Individual differences in memory and executive function abilities during normal aging

Loneliness and social isolation are not associated with executive functioning in a cross-sectional study of cognitively healthy older adults

The literature on the relationship between social interaction and executive functions (EF) in older age is mixed, perhaps stemming from differences in EF measures and the conceptualization/measurement of social interaction. We investigated the relationship between social interaction and EF in 102 cognitively unimpaired older adults (ages 65-90). Participants received an EF battery to measure working memory, inhibition, shifting, and global EF. We measured loneliness subjectively through survey and social isolation objectively through naturalistic observation. Loneliness was not significantly related to any EF measure (p-values = .13-.65), nor was social isolation (p-values = .11-.69). Bayes factors indicated moderate to extremely strong evidence (BF01 = 8.70 to BF01 = 119.49) in support of no relationship..   Overall, these findings suggest that, among cognitively healthy older adults, there may not be a robust cross-sectional relationship between EF and subjective loneliness or objective social isolation.

The effect of memory cue duration on performance in the directed forgetting task in healthy aging

Although forgetting is usually considered a memory error, intentional forgetting can function as an adaptive mechanism. The current study examined the effect of increased processing time on directed forgetting in aging as a mechanism to compensate for age-related forgetting. Specifically, an item-method directed forgetting paradigm was used in conjunction with Remember/Know/New responding to examine the effect of cue duration (1, 3, 5 s) on directed forgetting and remembering in younger and older adults. Results indicated that increased processing time improved performance in both age groups. Critically, older adults exhibited a linear increase in directed remembering performance across all cue durations which was related to individual differences in cognitive reserve. Specifically, those older adults with the highest levels of cognitive functioning showed the greatest memory benefit in the longest cue duration condition. These findings indicate the importance of processing time in accounting for intentional memory performance in older adults.

Engagement in Cognitively Stimulating Activities Mediates the Relationship between Openness and Attention/Executive Functions, but Not Memory in Older Adults

OBJECTIVE

Openness has a positive association with cognitive functioning and engagement in cognitively stimulating activities (CSA). Older adults who engage in more CSA tend to show greater preservation of their cognitive skills; thus, we examined whether: higher Openness would be associated with higher attention/executive functions (AEF) and verbal memory; and CSA would mediate the relationship between Openness and AEF, as well as verbal memory.

METHOD

477 community-dwelling older adults (65+ years) were included in the current cross-sectional study. Composite variables of AEF (TMT-A&B, COWAT, and DSST) and verbal memory (RBANS immediate and delayed verbal memory subtasks) were included. Openness was assessed via the Big-5 Inventory and CSA with the Leisure Activity Questionnaire.

METHOD

477 community-dwelling older adults (65+ years) were included in the current cross-sectional study. Composite variables of AEF (TMT-A&B, COWAT, and DSST) and verbal memory (RBANS verbal memory subtasks) were included. Openness was assessed via the Big-5 Inventory and CSA with the Leisure Activity Questionnaire.

RESULTS

Linear regressions indicated a significant positive association between Openness and AEF (β = .09, p < .01), but not verbal memory (β = .06, p = .06). A significant partial mediation was demonstrated between Openness, CSA, and AEF (c: β = .08, p < .05, 95%CI = .02-.14; c': β = .02, 95%CI = .01-.03). The mediation of Openness, CSA, and verbal memory was not significant (c: β = .06, p > .05, 95%CI = .01-.11; c': β = .00, 95%CI = -.01-.01).

CONCLUSIONS

The association between Openness and AEF, but not verbal memory, was partially mediated by CSA in healthy older adults. The findings suggest that those who are more open to and highly engaged in CSA may have a later in life advantage in preserving their AEF abilities.

Brain Network Connectivity Mediates Education-related Cognitive Performance in Healthy Elderly Adults

BACKGROUND

Among the protective factors for cognitive decline related to aging and Alzheimer's disease, education level is one of the most prominent. However, the mechanisms underlying the protective effects of education on cognition remain to be elucidated. In this study, we aimed to systematically assess the role of Functional Connectivity (FC) of resting-state brain networks playing in the cognition-protection effect of education.

METHODS

Data from a battery of neuropsychological tests and functional magnetic resonance imaging in resting-state were acquired in 77 cognitively normal elderly participants from local communities in Beijing, China. Six resting-state networks related to primary function or complex cognition were extracted through independent component analysis. We then explored the relationships between education level, cognition, and FC of these networks.

RESULTS

We found that education level was positively associated with a wide range of complex cognitive domains including general mental status, episodic memory, language, attention, executive function and visuospatial processing, and it showed significantly negative correlations with FC of multiple areas in the Default Mode Network (DMN) and Left Frontal-parietal Network (LFP) which are related to complex cognition. And regional connectivity of DMN was significantly negatively correlated with episodic memory performance. Further mediation analysis suggested that higher education level was associated with higher episodic memory performance through lower regional connectivity of DMN.

CONCLUSION

Our findings indicate that inhibitory modulation in the resting-state brain networks related to complex cognition is one of the main routes through which education exerts its protective effects on cognition in normal aging.

Normative Study of the Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES) Test in the French-Canadian Population

PURPOSE

The Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES; MacDonald, 2005) test was designed for use by speech-language pathologists to assess verbal reasoning, complex comprehension, discourse, and executive skills during performance on a set of challenging and ecologically valid functional tasks. A recent French version of this test was translated from English; however, it had not undergone standardization. The development of normative data that are linguistically and culturally sensitive to the target population is of importance. The present study aimed to establish normative data for the French version of the FAVRES, a commonly used test with native French-speaking patients with traumatic brain injury in Québec, Canada.

METHOD

The normative sample consisted of 181 healthy French-speaking adults from various regions across the province of Québec. Age and years of education were factored into the normative model.

RESULTS

Results indicate that age was significantly associated with performance on time, accuracy, reasoning subskills, and rationale criteria, whereas the level of education was significantly associated with accuracy and rationale.

CONCLUSION

Overall, mean scores on each criterion were relatively lower than in the original English version, which reinforces the importance of using the present normative data when interpreting performance of French speakers who have sustained a traumatic brain injury.

Cognitive flexibility: A trait of bipolar disorder that worsens with length of illness

INTRODUCTION

Deficits in cognitive flexibility, a difficulty altering thoughts and behavioral responses in a changing environment, are found in individuals with bipolar disorder (BD) and are associated with poor social and work functioning. However, the current literature is inconsistent in clarifying the long-term nature of these deficits for those with BD. We administered a common task of cognitive flexibility, the Wisconsin Card Sorting Task (WCST) and accounted for demographics, clinical, and cognitive features of BD, to determine the state versus trait characteristics of these deficits.

METHOD

The Wisconsin Card Sorting Test (WCST) was administered to 154 adults with BD and 95 healthy controls twice, one year apart.

RESULTS

The main findings show that cognitive inflexibility is a trait feature of BD, independent of clinical features, that may modestly worsen over time due to the presence of certain demographic, cognitive, and functional features of the disorder. In addition, improvements in WCST performance over an extended period of time in both those with and those without already existing cognitive flexibility deficits indicate potential practice effects.

CONCLUSIONS

These findings suggest that the implementation of early interventions before the illness progresses could potentially prevent further cognitive impairment, mitigate functional outcomes, and improve the quality of life of the individual with BD.

The illiterate brain and the neuropsychological assessment: From the past knowledge to the future new instruments

The lifetime learning of illiterate and low-educated individuals shapes their cognitive skills, which are challenging to grade by the current available neuropsychological tools. Eight hundred million of the global population are illiterate. It is very challenging to interpret the cognitive performance of this population by the available formal neuropsychological tests, mainly developed for higher educated people. From extensive literature investigation, we reviewed the cognitive process and performance of illiterate and low-educated population on various cognitive domains including language, executive function, memory, visual-related function, and motor skills. We also suggested the concept in the development of the appropriate tools for the cognitive assessment among this population. Finally, we provide the available cognitive screening tools validated in the illiterate and low-educated subjects within the last three decades.

Language Development across the Life Span: A Neuropsychological/Neuroimaging Perspective

Language development has been correlated with specific changes in brain development. The aim of this paper is to analyze the linguistic-brain associations that occur from birth through senescence. Findings from the neuropsychological and neuroimaging literature are reviewed, and the relationship of language changes observable in human development and the corresponding brain maturation processes across age groups are examined. Two major dimensions of language development are highlighted: naming (considered a major measure of lexical knowledge) and verbal fluency (regarded as a major measure of language production ability). Developmental changes in the brain lateralization of language are discussed, emphasizing that in early life there is an increase in functional brain asymmetry for language, but that this asymmetry changes over time, and that changes in the volume of gray and white matter are age-sensitive. The effects of certain specific variables, such as gender, level of education, and bilingualism are also analyzed. General conclusions are presented and directions for future research are suggested.

Improving Cognitive Function from Children to Old Age: A Systematic Review of Recent Smart Ageing Intervention Studies

Background. Cognitive functions are important for daily life at any age. One purpose of Smart Ageing is to investigate how to improve cognitive functions. This systematic review evaluates beneficial effects of the intervention on cognitive functions. Method. We conducted a systematic review of intervention studies of improvements of cognitive functions published or in press before December 2013. Because of the heterogeneity of the intervention programs, a systematic and critical review of the interventions and outcomes was conducted instead of a meta-analysis. Results. We identified nine completed and published studies, which were divided into four categories: cognitive training using video game, cognitive training using PC, cognitive training using paper and pencil, and exercise training. Review results showed that various intervention programs can improve cognitive functions such as executive functions, working memory, episodic memory, processing speed, and general cognitive ability/IQ. Conclusions. The systematic review demonstrated that some intervention programs can be effective for improving various aspects of cognitive functioning at any age. Some limitations to this review include its small sample size and heterogeneity of programs and cognitive function measures, in addition to unresolved issues such as transfer of everyday skills and effectiveness for nonhealthy people.

Normative data for a battery of free recall, cued recall and recognition tests in the elderly Italian population

The present study aimed to provide normative data on a large sample of the elderly Italian population (N = 464; range of age = 49-94; range of education = 3-25) on both the word and the picture versions of a battery of free recall, cued recall, and recognition tests of memory. Results from multiple regression analyses showed that both age and education were significant predictors of performance. Therefore, norms were calculated taking into account these demographic variables. The availability of normative data based on a large sample will allow a more reliable use of the battery for clinical assessment in Italian-speaking dementia population.

Viabilidade da estimativa de QI a partir dos subtestes Vocabulário e Cubos da WAIS-III

Objetivou-se avaliar a viabilidade de estimar o Quociente de Inteligência (QI) de adultos por meio de duas estratégias que utilizam uma forma curta constituída pelos subtestes Vocabulário e Cubos da Escala Wechsler de Inteligência para Adultos (WAIS-III). Participaram do estudo 77 homens e mulheres, com idade média de 39,1 anos (dp=13,4). Foi aplicada a WAIS-III e questionários para cumprir os critérios de inclusão dos participantes sem prejuízos neurológicos e psiquiátricos. Para avaliar a concordância entre as duas estratégias de estimar o QI, utilizou-se o método estatístico proposto por Bland e Altman. Como resultado, encontrou-se que as estimativas de QI geradas pelas duas estratégias apresentam concordância com a medida do QI realizada pela aplicação da escala completa apenas em alguns dos casos avaliados. Sugere-se cautela na utilização dessas estratégias para estimar o QI de adultos.

Preliminary Arabic normative data of neuropsychological tests: the verbal and design fluency

OBJECTIVES

The objective of the present study was to provide preliminary norms for three fluency tests in Arabic language: the verbal fluency (phonemic and semantic) and design fluency tests.

METHODS

Three Arabic letters have been chosen for the phonemic fluency task, in accordance with the letter selection procedure described in the development of the standard test. Animal fluency was chosen for the semantic fluency, and the Five-Point test for the design fluency test.

PARTICIPANTS

An Arabic speaking sample of 215 healthy participants (125 male, 90 female), with age ranging from 18-59 years and with different educational levels, were selected for this study.

RESULTS

Age and education significantly influenced performance in the verbal phonemic and semantic tasks, but not in the design fluency test. No gender effect was found in any of the three tasks. The education effects were linear, while age effects appeared to be curvilinear.

CONCLUSION

This pattern is congruent with that reported in the western literature. The implications of these results in relation to the development of Arabic norms were discussed. It was concluded that these tests could be used in an Arabic-speaking population with due considerations to the effects of age and education.

Immediate recall of short stories depends on educational level

Memory complaints are frequent in the elderly but the confirmation of memory decline is challenging. Tests employing the recall of paragraphs or short stories have been proposed for the diagnosis of Alzheimer’s disease and amnestic mild cognitive impairment.

Heterogeneity of neuroendocrine stress responses in aging rat strains

Hyperactivity of the hypothalamo-pituitary-adrenocortical (HPA) axis is linked with age-related decrements in cognition and neuronal survival. However, the nature and extent of age-related HPA axis deficits vary considerably across and indeed, within strains. The current study was designed to assess variance in HPA axis function using two rodent models commonly used in aging studies: Fischer 344 (F344) and F344/Brown-Norway F1 hybrid rats (F344/BN). We examined both basal and stress-induced ACTH and corticosterone (CORT) release in two stress contexts thought to differ in intensity: novel environment ('mild') and restraint ('intense'). Variability of the data was tested with a modification of the Brown-Forsythe test of homoscedasticity. The results indicated that F344 rats exhibit greater peak HPA responses. Furthermore, in most cases variability was increased in aged rats relative to young and middle-aged rats of the same strain, indicative of the emergence of individual differences in stress responsivity amongst older rats. The results suggest that these older rat strains may be useful models to further assess individual differences in neuroendocrine aging.

Aging and Inhibition of a Prepotent Motor Response during an Ongoing Action

Inhibitory functions are key mechanisms underlying age related decline (Park & Gutchess, 2000, in: Cognitive aging: A primer. Hove: Psychology Press), yet few studies have investigated their impact on everyday tasks involving action as well as cognition. Using an everyday-based go/no-go task we devised a motor analogy of traditional neuropsychological tests to investigate in 134 older (aged 60-88) and 133 younger adults (aged 20-59) the ability to inhibit a prepotent motor response during an ongoing action. Older adults produced more inhibition failures as expected, but more strikingly inhibitory errors were not all or none; even when the inappropriate response was successfully inhibited, difficulties controlling ongoing movements emerged from as young as people in their 40s. The ability to inhibit therefore does not ensure control of ongoing tasks, and traditional cognitive tests may be unable to detect such difficulties. Furthermore, performance did not covary with education or action speed. Implications for neuropsychological theory and assessing/enhancing functional ability are discussed.

The elusive nature of executive functions: a review of our current understanding

Executive functions include abilities of goal formation, planning, carrying out goal-directed plans, and effective performance. This article aims at reviewing some of the current knowledge surrounding executive functioning and presenting the contrasting views regarding this concept. The neural substrates of the executive system are examined as well as the evolution of executive functioning, from development to decline. There is clear evidence of the vulnerability of executive functions to the effects of age over lifespan. The first executive function to emerge in children is the ability to inhibit overlearned behavior and the last to appear is verbal fluency. Inhibition of irrelevant information seems to decline earlier than set shifting and verbal fluency during senescence. The sequential progression and decline of these functions has been paralleled with the anatomical changes of the frontal lobe and its connections with other brain areas. Generalization of the results presented here are limited due to methodological differences across studies. Analysis of these differences is presented and suggestions for future research are offered.

Differential Course of Executive Control Changes During Normal Aging

Normal aging has been associated with executive control deficits, but it is as yet unclear whether different executive subprocesses are differentially affected during the course of aging. The present study aimed to investigate age effects on a range of executive control subcomponents. Four consecutive age groups (20-30 years, 31-45 years, 46-60 years, 61-75 years), matched on present state IQ and mood, were compared on tasks of strategic memory processing, verbal fluency, reasoning, inhibition, task management, and self-rating of executive abilities. Deficits concerning the suppression of habitual and experimentally induced prepotent response tendencies and the ability to efficiently divide attention were observed in subjects over 60 years of age compared to the younger groups, while memory, verbal fluency, and reasoning were largely unaffected. Results suggest a sharp decline of executive function after age 60 and a differential course of different executive subcomponents across aging, adding further support to a multi-dimensional model of executive function.

The role of neuropsychologic tests in the diagnosis of attention deficit hyperactivity disorder

Attention, memory, executive function, language, and visual-motor skills were evaluated in a sample of 621 children, 6 to 11 years old, to assess the discriminant validity of neuropsychologic testing. Attention deficit hyperactivity disorder cases (249) and controls (372) were identified and tested. Analysis of covariance, nonparametric comparison tests, effect sizes, discriminant function, factor analyses, and receiver-operator characteristics curve analyses were used to establish the best diagnostic cutoff points for each variable. Statistically significant differences were found on cognitive effort, auditory skills, continuous performance test, working memory, visual-motor skills, verbal comprehension, and executive function measures (P < 0.05); however, the effect of group sizes was low to modest (0.24 to 0.54). Receiver-operator characteristics curve analysis showed modest sensitivity and low specificity, demonstrating that an important proportion of the variance in test scores was overlapping. Factor analysis of neuropsychologic testing results revealed a structure of six factors each for attention deficit hyperactivity disorder, control, and combined samples. The latent variables produced one discriminant function with a total correct classification accuracy of 61.9%. Neuropsychologic tests should be used as Attention Deficit Hyperactivity Disorder diagnostic tools with caution, but they hold promise for identifying core cognitive deficits and processes that can aid prevention and intervention.

The frontal hypothesis of cognitive aging: factor structure and age effects on four frontal tests among healthy individuals

With 101 healthy aging adult participants, the authors investigated whether executive functions are a unitary concept. The authors established the factor structure of the Wisconsin Card Sorting Test (WCST; E. A. Berg, 1948), the Stroop color and word test (C. J. Golden, 1978), verbal fluency using the Controlled Oral Word Association Test (COWAT; Benton, 1967), and the Digits Backwards subtest of the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981). The authors also evaluated the extent to which age and other demographic variables predicted common underlying properties of these frontal tests. Results revealed an age-related decline in executive abilities differentially reflected by the selected tasks. These data suggest caution using the COWAT to evaluate executive abilities in older people. The authors interpret findings to support the unitary view of executive abilities and the executive decline proposed by the frontal hypothesis.

Age-related differences in performance of phonemic verbal fluency measured by Controlled Oral Word Association Task (COWAT): a meta-analytic study

Meta-analytical procedures were used to examine the research findings on age-related changes in phonemic verbal fluency measured by the Controlled Oral Word Association Task (COWAT). Data from 26 studies comparing adults from different age ranges were analyzed. An effect of aging was found in almost all age comparisons especially after 40 years of age. Results revealed a decline of this verbal ability after 60 years, which accelerates through the late 80s. Gender may influence COWAT performance after the sixth decade, favoring women over men. These results may be important in clinical situations where COWAT is used to assert pathological changes.

[Cognitive dysfunction after abdominal surgery in elderly patients]

Elderly patients often suffer from postoperative cognitive deficits (POCD) after serious surgical operations. The reasons for this are not well understood. We investigated the influence of the invasiveness of the operation and the duration of the operation as well as the patient's preoperative physical status on measures of cognitive dysfunction. In a prospective study 59 elderly patients (mean age 69.2 years) were subjected to a neuropsychological test battery and a questionnaire following an abdominal surgical operation. The postoperative recovery with a focus on memory function was assessed using the Wechsler Memory Scale (WMS) seven days after the operation. Self-reported cognitive deficits were studied using the a questionnaire of experienced attention deficits (FEDA) three months after the operation. Postoperative psychological and self-reported test results varied as a function of the invasiveness and the duration of the operation. After more invasive operations patients reported a stronger deficit in activities of daily living and a reduction in drive than after less invasive operations. In addition, the duration of anesthesia influenced the experienced deficits. The self-reported deficits were more strongly influenced by the features of the operation than the psychological test data. The physical status of the patients according to the American Society of Anesthesiologists (ASA) along with the duration of anesthesia as covariate was identified as a good predictor for the cognitive recovery post operation.

Memory functions of Taiwanese American older adults

Memory complaints are common among older adults, of which ethnic minorities are the fastest growing group. Little is known about the memory function of Taiwanese American older adults. This article utilizes a cross-sectional, correlational design to examine the relationship between sleep, physical activity, depression, and memory self-efficacy and memory function and to determine the variance in memory function explained by the four independent variables and six control variables in Taiwanese American older adults. Memory self-efficacy correlated significantly with memory performance. Among the independent variables and control variables, age was the strongest predictor of memory function. A simultaneous multiple regression analysis showed that the four independent and six control variables together accounted for 41.8% of the variance in memory function. Results of this study are consistent with that of many other studies conducted in the United States: Memory declined with age.