The impact of physical activity and sex differences on intraindividual variability in inhibitory performance in older adults

It is well-known that processing speed and executive functions decline with advancing age. However, physical activity (PA) has a positive impact on cognitive performances in aging, specifically for inhibition. Less is known concerning intraindividual variability (iiV) in reaction times. This study aims to investigate the influence of PA and sex differences on iiV in inhibitory performance during aging. Healthy adults were divided into active and sedentary groups according to PA level. To analyse iiV in reaction times, individual mean, standard deviation and the ex-Gaussian parameters were considered. An interaction between activity level and sex was revealed, sedentary females being slower and more variable than sedentary men. No sex differences were found in the active groups. These results indicate that the negative impact of sedentariness on cognitive performance in older age is stronger for females. The present findings underline the need to consider sex differences in active aging approaches.     

Executive functions in decision making: An individual differences approach

This individual differences study examined the relationships between three executive functions (updating, shifting, and inhibition), measured as latent variables, and performance on two cognitively demanding subtests of the Adult Decision Making Competence battery: Applying Decision Rules and Consistency in Risk Perception. Structural equation modelling showed that executive functions contribute differentially to performance in these two tasks, with Applying Decision Rules being mainly related to inhibition and Consistency in Risk Perception mainly associated to shifting. The results suggest that the successful application of decision rules requires the capacity to selectively focus attention and inhibit irrelevant (or no more relevant) stimuli. They also suggest that consistency in risk perception depends on the ability to shift between judgement contexts.     

Working memory training improvements and gains in non-trained cognitive tasks in young and older adults

Previous studies on working memory training have indicated that transfer to non-trained tasks of other cognitive domains may be possible. The aim of this study is to compare working memory training and transfer effects between younger and older adults (n = 60). A novel approach to adaptive n-back training (12 sessions) was implemented by varying the working memory load and the presentation speed. All participants completed a neuropsychological battery of tests before and after the training. On average, younger training participants achieved difficulty level 12 after training, while older training participants only reached difficulty level 5. In younger participants, transfer to Verbal Fluency and Digit Symbol Substitution test was found. In older participants, we observed a transfer to Digit Span Forward, CERAD Delayed Recall, and Digit Symbol Substitution test. Results suggest that working memory training may be a beneficial intervention for maintaining and improving cognitive functioning in old age.     

COMT gene polymorphisms,cognitive performance,and physical fitness in older adults

ObjectiveIt is well known that genetic predispositions might influence cognitive performance, particularly in older adults. One gene related to executive functioning is the COMT gene with met/met carriers outperforming val/val carriers in cognitive tasks. Further, it has been shown that fitness is positively related to cognitive functioning in older adults. As both, the COMT genotype and physical exercise have been shown to influence dopamine availability and as changes in dopamine metabolism seem to play a key role in cognitive aging, the aim of this study was to analyze the association of the COMT gene polymorphisms with the relationship between fitness and cognition.DesignWe used a cross-sectional design.MethodSixty-eight healthy older adults between 62 and 79 years of age were analyzed in this study. DNA was extracted from capillary blood samples. Participants performed a modified version of the Flanker Task as an indicator of executive control and a battery of motor and physical tests as indicators of fitness.ResultsHierarchical regression analyses revealed a positive influence of overall fitness and an interactive effect of fitness and COMT polymorphisms on Flanker accuracy performance. Val/val carriers revealed the highest positive correlation between fitness and cognition.ConclusionsOur data suggest that particularly val/val allele carriers benefit from exercise by improved cognitive functioning whereas met/met carriers already perform closer at their optimum level.     

Random noun generation in younger and older adults

We examined age-related changes of executive functions by means of random noun generation. Consistent with previous observations on random letter generation, older participants produced more prepotent responses than younger ones. In the case of random noun generation, prepotent responses are nouns of the same category as the preceding noun. In contrast to previous observations, older participants exhibited stronger repetition avoidance and a stronger tendency toward local evenness—that is, toward equal frequencies of the alternative responses even in short subsequences. These data suggest that at higher adult age inhibition of prepotent responses is impaired. In addition, strategic attentional processes of response selection are strengthened, in particular the application of a heuristic for randomness. In this sense response selection is more controlled in older than in younger adults.     

Variation in verbal fluency: A latent variable analysis of clustering,switching, and overall performance

Verbal fluency tasks have long been used to assess and estimate group and individual differences in executive functioning in both cognitive and neuropsychological research domains. Despite their ubiquity, however, the specific component processes important for success in these tasks have remained elusive. The current work sought to reveal these various components and their respective roles in determining performance in fluency tasks using latent variable analysis. Two types of verbal fluency (semantic and letter) were compared along with several cognitive constructs of interest (working memory capacity, inhibition, vocabulary size, and processing speed) in order to determine which constructs are necessary for performance in these tasks. The results are discussed within the context of a two-stage cyclical search process in which participants first search for higher order categories and then search for specific items within these categories.     

A preliminary investigation of sex differences in associations between emotion regulation difficulties and higher-order cognitive abilities

The present study sought to clarify the cognitive correlates of emotion regulation difficulties (ERD). Further, because prior evidence suggests sex differences in emotion regulation, sex was examined as a moderator of associations between cognitive abilities and ERD. Participants (N = 154) completed self-report measures of ERD, and were administered neuropsychological tests assessing crystallized and fluid intelligence, as well as various components of executive functioning. Bivariate correlations and results from regression analyses suggested sex-dependent associations among cognitive processes and ERD. For men, inhibition of dominant response tendencies was associated with lower ERD, whereas for women, a host of executive abilities (e.g., greater inhibition, cognitive flexibility, semantic processing, abstract reasoning) were associated with greater ERD. Implications for the neurocognitive conceptualization of emotion dysregulation will be discussed.     

Gender differences in unilateral spatial neglect within 24 hours of ischemic stroke

Hemispatial neglect is a common and disabling consequence of stroke. Previous reports examining the relationship between gender and the incidence of unilateral spatial neglect (USN) have included either a large numbers of patients with few neglect tests or small numbers of patients with multiple tests. To determine if USN was more common and/or severe in men or women, we examined a large group of patients (312 right-handed) within 24 hours of acute right hemisphere ischemic stroke. Multiple spatial neglect tasks were used to increase the sensitivity of neglect detection. No differences based upon gender were observed for the prevalence, severity, or a combined task measure of USN.     

Aided speech-identification performance in single-talker competition by older adults with impaired hearing

This study examined the effects of increased processing load on the closed-set speech-identification performance of young and older adults in a one-talker background. Since the older adults had impaired hearing, speech-identification performance was measured for spectrally shaped stimuli comparable to those experienced when wearing well-fit hearing aids. There were three groups of listeners: (1) 19 older adults with high-frequency sensorineural hearing loss; (2) 10 young adults with normal hearing who were assessed with the same spectrally shaped stimuli as the older adults; (3) 9 young adults with normal hearing who were assessed without spectral shaping and at a poorer target-to-competition ratio in an effort to equate overall performance to that of the older adults. In addition to this group factor, there were three within-participant repeated-measures independent variables designed to increase the demands on processing for the target and competing speech stimuli. These were: (1) competition meaningfulness (played in forward or reverse direction); (2) gender match between target and competing talkers (same or different gender); and (3) talker uncertainty (either the same target/competition talker pair or one of many such pairs on each trial). These three repeated-measures independent variables were examined in a 2 × 2 × 2 factorial design. They showed roughly independent and additive effects on speech-identification such that combinations of these variables decreased performance cumulatively. Older adults performed worse than young adults across the board, but also showed diminished relative improvement as the processing load was decreased. Individual differences in performance among the older adults were also examined.     

Sex differences in cognition in healthy elderly individuals

ABSTRACT

Sex differences in patterns of cognitive test performance have been attributed to factors, such as sex hormones or sexual dimorphisms in brain structure, that change with normal aging. The current study examined sex differences in patterns of cognitive test performance in healthy elderly individuals. Cognitive test scores of 957 men and women (age 67–89), matched for overall level of cognitive test performance, age, education, and depression scale score, were compared. Men and women were indistinguishable on tests of auditory divided attention, category fluency, and executive functioning. In contrast, women performed better than men on tests of psychomotor speed and verbal learning and memory, whereas men outperformed women on tests of visuoconstruction and visual perception. Our finding that the pattern of sex differences in cognition observed in young adults is observed in old age has implications for future studies of both healthy elderly individuals and of those with cognitive disorders.     

Exercise type relates to inhibitory and error processing functions in older adults

ABSTRACT

This study investigated the association between exercise type and inhibition of prepotent responses and error detection. Totally, 75 adults (M = 68.88 years) were classified into one of three exercise groups: those who were regular participants in open- or closed-skill forms of exercise, and those who exercised only irregularly. The participants completed a Stroop and task-switching tasks with event-related brain potentials (ERPs) recorded. The results revealed that regular exercisers displayed faster reaction times (RTs) in the Stroop task compared with irregular exercisers. The open-skill exercisers exhibited smaller N200 and larger P300a amplitudes in the Stroop task compared with irregular exercisers. Furthermore, the open-skill exercisers showed a tendency of shorter error-related negativity latencies at the task-witching test. The findings suggest that older adults may gain extra cognitive benefits in areas such as inhibition functioning and error processing from participating in open-skill forms of physical exercises.     

Type of physical exercise and inhibitory function in older adults: An event-related potential study

ObjectivesThe present study was to examine the relationship between exercise type and inhibitory function in older adults using neuroelectric indices.DesignA cross-sectional design was employed in the present study.MethodSixty adults (M = 69.42 years) were categorized into open-skill, closed-skill, and irregular exercise groups according to their history of exercise participation. The participants conducted a flanker task while their behavioral performance and event-related brain potentials were assessed.ResultsThe results indicated that regular exercisers, regardless of exercise type, exhibited a faster reaction time across conditions of the flanker task compared to irregular exercisers. For the P300 amplitude of the open-skill exerciser group, the peak amplitude was larger at the vertex site compared to the frontal site, whereas no site differences were observed in the closed-skill and irregular exerciser groups.ConclusionsThese findings extend current knowledge by suggesting that, for older adults, participation in physical exercise involving increased cognitive demand is associated with better neural efficiency in resource allocation for tasks that require interference control.     

Space Fortress game training and executive control in older adults: A pilot intervention

ABSTRACT

We investigated the feasibility of using the Space Fortress (SF) game, a complex video game originally developed to study complex skill acquisition in young adults, to improve executive control processes in cognitively healthy older adults. The study protocol consisted of 36 one-hour game play sessions over 3 months with cognitive evaluations before and after, and a follow-up evaluation at 6 months. Sixty participants were randomized to one of three conditions: Emphasis Change (EC) – elders were instructed to concentrate on playing the entire game but place particular emphasis on a specific aspect of game play in each particular game; Active Control (AC) – game play with standard instructions; Passive Control (PC) – evaluation sessions without game play. Primary outcome measures were obtained from five tasks, presumably tapping executive control processes. A total of 54 older adults completed the study protocol. One measure of executive control, WAIS-III letter–number sequencing, showed improvement in performance from pre- to post-evaluations in the EC condition, but not in the other two conditions. These initial findings are modest but encouraging. Future SF interventions need to carefully consider increasing the duration and or the intensity of the intervention by providing at-home game training, reducing the motor demands of the game, and selecting appropriate outcome measures.     

Sequential difficulty effects during execution of memory strategies in young and older adults

This study aimed at uncovering factors influencing execution of memory strategies and at furthering our understanding of ageing effects on memory performance. To achieve this end, we investigated strategy sequential difficulty (SSD) effects recently demonstrated by Uittenhove and Lemaire in the domain of problem solving. We found that both young and older participants correctly recalled more words using a sentence-construction strategy when this strategy followed an easier strategy (i.e., repetition strategy) or a harder strategy (i.e., mental-image strategy). These SSD effects were of equal magnitude in young and older adults, correlated significantly with Stroop performance in both young and older adults and correlated with N-back performance only in young adults. These findings have important implications for furthering our understanding of memory strategy execution and age-related variations in memory performance, as well for understanding mechanisms underlying SSD effects.     

Decision-making quality of younger and older adults in familiar and unfamiliar domains

Age-related differences in purchasing decisions were examined as a function of age and familiarity. On each trial, participants received purchasing options which varied in quality but ultimately cost the same amount of money. On half the trials, participants made decisions about items familiar to younger adults and on the other half of the trials, participants made decisions about products familiar to older adults. The participants’ task was to choose the option that provided the best value for the money. We were particularly interested in participants’ performance when inferencing was required to select the optimal option from the two choices. Younger adults outperformed older adults in unfamiliar but not familiar domains. It appeared that both younger and older adults used inferencing and elaborative processing to make the best decision in familiar domains but that only younger adults used inferencing and elaborative processing in unfamiliar domains.     

A coordinated analysis of the associations among personality traits,cognitive decline,and dementia in older adulthood

There are individual differences in the rates of cognitive decline across later adulthood. Personality traits are among the factors that may account for these differences. The current project investigated whether personality traits were associated with trajectories of cognitive decline, and whether the associations were different before and after dementia diagnosis. The data was analyzed using linear mixed effects regression. Across study aims is a focus on replicability and generalizability. Each question was addressed in four independent longitudinal studies (EAS, MAP, ROS, SATSA), then meta-analyzed, providing estimates of replicability. Results indicated that low neuroticism and high openness were associated with total cognitive function. We detected evidence for cognitive decline in all four samples, and openness was associated with decline post dementia diagnosis.     

Executive process training in young and old adults

There is a growing body of research on the modifiability of executive functions in different stages of life. Previous studies demonstrate robust training effects but limited transfer in younger and particularly in older adults. The aim of the present study was to investigate whether a theoretically derived intervention for executive functioning, addressing several basic processes (updating, shifting, and inhibition), can induce transfer effects in early and late adulthood. Fifty-nine healthy adults, 29 young and 30 older adults, were randomly assigned to either training or no-contact control groups. The training groups received 15 sessions of executive process training for about 45 min/session during 5 weeks. A test battery including a criterion task and near, intermediate, and far transfer tasks was administered before and after training. Results showed pronounced age-equivalent gains on the criterion task. Near transfer was seen to non-trained updating and inhibition tasks for the young and older trained participants. However, only the young adults showed intermediate transfer to two complex working memory tasks. No far transfer effects were seen for either age group. These findings provide additional evidence for age-related constraints in the ability to generalize acquired executive skills, and specifically show that training of multiple executive processes is not sufficient to foster transfer beyond the very near in older adults.     

Training attentional control in older adults

ABSTRACT

Recent research has demonstrated benefits for older adults from training attentional control using a variable priority strategy, but the construct validity of the training task and the degree to which benefits of training transfer to other contexts are unclear. The goal of this study was to characterize baseline performance on the training task in a sample of 105 healthy older adults and to test for transfer of training in a subset (n?=?21). Training gains after 5 days and extent of transfer was compared to another subset (n?=?20) that served as a control group. Baseline performance on the training task was characterized by a two-factor model of working memory and processing speed. Processing speed correlated with the training task. Training gains in speed and accuracy were reliable and robust (ps <.001, η²?=?.57 to .90). Transfer to an analogous task was observed (ps <.05, η²?=?.10 to .17). The beneficial effect of training did not translate to improved performance on related measures of processing speed. This study highlights the robust effect of training and transfer to a similar context using a variable priority training task. Although processing speed is an important aspect of the training task, training benefit is either related to an untested aspect of the training task or transfer of training is limited to the training context.