P3‐164: Less daily computer use is related to smaller hippocampal volumes in dementia‐free elderly

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152632/1/alzjjalz2015061535.pd

Risk of Incident Clinical Diagnosis of Alzheimer\u27s Disease-Type Dementia Attributable to Pathology-Confirmed Vascular Disease

INTRODUCTION: The presence of cerebrovascular pathology may increase the risk of clinical diagnosis of Alzheimer\u27s disease (AD). METHODS: We examined excess risk of incident clinical diagnosis of AD (probable and possible AD) posed by the presence of lacunes and large infarcts beyond AD pathology using data from the Statistical Modeling of Aging and Risk of Transition study, a consortium of longitudinal cohort studies with more than 2000 autopsies. We created six mutually exclusive pathology patterns combining three levels of AD pathology (low, moderate, or high AD pathology) and two levels of vascular pathology (without lacunes and large infarcts or with lacunes and/or large infarcts). RESULTS: The coexistence of lacunes and large infarcts results in higher likelihood of clinical diagnosis of AD only when AD pathology burden is low. DISCUSSION: Our results reinforce the diagnostic importance of AD pathology in clinical AD. Further harmonization of assessment approaches for vascular pathologies is required

S1‐01‐01: Pathology Underlying Regional Brain Atrophy

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152747/1/alzjjalz201404035.pd

Lower average daily step count is associated with poorer executive function and rurality in a veteran cohort

BackgroundAn active lifestyle is associated with better cognitive health in older individuals. This relationship is understudied in U.S. Veterans, a population at risk of cognitive impairment due to the high prevalence of associated risk factors and comorbidities. Passive monitoring of daily activities provides objective measures of activity that may serve as a sensitive index of day‐to‐day function and dementia risk.MethodParticipants (age > 57) were enrolled as part of Collaborative Aging Research using Technology (CART), a multi‐site study examining the feasibility of unobtrusive remote sensing and monitoring of physical, cognitive, and health‐related activities. The Veteran cohort consists of volunteers living in largely rural communities in the Pacific Northwest, self‐identified as being a Veteran, and included their cohabitant, if applicable. Daily step counts were acquired using a wrist‐worn device. Baseline one‐month averages were compared with rurality and cognitive function.Result114 nondemented participants residing in 67 homes underwent neuropsychological assessment and passive monitoring of daily activities (55% male, age 70.7, MOCA 23.4). 70% resided in a rural area (rural‐urban commuting area (RUCA) score > 4 ) and 29% had > three vascular risk factors. Participants with 14+ days of gait activity measured within a one‐month period near baseline cognitive assessments not using a walker in the home were included (n = 107). Average daily step count obtained over an average of 27.7 days was 3,065 (median 2,515) and was greater in large rural towns compared with small‐isolated rural (p = 0.07) or urban (p = 0.04) towns. After adjusting for potential confounders, lower average daily steps were associated with worse performance in executive function, a relationship observed in Veterans in large rural, but not urban or small rural towns.ConclusionIn a cohort comprised primarily of rural Veteran’s and their spouses, lower average number of steps per day is associated with poorer executive function and this relationship varied by rurality. Real‐world monitoring of daily activities may identify those at greatest risk of cognitive decline for interventional studies aimed at dementia prevention in older individuals, and is of particular relevance in rural settings, where access to specialty care is limited.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163785/1/alz046393.pd

Sleep duration and its association with cognition vary with rurality in older veterans

BackgroundSleep duration is associated with cognitive health in older individuals and is increasingly recognized as an important modifiable factor related to dementia risk. Sleep and its relationship with cognitive function is understudied in rural U.S. Veterans, who are under‐represented in clinical research aging studies.MethodParticipants (age > 57) were enrolled as part of Collaborative Aging Research using Technology (CART), a multi‐site study examining the feasibility of unobtrusive remote sensing and monitoring of physical, cognitive, behavioral, physiological, and health‐related activities. The VA cohort consists of volunteers living in largely rural communities in the Pacific Northwest, self‐identified as being a Veteran, and included their cohabitant, if applicable. Nightly hours of sleep were estimated using a wrist worn device and baseline one month averages were compared with rural status and cognitive function.Result114 nondemented participants from 67 homes underwent neuropsychological testing and passive monitoring of daily activities (55% male, age 70.7, MOCA 23.4). 70% resided in a rural area, defined as having a rural‐urban commuting area (RUCA) score of 4 or higher (30% urban, 28% large‐rural, 34% small‐isolated‐rural). Participants with 7+ days of recorded sleep measured within a one‐month period near baseline cognitive assessments were included in the analysis (n = 99). Mean hours of sleep obtained over an average of 24.4 days was 7.8 hours (SD 1.7). Participants living in urban areas slept less (7.3 hrs) than those living in large‐rural (8.3 hrs) but not small‐isolated rural areas (7.6 hrs)(p<0.05). Poorer executive function and global cognition were related to decreased sleep duration in Veterans living in small‐isolated and large rural areas, respectively.ConclusionIn a cohort comprised of mostly rural Veteran’s and their spouses, living just outside of an urban area was associated with longer sleep duration. However, this relationship did not exist in Veterans living in smaller rural centers. Sleep duration was associated with poorer cognition in rural, not urban, Veterans. Passive, in‐home monitoring can provide objective measures of sleep activity that may serve as a sensitive index of dementia risk and as a tool to investigate sleep dysfunction and its relationship with cognitive health in older rural Veterans.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163860/1/alz046482.pd

IC‐P‐076: Less daily computer use is related to smaller hippocampal volumes in dementia‐free elderly

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153184/1/alzjjalz201506097.pd

Use of High-Frequency In-Home Monitoring Data May Reduce Sample Sizes Needed in Clinical Trials

<div><p>Background</p><p>Trials in Alzheimer’s disease are increasingly focusing on prevention in asymptomatic individuals. This poses a challenge in examining treatment effects since currently available approaches are often unable to detect cognitive and functional changes among asymptomatic individuals. Resultant small effect sizes require large sample sizes using biomarkers or secondary measures for randomized controlled trials (RCTs). Better assessment approaches and outcomes capable of capturing subtle changes during asymptomatic disease stages are needed.</p><p>Objective</p><p>We aimed to develop a new approach to track changes in functional outcomes by using individual-specific distributions (as opposed to group-norms) of unobtrusive continuously monitored in-home data. Our objective was to compare sample sizes required to achieve sufficient power to detect prevention trial effects in trajectories of outcomes in two scenarios: (1) annually assessed neuropsychological test scores (a conventional approach), and (2) the likelihood of having subject-specific low performance thresholds, both modeled as a function of time.</p><p>Methods</p><p>One hundred nineteen cognitively intact subjects were enrolled and followed over 3 years in the Intelligent Systems for Assessing Aging Change (ISAAC) study. Using the difference in empirically identified time slopes between those who remained cognitively intact during follow-up (normal control, NC) and those who transitioned to mild cognitive impairment (MCI), we estimated comparative sample sizes required to achieve up to 80% statistical power over a range of effect sizes for detecting reductions in the difference in time slopes between NC and MCI incidence before transition.</p><p>Results</p><p>Sample size estimates indicated approximately 2000 subjects with a follow-up duration of 4 years would be needed to achieve a 30% effect size when the outcome is an annually assessed memory test score. When the outcome is likelihood of low walking speed defined using the individual-specific distributions of walking speed collected at baseline, 262 subjects are required. Similarly for computer use, 26 subjects are required.</p><p>Conclusions</p><p>Individual-specific thresholds of low functional performance based on high-frequency in-home monitoring data distinguish trajectories of MCI from NC and could substantially reduce sample sizes needed in dementia prevention RCTs.</p></div

Web-enabled conversational interactions as a method to improve cognitive functions: Results of a 6-week randomized controlled trial

AbstractIntroductionIncreasing social interaction could be a promising intervention for improving cognitive function. We examined the feasibility of a randomized controlled trial to assess whether conversation-based cognitive stimulation through personal computers, webcams, and a user-friendly interactive Internet interface had high adherence and a positive effect on cognitive function among older adults without dementia.MethodsDaily 30-minute face-to-face communications were conducted during a 6-week trial period in the intervention group. The control group received only a weekly telephone interview. The cognitive status of normal subjects and those with mild cognitive impairment was operationally defined as a global clinical dementia rating of 0 and 0.5, respectively. Age, sex, education, mini mental state examination score, and clinical dementia rating score were balancing factors in randomization. The subjects were recruited using mass-mailing invitations. The pre- to postintervention differences in the cognitive test scores and loneliness scores were compared between the control and intervention groups using linear regression models.ResultsEighty-three subjects participated (41 in the intervention group and 42 in the control group). Their mean ± standard deviation age was 80.5 ± 6.8 years. Adherence to the protocol was high. There was no dropout and mean percentage of days completed of the targeted trial days among the intervention group was 89% (range 77%–100%). Among the cognitively intact participants, the intervention group improved more than did the control group on a semantic fluency test (P = .003) at the post-trial assessment and a phonemic fluency test (P = .004) at the 18-week assessments. Among those with mild cognitive impairment, a trend (P = .04) toward improved psychomotor speed was observed in the intervention group.ConclusionDaily conversations by way of user-friendly Internet communication programs demonstrated high adherence. Among the cognitively intact, the intervention group showed greater improvement in tests of language-based executive functions. Increasing daily social contacts through communication technologies could offer cost-effective home-based prevention methods. Additional studies with a longer follow-up duration are required to examine whether the intervention slows cognitive declines and delays the onset of dementia