Executive Functioning as a Potential Mediator of Age-Related Cognitive Decline in Normal Adults.

Critical requirements for the hypothesis that executive functioning is a potential mediator of age-related effects on cognitive functioning are that variables assumed to reflect executive functioning represent a distinct construct and that age-related effects on other types of cognitive functioning are reduced when measures of executive functioning are statistically controlled. These issues were investigated in a study involving 261 adults between 18 and 84 years of age. Although age-related effects on various cognitive abilities were substantially reduced after statistical control of the variance in measures hypothesized to represent executive functioning, there was only weak evidence for the existence of distinct constructs corresponding to executive functioning or to aspects of executive control concerned with inhibition, updating, or time sharing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality–cognition relations across adulthood.

Although an increasing number of studies have investigated relations between dimensions of personality and level of cognitive functioning, the research results have been somewhat inconsistent. Furthermore, relatively little is known about whether the personality–cognition relations vary as a function of age in adulthood. The current project examined these issues with data from a sample of 2,317 adults between 18 and 96 years of age who each completed a personality inventory and performed a broad battery of cognitive tests. The results revealed strong relations of the personality trait of Openness with several distinct cognitive abilities and smaller relations of other personality traits with specific cognitive abilities. Comparisons across different age groups indicated that the personality–cognition relations were both qualitatively and quantitatively similar across the adult years. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Is There Anything Special About the Aging of Source Memory?

A battery of cognitive tests designed to measure the constructs of episodic memory, perceptual speed, fluid ability, executive functioning, and vocabulary was administered to 330 adults between the ages of 18 and 89. Each participant also performed 4 different tasks designed to assess source memory. Structural equation modeling was used to evaluate the validity of a source-memory construct and to explore the relation of the source-memory construct to age and to the other cognitive variables. The variance common to the source-memory variables was strongly related to other cognitive abilities, suggesting that source memory may not have discriminant validity, and there were only small unique age-related effects on the source-memory construct after the influence of other abilities was considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological mediators of the links among age, chronic illness, and everyday problem solving.

Reductions in everyday problem solving (EPS) are often reported in older age, although the underlying mechanisms remain unclear. The authors examined the role of 2 variables predicted to mediate (neuropsychological abilities and health status) or moderate (health status) the relationship between age and EPS performance. Toward these ends, they compared EPS and neuropsychological performance in 50 functionally independent adults with chronic kidney disease (CKD) and 64 control participants matched on age and education. Both older age and CKD were associated with worse performance on measures of EPS and memory/executive abilities. Neuropsychological abilities were positively associated with EPS performance. In both the full sample and control participants only, memory/executive functioning mediated the association between presence of chronic illness and EPS. Furthermore, memory/executive functioning partially mediated the link between age and EPS. Findings indicate that relations among age, health status, and EPS are not straightforward. Although performance on neuropsychological measures appeared to underlie EPS declines in chronic illness, increasing age remained independently associated with reduced EPS. The authors discuss implications for models of adult developmental changes in everyday cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relation between instrumental musical activity and cognitive aging.

Objective: Intensive repetitive musical practice can lead to bilateral cortical reorganization. However, whether musical sensorimotor and cognitive abilities transfer to nonmusical cognitive abilities that are maintained throughout the life span is unclear. In an attempt to identify modifiable lifestyle factors that may potentially enhance successful aging, we evaluated the association between musical instrumental participation and cognitive aging. Method: Seventy older healthy adults (ages 60–83) varying in musical activity completed a comprehensive neuropsychological battery. The groups (nonmusicians, low and high activity musicians) were matched on age, education, history of physical exercise, while musicians were matched on age of instrumental acquisition and formal years of musical training. Musicians were classified in the low (1–9 years) or high (>10 years) activity group based on years of musical experience throughout their life span. Results: The results of this preliminary study revealed that participants with at least 10 years of musical experience (high activity musicians) had better performance in nonverbal memory (η2 = .106), naming (η2 = .103), and executive processes (η2 = .131) in advanced age relative to nonmusicians. Several regression analyses evaluated how years of musical activity, age of acquisition, type of musical training, and other variables predicted cognitive performance. Conclusions: These correlational results suggest a strong predictive effect of high musical activity throughout the life span on preserved cognitive functioning in advanced age. A discussion of how musical participation may enhance cognitive aging is provided along with other alternative explanations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effects of age and naturally occurring experience on spatial visualization performance.

A questionnaire designed to assess experience with activities presumed to require spatial visualization abilities, and psychometric tests of these abilities, were administered to 383 adults ranging from 20 to 83 years of age. Although research participants varied considerably in the amount of self-reported experience, statistical control of experience resulted in relatively modest attenuations of the relations between age and spatial visualization performance. These findings seem inconsistent with a strong disuse interpretation of cognitive aging phenomena and suggest that at least some age-related differences in cognitive functioning are independent of the amount of experience with relevant activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the specificity of face cognition compared with general cognitive functioning across adult age.

Face cognition is considered a specific human ability, clearly differentiable from general cognitive functioning. Its specificity is primarily supported by cognitive-experimental and neuroimaging research, but recently also from an individual differences perspective. However, no comprehensive behavioral data are available, which would allow estimating lifespan changes of the covariance structure of face-cognition abilities and general cognitive functioning as well as age-differences in face cognition after accounting for interindividual variability in general cognition. The present study aimed to fill this gap. In an age-heterogeneous (18–82 years) sample of 448 adults, we found no factorial dedifferentiation between face cognition and general cognition. Age-related differences in face memory were still salient after taking into account changes in general cognitive functioning. Face cognition thus remains a specific human ability compared with general cognition, even until old age. We discuss implications for models of cognitive aging and suggest that it is necessary to include more explicitly special social abilities in those models. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Olfactory acuity and cognitive function converge in older adulthood: Support for the common cause hypothesis.

Visual and auditory thresholds and cognitive variables have shown converging losses in old age, which might exist because standard cognitive tests rely on these modalities for assessment. The present study examined convergence between olfactory acuity and cognitive function to investigate the common cause hypothesis in another sensory modality. Multiple-groups structural equation modeling techniques (EQS) were used to test the fit of a model representing the common cause hypothesis for olfactory acuity (threshold, detection) and cognitive function (verbal memory, letter and category fluency, reasoning, processing speed, and vocabulary level) data from 98 nondemented older adults (aged 55 to 97) and 103 younger adults (aged 18 to 45). The model fit better the data from the older adults, consistent with the hypothesis that measures of sensory and cognitive functioning converge in older adulthood due to a common factor; however, direct chronological age effects were found that suggest that there are unique influences of age beyond those shared between cognitive and sensory variables. The results suggest that olfactory functioning may be a valid indicator of the integrity of the aging brain in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What needs to be explained to account for age-related effects on multiple cognitive variables?

Structural equation methodology was used to investigate age-related influences across a number of cognitive variables in 204 adults ranging from 18 to 91 years of age with a hierarchical structure that contained 4 1st-order factors and 1 2nd-order common factor. Direct age relations were found to the common factor as well as to 1st-order speed and memory factors. Replicability of the findings was explored by investigating the same structure of age relations, using 2 different data sets, and a similar pattern was found in each. These results suggest that at least 3 statistically distinct types of age-related influences are operating on a wide variety of cognitive variables and presumably require separate explanatory mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neurocognitive influences on health behavior in a community sample.

Context: Dominant models of individual health behavior omit biological variables entirely and are composed almost exclusively of social-cognitive and conative variables. Research from the neurosciences suggests a role for brain function in explaining behaviors that require active self-regulation for consistent performance. However, the association between brain function and health behavior is underexplored. Objective: To examine the predictive power of executive function for 2 health risk behaviors and 2 health protective behaviors in healthy adults. Design: A cross-sectional community sample (N = 216) of adults 20-100 years of age were administered a battery of neuropsychological tests and completed self-report questionnaires regarding their health practices. It was hypothesized that poor performance on neuropsychological tests tapping executive function would be associated with poor health behavior tendencies. Results: Errors on the Stroop task were positively associated with health risk behavior and negatively associated with health protective behavior after controlling for demographics, education, and IQ. Conclusion: Executive function is associated with health behavior tendencies. If the association is causal, explanatory models of individual health behavior should be revised to account for individual differences in biologically imbued self-regulatory abilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Well- and ill-defined measures of everyday cognition: Relationship to older adults' intellectual ability and functional status.

The present study examined 2 approaches to the measurement of everyday cognition in older adults. Measures differing in the degree of structure offered for solving problems in the domains of medication use, financial management, and food preparation and nutrition were administered to a sample of 130 community-dwelling older adults ranging in age from 60 to 90 (M=73 years, SD=7.02 years). Well-defined and ill-defined everyday problem-solving measures, which varied in the amount of means--end-related information provided to participants, were used. The study found that (a) well- and ill-defined measures were moderately interrelated, (b) the 2 approaches were differentially related to basic cognitive abilities, and (c) together the 2 approaches explained over half of the variance in older adults' everyday instrumental functioning and were in fact better predictors of everyday functioning than traditional psychometric cognitive measures. Discussion focuses on the differential importance of both methods for assessing older adults' everyday cognitive functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developing a tool for measuring the decision-making competence of older adults.

The authors evaluated the reliability and validity of a tool for measuring older adults' decision-making competence (DMC). A sample of 205 younger adults (25–45 years), 208 young-older adults (65–74 years), and 198 old-older adults (75–97 years) made judgments and decisions related to health, finance, and nutrition. Reliable indices of comprehension, dimension weighting, and cognitive reflection were developed. Comparison of the performance of old-older and young-older adults was possible in this study, unlike previous research. As hypothesized, old-older adults performed more poorly than young-older adults; both groups of older adults performed more poorly than younger adults. Hierarchical regression analyses showed that a large amount of variance in decision performance across age groups (including mean trends) could be accounted for by social variables, health measures, basic cognitive skills, attitudinal measures, and numeracy. Structural equation modeling revealed significant pathways from 3 exogenous latent factors (crystallized intelligence, other cognitive abilities, and age) to the endogenous DMC latent factor. Further research is needed to validate the meaning of performance on these tasks for real-life decision making. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of adult age and working memory on reasoning and spatial abilities.

Three predictions were derived from the hypothesis that adult age differences in certain measures of cognitive functioning are attributable to age-related reductions in a processing resource such as working-memory capacity. Each prediction received at least some degree of empirical support in a study involving 120 males ranging between 20 and 79 years of age. First, older adults exhibited greater impairments of performance than did young adults when task complexity increased and more demands were placed on the limited processing resources: second, the magnitudes of these complexity effects were highly correlated across verbal (reasoning) and spatial (paper folding) tasks. Finally, statistical control of an index of a working-memory processing resource attenuated the effects of age on the measures of cognitive performance. It was concluded that further progress in understanding the mechanisms of the relation between age and cognitive functioning will require improved conceptualizations of the nature of working memory or other hypothesized mediating constructs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hearing loss and cognition in the Baltimore Longitudinal Study of Aging.

Objective: To determine the relationship between hearing loss and cognitive function as assessed with a standardized neurocognitive battery. We hypothesized a priori that greater hearing loss is associated with lower cognitive test scores on tests of memory and executive function. Method: A cross-sectional cohort of 347 participants ≥55 years in the Baltimore Longitudinal Study of Aging without mild cognitive impairment or dementia had audiometric and cognitive testing performed in 1990–1994. Hearing loss was defined by an average of hearing thresholds at 0.5, 1, 2, and 4 kHz in the better-hearing ear. Cognitive testing consisted of a standardized neurocognitive battery incorporating tests of mental status, memory, executive function, processing speed, and verbal function. Regression models were used to examine the association between hearing loss and cognition while adjusting for confounders. Results: Greater hearing loss was significantly associated with lower scores on measures of mental status (Mini-Mental State Exam), memory (Free Recall), and executive function (Stroop Mixed, Trail Making B). These results were robust to analyses accounting for potential confounders, nonlinear effects of age, and exclusion of individuals with severe hearing loss. The reduction in cognitive performance associated with a 25 dB hearing loss was equivalent to the reduction associated with an age difference of 6.8 years. Conclusion: Hearing loss is independently associated with lower scores on tests of memory and executive function. Further research examining the longitudinal association of hearing loss with cognitive functioning is needed to confirm these cross-sectional findings. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Evidence for deficits on different components of theory of mind in Huntington's disease.

Objective: The main aim of this study was to investigate the effects of Huntington's disease (HD) on cognitive and affective Theory of Mind (ToM) abilities. The relation of ToM performance and executive functions was also examined. Method: Eighteen HD patients, early in the course of the disease, and 18 healthy volunteers matched for age and educational levels, were given two tasks: a nonverbal cognitive ToM task assessing attribution of intentions to others and a revised version of the 'Reading the Mind in the Eyes' test, which is an affective ToM task assessing the understanding of other people's mental states from their eyes. Participants were also given various executive tests. Results: The two ToM tasks revealed a significant impairment of ToM abilities in HD patients. Executive functioning was impaired in the HD group and ToM performance on the attribution of intentions task was dependent on several executive processes. Conclusions: Our results are consistent with the idea that both cognitive and affective aspects of ToM could be impaired in HD patients, indicating that cortico-subcortical circuits are underlying higher social functions such as ToM. The results are also consistent with the idea that only a few executive mechanisms regulate the ToM abilities we tested in this work. They also provide a basis for the understanding of the disorganized behavior and the breakdown of interpersonal relationships in daily life after HD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Speed and intelligence in old age.

Past research suggests that age differences in measures of cognitive speed contribute to differences in intellectual functioning between young and old adults. To investigate whether speed also predicts age-related differences in intellectual performance beyond age 70 yrs, tests indicating 5 intellectual abilities (speed, reasoning, memory, knowledge, and fluency) were administered to a close-to-representative, age-stratified sample of old and very old adults. Age trends of all 5 abilities were well described by a negative linear function. The speed-mediated effect of age fully explained the relationship between age and both the common and the specific variance of the other 4 abilities. Results offer strong support for the speed hypothesis of old age cognitive decline but need to be qualified by further research on the reasons underlying age differences in measures of speed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactions between self-reported alcohol outcome expectancies and cognitive functioning in the prediction of alcohol use and associated problems: A further examination.

A recent debate regarding the theoretical distinction between explicit and implicit cognitive processes relevant to alcohol-related behaviors was strongly shaped by empirical findings from dual-process models (Moss & Albery, 2009; Wiers & Stacy, 2010; Moss & Albery, 2010). Specifically, as part of a broader discussion, Wiers & Stacy (2010) contended that alcohol-related behaviors are better predicted by self-reported alcohol expectancies for individuals with good executive control and verbal abilities relative to those without such abilities. The purpose of the current paper is to further test whether self-reported alcohol outcome expectancies are moderated by measures of cognitive functioning. Using multiple indices of alcohol use, alcohol-related consequences, self-reported alcohol outcome expectancies, and cognitive functioning, both cross-sectional and longitudinal analyses were conducted in a prospective sample of 489 individuals at varying risk for alcohol use disorders. Results from a series of regression analyses testing interactions between self-reported alcohol expectancies and cognitive functioning showed minimal support for the hypothesized pattern discussed by Wiers and Stacy, 2010 regarding self-reported alcohol outcome expectancies. The overall rates of significance were consistent with Type I error rates and a substantial proportion of the significant interactions were inconsistent with previous findings. Thus, the conclusion that cognitive measures consistently moderate the relation between self-reported alcohol expectancies and alcohol use and outcomes should be tempered. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correlates of Within-Person (Across-Occasion) Variability in Reaction Time.

A total of 420 adults between 18 and 91 years of age carried palm pilot (Palm M100; PalmOne, Milpitas, CA) devices and performed several reaction time trials when prompted at random times during the day. On the average, within-person variability in median reaction time from one occasion to the next was nearly the same magnitude as the between-persons variability in across-occasion mean reaction time. Analyses controlling the variation in one variable when examining relations involving the other variable suggested that an individual's mean reaction time is a more powerful predictor of relations with age and with the level of various cognitive abilities than his or her across-occasion SD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring effects of type 2 diabetes on cognitive functioning in older adults.

Type 2 diabetes may be associated with exacerbated aging-related declines in cognitive neuropsychological performance. The authors examined whether such effects are systematic (i.e., broadly distributed across domains or domain-specific) or moderated by age (i.e., varying across age within older adults). The authors assembled recent cross-sectional data from the Victoria Longitudinal Study (VLS) Sample 3 (Wave 1; initial n = 570; initial age = 53-90 years). Using a comprehensive, multidimensional spectrum of cognitive neuropsychological tests, the authors examined performance differences by diabetes status (diabetes group vs. healthy controls) and age (young-old vs. old-old). Our results showed that healthy controls significantly outperformed the diabetes group only on markers of executive functioning and speed. Notably, the diabetes-related effects were robust across the two late-life age groups. Future research examining longitudinal changes is recommended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)