Hiroko H. Dodge

Mild cognitive impairment, amnestic type An epidemiologic study

Objective: To estimate the prevalence and examine the course of mild cognitive impairment (MCI), amnestic type, using current criteria, within a representative community sample. Methods: Retroactive application of MCI criteria to data collected during a prospective epidemiologic study was performed. The subjects were drawn from voter registration lists, composing a cohort of 1,248 individuals with mean age of 74.6 (5.3) years, who were nondemented at entry and who were assessed biennially over 10 years of follow-up. The Petersen amnestic MCI criteria were operationalized as 1) impaired memory: Word List Delayed Recall score of <1 SD below mean; 2) normal mental status: Mini-Mental State Examination score of 25+; 3) normal daily functioning: no instrumental impairments; 4) memory complaint: subjective response to standardized question; 5) not demented: Clinical Dementia Rating Scale score of <1. Results: At the five assessments, amnestic MCI criteria were met by 2.9 to 4.0% of the cohort. Of 40 persons with MCI at the first assessment, 11 (27%) developed dementia over the next 10 years. Over each 2-year interval, MCI persons showed increased risk of dementing (odds ratio = 3.9, 95% CI = 2.1 to 7.2); 11.1 to 16.7% progressed to Alzheimer disease and 0 to 5.0% progressed to other dementias. Over the same intervals, 11.1 to 21.2% of those with MCI remained MCI; of 33.3 to 55.6% who no longer had MCI, half had reverted to normal. Conclusions: In this community-based sample, 3 to 4% of nondemented persons met MCI operational criteria; despite increased risk of progressing to dementia, a substantial proportion also remained stable or reverted to normal during follow-up. Amnestic MCI as currently defined is a high-risk but unstable and heterogeneous group.

Incidence of Alzheimer’s disease in a rural community in India: The Indo–US Study

Objective: To determine overall and age-specific incidence rates of AD in a rural, population-based cohort in Ballabgarh, India, and to compare them with those of a reference US population in the Monongahela Valley of Pennsylvania. Methods: A 2-year, prospective, epidemiologic study of subjects aged ≥55 years utilizing repeated cognitive and functional ability screening, followed by standardized clinical evaluation using the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, and the National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association criteria for the diagnosis, and the Clinical Dementia Rating scale for the staging, of dementia and AD. Results: Incidence rates per 1000 person–years for AD with CDR ≥0.5 were 3.24 (95% CI: 1.48–6.14) for those aged ≥65 years and 1.74 (95% CI: 0.84–3.20) for those aged ≥55 years. Standardized against the age distribution of the 1990 US Census, the overall incidence rate in those aged ≥65 years was 4.7 per 1000 person–years, substantially lower than the corresponding rate of 17.5 per 1000 person–years in the Monongahela Valley. Conclusion: These are the first AD incidence rates to be reported from the Indian subcontinent, and they appear to be among the lowest ever reported. However, the relatively short duration of follow-up, cultural factors, and other potential confounders suggest caution in interpreting this finding.

The Trajectory of Gait Speed Preceding Mild Cognitive Impairment

OBJECTIVES To compare the trajectory of motor decline, as measured by gait speed and finger-tapping speed, between elderly people who developed mild cognitive impairment (MCI) and those who remained cognitively intact. We also sought to determine the approximate time at which the decline in motor function accelerated in persons who developed MCI. DESIGN Longitudinal cohort study. PARTICIPANTS Participants were 204 healthy seniors (57.8% women) from the Oregon Brain Aging Study evaluated for up to 20 years using annual neurologic, neuropsychological, and motor examinations. MAIN OUTCOME MEASURES The pattern of motor decline with aging was compared using a mixed-effects model with an interaction term for age and a clinical diagnosis of MCI. The time before diagnosis of MCI, when the change in gait or finger-tapping speed accelerates, was assessed using a mixed-effects model with a change point for men and women, separately and combined, who developed MCI. RESULTS The rates of change, with aging, in gait speed (P < .001) and finger-tapping speed in the dominant hand (P = .003) and nondominant hand (P < .001) were significantly different between participants who developed MCI (converters) and those who did not (nonconverters). Using a change point analysis for MCI converters, the decrease in gait speed accelerated by 0.023 m/s/y (P < .001), occurring 12.1 years before the onset of MCI. An acceleration in gait speed decline occurred earlier in men than women. For tapping speed, the change point occurred after the onset of MCI for both dominant and nondominant hands when men and women were combined. CONCLUSIONS Motor decline as indexed by gait speed accelerates up to 12 years before MCI. Longitudinal changes in motor function may be useful in the early detection of dementia during preclinical stages, when the utility of disease-modifying therapies would be greatest.

Predictors of nursing facility admission: a 12-year epidemiological study in the United States

Objectives: To identify predictors of institutionalization in a community‐based cohort of older adults.

Exercise level and cognitive decline: The MoVIES project

Growing evidence suggests that physical exercise may be protective against cognitive impairment and decline. A prospective study of a representative rural community sample (N = 1,146) aged 65+ years examined self-reported exercise habits and measured global cognitive function using the Mini-Mental State Examination (MMSE). A composite variable “exercise level” combining type, frequency, and duration of exercise was created with three levels: “high exercise” (aerobic exercise of ≥ 30 minute duration ≥ 3 times a week), “low exercise” (all other exercise groups), and “no exercise.” Cognitive decline was defined as being in the 90th percentile of decline in this cohort, ie, declining by 3 or more MMSE points during the 2-year interval between two assessments. In a multiple regression model, high exercise level at the baseline assessment was negatively associated with, ie, was protective against, being in the group with the greatest amount of decline at the follow-up assessment, after adjusting for likely confounders (odds ratio = 0.39; 95% confidence interval, 0.19, 0.78). When high exercise was redefined using frequency as ≥ 5 days per week as the threshold, as per the Surgeon General’s guidelines, both low exercise and high exercise were negatively associated with cognitive decline. Exercise may have implications for prevention of cognitive decline.

Ten-year incidence of dementia in a rural elderly US community population The MoVIES Project

Objective: To determine incidence rates by age, sex, and education of overall dementia and probable/possible AD in a largely rural community. Methods: Ten-year prospective study of a randomly selected community sample aged 65+; biennial cognitive screening followed by standardized clinical evaluation. Incidence rates were estimated for overall dementia (Diagnostic and Statistical Manual of Mental Disorders, 3rd ed., revised, criteria and Clinical Dementia Rating [CDR]) and for probable/possible AD (National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association criteria). Results: The cohort consisted of 1,298 individuals free of dementia at study entry. Among these, 199 incident (new) cases of overall (all-cause) dementia with CDR stage ≥ 0.5, including 110 with CDR ≥ 1, were detected during follow-up. Among the incident cases, 153 (76.9%) had probable/possible AD. Age-specific incidence rates are reported for all dementia and for probable/possible AD, by sex and CDR stage. Among all-cause dementias with CDR = 0.5, controlling for age and education, men had a higher incidence rate than women. In the same group, those with less than high school education had significantly higher incidence rates than those with more education. Rates did not vary significantly by sex or education for probable/possible AD or for dementia with CDR ≥ 1. Conclusions: Incidence rates of all dementias and of AD increased with age; men and those with lesser education had higher rates of possible/incipient dementia (CDR = 0.5) in this community. Potential explanations for these sex and education effects are discussed.

Intelligent Systems for Assessing Aging Changes: Home-Based, Unobtrusive, and Continuous Assessment of Aging

OBJECTIVES To describe a longitudinal community cohort study, Intelligent Systems for Assessing Aging Changes, that has deployed an unobtrusive home-based assessment platform in many seniors homes in the existing community. METHODS Several types of sensors have been installed in the homes of 265 elderly persons for an average of 33 months. Metrics assessed by the sensors include total daily activity, time out of home, and walking speed. Participants were given a computer as well as training, and computer usage was monitored. Participants are assessed annually with health and function questionnaires, physical examinations, and neuropsychological testing. RESULTS Mean age was 83.3 years, mean years of education was 15.5, and 73% of cohort were women. During a 4-week snapshot, participants left their home twice a day on average for a total of 208 min per day. Mean in-home walking speed was 61.0 cm/s. Participants spent 43% of days on the computer averaging 76 min per day. DISCUSSION These results demonstrate for the first time the feasibility of engaging seniors in a large-scale deployment of in-home activity assessment technology and the successful collection of these activity metrics. We plan to use this platform to determine if continuous unobtrusive monitoring may detect incident cognitive decline.

Depression After Stroke: A Prospective Epidemiological Study

Objectives: To elucidate the relationship between stroke and depressive symptoms and to determine whether disability or cerebrovascular risk factors mediate that relationship.

Nutrient Biomarker Patterns, Cognitive Function, and Mri Measures of Brain Aging

Objective: To examine the cross-sectional relationship between nutrient status and psychometric and imaging indices of brain health in dementia-free elders. Methods: Thirty plasma biomarkers of diet were assayed in the Oregon Brain Aging Study cohort (n = 104). Principal component analysis constructed nutrient biomarker patterns (NBPs) and regression models assessed the relationship of these with cognitive and MRI outcomes. Results: Mean age was 87 ± 10 years and 62% of subjects were female. Two NBPs associated with more favorable cognitive and MRI measures: one high in plasma vitamins B (B1, B2, B6, folate, and B12), C, D, and E, and another high in plasma marine ω-3 fatty acids. A third pattern characterized by high trans fat was associated with less favorable cognitive function and less total cerebral brain volume. Depression attenuated the relationship between the marine ω-3 pattern and white matter hyperintensity volume. Conclusion: Distinct nutrient biomarker patterns detected in plasma are interpretable and account for a significant degree of variance in both cognitive function and brain volume. Objective and multivariate approaches to the study of nutrition in brain health warrant further study. These findings should be confirmed in a separate population. Neurology® 2012;78:241–249

Alcohol consumption and cognitive function in late life: A longitudinal community study

Objective: To examine the association between alcohol use and cognitive decline in a longitudinal study of a representative elderly community sample free of dementia at baseline. Methods: Cognitive functions and self-reported drinking habits were assessed at 2-year intervals over an average of 7 years of follow-up. Cognitive measures, grouped into composites, were examined in association with alcohol consumption. Trajectory analyses identified latent homogeneous groups with respect to alcohol use frequency over time, and their association with average decline over the same period in each cognitive domain. Models controlled for age, sex, education, depression, smoking, general mental status (Mini-Mental State Examination [MMSE]), performance on the given test at baseline, and subsequent new-onset dementia during follow-up. Results: The authors found three homogeneous trajectories that they characterized as no drinking, minimal drinking, and moderate drinking. Few heavy drinkers were identified in this elderly cohort. Compared to no drinking, both minimal and moderate drinking were associated with lesser decline on the MMSE and Trailmaking tests. Minimal drinking was also associated with lesser decline on tests of learning and naming. These associations were more pronounced when comparing current drinkers to former drinkers (quitters) than to lifelong abstainers. Conclusion: In a representative elderly cohort over an average of 7 years, a pattern of mild-to-moderate drinking, compared to not drinking, was associated with lesser average decline in cognitive domains over the same period.