Aging and cognition: methodological differences in outcome

The effect of age on executive functions in adults is not sex specific

OBJECTIVE

Numerous studies have shown a decrease in executive functions (EF) associated with aging. However, few investigations examined whether this decrease is similar between sexes throughout adulthood. The present study investigated if age-related decline in EF differs between men and women from early to late adulthood.

METHODS

A total of 302 participants (181 women) aged between 18 and 78 years old completed four computer-based cognitive tasks at home: an arrow-based Flanker task, a letter-based Visual search task, the Trail Making Test, and the Corsi task. These tasks measured inhibition, attention, cognitive flexibility, and working memory, respectively. To investigate the potential effects of age, sex, and their interaction on specific EF and a global EF score, we divided the sample population into five age groups (i.e., 18-30, 31-44, 45-54, 55-64, 65-78) and conducted analyses of covariance (MANCOVA and ANCOVA) with education and pointing device as control variables.

RESULTS

Sex did not significantly affect EF performance across age groups. However, in every task, participants from the three youngest groups (< 55 y/o) outperformed the ones from the two oldest. Results from the global score also suggest that an EF decrease is distinctly noticeable from 55 years old onward.

CONCLUSION

Our results suggest that age-related decline in EF, including inhibition, attention, cognitive flexibility, and working memory, becomes apparent around the age of 55 and does not differ between sexes at any age. This study provides additional data regarding the effects of age and sex on EF across adulthood, filling a significant gap in the existing literature.

Natural Pattern of Cognitive Aging

BACKGROUND

Considering the world's rapidly increasing life expectancy, with people working and maintaining active lifestyles longer than ever before, addressing the effects of aging on cognition is of utmost importance. A greater understanding of cognitive aging may also be critical in distinguishing natural cognitive aging from pre-clinical stages of Alzheimer's disease and related cognitive disorders.

OBJECTIVE

To systematically examine the association between aging and cognitive performance in a cognitively and otherwise healthy probability population-based sample using a computer-based method.

METHODS

This cross-sectional study enrolled 673 cognitively and otherwise healthy participants aged 25-89 years (mean age 52.3±14.2 years, 52.5% of whom were female) from the Kardiovize study cohort. Mild cognitive impairment and dementia cases were excluded, followed by measurement of cognitive performance with the computer-administered Cogstate Brief Battery. We used ANCOVA and Modified Signed-Likelihood Ratio tests to examine patterns of cognition across age groups.

RESULTS

We found a gradual decrease in cognitive performance across the lifespan, which required two decades to demonstrate significant changes. In contrast to attention and learning, psychomotor speed and working memory showed the most significant age-related decrease and variability in performance. The established pattern of cognitive aging was not altered by sex or education.

CONCLUSION

These findings corroborate, validate, and extend the current understanding of natural cognitive aging and pinpoint specific cognitive domains with the most extensive age-related interindividual differences. This will contribute to the development of strategies to preserve cognition with aging and may also serve to improve early diagnostics of cognitive disorders using computer-based methods.

Age, executive functioning, and decision-making styles in adults: a moderated mediation model

The current study aimed to assess: i) whether executive functioning (EF) mediates the association of age with different decision-making (DM) styles in adults, and ii) whether these mediational associations change with age in adulthood. Our sample included 195 adults (110 young adults and 85 middle-aged adults; 95 males) selected from different government, semi-government, and private sector organizations. They were assessed on a self-report measure of General Decision-making Styles and on two EF tests: the Design Fluency Test and the Color-Word Interference Test from the Delis-Kaplan Executive Functions System. Results indicated that EF mediated the association of age with three decision-making styles including dependent, avoidant, and spontaneous DM. However, a conditional indirect effect of EF was significant only for spontaneous DM, indicating stronger indirect effects for middle-aged adults than for young adults. The findings highlight the idea that EF is an important factor in DM, particularly during middle adulthood.

Diagnostic accuracy of a global cognitive screen for Māori and non-Māori octogenarians

INTRODUCTION

We assessed the sensitivity and specificity of the Modified Mini-Mental State Examination (3MS) in predicting dementia and cognitive impairment in Māori (indigenous people of New Zealand) and non-Māori octogenarians.

METHODS

A subsample of participants from Life and Living in Advanced Age: a Cohort Study in New Zealand were recruited to determine the 3MS diagnostic accuracy compared with the reference standard.

RESULTS

Seventy-three participants (44% Māori) completed the 3MS and reference standard assessments. The 3MS demonstrated strong diagnostic accuracy to detect dementia with areas under the curve of 0.87 for Māori and 0.9 for non-Māori. Our cutoffs displayed ethnic variability and are approximately 5 points greater than those commonly applied. Cognitive impairment yielded low accuracy, and discriminatory power was not established.

DISCUSSION

Cutoffs that are not age or ethnically appropriate may compromise the accuracy of cognitive screens. Consequently, older age and indigeneity increase the risk of mislabeled cognitive status.

Normal cognitive aging

Even those who do not experience dementia or mild cognitive impairment may experience subtle cognitive changes associated with aging. Normal cognitive changes can affect an older adult's everyday function and quality of life, and a better understanding of this process may help clinicians distinguish normal from disease states. This article describes the neurocognitive changes observed in normal aging, followed by a description of the structural and functional alterations seen in aging brains. Practical implications of normal cognitive aging are then discussed, followed by a discussion of what is known about factors that may mitigate age-associated cognitive decline.

Cognitive profiles of aging and aging-related conditions

This review presents some of the current research and thinking regarding the neuropsychological features associated with aging and aging-related conditions. In the context of the current longevity revolution, many older adults are increasingly concerned about their cognitive performance and the risk for cognitive decline. This makes it critically important to understand the neuropsychological profiles of normal aging and the cognitive features of conditions associated with aging, such as age-associated memory impairment, mild cognitive impairment and dementia. There are also several factors that can modify the neuropsychological abilities and outcomes associated with aging, including gender, genetic status, lifestyle issues and education. The authors point to the importance for future research to embrace a fluid or multifactorial approach to neuropsychology, to focus on those factors contributing to healthy cognition and successful aging, and to correlate neuropsychological changes with the results of neuroimaging.