Association of inflammatory markers with muscle and cognitive function in early and late-aging older adults.

OBJECTIVES: Age-related loss in muscle and cognitive function is common in older adults. Numerous studies have suggested that inflammation contributes to the decline in physical performance and increased frailty in older adults. We sought to investigate the relationship of inflammatory markers, including CRP, IL-6, IL-10, TNF-α, TNFR1, and TNFR2, with muscle and cognitive function in frail early-aging and non-frail late-aging older adults. DESIGN: Secondary analysis of a cross-sectional study. SETTINGS AND PARTICIPANTS: Two hundred community-dwelling older men and women were included. They had been recruited in two groups based on age and functional status: 100 early-agers (age 65-75, who had poor functional status, and more co-morbidities) and 100 late-agers (older than 75 years, who were healthier and had better functional status). MEASUREMENTS: We assessed CRP, IL-6, IL-10, TNF-α, TNFR1, TNFR2, grip strength, Short Physical Performance Battery (SPPB) score, and cognitive function. We used correlation coefficients, partial correlations, and regression modeling adjusted for age, BMI, gender, and exercise frequency. RESULTS: The mean age in the two groups were 70.4 and 83.2, respectively. In regression models adjusting for age, BMI, gender and exercise frequency, early-agers demonstrated significant associations between inflammatory markers and outcomes. Each mg/dl of CRP was associated with (regression coefficient ± standard error) -0.6 ± 0.2 kg in grip strength (p = 0.0023). Similarly, each pg/mL of TNF-α was associated with -1.4 ± 0.7 (p = 0.0454), each 500 pg/mL of TNFR1 was associated with -1.9 ± 0.6 (p = 0.0008), and each 500 pg/mL of TNFR2 was associated with -0.5 ± 0.2 (p = 0.0098) in grip strength. Each 500 pg/mL of TNFR1 was associated with -0.4 ± 0.2 point in SPPB (p = 0.0207) and each pg/mL in IL-10 with 0.2 ± 0.1 point in MoCA (p = 0.0475). In late-agers, no significant correlation was found between any of the inflammatory markers and functional outcomes. CONCLUSION: In early-agers with frailty and more co-morbidities, the inflammatory markers CRP, TNF-α, TNFR1, and TNFR2 were associated with grip strength, TNFR1 was correlated with physical performance, and IL-10 was correlated with cognitive function. However, in healthier late-agers, no relationship was found between inflammatory markers and muscle or cognitive function. Our findings suggest presence of a relationship between inflammation and loss of muscle performance and cognitive function in frailer and sicker individuals, regardless of their chronological age.

Role of Intraoperative Neuromonitoring to Predict Postoperative Delirium in Cardiovascular Surgery.

OBJECTIVE: Postoperative delirium (POD) can occur in up to 50% of older patients undergoing cardiovascular surgery, resulting in hospitalization and significant morbidity and mortality. This study aimed to determine whether intraoperative neurophysiologic monitoring (IONM) modalities can be used to predict delirium in patients undergoing cardiovascular surgery. DESIGN: Adult patients undergoing cardiovascular surgery with IONM between 2019 and 2021 were reviewed retrospectively. Delirium was assessed multiple times using the Intensive Care Delirium Screening Checklist (ICDSC). Patients with an ICDSC score ≥4 were considered to have POD. Significant IONM changes were evaluated based on a visual review of electroencephalography (EEG) and somatosensory evoked potentials data and documentation of significant changes during surgery. SETTING: University of Pittsburgh Medical Center hospitals. PARTICIPANTS: Patients 18 years old and older undergoing cardiovascular surgery with IONM monitoring. MEASUREMENTS AND MAIN RESULTS: Of the 578 patients undergoing cardiovascular surgery with IONM, 126 had POD (21.8%). Significant IONM changes were noted in 134 patients, of whom 49 patients had delirium (36.6%). In contrast, 444 patients had no IONM changes during surgery, of whom 77 (17.3%) patients had POD. Upon multivariate analysis, IONM changes were associated with POD (odds ratio 2.12; 95% CI 1.31-3.44; p < 0.001). Additionally, baseline EEG abnormalities were associated with POD (p = 0.002). CONCLUSION: Significant IONM changes are associated with an increased risk of POD in patients undergoing cardiovascular surgery. These findings offer a basis for future research and analysis of EEG and somatosensory evoked potential monitoring to predict, detect, and prevent POD.

Effect of Timing and Coordination Training on Mobility and Physical Activity Among Community-Dwelling Older Adults: A Randomized Clinical Trial.

Importance: Standard exercise interventions targeting underlying physiologic system impairments have limited success in improving walking. Augmenting standard interventions with timing and coordination training, which incorporates the principles of motor learning and integrates multiple systems, may be more successful. Objective: To determine whether a standard strength and endurance program incorporating timing and coordination training (standard-plus) improves gait speed more than strength and endurance training alone. Design, Setting, and Participants: The Program to Improve Mobility in Aging (PRIMA) study was an assessor-blinded, randomized, 2-group intervention trial that included a 12-week intervention and 24-week follow-up period. The trial was conducted at a university research clinic from 2016 to 2020. Participants included 249 community-dwelling older adults (aged ≥65 years) with gait speed between 0.60 and 1.20 m/s. Statistical analysis was performed from December 2020 to March 2021. Interventions: Participants were randomized to standard strength and endurance (n = 125) or standard-plus, including timing and coordination training (n = 124), 50 to 60 minutes, twice a week for 12 weeks. Main Outcomes and Measures: Primary outcome of gait speed and secondary outcomes representing components of the intervention (leg strength and power, 6-minute walk test, chair sit-and-reach test, and figure of 8 walk test) and activity and participation (Late Life Function and Disability Instrument and daily physical activity measured by accelerometry) were measured at 12, 24, and 36 weeks. Results: Among 249 randomized participants, 163 (65.5%) were female, 22 (8.8%) were Black, 219 (88.0%) were White; mean (SD) age was 77.4 (6.6) years; mean (SD) gait speed was 1.07 (0.16) m/s; and 244 (98.0%) completed the intervention. The 2 groups did not have significantly different improvements in gait speed or secondary outcomes representing the components of the intervention at any time point. For gait speed, individuals in the standard-plus group had a mean (SD) improvement of 0.079 (0.135) m/s over 12 weeks, 0.065 m/s (0.141) over 24 weeks, and 0.059 (0.150) m/s over 36 weeks; individuals in the standard group improved gait speed by 0.081 (0.124) m/s over 12 weeks, 0.051 (0.129) m/s over 24 weeks, and 0.065 (0.148) m/s over 36 weeks. Conclusions and Relevance: This randomized clinical trial found no difference in gait speed change between the standard and standard-plus intervention groups, and both groups showed sustained improvements in mobility 24 weeks after the intervention. Trial Registration: ClinicalTrials.gov Identifier: NCT02663778.

Alzheimer's disease pathology in a community-based sample of older adults without dementia: The MYHAT neuroimaging study.

A true understanding of the distribution and functional correlates of Alzheimer's disease pathology in dementia-free older adults requires a population-based perspective. Here we report initial findings from a sample of 102 cognitively unimpaired participants (average age 77.2 years, 54.9% women, 13.7% APOE*4 carriers) recruited for neuroimaging from a larger representative population-based cohort participating in an ongoing longitudinal study of aging, the Monongahela-Youghiogheny Healthy Aging Team (MYHAT). All participants scored < 1.0 on the Clinical Dementia Rating (CDR) Scale, with 8 participants (7.8%) scoring CDR = 0.5. Participants completed a positron emission tomography scan using the tracers [C-11]Pittsburgh Compound-B (PiB) and [F-18]AV-1451 to estimate amyloid and tau deposition. PiB positivity was defined on a regional basis using established standardized uptake value ratio cutoffs (SUVR; cerebellar gray matter reference), with 39 participants (38.2%) determined to be PiB(+). Health history, lifestyle, and cognitive abilities were assessed cross-sectionally at the nearest annual parent MYHAT study visit. A series of adjusted regression analyses modeled cognitive performance as a function of global PiB SUVR and [F-18]AV-1451 SUVR in Braak associated regions 1, 3/4, and 5/6. In comparison to PiB(-) participants (n = 63), PiB(+) participants were older, less educated, and were more likely to be APOE*4 carriers. Global PiB SUVR was significantly correlated with [F-18]AV-1451 SUVR in all Braak-associated regions (r = .38-0.53, p < .05). In independent models, higher Global PiB SUVR and Braak 1 [F-18]AV-1451 SUVR were associated with worse performance on a semantic interference verbal memory test. Our findings suggest that brain amyloid is common in a community-based setting, and is associated with tau deposition, but both pathologies show few associations with concurrent cognitive performance in a dementia-free sample.

Hippocampal sclerosis, TDP-43, and the duration of the symptoms of dementia of AD patients.

OBJECTIVES: To examine the relationship between duration of the cognitive symptoms, from the earliest reported symptom to death, and hippocampal sclerosis (HS) and TAR-DNA binding protein of 43kDA (TDP-43) in Alzheimer's disease (AD) patients. METHODS: The study was conducted in 359 cognitively impaired patients who met the pathological criteria for AD (NIA-Reagan intermediate or high). The mean age at onset was 69.5 ± 8.8 years (range 37-95) and the mean duration of the symptoms was 10.5 ± 4.2 years. The association between symptoms duration and HS and TDP-43 was examined with logistic regression analyses controlling for age at death, atherosclerosis in the Circle of Willis (CW), cerebral infarcts, gender, baseline Mini Mental State Examination scores, APOE-4 allele, and presence of Lewy bodies (LB). RESULTS: HS was present in 18% (n = 64) and TDP-43 in 51.5% (n = 185) of the patients. HS and TDP-43 were more frequent in patients whose symptoms lasted more than 10 years. LBs were present in 72% of the patients with HS and in 64% of the patients with TDP-43. Age at onset was not associated with TDP-43 or HS. HS was associated with duration of symptoms and LB, TDP-43, and atherosclerosis in the CW. TDP-43 was associated with duration of symptoms, LB, and HS. INTERPRETATION: HS and TDP-43 are present in early and late onset AD. However, their presence is mainly driven by the duration of symptoms and the presence of LB. This suggests that HS and TDP-43 are part of the later neuropathological changes in AD.

A randomized controlled trial of amyloid positron emission tomography results disclosure in mild cognitive impairment.

INTRODUCTION: Recent studies suggest that Alzheimer's disease (AD) biomarker disclosure has no discernable psychological impact on cognitively healthy persons. Far less is known about how such results affect symptomatic individuals and their caregivers. METHODS: Randomized controlled trial of 82 mild cognitive impairment (MCI) patient and caregiver dyads (total n = 164) to determine the effect of receiving amyloid positron emission tomography results on understanding of, and perceived efficacy to cope with, MCI over 52 weeks of follow-up. RESULTS: Gains in the primary outcomes were not consistently observed. Amyloid negative patients reported greater perceived ambiguity regarding MCI at follow-up, while moderate and sustained emotional distress was observed in patients, and to a lesser extent, caregivers, of those who were amyloid positive. There was no corresponding increase in depressive symptoms. DISCUSSION: These findings point to the possibility that both MCI patients and caregivers may need emotional support after the disclosure of amyloid scan results.

Associations between NIH Toolbox Cognition Battery and in vivo brain amyloid and tau pathology in non-demented older adults.

INTRODUCTION: The National Institutes of Health (NIH) Toolbox Cognition Battery (NIHTB-CB) was developed to be a common assessment metric across a broad array of research studies. We investigated associations between NIHTB-CB and brain amyloid and tau deposition in cognitively unimpaired older adults. METHODS: One hundred eighteen community-based volunteers completed magnetic resonance imaging (MRI), Pittsburgh compound B (PiB)-PET (positron emission tomography) and AV-1451-PET neuroimaging, a neuropsychological evaluation, NIHTB-CB, and the Clinical Dementia Rating (CDR) scale. Demographically adjusted regression models evaluated cognition-biomarker associations; standardized effect sizes allowed comparison of association strength across measures. RESULTS: No NIHTB-CB measures were associated with amyloid deposition. NIHTB-CB measures of fluid cognition, including Pattern Comparison Processing Speed, Dimensional Change Card Sort, and Fluid Cognition Composite, were associated with tau deposition in higher Braak regions. Pattern Comparison Processing Speed was the most robust association with sensitivity analyses. DISCUSSION: NIHTB-CB tasks of processing speed and executive functions may be sensitive to pathologic tau deposition on imaging in normal aging.

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.

Program to improve mobility in aging (PRIMA) study: Methods and rationale of a task-oriented motor learning exercise program.

Walking difficulty is a common and costly problem in older adults. A potentially important yet unaddressed strategy to enhance walking ability through exercise intervention is to add a timing and coordination component in gait training (i.e. task specific timing and coordination exercise intervention) to the usual strength, endurance, and flexibility training. We describe the methods and rationale of a randomized single-blind, physical therapist supervised, exercise intervention trial to compare the effects of a standard strength, endurance, and flexibility program to a standard plus timing and coordination program in community-dwelling older adults walking slower than the desired gait speed of 1.2 m/s. Exercise sessions are twice weekly for 12 weeks. Participants are assessed at baseline, 12 weeks (post intervention), 24 weeks and 36 weeks. The primary outcome is gait speed, secondary outcomes represent components of the interventions (strength, endurance, flexibility, timing and coordination), and tertiary outcomes are measure of activity and participation (Late Life Function and Disability Instrument and physical activity). The findings of this trial will (1) establish if a standard-plus task specific timing and coordination program is superior to a standard strength and endurance program in improving mobility, activity and participation and (2) determine if the improvements are sustained over time. The information derived from this project will provide valuable insight into the prevention and management of walking difficulty, which is so common in older Americans.

Research Use of Ecological Momentary Assessment for Adverse Event Monitoring Following Amyloid-ß Results Disclosure.

As calls for transparency in human subjects research grow, investigators conducting Alzheimer's disease (AD) biomarker research are increasingly required to consider their ethical obligations regarding the return of AD biomarker test results to research participants. When disclosing these test results to potentially vulnerable participants, investigators may face unique challenges to identify adverse events, particularly psychological events. The purpose of this paper is to describe our research team's experience with developing and implementing a process for enhanced adverse event monitoring following the return of amyloid-ß (Aß) imaging results to research participants with mild cognitive impairment (MCI). Ethical and logistical considerations are presented along with preliminary findings from an ongoing randomized controlled trial of Aß imaging results disclosure in MCI. Following receipt of amyloid imaging results, participants underwent 14 days of adverse event monitoring using ecological momentary assessment (EMA), a strategy to capture health, behaviors, and mood as they occur in participants' natural settings in real time. EMA telephone calls were placed at random during waking hours to screen for mood changes. Investigators were alerted for positive depression, anxiety, suicidal ideation screenings, or for two days of failed call attempts. Preliminary feasibility of twenty-four participants with MCI who participated in EMA mood assessments was successfully completed 83% (SD = 0.4) of the time over 14 days with no alerts for anxiety or depression screening items. EMA, when used with standard adverse event monitoring, is a promising and novel approach to maximize early detection of negative psychological reactions following AD biomarker results disclosed in research settings.

Association Between Amyloid-ß, Small-vessel Disease, and Neurodegeneration Biomarker Positivity, and Progression to Mild Cognitive Impairment in Cognitively Normal Individuals.

BACKGROUND: We estimated the prevalence and incidence of amyloid-ß deposition (A), small-vessel disease (V), and neurodegeneration (N) biomarker positivity in community-dwelling cognitively normal individuals (CN). We determined the longitudinal association between the respective biomarker indices with progression to all-cause mild cognitive impairment (MCI) and its amnestic and nonamnestic subtypes. METHODS: CN participants, recruited by advertising, underwent brain [C-11]Pittsburgh Compound-B (PiB)-positron emission tomography (PET), magnetic resonance imaging, and [F-18]fluoro-2-deoxy-glucose (FDG)-PET, and were designated as having high or low amyloid-ß (A+/A-), greater or lower white matter hyperintensities burden (V+/V-) and diminished or normal cortical glucose metabolism (N+/N-). MCI was adjudicated using clinical assessments. We examined the association between A, V, and N biomarker positivity at study baseline and endpoint, with progression to MCI using linear regression, Cox proportional hazards and Kaplan-Meier analyses adjusted for age and APOE-ε4 carrier status. RESULTS: In 98 CN individuals (average age 74 years, 65% female), A+, V+, and N+ prevalence was 26%, 33%, and 8%, respectively. At study endpoint (median: 5.5 years), an A+, but not a V+ or N+ scan, was associated with higher odds of all-cause MCI (Chi-square = 3.9, p = .048, odds ratio, 95% confidence interval = 2.6 [1.01-6.8]). Baseline A+, V+, or N+ were not associated with all-cause MCI, however, baseline A+ (p = .018) and A+N+ (p = .049), and endpoint A+N+ (p = .025) were associated with time to progression to amnestic, not nonamnestic, MCI. CONCLUSION: Longitudinal assessments clarify the association between amyloid-ß and progression to all-cause MCI in CN individuals. The association between biomarker positivity indices of amyloid-ß and neurodegeneration, and amnestic MCI reflects the underlying pathology involved in the progression to prodromal Alzheimer's disease.

Complex Walking Tasks and Risk for Cognitive Decline in High Functioning Older Adults.

BACKGROUND: Performance on complex walking tasks may provide a screen for future cognitive decline. OBJECTIVE: To identify walking tasks that are most strongly associated with subsequent cognitive decline. METHODS: Community-dwelling older adults with Modified Mini-Mental State (3MS) >85 at baseline (n = 223; mean age = 78.7, 52.5% women, 25.6% black) completed usual-pace walking and three complex walking tasks (fast-pace, narrow-path, visuospatial dual-task). Slope of 3MS scores for up to 9 subsequent years (average = 5.2) were used to calculate a cognitive maintainer (slope ≥0) or decliner (slope <0) outcome variable. Logistic regression models assessed associations between gait speeds and being a cognitive decliner. A sensitivity analysis in a subsample of individuals (n = 66) confirmed results with adjudicated mild cognitive impairment (MCI) or dementia at 8-9 years post-walking assessment. RESULTS: Cognitive decliners were 52.5% of the sample and on average were slower for all walking tasks compared to maintainers. In models adjusted for demographic and health variables, faster fast-pace (OR = 0.87 per 0.1 m/s, 95% CI: 0.78, 0.97) and dual-task (OR = 0.84 per 0.1 m/s, 95% CI: 0.73, 0.96) gait speeds were associated with lower likelihood of being a cognitive decliner. Usual-pace gait speed was not associated (OR = 0.96 per 0.1 m/s, 95% CI: 0.85, 1.08). Results were nearly identical in analyses with adjudicated MCI or dementia as the outcome. CONCLUSION: Fast-pace and dual-task walking may provide simple and effective tools for assessing risk for cognitive decline in older individuals with high cognitive function. Such screening tools are important for strategies to prevent or delay onset of clinically meaningful change.

Community-Based Activity and Sedentary Patterns Are Associated With Cognitive Performance in Mobility-Limited Older Adults.

Over the last few decades, considerable evidence shows that greater levels of aerobic exercise and cardiovascular fitness benefit cognitive performance. However, the degree to which free-living activity in community settings is related to cognitive performance remains unclear, particularly in older adults vulnerable to disability. Also, it is unknown whether the manner in which daily physical activity (PA) and sedentary time are accumulated throughout the day is associated with cognition. Cross-sectional associations between accelerometer-characterized PA and sedentary patterns and cognitive performance were examined in 1,274 mobility-limited older adults. Percent time spent in various bout lengths of PA (≥1, ≥2, and ≥5 min) and sedentary (≥1, ≥30, and ≥60 min) was defined as the number of minutes registered divided by total wear time × 100. Percent time was then tertiled for each bout length. Multiple linear regression models were used to estimate the associations between accelerometer bout variables and separate cognitive domains that included processing speed (Digit Symbol Coding; DSC), immediate and delayed recall (Hopkins Verbal Learning Test; HVLT), information processing and selective attention (Flanker), working memory (n-back), reaction time (switch and non-switch reaction time), and a composite score that averaged results from all cognitive tests. After adjusting for demographics, behavioral factors, and morbid conditions, more time spent in PA was associated with higher DSC for all bout lengths (p < 0.03 for all). Higher PA was associated with higher HVLT and global cognition scores but only for longer bout lengths (p < 0.05 for all). The association was largely driven by participants who spent the lowest amount of time performing activity while awake (p < 0.04). An inverse linear relationship was observed between total sedentary time and DSC (p = 0.02), but not for other measures of cognition. These results suggest that, while higher PA was associated with higher cognitive performance, PA's association with memory was sensitive to bout duration. The time, but not the manner, spent in sedentary behaviors showed a minor association with executive function. Further research is warranted to characterize longitudinal changes in daily activity and sedentary patterns as potential biophysical markers of cognitive status in older adults.

Serious adverse events of older adults in nursing home and community intervention trials.

BACKGROUND/AIMS: Clinical trials of older adults are increasingly common, but risks of serious adverse events (SAE) may vary. We describe the incidence of SAE in two randomized trials, one community-based and one nursing home-based. METHODS: We performed a secondary data analysis from two randomized clinical trials at one academic health center and 21 nursing homes involving 200 sedentary community dwellers aged 70-89 years and 185 female nursing home residents aged 65 years or older. Interventions included structured physical activity to reduce mobility disability in the Lifestyle Interventions and Independence for Elders (LIFE) study and oral cranberry capsules to reduce bacteriuria plus pyuria in nursing home residents (CRANNY) trial. We measured SAE incidence per 100 person-years and incidence of protocol-related unanticipated SAE per 100 person-years in LIFE and CRANNY trials. RESULTS: Mean age and proportion of patients with dementia in LIFE and CRANNY trials were 79.3 years and 86.4 years and 0% and 78%, respectively. There were 179 total SAE in LIFE including 8 (4%) deaths, and 116 total SAE in CRANNY including 33 (28%) deaths. SAE incidence was 33.7 (95% CI 27.2, 41.8) events per 100 person-years in LIFE and 69.4 (95% CI 49.1, 98.1) events per 100 person-years in CRANNY. No protocol-related unanticipated SAE occurred in either trial. CONCLUSIONS: The frequency and severity of SAE vary in older adults. While SAE are common in nursing home residents, protocol-related, unanticipated SAE are rare in nursing home residents and community dwellers. This finding can inform trial monitoring protocols. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT01072500 and NCT01691430.

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.

Association of Brain Amyloid-ß With Slow Gait in Elderly Individuals Without Dementia: Influence of Cognition and Apolipoprotein E ε4 Genotype.

IMPORTANCE: Motor slowing appears in preclinical Alzheimer disease (AD), progresses with AD progression, and is associated with AD pathologic findings at autopsy. Whether amyloid-ß (Aß) is associated with gait speed in elderly individuals without dementia and whether cognition and apolipoprotein E ε4 (APOE ε4) influence this association remain unknown. OBJECTIVES: To examine the association between Aß and gait speed in elderly individuals without dementia and to study the influence of cognition and APOE ε4 status on this association. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional analysis included 183 elderly individuals without dementia, including a cognitively normal (CN) subsample of 144 adults, enrolled in the Ginkgo Evaluation of Memory study at a university center from January 1, 2000, through December 31, 2009, and enrolled in a follow-up substudy a mean (SD) of 10 (3) months after the initial study closeout. Data analysis was performed from October 1, 2015, to June 1, 2016. MAIN OUTCOMES AND MEASURES: We assessed cerebral Aß on Pittsburgh Compound B (PiB) positron emission tomography, gait speed over 4.57 m (15 ft), and cognition on the Mini-Mental State Examination and Trail Making Test Parts A and B. We grouped participants into high Aß (PiB+) and low Aß (PiB-) groups on standardized global PiB cutoffs and examined group differences. We studied the influence of cognition and APOE ε4 on the global and regional associations between gait speed and Aß in the whole sample and the CN subsample. RESULTS: Among the 183 study participants, mean (SD) age was 85.5 (3) years, 76 were women (41.5%), and 177 were white (96.7%). The PiB+ individuals were comparable to the PiB- individuals on demographics, comorbidities, cognition, hippocampal volume, and small-vessel disease but not on gait speed (0.85 vs 0.92 m/s, P = .01) or proportion of APOE ε4 carriers (29 [29.0%] vs 5 [6.0%], P < .001). In the whole sample and the CN subsample, the association between global PiB retention and slower gait withstood adjustment for covariates (ß = -0.068, P = .03 and ß = -0.074, P = .04, respectively); however, this association was attenuated by Mini-Mental State Examination and Trail Making Test Parts A and B and was rendered statistically nonsignificant by APOE ε4 in both samples (ß = -0.055 and ß = -0.058, respectively; both P ≥ .10). Several regional associations between gait speed and PiB uptake withstood relevant adjustments; however, APOE ε4 rendered only the medial (ß = -0.22, P = .03) and lateral (ß = -0.08, P = .03) temporal regions, subcortical white matter (ß = -0.13, P = .02), and occipital regions (ß = -0.15, P = .03) in the whole sample and the occipital regions (ß = -0.21, P = .01) in the CN subsample statistically significant. CONCLUSIONS AND RELEVANCE: Cerebral Aß deposition is associated with slower gait speed in elderly individuals without dementia; however, this association is weaker in those who are CN. Cognition and APOE ε4 carrier status influence the association between Aß and gait speed in elderly individuals without dementia.

Cerebral Amyloid Deposition and Dual-Tasking in Cognitively Normal, Mobility Unimpaired Older Adults.

Background: We examined relationships between cerebral amyloid-beta (Aß) and cognitive-gait dual-task performance in 27 cognitively normal, mobility unimpaired elders. Methods: We assessed Aß on Pittsburgh Compound B (PiB)-PET. We measured gait speed separately and while performing working-memory, response-inhibition, motor-sequencing, and phone-dialing tasks. We compared dual-task costs on gait and cognitive performance in high-Aß (PiB(+)) and low-Aß (PiB(-)) groups and examined the association between Aß and dual-task performance decrements. Results: PiB(+) (n = 16) were comparable with the PiB(-) (n = 11) individuals on demographics, general cognitive and physical performance, and key brain MRI characteristics. PiB(+) group demonstrated greater dual-task costs on gait speed on all cognitive tasks (p < .05) except on response inhibition. Dual-task costs on cognition were similar between groups. Overall, Aß was associated with dual-task decrement on gait speed but not on dual-task decrement on cognitive performance. Conclusions: Preliminary evidence indicates that cerebral Aß is associated with gait slowing on dual-tasking in healthy older adults.

Slow gait, white matter characteristics, and prior 10-year interleukin-6 levels in older adults.

OBJECTIVE: To examine the relationship between gait speed and prior 10 years interleukin-6 (IL-6) burden in older adults. We then assessed whether white matter characteristics influence this relationship. METHODS: In 179 community-dwelling older adults, gait speed was assessed on an automated walkway and serum IL-6 was assayed on ELISA. Concurrently, white matter characteristics were assessed on MRI by quantifying volume of white matter hyperintensities (WMH), a marker of small vessel disease, and normal-appearing white matter on fractional anisotropy (NAWM-FA), a marker of axonal integrity. IL-6 was assayed at regular intervals at gait assessment and over the prior 10 years and estimates of sustained 10-year IL-6 exposure and the rate of change in IL-6 over 10 years were obtained. Multivariate linear regressions were used to examine the relationships among sustained IL-6 exposure, rate of change in IL-6, gait speed, and white matter characteristics. RESULTS: In this sample (age 83 years, 58% female, 41% black, gait speed 0.9 m/s), higher sustained IL-6 levels, but not the rate of change in IL-6 or IL-6 at gait assessment, was significantly related to slower gait (ß = -0.27, p < 0.001) and to higher WMH (ß = 0.23, p = 0.002), but not NAWM-FA, withstanding covariate adjustments. WMH accounted for 30% attenuation in the relationship between higher sustained IL-6 levels and slower gait speed (p = 0.043) in the mediation analyses. CONCLUSIONS: Sustained exposure to high IL-6 over 10 years rather than the rate of change in IL-6 or an isolated high IL-6 level may adversely affect gait speed by influencing cerebral WMH.