Task coordination and aging: explorations of executive control processes in the task switching paradigm

Walking Interventions and Cognitive Health in Older Adults: A Systematic Review of Randomized Controlled Trials

ObjectiveThis systematic review summarizes the effectiveness and the dose of walking interventions on specific cognition domains in older adults, including executive function, memory, attention, processing speed, and global cognition.Data sourcePublished randomized controlled trials in PubMed, Embase, and Web of Science until 10 May 2023.Study Inclusion and Exclusion CriteriaStudies include older adults without Alzheimer's or related dementias, involving a walking intervention and performance-based neuropsychological assessments for executive function, memory, processing speed, attention, or global cognition.Data ExtractionTwo independent research assistants reviewed 8424 studies and included 17 studies.Data SynthesisParticipant demographics, intervention features (type, intensity, time, frequency, duration, format, and context), cognitive assessment tools, and main findings.ResultsNine studies found a favorable effect of walking interventions on at least one cognitive domain. Walking interventions improved executive function (n = 6) and memory (n = 3). These studies delivered the intervention individually (n = 3) for at least 40 minutes (n = 6) each time, three times per week (n = 8), between 6 to 26 weeks (n = 8), and walking at a moderate to vigorous intensity (n = 7).ConclusionWalking interventions may improve specific domains of cognitive function in older adults, particularly executive function and memory. More standardized reporting of intervention design and participant compliance based on published guidelines is needed to determine the dose-response association and the long-term effect of walking interventions on cognition.

The effect of the APOE4 genotype on physiological and cognitive health in randomised controlled trials with an exercise intervention: a systematic review and meta-analysis

BACKGROUND

Alzheimer's disease is caused by modifiable and non-modifiable risk factors. Randomised controlled trials have investigated whether the strongest genetic risk factor for Alzheimer's disease, APOE4, impacts the effectiveness of exercise on health. Systematic reviews are yet to evaluate the effect of exercise on physical and cognitive outcomes in APOE genotyped participants. A quality assessment of these randomised controlled trials is needed to understand the impact genotype has on the potential success of intervention. This systematic review aimed to determine if the APOE4 genotype influences the effectiveness of exercise-based randomised controlled trials.

METHOD

Searches on MEDLINE, EMBASE, and PsycINFO identified eligible exercise based randomised controlled trials incorporating participants with varied cognitive abilities. Quality assessments were conducted.

RESULTS

Nineteen studies met the inclusion criteria for systematic review, and 3 for the meta-analysis. Very low to moderate quality evidence showed that APOE4 carriers benefitted more than APOE4 non-carriers on cognitive (e.g. executive function, learning) and physical (e.g. relative telomere length) outcomes after exercise; and that APOE4 non-carriers benefited over carriers for physical (serum BDNF, gait speed) and cognitive (global cognition, verbal memory) markers. Very low quality evidence indicated that there was no evidence of difference between APOE4 carriers and non-carriers on physical function outcomes in meta-analysis. Several areas of study design and reporting, including maintenance of relative exercise intensity and complete statistical reporting, were identified as needing improvement.

DISCUSSION

This systematic review found very limited evidence to suggest that exercise interventions can benefit APOE4 carriers and non-carriers equally, though conclusions were limited by evidence quality. Further randomised controlled trials, stratifying participants by APOE status are required to better understand the relationship between APOE genotype and the effect of exercise on health-related outcomes.

TRIAL REGISTRATION

This review was registered with PROSPERO (CRD42023436842). Registered on June 16, 2023.

Drawing as an efficient encoding tool in younger but not always older adults: The case of associative memory

Episodic memory strongly declines in healthy aging, at least partly because of reduced abilities to create and remember associations (associative memory) and to use efficient memory strategies. Several studies have shown that drawing the to-be-remembered material is a reliable encoding tool to enhance memory of individual items (item memory) because it simultaneously integrates elaborative, pictorial, and motoric processes. These processes in isolation can enhance associative memory in older adults. Nevertheless, their simultaneous impact on associative memory has never been investigated in drawing as an encoding tool. We aimed to investigate whether drawing as an encoding tool not only enhances item memory, but whether its benefit extends to associative memory in younger and older adults. Therefore, we tested 101 older and 100 younger participants in two online experiments and one in-person experiment. Using a memory task for unrelated word-pairs, we compared relational drawing and repeatedly writing (non-relational) as encoding tools and assessed immediate recognition memory of items and associations. In Experiment 2, we additionally assessed recognition memory after 1 week. The findings were consistent across the three experiments: while younger participants benefited from drawing over writing in item and associative memory, older participants benefited in item but not in associative memory. The observed effects remained after 1 week. Thus, we could extend the benefit of drawing to relational drawing in associative memory in younger adults. The lack of benefit in older adults' associative memory might be explained by age-related difficulties in benefiting from memory strategies, and in creating and retrieving associations.

Resting-state EEG correlates of sustained attention in healthy ageing: Cross-sectional findings from the LEISURE study

While structural and biochemical brain changes are well-documented in ageing, functional neuronal network differences, as indicated by electrophysiological markers, are less clear. Moreover, age-related changes in sustained attention and their associated electrophysiological correlates are still poorly understood. To address this, we analysed cross-sectional baseline electroencephalography (EEG) and cognitive data from the Lifestyle Intervention Study for Dementia Risk Reduction (LEISURE). Participants were 96 healthy older adults, aged 50-84. We examined resting-state EEG periodic (individual alpha frequency [IAF], aperiodic-adjusted individual alpha power [aIAP]) and aperiodic (exponent and offset) activity, and their associations with age and sustained attention. Results showed associations between older age and slower IAF, but not aIAP or global aperiodic exponent and offset. Additionally, hierarchical linear regression revealed that after controlling for demographic variables, faster IAF was associated with better Sustained Attention to Response Task performance, and mediation analysis confirmed IAF as a mediator between age and sustained attention performance. These findings indicate that IAF may be an important marker of ageing, and a slower IAF may signal diminished cognitive processing capacity for sustained attention in older adults.

Alpha oscillations during visual selective attention are aberrant in youth and adults with cerebral palsy

Our understanding of the neurobiology underlying cognitive dysfunction in persons with cerebral palsy is very limited, especially in the neurocognitive domain of visual selective attention. This investigation utilized magnetoencephalography and an Eriksen arrow-based flanker task to quantify the dynamics underlying selective attention in a cohort of youth and adults with cerebral palsy (n = 31; age range = 9 to 47 yr) and neurotypical controls (n = 38; age range = 11 to 49 yr). The magnetoencephalography data were transformed into the time-frequency domain to identify neural oscillatory responses and imaged using a beamforming approach. The behavioral results indicated that all participants exhibited a flanker effect (greater response time for the incongruent compared to congruent condition) and that individuals with cerebral palsy were slower and less accurate during task performance. We computed interference maps to focus on the attentional component and found aberrant alpha (8 to 14 Hz) oscillations in the right primary visual cortices in the group with cerebral palsy. Alpha and theta (4 to 7 Hz) oscillations were also seen in the left and right insula, and these oscillations varied with age across all participants. Overall, persons with cerebral palsy exhibit deficiencies in the cortical dynamics serving visual selective attention, but these aberrations do not appear to be uniquely affected by age.

Sensorimotor Adaptation to Formant-Shifted Auditory Feedback Is Predicted by Language-Specific Factors in L1 and L2 Speech Production

Auditory feedback plays an important role in the long-term updating and maintenance of speech motor control; thus, the current study explored the unresolved question of how sensorimotor adaptation is predicted by language-specific and domain-general factors in first-language (L1) and second-language (L2) production. Eighteen English-L1 speakers and 22 English-L2 speakers performed the same sensorimotor adaptation experiments and tasks, which measured language-specific and domain-general abilities. The experiment manipulated the language groups (English-L1 and English-L2) and experimental conditions (baseline, early adaptation, late adaptation, and end). Linear mixed-effects model analyses indicated that auditory acuity was significantly associated with sensorimotor adaptation in L1 and L2 speakers. Analysis of vocal responses showed that L1 speakers exhibited significant sensorimotor adaptation under the early adaptation, late adaptation, and end conditions, whereas L2 speakers exhibited significant sensorimotor adaptation only under the late adaptation condition. Furthermore, the domain-general factors of working memory and executive control were not associated with adaptation/aftereffects in either L1 or L2 production, except for the role of working memory in aftereffects in L2 production. Overall, the study empirically supported the hypothesis that sensorimotor adaptation is predicted by language-specific factors such as auditory acuity and language experience, whereas general cognitive abilities do not play a major role in this process.

Reduced spatial attentional distribution in older adults

Older adults show decline in visual search performance, but the underlying cause remains unclear. It has been suggested that older adults' altered performance may be related to reduced spatial attention to peripheral visual information compared with younger adults. In this study, 18 younger (M = 21.6 years) and 16 older (M = 69.1 years) participants performed pop-out and serial visual search tasks with variously sized gaze-contingent artificial central scotomas (3°, 5°, or 7° diameter). By occluding central vision, we measured how attention to the periphery was contributing to the search performance. We also tested the effect of target eccentricity on search times and eye movements. We hypothesized that, if attention is reduced primarily in the periphery in older adults, we would observe longer search times for more eccentric targets and with central occlusion. During the pop-out search, older adults showed a steeper decline in search performance with increasing eccentricity and central scotoma size compared with younger adults. In contrast, during the serial search, older adults had longer search times than younger adults overall, independent of target eccentricity and scotoma size. Longer search times were attributed to higher cost-per-item slopes, indicating increased difficulty in simultaneously processing complex symbols made up of separable features in aging, possibly stemming from challenges in spatially binding individual features. Altogether, our findings point to fewer attentional resources of simultaneous visual processing to distribute over space or separable features of objects, consistent with decreased dorsal visual stream functioning in aging.

Assessing the impact of age on everyday cognitive function with a virtual environment task: The EcoKitchen

More realistic assessment tools are imperative for a better understanding of the impact of age-related cognitive deficits on functional status. With this in mind, we probed the ability of the EcoKitchen, a non-immersive virtual environment task with increasing executively demanding kitchen chores, to detect the effects of aging on the simulated everyday functioning of healthy adults. Fifty-three adults (age between 23 and 77 years) were assessed with the EcoKitchen and a set of conventional paper-and-pencil neuropsychological tests. The associations between the baseline features of study participants and each of the two different assessment methods were examined. The associations between the EcoKitchen variables and an executive composite score were also explored. Our results showed that older individuals present deficits in the performance of both the EcoKitchen task and standard assessment methods. Notably, we found that, unlike conventional tests, accuracy in the EcoKitchen task was not related to the education level and IQ score of participants. Moreover, the EcoKitchen performance time was significantly correlated with executive tests. We have demonstrated that the EcoKitchen task, an ecologically relevant computerized neuropsychological assessment tool, might be more suitable than classic paper-and-pencil tests to capture the impact of aging on everyday cognitive function, as it proved to be less prone to the influence of confounding factors. Additionally, we have shown that executive function plays an important role in the timely performance of cognitively challenging virtual environment tasks.

Functional Connectivity Alterations of Cognitive Flexibility in Aging: Different Patterns of Global and Local Switch Costs

OBJECTIVES

Cognitive flexibility declines with aging and is usually indicated by task switch costs including global and local switch costs. Cognitive flexibility in aging is associated with alterations in functional connectivity. However, whether different task-modulated connectivity mechanisms underlying global and local switch costs remain unclear.

METHODS

Here we use the support vector machine to identify age-related functional connectivity in global and local switch costs between older (n = 32) and young adults (n = 33). Participants completed a cued task-switching task during the functional magnetic resonance imaging scan.

RESULTS

Results show an age-related decline behaviorally in global but not in local switch costs. Moreover, distinct patterns of age-related alterations of connectivity were observed for each cost. Specifically, only multivariate changes in connectivity patterns were observed for local switch cost, whereas specific age-related connections were revealed for global switch cost. In older adults, the task-modulated left dorsal premotor cortex-left precuneus connectivity decreased, and the left inferior frontal junction-left inferior parietal sulcus connectivity correlated with decreased global switch cost.

DISCUSSION

This study provides novel evidence for different neural patterns in global and local switch costs by illuminating connectivity mechanisms underlying cognitive flexibility in aging.

The effect of age on task switching: updated and extended meta-analyses

Cognitive flexibility is one of the crucial abilities for human survival. As people get older, whether their flexibility ability will be affected is one of the core research topics in aging research. Researchers have developed a task-switch paradigm in laboratories to mimic daily-life shifting task-set scenarios. However, the empirical evidence is equivocal. Considering every single study may have a biased sample; therefore, we hoped to combine smaller studies, making them into one extensive investigation, which may help show an actual effect. In the current study, we used two meta-analysis techniques, the Brinley plot (along with the State-trace plot) and conventional meta-analysis, to re-evaluate whether healthy aging influences cognitive flexibility. The results of the Brinley plot analysis showed no evidence of switch-specific age-related impairment as indexed by the local switch cost. Yet, older adults performed more slowly than younger adults across task conditions. The conventional meta-analysis further showed that the currently available findings were heterogenous and exhibited publication bias. Therefore, this study suggests that researchers should interpret their results cautiously while using a task-switching paradigm to address older adults' shifting abilities. More parametric variables must be considered and developed in a task-switching paradigm to enhance its sensitivity and reveal older adults' actual shifting ability.

Feasibility and acceptability of a new web-based cognitive training platform for cognitively healthy older adults: the breakfast task

BACKGROUND

Developing efficient cognitive training for the older population is a major public health goal due to its potential cognitive benefits. A promising training target is executive control, critical for multitasking in everyday life. The aim of this pilot study was to establish the feasibility and acceptability of the Breakfast Task training in older adults, a new web-based cognitive training platform that simulates real-life multitasking demands.

METHODS

A community-based sample of 24 cognitively healthy participants aged between 60 and 75 (M = 69.12, SD = 3.83) underwent 5-session cognitive training protocol, delivered online. Each session lasted 45 min and occurred twice a week at participant's homes. Performance was recorded, and participants completed questionnaires at baseline and after the intervention.

RESULTS

Feasibility metrics showed overall high recruitment (82.7%), adherence and retention rates (100%). Acceptability was considered good based on participant's quantitative and qualitative responses. On average, participants rated the game as interesting, enjoyable and did not report difficulties in accessing the game online without supervision or in understanding the instructions. Participants showed a learning curve across sessions, suggesting improvement in the game outcomes and potential benefits from the emphasis change training approach. The study identified relevant areas that need improvements and adjustments, such as technical issues, session's structure, and dose.

CONCLUSIONS

The findings provide preliminary support for the feasibility and acceptability of the web-based Breakfast Task training platform in cognitively healthy older adults. Results suggest the value of further research to investigate the Breakfast Task training features and dose-response relationship, as well as its potential efficacy in older adults via larger randomized controlled trials.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04195230 (Registered 11 December 2019).

Older adults compensate for switch, but not mixing costs, relative to younger adults on an intrinsically cued task switching experiment

Introduction

Aging negatively impacts the ability to rapidly and successfully switch between two or more tasks that have different rules or objectives. However, previous work has shown that the context impacts the extent of this age-related impairment: while there is relative age-related invariance when participants must rapidly switch back and forth between two simple tasks (often called "switch costs"), age-related differences emerge when the contexts changes from one in which only one task must be performed to one in which multiple tasks must be performed, but a trial-level switch is not required (e.g., task repeat trials within dual task blocks, often called "mixing costs"). Here, we explored these two kinds of costs behaviorally, and also investigated the neural correlates of these effects.

Methods

Seventy-one younger adults and 175 older adults completed a task-switching experiment while they underwent fMRI brain imaging. We investigated the impact of age on behavioral performance and neural activity considering two types of potential costs: switch costs (dual-task switch trials minus dual-task non-switch trials), and mixing costs (dual-task non-switch minus single-task trials).

Results

We replicated previous behavioral findings, with greater age associated with mixing, but not switch costs. Neurally, we found age-related compensatory activations for switch costs in the dorsal lateral prefrontal cortex, pars opercularis, superior temporal gyrus, and the posterior and anterior cingulate, but age-related under recruitment for mixing costs in fronto-parietal areas including the supramarginal gyrus and pre and supplemental motor areas.

Discussion

These results suggest an age-based dissociation between executive components that contribute to task switching.

Imposed load versus voluntary investment: Executive control and attention management in dual-task performance

Dual task performance is one of the most frequently used paradigm in the evaluation of coping with concurrent task demands. The Breakfast Task experimented in this paper, was originally developed as a general indicator of coping ability with high demand executive control and attention management requirements. It is a computer-based simulation, in which the performer is required to cook several food items while concurrently setting table for guests. The task was employed in different studies, to compare young to old adults, monolinguals to bilinguals, influence of Parkinson disease and brain injury. However, in a closer examination, it is a dual task setting, in which cooking reflects coping with imposed load while table setting is an indicator of strategy free, voluntary invested effort. Models of workload did not examine the impact of such asymmetric flexibility on concurrent performance. Three experiments with elaborated versions of the breakfast task, show that the difference between the tasks affects concurrent performance formats in response to manipulations of task difficulty, priority change and practice. These results and their implications are discussed in reference to limited capacity, resource and executive control models of multitasking and task load.

The Relative Contribution of Executive Functions and Aging on Attentional Control During Road Crossing

As we age, many physical, perceptual and cognitive abilities decline, which can critically impact our day-to-day lives. However, the decline of many abilities is concurrent; thus, it is challenging to disentangle the relative contributions of different abilities in the performance deterioration in realistic tasks, such as road crossing, with age. Research into road crossing has shown that aging and a decline in executive functioning (EFs) is associated with altered information sampling and less safe crossing decisions compared to younger adults. However, in these studies declines in age and EFs were confounded. Therefore, it is impossible to disentangle whether age-related declines in EFs impact on visual sampling and road-crossing performance, or whether visual exploration, and road-crossing performance, are impacted by aging independently of a decline in EFs. In this study, we recruited older adults with maintained EFs to isolate the impacts of aging independently of a decline EFs on road crossing abilities. We recorded eye movements of younger adults and older adults while they watched videos of road traffic and were asked to decide when they could cross the road. Overall, our results show that older adults with maintained EFs sample visual information and make similar road crossing decisions to younger adults. Our findings also reveal that both environmental constraints and EF abilities interact with aging to influence how the road-crossing task is performed. Our findings suggest that older pedestrians' safety, and independence in day-to-day life, can be improved through a limitation of scene complexity and a preservation of EF abilities.

Potential Diffusion Tensor Imaging Biomarkers for Elucidating Intra-Individual Age-Related Changes in Cognitive Control and Processing Speed

Cognitive aging, especially cognitive control, and processing speed aging have been well-documented in the literature. Most of the evidence was reported based on cross-sectional data, in which inter-individual age effects were shown. However, there have been some studies pointing out the possibility of overlooking intra-individual changes in cognitive aging. To systematically examine whether age-related differences and age-related changes might yield distinctive patterns, this study directly compared cognitive control function and processing speed between different cohorts versus follow-up changes across the adult lifespan. Moreover, considering that cognitive aging has been attributed to brain disconnection in white matter (WM) integrity, this study focused on WM integrity via acquiring diffusion-weighted imaging data with an MRI instrument that are further fitted to a diffusion tensor model (i.e., DTI) to detect water diffusion directionality (i.e., fractional anisotropy, FA; mean diffusivity, MD; radial diffusivity, RD; axial diffusivity, AxD). Following data preprocessing, 114 participants remained for further analyses in which they completed the two follow-up sessions (with a range of 1-2 years) containing a series of neuropsychology instruments and computerized cognitive control tasks. The results show that many significant correlations between age and cognitive control functions originally shown on cross-sectional data no longer exist on the longitudinal data. The current longitudinal data show that MD, RD, and AxD (especially in the association fibers of anterior thalamic radiation) are more strongly correlated to follow-up aging processes, suggesting that axonal/myelin damage is a more robust phenomenon for observing intra-individual aging processes. Moreover, processing speed appears to be the most prominent cognitive function to reflect DTI-related age (cross-sectional) and aging (longitudinal) effects. Finally, converging the results from regression analyses and mediation models, MD, RD, and AxD appear to be the representative DTI measures to reveal age-related changes in processing speed. To conclude, the current results provide new insights to which indicator of WM integrity and which type of cognitive changes are most representative (i.e., potentially to be neuroimaging biomarkers) to reflect intra-individual cognitive aging processes.

Ageing and selective inhibition of irrelevant information in an attention-demanding rapid serial visual presentation task

Attention involves both an ability to selectively focus on relevant information and simultaneously ignore irrelevant information (i.e. inhibitory control). Many factors impact inhibitory control such as individual differences, relative timing of stimuli presentation, distractor characteristics, and participant age. Previous research with young adults responding to an attention-demanding rapid serial visual presentations of pictures superimposed with task-irrelevant words evaluated the extent to which unattended information may be subject to inhibitory control. Surprise recognition tests following the rapid serial visual presentation task showed that recognition for unattended words presented with non-targets (i.e. non-aligned or ‘NA’ words) during the rapid serial visual presentation task were recognised at chance levels. However, when the unattended words were infrequently paired with the attended picture targets (i.e. target-aligned or ‘TA’ words), recognition rates were significantly below chance and significantly lower compared to NA words, suggesting selective inhibitory control for the previously unattended TA words. The current study adapted this paradigm to compare healthy younger and older adults’ ability to engage in inhibitory control. In line with previous research, younger adults demonstrated selective inhibition with recognition rates for TA words significantly lower than NA words and chance, while NA words were recognised at chance levels. However, older adults showed no difference in recognition rates between word types (TA versus NA). Rather all items were recognised at rates significantly below chance suggesting inhibited recognition for all unattended words, regardless of when they were presented during the primary task. Finally, older adults recognised significantly fewer NA words compared to young adults. These findings suggest that older adults may experience a decline in their ability to selectively inhibit the processing of irrelevant information, while maintaining the capacity to exercise global inhibition over unattended lexical information.

A single mode of population covariation associates brain networks structure and behavior and predicts individual subjects' age

Multiple human behaviors improve early in life, peaking in young adulthood, and declining thereafter. Several properties of brain structure and function progress similarly across the lifespan. Cognitive and neuroscience research has approached aging primarily using associations between a few behaviors, brain functions, and structures. Because of this, the multivariate, global factors relating brain and behavior across the lifespan are not well understood. We investigated the global patterns of associations between 334 behavioral and clinical measures and 376 brain structural connections in 594 individuals across the lifespan. A single-axis associated changes in multiple behavioral domains and brain structural connections (r = 0.5808). Individual variability within the single association axis well predicted the age of the subject (r = 0.6275). Representational similarity analysis evidenced global patterns of interactions across multiple brain network systems and behavioral domains. Results show that global processes of human aging can be well captured by a multivariate data fusion approach.

Using SHRP2 NDS data to examine infrastructure and other factors contributing to older driver crashes during left turns at signalized intersections

Drivers age 65 and over have higher rates of crashes and crash-related fatalities than other adult drivers and are especially over-represented in crashes during left turns at intersections. This research investigated the use of SHRP2 Naturalistic Driving Study (NDS) data to assess infrastructure and other factors contributing to left turn crashes at signalized intersections, and how to improve older driver safety during such turns. NDS data for trips involving signalized intersections and crash or near-crash events were obtained for two driver age groups: drivers age 65 and over (older drivers) and a sample of drivers age 30-49, along with NDS pre-screening and questionnaire data. Video scoring of all trips was performed to collect additional information on intersection and trip conditions. To identify the most influential factors of crash risk during left turns at signalized intersections, machine learning and regression models were used. The results found that in the obtained NDS dataset, there was a relatively small volume of crashes during left turns at signalized intersections. Further, model results found the statistically significant variables of crash risk for older drivers were associated more with health and cognitive factors rather than the infrastructure or design of the intersections. The results suggest that a study using only SHRP2 NDS data will not lead to definitive findings or recommendations for infrastructure changes to increase safety for older drivers at signalized intersections and during left turns. Moreover, the findings of this study indicates the need to consider other data sources and data collection methods to address this critical literature gap in older driver safety.

Can Attention and Working Memory Impairments of Intimate Partner Perpetrators Explain Their Risky Decision Making?

Intimate partner violence (IPV) perpetrators commonly exhibit deficits in a wide range of cognitive domains, such as attention, memory, and executive functions. Executive dysfunctions tend to be related to a preference for disadvantageous decisions, which could be explained by a pattern of focusing on positive outcomes (gains) while disregarding negative ones. Nonetheless, it is less clear whether risk-taking and decision-making problems should be attributed to motivational and/or emotional causes or to cognitive deficits in attention and/or working memory. The main goal of the present study was to examine whether IPV perpetrators can be distinguished from non-violent controls based on their performance on attention, working memory, and decision-making tests from a computerized battery of tests. In addition, this study investigated the potential relationship between attention and working memory impairments in the decision-making abilities of IPV perpetrators. Our data indicated that IPV perpetrators perform worse than controls on measures of attention and sustained attention, processing speed, working memory, spatial span, and decision making. Moreover, IPV perpetrators' preference for disadvantageous and risky decisions could be partially explained by attention and working memory impairments. Our study has enabled us to explore the cognitive deficits underlying IPV perpetration as key factors in reducing IPV risky decisions. Moreover, it reinforces the need to develop specific neuropsychological training in the attention-switching ability in general and working memory, which could lead to improvements in decision-making processes or other executive functions.

Training and Transfer of Cue Updating in Older Adults Is Limited: Evidence From Behavioral and Neuronal Data

Cognitive control processes, such as updating task-relevant information while switching between multiple tasks, are substantially impaired in older adults. However, it has also been shown that these cognitive control processes can be improved by training interventions, e.g., by training in task switching. Here, we applied an event-related potential (ERP) approach to identify whether a cognitive training improves task-preparatory processes such as updating of relevant task goals. To do so, we applied a pretest-training-posttest design with eight training sessions. Two groups of older adults were either trained in task switching (treatment group) or in performing single tasks (control group) and we compared their performance to a group of untrained younger adults. To foster cue updating in the treatment group, we applied a cue-based switching task in which the two task cues were randomly selected prior to target presentation so that participants had time to prepare for the upcoming task. In contrast, the control group also received task cues but those were redundant as only one task had to be performed. We also examined whether training in cue updating during task switching can be transferred to a similar cognitive control task measuring updating of context information, namely a modified version of the AX-Continuous Performance Task (AX-CPT). The results revealed training-specific improvements in task switching, that is, a larger improvement in blocks requiring switching in comparison to single tasks at the behavioral level. In addition, training specific-effects were also found at the neuronal level. Older adults trained in cue updating while switching showed a reduction in mixing costs in the cue-related P3, indicating an improvement in preparatory updating processes. Additionally, P3 topography changed with training from a very broad to a parietally focused scalp distribution similar to the one found in younger adults. However, we did not obtain training-specific improvements in context updating in the AX-CPT neither at the behavioral level nor at the neuronal level. Results are discussed in the context of the ongoing debate on whether transfer of cognitive training improvements is possible.

Small molecule cognitive enhancer reverses age-related memory decline in mice

With increased life expectancy, age-associated cognitive decline becomes a growing concern, even in the absence of recognizable neurodegenerative disease. The integrated stress response (ISR) is activated during aging and contributes to age-related brain phenotypes. We demonstrate that treatment with the drug-like small-molecule ISR inhibitor ISRIB reverses ISR activation in the brain, as indicated by decreased levels of activating transcription factor 4 (ATF4) and phosphorylated eukaryotic translation initiation factor eIF2. Furthermore, ISRIB treatment reverses spatial memory deficits and ameliorates working memory in old mice. At the cellular level in the hippocampus, ISR inhibition (i) rescues intrinsic neuronal electrophysiological properties, (ii) restores spine density and (iii) reduces immune profiles, specifically interferon and T cell-mediated responses. Thus, pharmacological interference with the ISR emerges as a promising intervention strategy for combating age-related cognitive decline in otherwise healthy individuals.

Age-related functional brain connectivity during audio-visual hand-held tool recognition

INTRODUCTION

Previous studies have confirmed increased functional connectivity in elderly adults during processing of simple audio-visual stimuli; however, it is unclear whether elderly adults maximize their performance by strengthening their functional brain connectivity when processing dynamic audio-visual hand-held tool stimuli. The present study aimed to explore this question using global functional connectivity.

METHODS

Twenty-one healthy elderly adults and 21 healthy younger adults were recruited to conduct a dynamic hand-held tool recognition task with high/low-intensity stimuli.

RESULTS

Elderly adults exhibited higher areas under the curve for both the high-intensity (3.5 versus. 2.7) and low-intensity (3.0 versus. 1.2) stimuli, indicating a higher audio-visual integration ability, but a delayed and widened audio-visual integration window for elderly adults for both the high-intensity (390 - 690 ms versus. 360 - 560 ms) and low-intensity (460 - 690 ms versus. 430 - 500 ms) stimuli. Additionally, elderly adults exhibited higher theta-band (all p < .01) but lower alpha-, beta-, and gamma-band functional connectivity (all p < .05) than younger adults under both the high- and low-intensity-stimulus conditions when processing audio-visual stimuli, except for gamma-band functional connectivity under the high-intensity-stimulus condition. Furthermore, higher theta- and alpha-band functional connectivity were observed for the audio-visual stimuli than for the auditory and visual stimuli and under the high-intensity-stimulus condition than under the low-intensity-stimulus condition.

CONCLUSION

The higher theta-band functional connectivity in elderly adults was mainly due to higher attention allocation. The results further suggested that in the case of sensory processing, theta, alpha, beta, and gamma activity might participate in different stages of perception.

Hybrid foraging search in younger and older age

In hybrid foraging tasks, observers search visual displays, so called patches, for multiple instances of any of several types of targets with the goal of collecting targets as quickly as possible. Here, targets were photorealistic objects. Younger and older adults collected targets by mouse clicks. They could move to the next patch whenever they decided to do so. The number of targets held in memory varied between 8 and 64 objects, and the number of items (targets and distractors) in the patches varied between 60 and 105 objects. Older adults foraged somewhat less efficiently than younger adults due to a more exploitative search strategy. When target items became depleted in a patch and search slowed down, younger adults acted according to the optimal foraging theory and moved on to the next patch when the instantaneous rate of collection was close to their average rate of collection. Older adults, by contrast, were more likely to stay longer and spend time searching for the last few targets. Within a patch, both younger and older adults tended to collect the same type of target in "runs." This behavior is more efficient than continual switching between target types. Furthermore, after correction for general age-related slowing, RT × set size functions revealed largely preserved attention and memory functions in older age. Hybrid foraging tasks share features with important real-world search tasks. Differences between younger and older observers on this task may therefore help to explain age differences in many complex search tasks of daily life. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Age-Based Differences in Task Switching Are Moderated by Executive Control Demands

Objectives

Recent work has identified different aspects of executive function that may underlie cognitive changes associated with age. The current study used a multifactorial design to investigate age sensitivity in the ability to shift between different task sets and the interaction of this ability with several specific aspects of executive control.

Method

A large, well-characterized sample of younger (n = 40) and clinically healthy older (n = 51) adults completed a task switching paradigm in which 3 aspects of executive control were manipulated between subjects: a) sensorimotor demand (the number of distinct stimulus-response options); b) stimulus-level interference (i.e., flanker effects); and c) updating/monitoring (the frequency of task switches).

Results

Unique age-related deficits were observed for different aspects of local task switching performance costs and updating/monitoring, but not for interference. Sensorimotor demand was also an important additional factor that interacted with task switching performance.

Discussion

Our findings suggest that task switching, coupled with infrequent and unexpected transitions from one task set to another, in the context of high motoric demands, is particularly difficult for older adults.

Reorganization of brain networks and its association with general cognitive performance over the adult lifespan

Healthy aging is associated with structural and functional changes in the brain even in individuals who are free of neurodegenerative diseases. Using resting state functional magnetic resonance imaging data from a carefully selected cohort of participants, we examined cross sectional changes in the functional organization of several large-scale brain networks over the adult lifespan and its potential association with general cognitive performance. Converging results from multiple analyses at the voxel, node, and network levels showed widespread reorganization of functional brain networks with increasing age. Specifically, the primary processing (visual and sensorimotor) and visuospatial (dorsal attention) networks showed diminished network integrity, while the so-called core neurocognitive (executive control, salience, and default mode) and basal ganglia networks exhibited relatively preserved between-network connections. The visuospatial and precuneus networks also showed significantly more widespread increased connectivity with other networks. Graph analysis suggested that this reorganization progressed towards a more integrated network topology. General cognitive performance, assessed by Addenbrooke's Cognitive Examination-Revised total score, was positively correlated with between-network connectivity among the core neurocognitive and basal ganglia networks and the integrity of the primary processing and visuospatial networks. Mediation analyses further indicated that the observed association between aging and relative decline in cognitive performance could be mediated by changes in relevant functional connectivity measures. Overall, these findings provided further evidence supporting widespread age-related brain network reorganization and its potential association with general cognitive performance during healthy aging.

Street-crossing workload in young and older pedestrians

Although several studies have sought to identify both gap-acceptance difficulties with aging and gait differences, few have examined the extent to which crossing the street is physically and cognitively demanding for older pedestrians, in such a way that street crossing can be seen as a dual task. To gain insight into this issue, this study reports an experiment with 15 young (ages 19-26), 19 younger-old (ages 60-72), and 21 older-old (ages 73-82) adults. The participants carried out three tasks: (i) a simple walking task, (ii) a dual task involving walking while scanning (walking while pressing a button as soon as a visual or sound stimulus appeared), and (iii) a street-crossing task with vehicles approaching from two directions. The results indicated more street-crossing collisions in older-old than in younger-old and young participants. Longer reaction times were observed in the dual walking-scanning task for both old groups, especially for visual stimuli. Walking-speed comparisons yielded nonsignificant differences between the dual task and the street-crossing task in young participants, suggesting a correspondence in terms of demands and task priority. In contrast, old participants walked significantly faster in the street-crossing task than in the dual task, suggesting that they placed priority on walking rapidly than on scanning traffic. Finally, whereas the participants estimated the perceived workload to be greater when they were crossing the street than while simply walking or responding to the dual task, young participants gave the highest rating to the mental and physical demands, perhaps due to a lack of awareness of task demands among old participants.

Working Memory Capacity as a Predictor of Cognitive Training Efficacy in the Elderly Population

Aging is associated with a decline in a wide range of cognitive functions and working memory (WM) deterioration is considered a main factor contributing to this. Therefore, any attempt to counteract WM decline seems to have a potential benefit for older adults. However, determination of whether such methods like WM trainings are effective is a subject of a serious debate in the literature. Despite a substantial number of training studies and several meta-analyses, there is no agreement on the matter of their effectiveness. The other important and still not fully explored issue is the impact of the preexisting level of intellectual functioning on the training's outcome. In our study we investigated the impact of WM training on variety of cognitive tasks performance among older adults and the impact of the initial WM capacity (WMC) on the training efficiency. 85 healthy older adults (55-81 years of age; 55 female, 30 males) received 5 weeks of training on adaptive dual N-back task (experimental group) or memory quiz (active controls). Cognitive performance was assessed before and after intervention with measures of WM, memory updating, inhibition, attention shifting, short-term memory (STM) and reasoning. We found post-intervention group independent improvements across all cognitive tests except for inhibition and STM. With multi-level analysis individual learning curves were modeled, which enabled examining of the intra-individual change in training and inter-individual differences in intra-individual changes. We observed a systematic and positive, but relatively small, learning trend with time. Moderator analyses with demographic characteristics as moderators showed no additional effects on learning curves. Only initial WMC level was a significant moderator of training effectiveness. Older adults with initially lower WMC improved less and reached lower levels of performance, compared to the group with higher WMC. Overall, our findings are in accordance with the research suggesting that post-training gains are within reach of older adults. Our data provide evidence supporting the presence of transfer after N-back training in older adults. More importantly, our findings suggest that it is more important to take into account an initial WMC level, rather than demographic characteristics when evaluating WM training in older adults.

Age Differences in Emotion Regulation Choice: Older Adults Use Distraction Less Than Younger Adults in High-Intensity Positive Contexts

Objectives

Previous research demonstrates that younger and older adults prefer distraction over engagement (reappraisal) when regulating high-intensity negative emotion. Older adults also demonstrate a greater bias for positive over negative information in attention and memory compared with younger adults. In this study, we investigated whether emotion regulation choice preferences may differ as a function of stimulus valence with age.

Method

The effect of stimulus intensity on negative and positive emotion regulation strategy preferences was investigated in younger and older men. Participants indicated whether they favored distraction or reappraisal to attenuate emotional reactions to negative and positive images that varied in intensity.

Results

Men in both age-groups preferred distraction over reappraisal when regulating high-intensity emotion. As no age-related strategic differences were found in negative emotion regulation preferences, older men chose to distract less from high-intensity positive images than did younger men.

Discussion

Older men demonstrated greater engagement with highly positive emotional contexts than did younger men. Thus, age differences in emotion regulation goals when faced with intense emotional stimuli depend on the valence of the emotional stimuli.

The implementation of expectancy-based strategic processes is delayed in normal aging

The present research examined if the time needed to implement expectancy-based strategic processes is different in younger and healthy older adults. In four experiments participants from both age groups performed different strategic priming tasks. These included a greater proportion of incongruent (or unrelated; 80%) than of congruent (or related; 20%) trials. With this procedure performance is worse for congruent (less frequent) than for incongruent (more frequent) trials, thus demonstrating that the relative frequency information can be used to predict the upcoming target. To explore the time course of these expectancy-based effects, the prime-target SOA was manipulated across experiments through a range of intervals: 400, 1000 and 2000 ms. Participants also performed a change localization and an antisaccade task to assess their working memory and attention control capacities. The results showed that increases in age were associated with (a) a slower processing-speed, (b) a decline in WM capacity, and (c) a decreased capacity for attentional control. The latter was evidenced by a disproportionate deterioration of performance in the antisaccade trials compared to the prosaccade ones in the older group. Results from the priming tasks showed a delay in the implementation of expectancies in older adults. Whereas younger participants showed strategic effects already at 1000 ms, older participants consistently failed to show expectancy-based priming during the same interval. Importantly, these effects appeared later at 2000 ms, being similar in magnitude to those by the younger participants and unaffected by task practice. The present findings demonstrate that the ability to implement expectancy-based strategies is slowed down in normal aging.

Cross-modal transfer after auditory task-switching training

Task-switching training was shown to improve performance not only for the trained tasks (i.e., reduced performance costs resulting from the task switches), but also for structurally similar (near transfer) or even dissimilar tasks (far transfer). However, it is still unclear whether the improvement is specific to the trained input modality or whether cognitive control occurs at an amodal processing level enabling transfer of set-shifting abilities to different input modalities. In this study, training and transfer was assessed for an auditory task-switching paradigm in which spoken words from different semantic categories were presented dichotically requiring participants to switch between two auditory categorization tasks. Cross-modal transfer of task-switching training was assessed in terms of the performance costs in a visual task-switching situation using tasks that were structurally similar to the trained tasks. The 4-day training significantly reduced the costs resulting from mixing the two auditory tasks, as compared to both an active (auditory single-task training) and a passive control group (no training). More importantly, the auditory task-switching training was also found to reduce the mixing costs for untrained visual tasks, indicating cross-modal transfer. This finding suggests that the improvement resulting from task-switching training is not specific to the trained stimulus modality, but it seems to be driven by a cognitive control mechanism operating at an amodal processing level. The training did not reveal any far-transfer effects to working memory, inhibition, or fluid intelligence, suggesting that the modality-independent enhancement of set-shifting does not generalize to other cognitive control functions.

Older adults show impaired modulation of attentional alpha oscillations: Evidence from dichotic listening

Auditory attention is critical for selectively listening to speech from a single talker in a multitalker environment (e.g., Cherry, 1953). Listening in such situations is notoriously more difficult and more poorly encoded to long-term memory in older than in young adults (Tun, O'Kane, & Wingfield, 2002). Recent work by Payne, Rogers, Wingfield, and Sekuler (2017) in young adults demonstrated a neural correlate of auditory attention in the directed dichotic listening task (DDLT), where listeners attend to one ear while ignoring the other. Measured using electroencephalography, differences in alpha band power (8-14 Hz) between left and right hemisphere parietal regions mark the direction to which auditory attention is focused. Little prior research has been conducted on alpha power modulations in older adults, particularly with regard to auditory attention directed toward speech stimuli. In the current study, an older adult sample was administered the DDLT and delayed recognition procedures used by Payne et al. (2017). Compared to young adults, older adults showed reduced selective attention in the DDLT, evidenced by a higher rate of intrusions from the unattended ear. Moreover, older adults did not exhibit attention-related alpha modulation evidenced by young adults, nor did their event-related potentials (ERPs) to recognition probes differentiate between attended or unattended probes. Older adults' delayed recognition did not reveal a pattern of suppression of unattended items evidenced by young adults. These results serve as evidence for an age-related decline in selective auditory attention, potentially mediated by age-related decline in the ability to modulate alpha oscillations. (PsycINFO Database Record

The shifting self in aging

BACKGROUND AND AIMS

This study investigated the ability of older adults to shift between self-images.

METHODS

We designed a shifting-self task in which older adults and younger adults were invited to produce statements describing their physical self (e.g., "I am tall") and psychological self (e.g., "I am cheerful"). Participants were invited to shift between physical-self statements and psychological-self statements and, on a control task, to produce two blocks of physical-self statements and psychological-self statements. They also performed a typical shifting task (i.e., the plus-minus task).

RESULTS

Analysis showed slower completion time on the shifting-self task in older adults than in younger adults. Time to complete the shifting-self task was longer than that for the control task in both older and younger adults. Performances on the shifting-self task were significantly correlated with performances on the plus-minus task.

DISCUSSION

We hypothesized that older adults take more time to shift between self-images because they enjoy self-stability. In other words, the tendency of older adults to shift between self-images more slowly than younger adults might be because they have more consistent or stable self-concepts, and are therefore less inclined to "change" their self-images.

Cross-sectional white matter microstructure differences in age and trait mindfulness

The process of aging can be characterized by a decline in cognitive performance, which may be accompanied by deterioration in specific structural properties of the brain. In this study we sought to investigate to what extent mindfulness changes over the aging process, and which alterations in brain structure can be associated to aging and concomitant changes in mindfulness. We collected Mindful Attention Awareness Scale questionnaire data to assess trait mindfulness and acquired diffusion-weighted imaging data fitted to the diffusion tensor model (DTI) in a group of 97 middle-aged to elderly participants. Our results showed that trait mindfulness increased with age. In terms of white matter structure our results suggested that there was a general increase of omnidirectional diffusion, which favored radial over axial diffusivity, leading to a decrease in fractional anisotropy (FA) in older participants. We further showed that trait mindfulness mediated the FA-age effect in a localized area consisting of the internal and external capsule, as well as the corona radiata. The implication of this mediation analysis is that trait mindfulness may deter age-associated neurocognitive decline, perhaps by preventing age-associated microlesions specifically in cortico-subcortical white matter tracts. This study can be considered a pioneer of using DTI studies to investigate the relationship between age and trait mindfulness.

The interactive Physical and Cognitive Exercise System (iPACES™): effects of a 3-month in-home pilot clinical trial for mild cognitive impairment and caregivers

Background

Alzheimer’s and related dementias are on the rise, and older adults and their families are seeking accessible and effective ways to stave off or ameliorate mild cognitive impairment (MCI).

Aim

This pilot clinical trial (ClinicalTrials.gov Identifier: 03069391) examined neuropsychological and neurobiological outcomes of interactive physical and mental exercise.

Participants and methods

Older adults (MCI and caregivers) were enrolled in a 3-month, in-home trial of a portable neuro-exergame (the interactive Physical and Cognitive Exercise System [iPACES™]), in which they pedaled and steered along a virtual bike path to complete a list of errands (Memory Lane™). Neuropsychological function and salivary biomarkers were measured at pre-, mid-, and posttrial. Ten older adults complied with the recommended use of iPACES (complete dose; ≥2×/wk, 67% of the 15 who also had pre- and postevaluation data). Statistical analyses compared change over time and also change among those with a complete dose vs inadequate dose. Correlations between change in neuropsychological and biomarker measures were also examined.

Results

Executive function and verbal memory increased after 3 months (p = 0.01; no significant change was found with an inadequate dose). Change in salivary biomarkers was moderately associated with increasing cognition (cortisol, r = 0.68; IGF-1, r = 0.37).

Conclusion

Further research is needed, but these pilot data provide preliminary indications to suggest neuro-exergaming can impact cognitive function, perhaps via neurobiological mechanisms, and as such may provide an effective and practical way to promote healthy aging.

General Slowing and Education Mediate Task Switching Performance Across the Life-Span

Objective: This study considered the potential role of both protective factors (cognitive reserve, CR) and adverse ones (general slowing) in modulating cognitive flexibility in the adult life-span. Method: Ninety-eight individuals performed a task-switching (TS) paradigm in which we adopted a manipulation concerning the timing between the cue and the target. Working memory demands were minimized by using transparent cues. Additionally, indices of cognitive integrity, depression, processing speed and different CR dimensions were collected and used in linear models accounting for TS performance under the different time constraints. Results: The main results showed similar mixing costs and higher switching costs in older adults, with an overall age-dependent effect of general slowing on these costs. The link between processing speed and TS performance was attenuated when participants had more time to prepare. Among the different CR indices, formal education only was associated with reduced switch costs under time pressure. Discussion: Even though CR is often operationalized as a unitary construct, the present research confirms the benefits of using tools designed to distinguish between different CR dimensions. Furthermore, our results provide empirical support to the assumption that processing speed influence on executive performance depends on time constraints. Finally, it is suggested that whether age differences appear in terms of switch or mixing costs depends on working memory demands (which were low in our tasks with transparent cues).

More expertise for a better perspective: Task and strategy-driven adaptive neurofunctional reorganization for word production in high-performing older adults

The suggestion that neurofunctional reorganization may contribute to preserved language abilities is still emerging in aging studies. Some of these abilities, such as verbal fluency (VF), are not unitary but instead rely on different strategic processes that are differentially changed with age. Younger (n = 13) and older adults (n = 13) carried out an overt self-paced semantic and orthographic VF tasks within mixed fMRI design. Our results suggest that patterns of brain activation sustaining equivalent performances could be underpinned by different strategies facing brain changes during healthy aging. These main findings suggest that temporally mediated semantic clustering and frontally mediated orthographic switching were driven by evolutive neurofunctional resources in high-performing older adults. These age-related activation changes can appear to be compatible with the idea that unique neural patterns expressing distinctive cognitive strategies are necessary to support older adults' performance on VF tasks.

Brain Network Modularity Predicts Exercise-Related Executive Function Gains in Older Adults

Recent work suggests that the brain can be conceptualized as a network comprised of groups of sub-networks or modules. The extent of segregation between modules can be quantified with a modularity metric, where networks with high modularity have dense connections within modules and sparser connections between modules. Previous work has shown that higher modularity predicts greater improvements after cognitive training in patients with traumatic brain injury and in healthy older and young adults. It is not known, however, whether modularity can also predict cognitive gains after a physical exercise intervention. Here, we quantified modularity in older adults (N = 128, mean age = 64.74) who underwent one of the following interventions for 6 months (NCT01472744 on ClinicalTrials.gov): (1) aerobic exercise in the form of brisk walking (Walk), (2) aerobic exercise in the form of brisk walking plus nutritional supplement (Walk+), (3) stretching, strengthening and stability (SSS), or (4) dance instruction. After the intervention, the Walk, Walk+ and SSS groups showed gains in cardiorespiratory fitness (CRF), with larger effects in both walking groups compared to the SSS and Dance groups. The Walk, Walk+ and SSS groups also improved in executive function (EF) as measured by reasoning, working memory, and task-switching tests. In the Walk, Walk+, and SSS groups that improved in EF, higher baseline modularity was positively related to EF gains, even after controlling for age, in-scanner motion and baseline EF. No relationship between modularity and EF gains was observed in the Dance group, which did not show training-related gains in CRF or EF control. These results are consistent with previous studies demonstrating that individuals with a more modular brain network organization are more responsive to cognitive training. These findings suggest that the predictive power of modularity may be generalizable across interventions aimed to enhance aspects of cognition and that, especially in low-performing individuals, global network properties can capture individual differences in neuroplasticity.

Age-Related Brain Activation Changes during Rule Repetition in Word-Matching

Objective: The purpose of this study was to explore the age-related brain activation changes during a word-matching semantic-category-based task, which required either repeating or changing a semantic rule to be applied. In order to do so, a word-semantic rule-based task was adapted from the Wisconsin Sorting Card Test, involving the repeated feedback-driven selection of given pairs of words based on semantic category-based criteria. Method: Forty healthy adults (20 younger and 20 older) performed a word-matching task while undergoing a fMRI scan in which they were required to pair a target word with another word from a group of three words. The required pairing is based on three word-pair semantic rules which correspond to different levels of semantic control demands: functional relatedness, moderately typical-relatedness (which were considered as low control demands), and atypical-relatedness (high control demands). The sorting period consisted of a continuous execution of the same sorting rule and an inferred trial-by-trial feedback was given. Results: Behavioral performance revealed increases in response times and decreases of correct responses according to the level of semantic control demands (functional vs. typical vs. atypical) for both age groups (younger and older) reflecting graded differences in the repetition of the application of a given semantic rule. Neuroimaging findings of significant brain activation showed two main results: (1) Greater task-related activation changes for the repetition of the application of atypical rules relative to typical and functional rules, and (2) Changes (older > younger) in the inferior prefrontal regions for functional rules and more extensive and bilateral activations for typical and atypical rules. Regarding the inter-semantic rules comparison, only task-related activation differences were observed for functional > typical (e.g., inferior parietal and temporal regions bilaterally) and atypical > typical (e.g., prefrontal, inferior parietal, posterior temporal, and subcortical regions). Conclusion: These results suggest that healthy cognitive aging relies on the adaptive changes of inferior prefrontal resources involved in the repetitive execution of semantic rules, thus reflecting graded differences in support of task demands.

Differential age-related changes in localizing a target among distractors across an extended visual field

Age differences in the spatial distribution of attention over a wide field of view have only been described in terms of the spatial extent, leaving the topographical aspect unexplored. This study examined age differences between younger and older adults in good general health in an important topographical characteristic, the asymmetry between the upper and lower visual fields. In Experiment 1, we found age differences across the entire attentional visual field. In addition, age differences were greater in the upper compared to the lower field. In Experiment 2, we examined whether the finding of a greater age difference in the ability to localize a target among distractors in the upper visual field in Experiment 1 was a result of possible differential age differences between the upper and lower visual fields in the ability to localize a target even when there was no distractor competing for attention. Our results suggested that the age differences we observed were linked to age differences in the ability to filter out distractors that compete with the target for attention rather than the ability to process only the target over a wide field of view. While younger adults demonstrated an upper visual field advantage in the ability to localize a target among distractors, there was no such field advantage in older adults. We discuss this finding of diminished upper visual field advantage in older adults in light of an account of pervasive loss of neural specialization with age. We postulate that one possible explanation of age differences in the asymmetry between the upper and lower visual fields may be an adaptation to age-related physical decline. We also discuss important implications of our findings in risks of falls and vehicle crashes.

Intentional switching in auditory selective attention: Exploring age-related effects in a spatial setup requiring speech perception

Using a binaural-listening paradigm, age-related differences in the ability to intentionally switch auditory selective attention between two speakers, defined by their spatial location, were examined. Therefore 40 normal-hearing participants (20 young, Ø 24.8years; 20 older Ø 67.8years) were tested. The spatial reproduction of stimuli was provided by headphones using head-related-transfer-functions of an artificial head. Spoken number words of two speakers were presented simultaneously to participants from two out of eight locations on the horizontal plane. Guided by a visual cue indicating the spatial location of the target speaker, the participants were asked to categorize the target's number word into smaller vs. greater than five while ignoring the distractor's speech. Results showed significantly higher reaction times and error rates for older participants. The relative influence of the spatial switch of the target-speaker (switch or repetition of speaker's direction in space) was identical across age groups. Congruency effects (stimuli spoken by target and distractor may evoke the same answer or different answers) were increased for older participants and depend on the target's position. Results suggest that the ability to intentionally switch auditory attention to a new cued location was unimpaired whereas it was generally harder for older participants to suppress processing the distractor's speech.

Anticipatory Motor Planning in Older Adults

Objectives

The end-state comfort (ESC) effect represents an efficiency constraint in anticipatory motor planning. Although young adults usually avoid uncomfortable postures at the end of goal-directed movements, newer studies revealed that children's sensitivity for ESC is not fully in place before the age of 10 years. In this matter, it is surprising that nothing is known about the development of the ESC effect at older ages. Therefore, the aim of the present study was to examine the development of anticipatory motor planning in older adults.

Method

In 2 experiments, a total of 119 older adults (from 60 to 80 years old) performed in an unimanual (Experiment 1) and a bimanual version (Experiment 2) of the bar-transport-task.

Results

Across both experiments, the propensity of the ESC effect was significantly lower in the old-old (71-80 years old) as compared with the young-old (60-70 years old) participants.

Discussion

Although the performance of the young-old participants in the unimanual and bimanual task was comparable to what has been reported for young adults, the performance of the old-old participants was rather similar to the behavior of children younger than 10 years. Thus, for the first time, evidence is provided for the decrease of the ESC effect in older adults.

A Randomized Controlled ERP Study on the Effects of Multi-Domain Cognitive Training and Task Difficulty on Task Switching Performance in Older Adults

Executive functions are subject to a marked age-related decline, but have been shown to benefit from cognitive training interventions. As of yet, it is, however, still relatively unclear which neural mechanism can mediate training-related performance gains. In the present electrophysiological study, we examined the effects of multi-domain cognitive training on performance in an untrained cue-based task switch paradigm featuring Stroop color words: participants either had to indicate the word meaning of Stroop stimuli (word task) or perform the more difficult task of color naming (color task). One-hundred and three older adults (>65 years old) were randomly assigned to a training group receiving a 4-month multi-domain cognitive training, a passive no-contact control group or an active (social) control group receiving a 4-month relaxation training. For all groups, we recorded performance and EEG measures before and after the intervention. For the cognitive training group, but not for the two control groups, we observed an increase in response accuracy at posttest, irrespective of task and trial type. No training-related effects on reaction times were found. Cognitive training was also associated with an overall increase in N2 amplitude and a decrease of P2 latency on single trials. Training-related performance gains were thus likely mediated by an enhancement of response selection and improved access to relevant stimulus-response mappings. Additionally, cognitive training was associated with an amplitude decrease in the time window of the target-locked P3 at fronto-central electrodes. An increase in the switch positivity during advance task preparation emerged after both cognitive and relaxation training. Training-related behavioral and event-related potential (ERP) effects were not modulated by task difficulty. The data suggest that cognitive training increased slow negative potentials during target processing which enhanced the N2 and reduced a subsequent P3-like component on both switch and non-switch trials and irrespective of task difficulty. Our findings further corroborate the effectiveness of multi-domain cognitive training in older adults and indicate that ERPs can be instrumental in uncovering the neural processes underlying training-related performance gains.