Cognition-Mortality Associations Are More Pronounced When Estimated Jointly in Longitudinal and Time-to-Event Models.

With aging populations worldwide, there is growing interest in links between cognitive decline and elevated mortality risk-and, by extension, analytic approaches to further clarify these associations. Toward this end, some researchers have compared cognitive trajectories of survivors vs. decedents while others have examined longitudinal changes in cognition as predictive of mortality risk.

Cardiovascular symptoms and longitudinal declines in processing speed differentially predict cerebral white matter lesions in older adults.

It is well established that cerebral white matter lesions (WML), present in the majority of older adults, are associated with cardiovascular and cerebrovascular diseases and also with cognitive decline. However, much less is known about how WML are related to other important individual characteristics and about the generality vs. brain region-specificity of WML.

Illness and intelligence are comparatively strong predictors of individual differences in depressive symptoms following middle age.

Objective: We compared the importance of socio-demographic, lifestyle, health, and multiple cognitive measures for predicting individual differences in depressive symptoms in later adulthood.

Method: Data came from 6203 community-dwelling older adults (age 41-93 years at study entry) from the United Kingdom. Predictors (36 in total) were assessed up to four times across a period of approximately 12 years.

Speed of Visual Search in Old Age: 1950 to 2016.

Objectives: To review work on the effects of old age on speed of visual search and of discriminations between signals and choices of responses between 1950 and 2016.

Methods: Literature review and Brain Google.

Results: Mild existential despondency.

Think Fast, Feel Fine, Live Long: A 29-Year Study of Cognition, Health, and Survival in Middle-Aged and Older Adults.

In a 29-year study of 6,203 individuals ranging in age from 41 to 96 years at initial assessment, we evaluated the relative and combined influence of 65 mortality risk factors, which included sociodemographic variables, lifestyle attributes, medical indices, and multiple cognitive abilities. Reductions in mortality risk were most associated with higher self-rated health, female gender, fewer years as a smoker, and smaller decrements in processing speed with age. Thus, two psychological variables-subjective health status and processing speed-were among the top predictors of survival.

Life span decrements in fluid intelligence and processing speed predict mortality risk.

We examined life span changes in 5 domains of cognitive performance as predictive of mortality risk. Data came from the Manchester Longitudinal Study of Cognition, a 20-plus-year investigation of 6,203 individuals ages 42-97 years. Cognitive domains were general crystallized intelligence, general fluid intelligence, verbal memory, visuospatial memory, and processing speed.

Between-individual variability and interpretation of associations between neurophysiological and behavioral measures in aging populations: comment on Salthouse (2011).

Salthouse (2011) argued that (a) variance between individuals on cognitive test scores remains constant between 20 and 90 years of age and (b) widely recognized problems of deducing functional relationships from patterns of correlations between measurements become especially severe for neuropsychological indices, especially for gross indices of age-related brain changes (e.g., losses of brain volume or increases in white matter lesions).

Terminal pathologies affect rates of decline to different extents and age accelerates the effects of terminal pathology on cognitive decline.

Objectives: To test whether different terminal pathologies are associated with different rates of age-related decline in fluid and crystallized mental abilities and whether pathology-associated declines are accelerated by age.

Methods: During a 20-year longitudinal study, 6203 participants were quadrennially assessed on the Heim's (Heim, A 1970) The AH4 series of intelligence tests Slough, U.K.

Developing a self-reported comorbidity index to predict mortality of community-dwelling older adults.

Current common comorbidity measures have poor to moderate predictive validity of mortality of community-dwelling older adults. Hence, our aim is to develop a simpler resource-efficient self-reported comorbidity index in the prediction of survival. 113 older adults in Greater Manchester, United Kingdom attended a routine medical examination whereby information gathered was used to construct Charlson Comorbidity Index (CCI).

No association between Cholinergic Muscarinic Receptor 2 (CHRM2) genetic variation and cognitive abilities in three independent samples.

Cognitive ability has a substantial genetic component and more than 15 candidate genes have been identified over the past 8 years. One gene that has been associated with general cognitive ability is the cholinergic muscarinic 2 receptor (CHRM2). In an attempt to replicate this finding we typed marker rs8191992 (the originally reported CHRM2 SNP) in two population based cohorts-one Scottish aged over 50 years (N = 2,091) and the other English comprising non-demented elderly participants (N = 758)-and a family-based Australian adolescent sample (N = 1,537).

Further analyses of the effects of practice, dropout, sex, socio-economic advantage, and recruitment cohort differences during the University of Manchester longitudinal study of cognitive change in old age.

A sample of 4,314 volunteers who, when first recruited, were aged from 41 to 93 years were quadrennially tested from 2 to 4 occasions during the next 4 to 20 years on the Cattell Culture Fair intelligence test, 2 tests of information-processing speed, the Wechsler Adult Intelligence Scale (WAIS) vocabulary test, and 3 memory tests. After significant effects of practice, sex, demographics, socio-economic advantage, and recruitment cohort had been identified and considered, performance on all tests declined with age. These age-related declines accelerated for the Cattell and WAIS, 2 tests of information speed, and 2 of the memory tests.

Death, dropout, and longitudinal measurements of cognitive change in old age.

During a 20-year longitudinal study of cognitive change in old age 2,342 of 5,842 participants died and 3,204 dropped out. To study cognitive change as death approaches, we grouped participants by survival, death, dropout, or dropout followed by death. Linear mixed-effects pattern-mixture models compared rates of cognitive change before death and dropout from four quadrennial administrations of tests of fluid intelligence, vocabulary, and verbal learning.

Age and ability affect practice gains in longitudinal studies of cognitive change.

During a 20-year longitudinal study, 5,842 participants aged 49 to 93 years significantly improved over two to four successive experiences of the Heim AH4-1 intelligence test (first published in 1970), even with between-test intervals of 4 years and longer. After we considered significant attrition by death and dropout and the effects of gender, socioeconomic advantage, and recruitment cohort, we found that participants with high intelligence test scores showed greater improvement than did those with lower intelligence test scores. Practice gains also reduced with age, even after we took into consideration the individual differences in intelligence test scores.

Sudden declines in intelligence in old age predict death and dropout from longitudinal studies.

It is well known that approaching death accelerates cognitive decline. The converse issue, that is, the question of whether rapid declines in cognitive ability are risk factors for imminent death, has not been investigated. Every 4 years between 1983 and 2003, we gave 1,414 healthy community residents who were aged between 49 and 93 years the Heim AH4-1 test of fluid intelligence.

Investigation of a functional quinine oxidoreductase (NQO2) polymorphism and cognitive decline.

NAD(P)H dehydrogenase quinone 2 (NQO2) is a quinone reductase whose functions include the reduction of both oxidative stress during the redox cycle and neurotoxicity caused by the metabolism of catecholamines. We have investigated a functional non-synonymous exon 3 single nucleotide polymorphism (rs1143684) within the NQO2 gene for association with cognitive decline using a cohort of 722 community-dwelling older individuals aged 50 years and over. The volunteers had completed tests that measured fluid intelligence, processing speed, immediate/delayed verbal recall and semantic memory.

Age-associated losses of brain volume predict longitudinal cognitive declines over 8 to 20 years.

Absolute differences in global brain volume predict differences in cognitive ability among healthy older adults. However, absolute differences confound lifelong differences in brain size with amounts of age-related shrinkage. Measurements of cerebrospinal fluid (CSF) volume were made to estimate age-related shrinkage in 93 healthy volunteers aged 63 to 86 years.

Effects of global atrophy, white matter lesions, and cerebral blood flow on age-related changes in speed, memory, intelligence, vocabulary, and frontal function.

Brain images were obtained from 133 healthy people of ages 61-85 years who completed 20 tests of information processing speed, intelligence, frontal and executive function, memory, and vocabulary. Structural equation models examined relationships between cognitive test scores, ages and measurements of global age-associated atrophy, white matter lesions, and cerebral blood flow. These neurophysiological measures jointly account for all age-related variance in information processing speed.

White matter lesions account for all age-related declines in speed but not in intelligence.

MRI scans measured white matter lesion prevalence (WMLP) in 65 people ages 65-84 years who also took 17 cognitive tests: 3 tests of general fluid intelligence, 3 of vocabulary, 2 of episodic and 3 of working memory, 2 of processing speed, and 4 of frontal and executive function. Entry of age with WMLP into regression equations as predictors of test scores showed that inferences about the functional relationships between markers of brain aging and cognitive impairments are seriously misleading if they are based on simple correlations alone. A new finding that WMLP accounts for all of the age-related variance between individuals in tests of speed and executive ability but for none of the age-related variance in intelligence revises current hypotheses that gross brain changes affect general fluid intelligence and other mental abilities solely through their effects on information-processing speed.

Losses in gross brain volume and cerebral blood flow account for age-related differences in speed but not in fluid intelligence.

Age-related gross head size; adjusted age-related change in brain volume and carotid and basilar blood flow; as well as scores on 3 tests of fluid intelligence (gf), 2 tests of information-processing speed, 2 memory tests, and 3 tests of executive function were obtained from 69 volunteers aged from 62 to 84 years. Brain volume negatively predicted scores on all 10 cognitive tasks, accounting for up to 78% of age-related variance in scores on the speed tasks and on 1 executive task. Cerebral blood flow (CBF) negatively predicted scores on 8 cognitive tasks, accounting for up to 36% of age-related variance in speed scores.

Cognitive performance inconsistency: intraindividual change and variability.

Although many studies have examined inconsistency of cognitive performance, few have examined how inconsistency changes over time. 91 older adults (age 52 to 79) were tested weekly for 36 consecutive weeks on a series of multitrial memory speed (i.e.

Neglect of dropout underestimates effects of death in longitudinal studies.

Investigations of terminal declines in mental abilities have assessed cognitive performance at a single time point and retrospectively compared survivors and decedents at a single later census date. Neglect of outcomes other than death, such as dropout, causes a loss of information on the relative frailty of survivors and deceased persons before the census date and on incidence of mortality and frailty among survivors after the census date. This discards information on differences in health status between younger and older survivors.

Concordance of Cornell medical index self-reports to structured clinical assessment for the identification of physical health status.

Self-reported questionnaires are frequently used to assess health status in epidemiological studies. The Cornell medical index is one such tool used to determine the presence of physical and psychiatric illness but its accuracy and value have been questioned. In this study we have assessed the ability of the CMI to predict health status in two separate patient populations (n = 101, 88) by comparison to a structured medical assessment based on the SENIEUR protocol by two physicians.

Practice and drop-out effects during a 17-year longitudinal study of cognitive aging.

Interpretations of longitudinal studies of cognitive aging are misleading unless effects of practice and selective drop-out are considered. A random effects model taking practice and drop-out into account analyzed data from four successive presentations of each of two intelligence tests, two vocabulary tests, and two verbal memory tests during a 17-year longitudinal study of 5,899 community residents whose ages ranged from 49 to 92 years. On intelligence tests, substantial practice effects counteracted true declines observed over 3 to 5 years of aging and remained significant even with intervals of 7 years between successive assessments.