Relations Between Cognitive Abilities and Measures of Executive Functioning.

Although frequently mentioned in contemporary neuropsychology, the term executive functioning has been a source of considerable confusion. One way in which the meaning of a variable can be investigated involves examining its pattern of relations with established cognitive abilities. This method was applied to a variety of variables hypothesized to assess executive functioning in 2 data sets, 1 consisting of 328 adults between 18 and 93 years of age and a 2nd composite data set based on nearly 7,000 healthy adults between 18 and 95 years of age. Most of the hypothesized executive functioning variables were strongly related to reasoning and perceptual speed abilities, and very few had any unique relations with age after taking into consideration the relations of age through the cognitive abilities. These results raise questions about the extent to which neuropsychological tests of executive functioning measure a distinct dimension of variation in normal adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimating Retest Effects in Longitudinal Assessments of Cognitive Functioning in Adults Between 18 and 60 Years of Age.

Several analyses were conducted on data from samples of adults between 18 and 58 years of age who completed the same cognitive tests after an interval ranging from less than 1 week to 35 years. Because the retest interval varied across individuals, it was possible to determine the length of time needed before the gains associated with a retest decreased to 0 and to obtain simultaneous estimates of the magnitude of effects associated with increased age and a prior assessment. The results indicated that for adults within this age range, 7 or more years were needed before positive retest effects were no longer detectable. Age effects in longitudinal comparisons could be interpreted in terms of large positive effects associated with a prior assessment and negative effects associated with age that were comparable in magnitude to those observed in cross-sectional comparisons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlated and Coupled Cognitive Change in Older Adults With and Without Preclinical Dementia.

Common factor aging theories state that correlations among cognitive age effects signify a single underlying causal process. The logic underlying this proposition was evaluated by examining correlated cognitive change in a sample of 391 initially nondemented older adults who were tested annually for up to 16 years. Between-person correlations among rates of change (range=.56-.61) were partly attributable to model misspecification and the aggregation of heterogeneous groups of individuals. Correlated within-person cognitive change was much stronger in the cases (.45-.51) than in the noncases (.07-.18). These results demonstrate that correlated change may either signify causal commonality or the cumulative effects of multiple age-related conditions that can affect multiple cognitive systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-Related Differences in Performance on the Wisconsin Card Sorting Test: A Meta-Analytic Review.

Two meta-analyses investigating age-related differences in performance on a popular measure of executive function, the Wisconsin Card Sorting Test (WCST), are reported. The 1st meta-analysis examined age-related changes in performance for the number of categories achieved, and the 2nd meta-analysis examined performance for the number of perseverative errors committed. Results indicated that robust age differences were present on both measures. Further analysis of moderator variables revealed reliable effects of education and test version on both measures, whereas test modality led to marginally significant differences in effect sizes obtained only for the number of categories achieved. Findings are discussed along with current accounts of age differences in performance of the WCST. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of Executive Functioning in Verbal and Visual Memory.

G. Tremont, S. Halpert, D. J. Javorsky, and R. A. Stern (2000) found that individuals with executive dysfunction were more impaired on less structured versus more structured verbal memory tasks. In the present study, the authors investigated the relationship between executive functions and memory in patients with a history of traumatic brain injury by examining the effect of executive functioning on more structured and less structured verbal and visual memory tasks at baseline and 1-year follow-up. Matched subgroups controlled for differences in severity of neuropsychological impairment unrelated to specific executive functions. The G. Tremont et al. (2000) findings were not replicated. Results showed that when acuteness and severity of injury were controlled, executive impairment played no significant role in performance on either more or less structured memory tasks. However, regardless of structure, executive functions played a role in visual memory performance, suggesting that visual memory may be a more fluid ability than verbal memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological Assessment of Executive Functions in Women: Effects of Age and Education.

The cognitive processes underlying age-related alterations in tests assumed to reflect frontal lobe functions were investigated with a card sorting test and an alternate semantic fluency task. The tests were administered to 133 healthy women belonging to 3 age groups (range = 50-92 years) classed according to 2 education levels. The results revealed a negative association between total word fluency and perseveration in the sorting test. Aging similarly affected performance in both education groups in some components of the tasks (atypical word fluency and sensitivity to distraction). However, aging did not affect performance to the same extent in each education group in other components (particularly those reflecting switching abilities and strategies). This quasi-experimental approach provides useful tools to identify specific processing mechanisms underlying executive functions in normal aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Meta-Analytic Review of Verbal Fluency Deficits in Huntington's Disease.

A meta-analysis of 30 studies with 1,511 participants was conducted to estimate and compare the magnitude of deficits on tests of phonemic and semantic fluency for patients with Huntington's disease (HD) relative to healthy control participants. As has been found for patients with focal frontal cortical lesions (but not for patients with focal temporal cortical lesions), symptomatic HD patients were comparably impaired on tests of phonemic and semantic fluency (rs=.71 and .73, respectively). However, in contrast to patients with focal frontal lobe injuries, fluency deficits did not qualify as differential deficits relative to verbal intelligence or psychomotor speed. Therefore, for patients with HD, deficits on tests of phonemic and semantic fluency do not appear to reflect executive dysfunction but a more generalized cognitive impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Hypertension on Attention, Memory, and Executive Function in Older Adults.

Hypertension is associated with impairments in cognitive function in older adults, but the nature and extent of these deficits are unclear. Brief cognitive measures lack sensitivity, whereas comprehensive assessments produce numerous variables that are difficult to interpret. The authors performed a principal-components analysis using a computerized cognitive assessment battery and neuropsychological measures of executive function in 506 hypertensive and normotensive older participants. Composite factor scores were used to reanalyze data from 223 untreated participants without vascular complications. The hypertensive group had deficits in Speed of Cognition, Episodic and Working Memory, and Executive Function but not Continuity of Attention. Using composite scores simplified data interpretation and suggested differential effects of hypertension on cognitive performance not clearly evident in individual test results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Latent Growth Curve Analysis of Late-Life Sensory and Cognitive Function Over 8 Years: Evidence for Specific and Common Factors Underlying Change.

Correlations among rates of change in sensory and cognitive functioning in adulthood were evaluated. Measures of Vision, Hearing, Memory, Speed and Verbal ability were obtained in 1992, 1994, and 2000 in the Australian Longitudinal Study of Aging (N=2,087 at baseline). Data from 1,823 participants who undertook at least 1 clinical assessment were analyzed using latent growth curve models. A significant moderate-sized association between rates of change in Memory and Vision was found. This remained after statistically controlling for the effects of age, gender, education, self-rated health, medical conditions, and depressive symptoms. Rate of change in Hearing was weakly associated with rate of change in Memory. The results support a theory incorporating a major role for unique factors in addition to common factors underlying sensory and cognitive change in old age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal ability and executive functioning development in preschoolers at head start.

Research suggests that executive functioning skills may enhance the school readiness of children from disadvantaged homes. Questions remain, however, concerning both the structure and the stability of executive functioning among preschoolers. In addition, there is a lack of research addressing potential predictors of longitudinal change in executive functioning during early childhood. This study examined the structure of executive functioning from fall to spring of the preschool year using a multimethod battery of measures. Confirmatory factor analyses revealed a unidimensional model fit the data well at both time points, and tests of measurement invariance across time points indicated that children's mean latent executive functioning scores significantly improved over time. Verbal ability was a significant predictor of longitudinal change in executive functioning. Theoretical implications and directions for future research are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Cognitive control in adolescents with neurofibromatosis type 1.

Neurofibromatosis Type 1 (NF1) is a genetic disorder characterized by partial loss of growth control that affects the central nervous system. NF1 has been consistently associated with cognitive dysfunction, although there is no consensus on the cognitive profile in NF1 or on brain-cognition relationships. To clarify the pattern of cognitive dysfunction, performance of 16 NF1 patients and 16 age- and sex-matched controls (mean age = 14.5 years, SD = 1.3) was compared on computerized tasks measuring perception, executive functioning (inhibitory control, cognitive flexibility, and working memory), and motor control. A further aim of this study was to contrast performance on tasks or task parts requiring varying levels of cognitive control to find out whether this could explain potential difficulties experienced by this population in different cognitive domains or at different stages of information processing. Repeated measures analyses of variance showed that group differences, indicating poorer performance of NF1 patients, varied as a function of the level of cognitive control required. Evidence was also found for more basic motor skill problems in NF1 patients. Furthermore, NF1 patients were generally slower than controls. Results are discussed in the context of what is known about brain-cognition relationships in NF1. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling Memory Decline in Older Adults: The Importance of Preclinical Dementia, Attrition, and Chronological Age.

This longitudinal study examined memory loss in a sample of 391 initially nondemented older adults. Analyses decomposed observed memory loss into decline associated with preclinical dementia, study attrition, terminal decline, and chronological age. Measuring memory as a function of only chronological age failed to provide an adequate representation of cognitive change. Disease progression accounted for virtually all of the memory loss in the 25% of the sample that developed diagnosable dementia. In the remainder of the sample, both chronological age and study attrition contributed to observed memory loss. These results suggest that much of memory loss in aging adults may be attributable to the progression of preclinical dementia and other nonnormative aging processes that are not captured by chronological age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging, Subjective Experience, and Cognitive Control: Dramatic False Remembering by Older Adults.

Recent research suggests that older adults are more susceptible to interference effects than are young adults; however, that research has failed to equate differences in original learning. In 4 experiments, the authors show that older adults are more susceptible to interference effects produced by a misleading prime. Even when original learning was equated, older adults were 10 times as likely to falsely remember misleading information and were much less likely to increase their accuracy by opting not to answer under conditions of free responding. The results are well described by a multinomial model that postulates multiple modes of cognitive control. According to that model, older adults are likely to be captured by misleading information, a form of goal neglect or deficit in inhibitory functions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Part-Set Cuing Effects in Younger and Older Adults.

In 3 experiments, the authors examined part-set cuing effects in younger and older adults. Participants heard lists of category exemplars and later recalled them. Recall was uncued or cued with a subset of studied items. In Experiment 1, participants were cued with some of the category names, and they remembered fewer never-cued categories than a free-recall condition. In Experiment 2, a similar effect was observed for category exemplar cues. There was also an age difference: By some measures, a small number of cues impaired older adults more than younger. Experiment 3 replicated this result and found that older adults were disproportionately slow in the presence of cues. Across experiments, older adults showed robust part-set cuing effects, and sometimes, they were disproportionately impaired by cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contribution of specific cognitive processes to executive functioning in an aging population.

The current study investigated executive function measures emphasizing Alpha Span (ASp) to understand relationships among executive and nonexecutive tasks. Nondemented older participants (N = 417) received a comprehensive cognitive battery. Age and vocabulary adjusted correlations revealed associations among ASp, Wechsler Adult Intelligence Scale--Revised (D. Wechsler, 1981) Digit Span subtests, and fluency tasks. Principal-components analysis with varimax rotation revealed a 4 component solution (86.4% of the variance) with executive variables contributing to all loadings. Calculated component indices were submitted to a regression analysis predicting ASp performance. After accounting for age (6.3% of the variance), Component 3 reflecting brief attention-mental manipulation accounted for 13.4% of ASp variance; Component 1, verbal language ability, 11.5%; Component 2, sustained attention-mental tracking, 1.9%; and Component 4, visuoperceptual spatial organization-planning, 0.9%. Results stress the importance of considering executive and nonexecutive aspects of cognition when conceptualizing executive functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positive mood and executive function: Evidence from Stroop and fluency tasks.

Contrasting predictions have been made about the effects of positive mood states on the performance of frontal lobe tests that tap executive functions such as inhibition, switching, and strategy use. It has been argued that positive mood is likely to improve some cognitive processes, particularly those dependent on the frontal cortex and anterior cingulate of the brain. However, there is some evidence that happy mood may impair executive functioning. The current experiments investigated the effects of positive mood on Stroop and fluency tests, which are frequently used to assess executive function. Positive mood impaired performance on a switching condition of the Stroop test, but improved performance on a creative uses test of fluency. The effect of positive mood on an executive task may therefore depend on whether a task is inherently motivating or is impaired by diffuse semantic activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling Age and Retest Processes in Longitudinal Studies of Cognitive Abilities.

Mixed effects models were used to examine the separate effects associated with age and retest on changes in various cognitive abilities. Individuals (N > 800) ranging in age from 40 to 70 years at the 1st measurement occasion were assessed with measures of memory, spatial abilities, and speed on 4 occasions. All cognitive abilities showed decline associated with increased age and improvement across the 4 measurement occasions. The age-related effects were similar across variables, but the practice effects were largest for memory and smallest for speed. When retest effects were not included in the models, the age-related effects were underestimated, with the magnitude of bias depending on the size of the ignored retest effects. It is suggested that both age and retest should be modeled simultaneously when analyzing longitudinal data because part of the change across occasions may be attributable to practice or reactive effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Pain on Functioning and Well-Being in Older Adults With Osteoarthritis of the Knee.

The effects of pain on functioning and well-being were examined in 367 older adults with osteoarthritis (OA) of the knee. The relationship of OA-related pain to depressive symptoms and perceived health was hypothesized to be direct as well as mediated by physical and social functioning. Results showed that OA-related pain was related to poorer physical and social functioning, had a direct effect on depressive symptoms, and direct and indirect effects on perceived health. Lower social functioning was related to more depressive symptoms, and both lower social and physical functioning predicted worse perceived health. Thus, distinguishing between physical and social functioning when examining the costs of OA-related pain is useful. Moreover, existing pain-psychological well-being models can be generalized to perceived health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive efficiency modes in old age: Performance on sequential and coordinative verbal and visuospatial tasks.

In an experiment using a large set of verbal and spatial tasks requiring low or high degrees of executive control, 3 distinct age-related effects were found. The smallest effect (no slowing was tied to lexical tasks with low executive involvement, the largest deficit (age-related slowing factor of 2.2) was tied to visuospatial tasks with high executive involvement, an intermediate level of deficit (slowing factor of 1.7) was found for visuospatial tasks with low executive load and verbal tasks with high executive load. These age-related dissociations were incompatible with any "common cause" formulation. The mechanism responsible for the dissociation between verbal and visual tasks, and between low and high executive load remains to be determined. The latter may reflect capacity limits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of IQ-Adjusted Norms to Predict Progressive Cognitive Decline in Highly Intelligent Older Individuals.

Identifying high-functioning older individuals in preclinical phases of Alzheimer's disease (AD) may require more sensitive methods than the standard approach. The authors explored the utility of adjusting for premorbid intelligence to predict progressive cognitive decline or Mild Cognitive Impairment (MCI) in 42 highly intelligent older individuals. When scores were adjusted for baseline IQ, 9 participants had executive impairments, 11 had memory impairments, and 22 scored in the normal range. None were impaired according to standard age norms. Three and a half years later, 9 participants with IQ-adjusted memory impairment declined in naming, visuospatial functioning, and memory; 6 convened to MCI. Three participants with normal memory declined. Implications for using IQ-adjusted norms to predict preclinical AD are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)