Examining Gender Differences in Neurocognitive Functioning Across Adulthood.

Objective: Previous research has shown that women have an advantage on verbal episodic memory and processing speed tasks, while men show an advantage on spatial ability measures. Previous work has also found differences in cognition across age. The current study examines gender differences in neurocognitive functioning across adulthood, whether age moderates this effect, and whether these differences remain consistent with practice across multiple testing sessions.

Attrition in Longitudinal Data is Primarily Selective with Respect to Level Rather than Rate of Change.

Objectives: An important question in longitudinal research is whether the individuals who discontinue participation differ in their level of, or their change in, cognitive functioning relative to individuals who return for subsequent occasions.

Methods: Performance in five cognitive domains was examined in nearly 5000 participants between 18 and 85 years of age who completed between one and five longitudinal occasions.

Results: Little or no differences in cognitive performance were apparent between young adults who did or did not return for subsequent longitudinal occasions.

Brain biomarkers and cognition across adulthood.

Understanding the associations between brain biomarkers (BMs) and cognition across age is of paramount importance. Five hundred and sixty-two participants (19-80 years old, 16 mean years of education) were studied. Data from structural T1, diffusion tensor imaging, fluid-attenuated inversion recovery, and resting-state functional magnetic resonance imaging scans combined with a neuropsychological evaluation were used.

Trajectories of normal cognitive aging.

Although sensitive detection of pathological cognitive aging requires accurate information about the trajectory of normal cognitive aging, prior research has revealed inconsistent patterns of age-cognition relations with cross-sectional and longitudinal comparisons. Age trends in four cognitive domains were compared in over 5,000 adults with cross-sectional data, and in almost 1,600 adults with three-occasion longitudinal data. Quasi-longitudinal comparisons, which are similar to cross-sectional comparisons in that there is no prior test experience and are similar to longitudinal comparisons in that the participants are from the same birth cohorts, were also reported.

Why is cognitive change more negative with increased age?

Objective: The primary goal of the current study was to investigate factors contributing to more negative cognitive change at older ages.

Method: Longitudinal data on 12 cognitive tests were examined in 2,637 adults ranging from 18 to 85 years of age. Because both the intervals between measurement occasions and the number of occasions varied across participants, it was possible to investigate effects of interval and number of measurement occasions on cognitive change in adults of different ages.

Comparable Consistency, Coherence, and Commonality of Measures of Cognitive Functioning Across Adulthood.

Increased age is associated with lower scores in many cognitive tests, but interpretation of those results is based on the assumption that the measurement at different ages is equivalent, such that the differences reflect quantitative rather than qualitative changes. The assumption of measurement equivalence was investigated by comparing adult age differences in the relations among alternative versions of the same tests, among different tests of the same ability, and among different cognitive abilities. Results from three independent data sets revealed that only modest age differences were apparent at each level, which implies that cognitive abilities have similar measurement properties at different ages in adulthood.

Shared and unique influences on age-related cognitive change.

Objective: Decompose cognitive change into influences unique to particular cognitive domains, and influences shared across different cognitive domains.

Method: A total of 2,546 adults between 18 and 95 years of age performed a battery of 12 cognitive tests on 2 occasions separated by an average of 3 years. An estimate of general cognitive functioning based on the first principal factor was regressed from the observed cognitive scores to derive an estimate of specific influences on each measure, and this value was subtracted from the observed score to provide an estimate of general influences on the measure.

Age does not matter: Memory complaints are related to negative affect throughout adulthood.

Objectives: Memory complaints are present in adults of all ages but are only weakly related to objective memory deficits, raising the question of what their presence may indicate. In older adults, memory complaints are moderately related to negative affect, but there is little research examining this relationship in young and middle-aged adults. This study examined whether memory complaints and negative affect were similarly related across the adult lifespan and in adults with varying levels of objective memory performance.

Item analyses of memory differences.

Objective: Although performance on memory and other cognitive tests is usually assessed with a score aggregated across multiple items, potentially valuable information is also available at the level of individual items.

Method: The current study illustrates how analyses of variance with item as one of the factors, and memorability analyses in which item accuracy in one group is plotted as a function of item accuracy in another group, can provide a more detailed characterization of the nature of group differences in memory. Data are reported for two memory tasks, word recall and story memory, across age, ability, repetition, delay, and longitudinal contrasts.

Little relation of adult age with cognition after controlling general influences.

Both general (i.e., shared across different cognitive measures) and specific (i.

Contributions of the Individual Differences Approach to Cognitive Aging.

Objective: To review selected research in cognitive aging incorporating an individual differences approach.

Method: Three contributions of the individual differences perspective in cognitive aging are illustrated with data from the Virginia Cognitive Aging Project.

Results: Research capitalizing on the variability among individuals has been used to: (a) improve sensitivity and validity of measurement of cognitive functioning, and evaluate possible age differences in the meaning of the measures; (b) investigate relations between age and individual cognitive measures in the context of other types of cognitive measures; and (c) examine the degree to which age-related influences on target measures are statistically independent of age-related influences on other cognitive measures.

Selective association between cortical thickness and reference abilities in normal aging.

A previous study of reference abilities and cortical thickness reported that association between reference abilities and cortical thickness summarized over large ROIs suppressed was suppressed after controlling for mean cortical thickness and global cognition. In this manuscript, we showed that preserving detailed spatial patterns of cortical thickness can identify reference-ability-specific association besides the association explained by global cognition and mean cortical thickness. We identified associations between cortical thickness and 3 cognitive reference abilities after controlling for mean thickness, global cognition, and linear chronological age: (1) memory, (2) perceptual speed, and (3) vocabulary.

Relations of Naturally Occurring Variations in State Anxiety and Cognitive Functioning.

Although effects of anxiety on cognitive performance have been extensively examined, anxiety-cognition relationships are often defined by between-person relationships. The current research investigated the effects of within-person variations in state anxiety on cognitive performance based on measures from three separate sessions in a sample of 1,769 healthy adults ranging from 18 to 99 years of age. Some of the adults in the sample exhibited a wide range of state anxiety across the three sessions, whereas others were fairly stable.

Does Need for Cognition Have the Same Meaning at Different Ages?

Determining whether Need for Cognition (NC) has the same meaning across age may help understand why there are dramatically different age trends for cognitive abilities and for NC in adulthood. Data from 5,004 participants aged between 18 and 99 years were used to examine both internal relations and external relations of NC. Internal relations were investigated with measures of reliability, examination of factor invariance, and test-retest coefficients across three age groups.

Spatial working memory capacity predicts bias in estimates of location.

Spatial memory research has attributed systematic bias in location estimates to a combination of a noisy memory trace with a prior structure that people impose on the space. Little is known about intraindividual stability and interindividual variation in these patterns of bias. In the current work, we align recent empirical and theoretical work on working memory capacity limits and spatial memory bias to generate the prediction that those with lower working memory capacity will show greater bias in memory of the location of a single item.

Which Aspects of Social Support Are Associated With Which Cognitive Abilities for Which People?

Objectives: To assess the relations between 11 aspects of social support and five cognitive abilities (vocabulary, reasoning, spatial visualization, memory, and speed of processing) and to determine whether these relations between social support and cognition are moderated by age or sex.

Method: A sample of 2,613 individuals between the ages of 18 and 99 years completed a battery of cognitive tests and a questionnaire assessing aspects of social support. A measure of general intelligence was computed using principal components analysis.

The Reference Ability Neural Network Study: Life-time stability of reference-ability neural networks derived from task maps of young adults.

Analyses of large test batteries administered to individuals ranging from young to old have consistently yielded a set of latent variables representing reference abilities (RAs) that capture the majority of the variance in age-related cognitive change: Episodic Memory, Fluid Reasoning, Perceptual Processing Speed, and Vocabulary. In a previous paper (Stern et al., 2014), we introduced the Reference Ability Neural Network Study, which administers 12 cognitive neuroimaging tasks (3 for each RA) to healthy adults age 20-80 in order to derive unique neural networks underlying these 4 RAs and investigate how these networks may be affected by aging.

Do cognitive interventions alter the rate of age-related cognitive change?

There has recently been a great deal of interest in cognitive interventions, particularly when applied in older adults with the goal of slowing or reversing age-related cognitive decline. Although seldom directly investigated, one of the fundamental questions concerning interventions is whether the intervention alters the rate of cognitive change, or affects the level of certain cognitive measures with no effect on the trajectory of change. This question was investigated with a very simple intervention consisting of the performance of three versions (treatment) or one version (control) of the relevant cognitive tests at an initial occasion.

Breadth and age-dependency of relations between cortical thickness and cognition.

Recent advances in neuroimaging have identified a large number of neural measures that could be involved in age-related declines in cognitive functioning. A popular method of investigating neural-cognition relations has been to determine the brain regions in which a particular neural measure is associated with the level of specific cognitive measures. Although this procedure has been informative, it ignores the strong interrelations that typically exist among the measures in each modality.

Continuity of cognitive change across adulthood.

Although cross-sectional (between-person) comparisons consistently reveal age-related cognitive declines beginning in early adulthood, significant declines in longitudinal (within-person) comparisons are often not apparent until age 60 or later. The latter results have led to inferences that cognitive change does not begin until late middle age. However, because mean change reflects a mixture of maturational and experiential influences whose contributions could vary with age, it is important to examine other properties of change before reaching conclusions about the relation of age to cognitive change.

Test experience effects in longitudinal comparisons of adult cognitive functioning.

It is widely recognized that experience with cognitive tests can influence estimates of cognitive change. Prior research has estimated experience effects at the level of groups by comparing the performance of a group of participants tested for the second time with the performance of a different group of participants at the same age tested for the first time. This twice-minus-once-tested method was adapted in the current study to derive estimates of test experience at the level of individual participants.

Making cognitive latent variables manifest: distinct neural networks for fluid reasoning and processing speed.

Cognitive psychologists posit several specific cognitive abilities that are measured with sets of cognitive tasks. Tasks that purportedly tap a specific underlying cognitive ability are strongly correlated with one another, whereas performances on tasks that tap different cognitive abilities are less strongly correlated. For these reasons, latent variables are often considered optimal for describing individual differences in cognitive abilities.

Implications of the Flynn Effect for Age-Cognition Relations.

Many studies have documented that cognitive performance is often higher among people of the same age who are tested in more recent years, and it is sometimes suggested that this phenomenon will distort the relations between age and cognition in cross-sectional studies. This possibility was examined with data from two large projects involving adults across a wide age range. The results indicated that there were similar time-of-measurement increases in cognitive scores at different ages, which were accompanied by nearly constant cross-sectional age differences, but positively inflated estimates of longitudinal age differences.

Why are there different age relations in cross-sectional and longitudinal comparisons of cognitive functioning?

A major challenge for researchers interested in investigating relations between aging and cognitive functioning is distinguishing influences of aging from other determinants of cognitive performance. For example, cross-sectional comparisons may be distorted because people of different ages were born and grew up in different time periods, and longitudinal comparisons may be distorted because performance on a second occasion is influenced by the experience of performing the tests on the first occasion. One way in which these different types of influences might be investigated is with research designs involving comparisons of people of different ages from the same birth cohorts who are all tested for the first time in different years.

The Reference Ability Neural Network Study: motivation, design, and initial feasibility analyses.

We introduce and describe the Reference Ability Neural Network Study and provide initial feasibility data. Based on analyses of large test batteries administered to individuals ranging from young to old, four latent variables, or reference abilities (RAs) that capture the majority of the variance in age-related cognitive change have been identified: episodic memory, fluid reasoning, perceptual speed, and vocabulary. We aim to determine whether spatial fMRI networks can be derived that are uniquely associated with the performance of each reference ability.