the core substrate of fatigue, we hypothesized that cognitive fatigue would be observed only in executive attention. Consistent with our prediction, significant cognitive fatigue effect was observed in executive attention but not in alerting or orienting. In contrast, orienting improved over the course of the ANT and alerting showed a trend, though insignificant, that was consistent with learning. Cognitive fatigue is conceptualized as an executive failure to maintain and optimize performance over acute but sustained cognitive effort resulting in performance that is lower and more variable than the individual’s optimal ability.
Cognitive Fatigue; Executive Control; Aging; Attention Networks
The Attention Network Test (ANT) assesses alerting, orienting, and executive attention. The current study was designed to achieve three main objectives. First, we determined the reliability, effects, and interactions of attention networks in a relatively large cohort of non-demented older adults (n = 184). Second, in the context of this aged cohort, we examined the effect of chronological age on attention networks. Third, the effect of blood pressure on ANT performance was evaluated. Results revealed high-reliability for the ANT as a whole, and for specific cue and flanker types. We found significant main effects for the three attention networks as well as diminished alerting but enhanced orienting effects during conflict resolution trials. Furthermore, increased chronological age and low blood pressure were both associated with significantly worse performance on the executive attention network. These findings are consistent with executive function decline in older adults and the plausible effect of reduced blood flow to the frontal lobes on individual differences in attention demanding tasks.
Aging; Attention; Executive function; Blood pressure; Processing speed
While gait is widely used to assess health status in older adults, normative data is lacking. Our objective was to develop and compare norms for widely used gait parameters in adults age 70 and older using cross-sectional (conventional) and longitudinal (robust) approaches accounting for important confounders such as disease effects on gait.
Community-dwelling older adults (age>70, N=824) without dementia or disability
Eight quantitative gait parameters measured using an instrumented walkway.
Of the 824 subjects (conventional normal; CN sample), 304 were included in a ‘robust normal’ (RN) sample after excluding those with either prevalent or incident clinical gait abnormalities developing within one year of the baseline assessment to account for disease effects on gait performance. Descriptively, the RN sample showed better performance on all selected gait variables compared to the CN sample. For instance, mean gait velocity (± standard deviation) was 105.9±17.9 cm/sec in the RN sample compared to 93.3±23.2 cm/sec in the overall CN sample. Applying a one standard deviation below the mean (70.1 cm/sec) derived from CN sample to define slow gait, 15.9% (131) in overall cohort were classified as abnormal whereas the RN cut-off (88.0 cm/sec) classified 39.7% (327) in the overall cohort as abnormal.
Our findings suggest that cross-sectional conventional norms may under-estimate gait performance in aging. Longitudinal robust norms provide more accurate estimates of normal gait performance and thus may improve early detection of gait disorders in older adults.
gait; reference values; elderly
To determine whether offspring of parents with exceptional longevity (OPEL) have a lower rate of dementia than offspring of parents with usual survival (OPUS).
Community based prospective cohort study.
Bronx, New York
A volunteer sample of 424 non-demented, community residing older adults (age 75–85) recruited from Bronx County starting in 1980 and followed for up to 23 years.
Epidemiologic, clinical and neuropsychological assessments were completed every 12 to 18 months. OPEL were defined as having at least one parent who reached the age of at least 85 years. OPUS were those for whom neither parent reached the age of 85 years. Dementia was diagnosed by case conference consensus based on DSM-IIIR criteria without access to information on parental longevity. Alzheimer’s disease was diagnosed using established criteria.
Of 424 subjects, 149 (35%) were OPEL and 275 (65%) were OPUS. Mean age at entry for both groups was 79. In comparison with OPUS, the OPEL group had a reduced incidence of Alzheimer’s disease (HR 0.57; 95% CI: 0.35 – 0.93). After adjusting for sex, education, race, hypertension, myocardial infarction, diabetes and stroke results were essentially unchanged. OPEL also had a significantly reduced rate of memory decline on the Selective Reminding Test (SRT) in comparison with the OPUS group (p=0.034).
OPEL develop dementia and Alzheimer’s disease at a significantly lower rate than OPUS. This result is not explained by demographic or medical confounders. Factors associated with longevity may protect against dementia and Alzheimer’s Disease.
Memory decline; dementia; parental longevity; Alzheimer’s disease
frail; screening; gait; elderly
To estimate the validity of neurological gait evaluations in predicting falls in older adults.
We studied 632 adults age 70 and over (mean age 80.6 years, 62% women) enrolled in the Einstein Aging Study whose walking patterns were evaluated by study clinicians using a clinical gait rating scale. Association of neurological gaits and six subtypes (hemiparetic, frontal, Parkinsonian, unsteady, neuropathic, and spastic) with incident falls was studied using generalized estimation equation procedures adjusted for potential confounders, and reported as risk ratio with 95% confidence intervals (CI).
Over a mean follow-up of 21 months, 244 (39%) subjects fell. Mean fall rate was 0.47 falls per person year. At baseline, 120 subjects were diagnosed with neurological gaits. Subjects with neurological gaits were at increased risk of falls (risk ratio 1.49, 95% CI 1.11 – 2.00). Unsteady (risk ratio 1.52, 95% CI 1.04 – 2.22), and neuropathic gait (risk ratio 1.94, 95% CI 1.07 – 3.11) were the two gait subtypes that predicted risk of falls. The results remained significant after accounting for disability and cognitive status, and also with injurious falls as the outcome.
Neurological gaits and subtypes are independent predictors of falls in older adults. Neurological gait assessments will help clinicians identify and institute preventive measures in older adults at high risk for falls.
Gait; Clinical Neurology; Incidence studies; Falls; Epidemiology
To determine the influence of homocysteine on mobility decline in older adults.
Einstein Aging Study, community based aging study
574 non-demented seniors (mean age 80.2 ± 5.4 years, 61% women)
Mobility decline defined using gait velocity measurements at baseline and annual follow-up visits. We used linear mixed effects models to adjust for age, sex, education, and other potential confounders.
Higher homocysteine levels were associated with slower gait velocity at baseline. Adjusted for age, gender and education, a one-unit increase in baseline log homocysteine levels was associated with a 2.95 cm/sec faster mobility decline per year (p=0.01) over a median follow-up of 1.4 years. Compared to the 434 subjects in the lowest three quartiles of homocysteine (≤15 μmol/liter), the 140 subjects in the highest quartile of homocysteine had faster rate of mobility decline (1.75 cm/sec per year faster, p=0.01). The association of homocysteine with mobility decline remained robust even after adjusting for multiple confounders and accounting for presence of clinical gait abnormalities.
Higher homocysteine levels are associated with increased risk of mobility decline in community residing older adults.
mobility decline; gait; homocysteine
Gait variability is an important indicator of impaired mobility in older adults; however, little is known about the meaning of change in gait variability over time. This study estimated clinically meaningful change in measures of gait variability using both distribution-and anchor-based approaches.
Community-based observational cohort study.
Bronx County and the research center at Albert Einstein College of Medicine.
Of 1148 participants in the Einstein Aging Study, 241 had quantitative gait assessments in two consecutive years between 2001 and 2005.
Gait variables were collected using a 12-foot instrumented walkway as participants walked at their normal walking speed. Gait variability was defined as the within-person standard deviation (SD) across steps in two 12-foot walks. Distribution-based meaningful change estimates used Cohen’s effect size (0.2 for small and 0.5 for moderate effects). Anchor-based estimates were obtained using dichotomous and ordinal self-reported walking ability ratings as anchors.
Distribution based estimates for small and substantial changes of variability measures were: stance time 0.005 and 0.014 s; swing time 0.003 and 0.009 s; step length 0.24 and 0.61 cm; and step width 0.03 and 0.08 cm. Among those reporting no change in walking ability, measures of gait variability were stable over one year. Among those reporting a decline in walking, stance time and swing time variability increased. Among those reporting an improvement in walking, only step length variability improved.
Preliminary criteria for meaningful change are 0.01 s for stance time and swing time variability and 0.25 cm for step length variability. These estimates may identify important changes over time in both clinical settings and research studies.
gait speed; gait variability; meaningful change; aging
Recent reports indicate that gait dysfunction can occur early in the course of cognitive decline suggesting that motor and cognitive functions in older adults may share common underlying brain substrates, pathological processes, and risk factors.
This study was designed to report the association between gait and cognition in older adults in USA and the southern Indian state of Kerala.
Materials and Methods:
Literature review of gait and cognition studies conducted in Bronx County, USA as well as preliminary results from the Kerala-Einstein study (Kozhikode city, Kerala).
Review of published studies based in the Bronx shows that both clinical and quantitative gait dysfunction are common in older adults with cognitive impairment. Furthermore, clinical and quantitative gait dysfunction in cognitively normal older adults was a strong predictor of future cognitive decline and dementia. Our preliminary study in Kozhikode city shows that timed gait is slower in older adults diagnosed with dementia and mild cognitive impairment syndrome compared to healthy older controls.
A strong association between gait and cognition is seen in seniors in USA as well as Kerala. A better understanding of the relationship between gait and cognition may help improve current diagnostic and therapeutic approaches globally.
Dementia; elderly; gait; speed
Vascular lesions in the brain are common with advancing age; however, the independent and cumulative contributions of postmortem vascular lesions to antemortem cognitive status are not well established. We examined association of six vascular lesions (large infarcts, lacunar infarcts, leukoencephalopathy, microinfarcts, cribriform changes, and cerebral amyloid angiopathy) with antemortem diagnoses of dementia, Alzheimer’s disease (AD), and vascular dementia (VaD) in 190 older adults from an autopsy series. We also developed a summary score based on three macroscopic vascular lesions: large infarcts (0, 1, and≥2), lacunar infarcts (0, 1, and≥2), and leukoencephalopathy (none, mild, and moderate-to-severe). Sixty-eight percent of cases had vascular lesions. Only leukoencephalopathy was associated with dementia (odds ratio (OR) 3.5, 95% CI 1.0–12.4), and only large infarcts were associated with VaD (OR 4.3, 95% CI 1.2–15.4). The vascular score was associated with dementia (OR 1.6, 95% CI 1.2–2.3), AD (OR 1.5, 95% CI 1.0–2.1) and VaD (OR 2.0, 95% CI 1.4–3.0). Leukoencephalopathy, large infarcts, and higher vascular burden is associated with the clinical expression of dementia and subtypes.
Vascular; Pathology; Dementia; Stroke
Gait measures have been shown to predict cognitive decline and dementia in older adults. Investigation of the neurobiology associated with locomotor function is needed to elucidate this relationship with cognitive abilities. This study aimed to examine magnetic resonance imaging (MRI; hippocampal volume)- and proton magnetic resonance spectroscopy (MRS; N-acetylaspartate to creatine (NAA/Cr) ratios)-derived hippocampal correlates of quantitative gait function (swing time (seconds), stride length (cm), and stride length variability (standard deviation)) in a subset of 48 nondemented older adults (24 males; mean age=81 years) drawn from the Einstein Aging Study, a community-based sample of individuals over the age of 70 residing in the Bronx, New York. Linear regression analyses controlling for age were used to examine hippocampal volume and neurochemistry as predictors of gait function. We found that stride length was associated with hippocampal volume (β=0.36, p=0.03; overall model R2=0.33, p=0.01), but not hippocampal neurochemistry (β=0.09, p=0.48). Stride length variability was more strongly associated with hippocampal NAA/Cr (β=−0.38, p=0.01; overall model R2=0.14, p=0.04) than hippocampal volume (β=−0.33, p=0.08). Gait swing time was not significantly related to any neuroimaging measure. These relationships remained significant after accounting for memory and clinical gait impairments. These findings suggest that nondemented older adults exhibit increased stride length variability that is associated with lower levels of hippocampal neuronal metabolism, but not hippocampal volume. Conversely, decreased stride length is associated with smaller hippocampal volumes, but not hippocampal neurochemistry. Distinct neurobiological hippocampal substrates may support decreased stride length and increased stride length variability in older adults.
Motor processing; Memory; Hippocampus; Locomotion; Neuroimaging; Aging
Identifying quantitative gait markers of preclinical dementia may lead to new insights into early disease stages, improve diagnostic assessments and identify new preventive strategies.
To examine the relationship of quantitative gait parameters to decline in specific cognitive domains as well as the risk of developing dementia in older adults.
We conducted a prospective cohort study nested within a community based ageing study. Of the 427 subjects aged 70 years and older with quantitative gait assessments, 399 were dementia‐free at baseline.
Over 5 years of follow‐up (median 2 years), 33 subjects developed dementia. Factor analysis was used to reduce eight baseline quantitative gait parameters to three independent factors representing pace, rhythm and variability. In linear models, a 1 point increase on the rhythm factor was associated with further memory decline (by 107%), whereas the pace factor was associated with decline on executive function measured by the digit symbol substitution (by 29%) and letter fluency (by 92%) tests. In Cox models adjusted for age, sex and education, a 1 point increase on baseline rhythm (hazard ratio (HR) 1.48; 95% CI 1.03 to 2.14) and variability factor scores (HR 1.37; 95% CI 1.05 to 1.78) was associated with increased risk of dementia. The pace factor predicted the risk of developing vascular dementia (HR 1.60; 95% CI 1.06 to 2.41).
Our findings indicate that quantitative gait measures predict future risk of cognitive decline and dementia in initially non‐demented older adults.
Identifying quantitative gait markers of falls in older adults may improve diagnostic assessments and suggest novel intervention targets.
We studied 597 adults aged 70 and older (mean age 80.5 years, 62% women) enrolled in an aging study who received quantitative gait assessments at baseline. Association of speed and six other gait markers (cadence, stride length, swing, double support, stride length variability, and swing time variability) with incident fall rate was studied using generalized estimation equation procedures adjusted for age, sex, education, falls, chronic illnesses, medications, cognition, disability as well as traditional clinical tests of gait and balance.
Over a mean follow-up period of 20 months, 226 (38%) of the 597 participants fell. Mean fall rate was 0.44 per person-year. Slower gait speed (risk ratio [RR] per 10 cm/s decrease 1.069, 95% confidence interval [CI] 1.001–1.142) was associated with higher risk of falls in the fully adjusted models. Among six other markers, worse performance on swing (RR 1.406, 95% CI 1.027–1.926), double-support phase (RR 1.165, 95% CI 1.026–1.321), swing time variability (RR 1.007, 95% CI 1.004–1.010), and stride length variability (RR 1.076, 95% CI 1.030–1.111) predicted fall risk. The associations remained significant even after accounting for cognitive impairment and disability.
Quantitative gait markers are independent predictors of falls in older adults. Gait speed and other markers, especially variability, should be further studied to improve current fall risk assessments and to develop new interventions.
“Vascular cognitive impairment” refers to cognitive impairment caused or associated with vascular risk factors, and encompasses a cognitive spectrum ranging from mild cognitive impairment to dementia. We examined the association of leisure activity participation to risk of developing VCI in the Bronx aging study. Over 21 years, 71 of the 401 participants who were free of dementia or VCI at entry developed VCI (49 participants with VCI without dementia). We derived Cognitive and Physical Activity Scales based on frequency of leisure activity participation. A 1-point increase on the Cognitive, but not Physical Activity Scale, was associated with lower risk of VCI (hazard ratio 0.931, 95% confidence interval [CI] 0.895–0.970) in Cox analysis. Participation in cognitive but not physical leisure activities is associated with lower risk of VCI with or without dementia. Prospective studies and clinical trials are needed to define the causal role of cognitive leisure activities in influencing vascular risk for cognitive decline.
leisure activities; cognition; elderly; stroke