Lapses of intention and performance variability reveal age-related increases in fluctuations of executive control

Self-perceived cognitive fluctuations and their relationship to everyday functioning in older adults with and without HIV disease

Objective: HIV is associated with elevated performance-based cognitive intra-individual variability (IIV) in the laboratory that can reflect difficulty regulating cognitive resources over time (i.e., cognitive fluctuations) and disrupt everyday functioning. Whether persons living with HIV (PLWH) experience appreciable cognitive fluctuations in their daily lives is unclear. This study examined the presence of cognitive fluctuations and their relationship to everyday functioning in PLWH. Methods: Participants were 145 PLWH and 61 seronegative individuals age ≥ 50 years who completed a self-report version of the Mayo Fluctuations Scale (MFS), structured psychiatric interview, medical evaluation, and well-validated measures of mood, cognitive symptoms, and activities of daily living (ADLs). A confirmatory factor analysis of the MFS yielded three factors, including a 7-item cognitive fluctuations scale. Results: Univariable analyses showed that HIV was associated with moderately higher MFS Cognitive Fluctuation subscale scores (d = 0.46), but this effect was no longer significant a multiple regression model that included medical comorbidities and affective disorders, which emerged as unique predictors. Of clinical relevance, higher MFS Cognitive Fluctuation subscale scores were independently associated with more frequent cognitive symptoms and dependence in ADLs in the full sample. Conclusions: Higher frequency of self-perceived cognitive fluctuations disrupts management of ADLs among middle-aged and older adults independent of HIV status and general cognitive symptoms. Future studies are needed to understand the full clinical significance of self-perceived cognitive fluctuations among PLWH and their impact on daily life.

Naturalistic assessment of reaction time variability in older adults at risk for Alzheimer's disease

OBJECTIVE

Maintaining attention underlies many aspects of cognition and becomes compromised early in neurodegenerative diseases like Alzheimer's disease (AD). The consistency of maintaining attention can be measured with reaction time (RT) variability. Previous work has focused on measuring such fluctuations during in-clinic testing, but recent developments in remote, smartphone-based cognitive assessments can allow one to test if these fluctuations in attention are evident in naturalistic settings and if they are sensitive to traditional clinical and cognitive markers of AD.

METHOD

Three hundred and seventy older adults (aged 75.8 +/- 5.8 years) completed a week of remote daily testing on the Ambulatory Research in Cognition (ARC) smartphone platform and also completed clinical, genetic, and conventional in-clinic cognitive assessments. RT variability was assessed in a brief (20-40 seconds) processing speed task using two different measures of variability, the Coefficient of Variation (CoV) and the Root Mean Squared Successive Difference (RMSSD) of RTs on correct trials.

RESULTS

Symptomatic participants showed greater variability compared to cognitively normal participants. When restricted to cognitively normal participants, APOE ε4 carriers exhibited greater variability than noncarriers. Both CoV and RMSSD showed significant, and similar, correlations with several in-clinic cognitive composites. Finally, both RT variability measures significantly mediated the relationship between APOE ε4 status and several in-clinic cognition composites.

CONCLUSIONS

Attentional fluctuations over 20-40 seconds assessed in daily life, are sensitive to clinical status and genetic risk for AD. RT variability appears to be an important predictor of cognitive deficits during the preclinical disease stage.

Prefrontal intra-individual ERP variability and its asymmetry: exploring its biomarker potential in mild cognitive impairment

BACKGROUND

The worldwide trend of demographic aging highlights the progress made in healthcare, albeit with health challenges like Alzheimer's Disease (AD), prevalent in individuals aged 65 and above. Its early detection at the mild cognitive impairment (MCI) stage is crucial. Event-related potentials (ERPs) obtained by averaging EEG segments responded to repeated events are vital for cognitive impairment research. Consequently, examining intra-trial ERP variability is vital for comprehending fluctuations within psychophysiological processes of interest. This study aimed to investigate cognitive deficiencies and instability in MCI using ERP variability and its asymmetry from a prefrontal two-channel EEG device.

METHODS

In this study, ERP variability for both target and non-target responses was examined using the response variance curve (RVC) in a sample comprising 481 participants with MCI and 1,043 age-matched healthy individuals. The participants engaged in auditory selective attention tasks. Cognitive decline was assessed using the Seoul Neuropsychological Screening Battery (SNSB) and the Mini-Mental State Examination (MMSE). The research employed various statistical methods, including independent t-tests, and univariate and multiple logistic regression analyses. These analyses were conducted to investigate group differences and explore the relationships between neuropsychological test results, ERP variability and its asymmetry measures, and the prevalence of MCI.

RESULTS

Our results showed that patients with MCI exhibited unstable cognitive processing, characterized by increased ERP variability compared to cognitively normal (CN) adults. Multiple logistic regression analyses confirmed the association between ERP variability in the target and non-target responses with MCI prevalence, independent of demographic and neuropsychological factors.

DISCUSSION

The unstable cognitive processing in the MCI group compared to the CN individuals implies abnormal neurological changes and reduced and (or) unstable attentional maintenance during cognitive processing. Consequently, utilizing ERP variability measures from a portable EEG device could serve as a valuable addition to the conventional ERP measures of latency and amplitude. This approach holds significant promise for identifying mild cognitive deficits and neural alterations in individuals with MCI.

Development and Validity of Norms for Cognitive Dispersion on the Uniform Data Set 3.0 Neuropsychological Battery

OBJECTIVE

Cognitive dispersion indexes intraindividual variability in performance across a battery of neuropsychological tests. Measures of dispersion show promise as markers of cognitive dyscontrol and everyday functioning difficulties; however, they have limited practical applicability due to a lack of normative data. This study aimed to develop and evaluate normed scores for cognitive dispersion among older adults.

METHOD

We analyzed data from 4,283 cognitively normal participants aged ≥50 years from the Uniform Data Set (UDS) 3.0. We describe methods for calculating intraindividual standard deviation (ISD) and coefficient of variation (CoV), as well as associated unadjusted scaled scores and demographically adjusted z-scores. We also examined the ability of ISD and CoV scores to differentiate between cognitively normal individuals (n = 4,283) and those with cognitive impairment due to Lewy body disease (n = 282).

RESULTS

We generated normative tables to map raw ISD and CoV scores onto a normal distribution of scaled scores. Cognitive dispersion indices were associated with age, education, and race/ethnicity but not sex. Regression equations were used to develop a freely accessible Excel calculator for deriving demographically adjusted normed scores for ISD and CoV. All measures of dispersion demonstrated excellent diagnostic utility when evaluated by the area under the curve produced from receiver operating characteristic curves.

CONCLUSIONS

Results of this study provide evidence for the clinical utility of sample-based and demographically adjusted normative standards for cognitive dispersion on the UDS 3.0. These standards can be used to guide interpretation of intraindividual variability among older adults in clinical and research settings.

A Nomothetic Span Approach to the Construct Validation of Sustained Attention Consistency: Re-Analyzing Two Latent-Variable Studies of Performance Variability and Mind-Wandering Self-Reports

The ability to sustain attention consistency is frequently assessed using either objective behavioral measures, such as reaction time (RT) variability, or subjective self-report measures, such as rates of task-unrelated thought (TUT). The current studies examined whether the individual-difference covariation in these measures provides a more construct valid assessment of attention consistency than does either alone. We argue that performance and self-report measures mutually validate each other; each measurement approach has its own sources of error, so their shared variance should best reflect the attention consistency construct. We reanalyzed two latent-variable studies where RT variability and TUTs were measured in multiple tasks (Kane et al. in J Exp Psychol Gen 145:1017-1048, 2016; Unsworth et al. in J Exp Psychol Gen 150:1303-1331, 2021), along with several nomological network constructs to test the convergent and discriminant validity of a general attention consistency factor. Confirmatory factor analyses assessing bifactor (preregistered) and hierarchical (non-preregistered) models suggested that attention consistency can be modeled as the shared variance among objective and subjective measures. This attention consistency factor was related to working memory capacity, attention (interference) control, processing speed, state motivation and alertness, and self-reported cognitive failures and positive schizotypy. Although bifactor models of general attention consistency provide the most compelling construct validity evidence for a specific ability to sustain attention, multiverse analyses of outlier decisions suggested they are less robust than hierarchical models. The results provide evidence for the general ability to sustain attention consistency and suggestions for improving its measurement.

Mapping causal links between prefrontal cortical regions and intra-individual behavioral variability

Intra-individual behavioral variability is significantly heightened by aging or neuropsychological disorders, however it is unknown which brain regions are causally linked to such variabilities. We examine response time (RT) variability in 21 macaque monkeys performing a rule-guided decision-making task. In monkeys with selective-bilateral lesions in the anterior cingulate cortex (ACC) or in the dorsolateral prefrontal cortex, cognitive flexibility is impaired, but the RT variability is significantly diminished. Bilateral lesions within the frontopolar cortex or within the mid-dorsolateral prefrontal cortex, has no significant effect on cognitive flexibility or RT variability. In monkeys with lesions in the posterior cingulate cortex, the RT variability significantly increases without any deficit in cognitive flexibility. The effect of lesions in the orbitofrontal cortex (OFC) is unique in that it leads to deficits in cognitive flexibility and a significant increase in RT variability. Our findings indicate remarkable dissociations in contribution of frontal cortical regions to behavioral variability. They suggest that the altered variability in OFC-lesioned monkeys is related to deficits in assessing and accumulating evidence to inform a rule-guided decision, whereas in ACC-lesioned monkeys it results from a non-adaptive decrease in decision threshold and consequently immature impulsive responses.

Feasibility, reliability, and validity of ambulatory cognitive tests in fibromyalgia and matched controls

OBJECTIVE

This observational study examined the feasibility, reliability, and validity of repeated ambulatory cognitive tests in fibromyalgia (FM).

METHOD

Adults with FM (n = 50) and matched controls (n = 50) completed lab-based neuropsychological tests (NIH Toolbox) followed by eight days of smartphone-based ambulatory testing of processing speed (symbol search) and working memory (dot memory) five times daily. Feasibility was assessed based on response rates. Reliability was evaluated using overall average between-person reliabilities for the full assessment period and by determining the number of assessment days necessary to attain reliabilities of >.80 and >.90. To assess convergent validity, correlations were calculated between ambulatory test scores and NIH Toolbox scores. Test performance was contrasted between the FM and non-FM groups to examine known-groups validity.

RESULTS

Average rates of response to the ambulatory cognitive tests were 89.5% in FM and 90.0% in non-FM. Overall average between-person reliabilities were ≥.96. In FM, between-person reliability exceeded .90 after two days for symbol search and three days for dot memory. Symbol search scores correlated with NIH Toolbox processing speed scores in both groups, though there were no significant group differences in symbol search performance. Dot memory scores correlated with NIH Toolbox working memory scores in both groups. FM participants exhibited worse dot memory performance than did non-FM participants.

CONCLUSIONS

Repeated ambulatory tests of processing speed and working memory demonstrate feasibility and reliability in FM, though evidence for construct validity is mixed. The findings demonstrate promise for future research and clinical applications of this approach to assessing cognition in FM.

It's complicated: Executive functioning moderates impacts of daily busyness on everyday functioning in community-dwelling older adults

OBJECTIVE

Research shows that cognitively healthy older adults with mild executive function (EF) weaknesses are vulnerable to the negative impacts of life complexity (or daily busyness) when performing instrumental activities of daily living (IADLs). However, past research assessed life complexity only at one timepoint, not capturing daily fluctuations. Importantly, fluctuations in busyness can themselves have deleterious impacts on functioning. This study extended past research by examining whether (1) variability in daily busyness would be more detrimental than level of busyness to performance of IADLs, and (2) EF assessed at home would moderate deleterious impact of busyness on IADLs.

METHOD

Fifty-two community-dwelling older adults aged 60 to 95 completed daily IADL tasks and daily measures of EF and busyness via ecological momentary assessment, independently at home for 18 days.

RESULTS

(1) In a subset of participants with mild EF weaknesses, high variability in busyness across days was associated with fewer tasks completed correctly; and (2) across all participants (regardless of EF), high levels of daily busyness were associated with fewer tasks completed on time.

CONCLUSIONS

Findings indicate that high variability in daily busyness, potentially reflecting a lack of daily routine, was associated with IADL errors among cognitively healthy older adults with mild EF weaknesses. Additionally, consistently high levels of busyness were associated with failures to complete tasks, or failures to complete them on time, regardless of EF. These results further support the Contextually Valid Executive Assessment (ConVExA) model, which posits that EF and contextual factors interact to predict functional outcomes.

Strategic monitoring improves prospective memory: A meta-analysis

Monitoring the environment for target events that trigger prospective memory (PM) retrieval requires cognitive resources, reflected by costs to ongoing task performance (i.e., worse accuracy and/or slower response times). Strategic monitoring refers to the use of context to engage or disengage monitoring when a PM target is anticipated or unanticipated. Laboratory strategic monitoring studies have found mixed results as to whether context specification improves PM performance. This study employed a meta-analytic technique to assess the overall effect of context specification on PM performance and ongoing task metrics of strategic monitoring. Overall, context specification improved PM performance when the target was anticipated and improved ongoing task performance (speed and accuracy) when the target was not anticipated. Moderator analyses revealed the degree of slowing in anticipated contexts predicted how much context specification improved PM performance. However, the benefits to PM performance from context specification differed by the type of procedure used. PM performance was improved when context changes could be predicted during blocked or proximity procedures, but not when context varied randomly in trial-level procedures. These results provide insights into the mechanisms underlying strategic monitoring and guidance for researchers on which procedures to be use depending on the theory-driven questions.

Improved attention and performance monitoring in high procrastinating students after positive relative to negative norm-referenced feedback

Procrastination is an irrational delay of task completion. Previous studies have demonstrated that individuals who often procrastinate present deficits in attentional control and performance monitoring and that these dysfunctions might be differentially manifested depending on the motivational context. Building upon these results, the present event-related potential (ERP) study aimed to investigate the impact of norm-referenced feedback on executive functions among students with high (HP; N = 75) or low (LP; N = 77) procrastination levels. Participants completed the parametric Go/No-Go task, while receiving either positive or negative false feedback indicating how well they performed in comparison to others. The results indicated that positive (as opposed to negative) feedback led to higher self-reported arousal and increased post-error slowing in HP (vs. LP) participants. Moreover, neurophysiological measures indicated lower neural activation linked to attentional control (P300) and performance monitoring (ERN, CRN and Pe) in HP than LP participants, while the groups did not differ in these indices during the positive feedback condition. Obtained findings indicate that HP might be more sensitive to the motivating effects of success and more vulnerable to the detrimental influence of failure.

Cognitive intraindividual variability, cognitive impairment and psychosocial functioning in first-episode psychosis patients

Cognitive intraindividual variability (IIV) refers to fluctuations in performance across tasks (i.e. dispersion) or in a single task on multiple occasions (i.e. inconsistency). Little is known about IIV in patients with first-episode psychosis (FEP). We aimed to explore the association between IIV and both global cognitive performance and psychosocial functioning in a sample of 103 FEP patients. Patients were recruited at discharge from the PEPsNa program, a FEP follow-up intervention program lasting 24 months. The Social and Occupational Functioning Scale (SOFAS) and the Cognitive Assessment Interview (CAI-Sp) were employed for assessing psychosocial functioning. Cognitive assessments were performed using the MATRICS Cognitive Assessment Battery (MCCB), and the variability in the cognitive functions assessed with the MCCB was used to calculate the IIV. Significant correlations were obtained between IIV and global MCCB scores, the CAI-Sp and the SOFAS. We found significant differences in psychosocial functioning and cognitive performance between patients with high and low IIV. A higher IIV in FEP patients was related both to worse psychosocial functioning and worse global cognitive performance. Unlike global cognitive performance, IIV was not related to clinical characteristics, suggesting that it could be an indicator of cognitive impairment even in the absence of global impairment.

Intra-individual variability adaptively increases following inhibition training during middle childhood

There is ongoing debate on the relationship between intra-individual variability (IIV) of cognitive processes and task performance. While psychological research has traditionally assumed that lower intra-individual variability (IIV) aids consistent task performance, some studies suggest that greater IIV can also be adaptive, especially when flexible responding is required. Here we selectively manipulate inhibitory control (Stopping) and response speed (Going) by means of a training paradigm to 1) assess how this manipulation impacts Stopping IIV and its relationship to task performance, and 2) replicate previous findings showing that reductions in Going IIV are adaptive. A group of 208 6-13-year-old children were randomly allocated to an 8-week training targeting Stopping (experimental group) or Going (control group). The stop signal task was administered before and after training. Training Stopping led to adaptive increases in Stopping IIV, where greater flexibility in cognitive processing may be required to meet higher task demands. In line with previous studies, training Going led to adaptive reductions in Going IIV, which allows more consistent and efficient Going performance. These findings provide systematic and causal evidence of the process-dependent relationship of IIV and task performance in the context of Stopping and Going, suggesting a more nuanced perspective on IIV with implications for developmental, ageing and intervention studies.

Influence of game features on attention in adults

Introduction

The incorporation of game features into cognitive tasks can inform us about the influence of reward and motivation on attention. Continuous performance tasks (CPTs), designed to assess attention abilities, are examples of cognitive tasks that have been targeted for the addition of game features. However, previous results have been mixed regarding how game elements affect attention abilities and task performance.

Methods

Here, we studied if there were factors that predict which individuals exhibit changes in attention from game features added to a CPT. Participants (N = 94, aged 21-71) played a traditional CPT and a game CPT with identical mechanics, but featured engaging game elements (aesthetics, storyline, competition, feedback, and reward).

Results

We first found corroborating evidence that game features have mixed effects on attention performance: most attention metrics of interest exhibited no overall difference between the traditional and game CPT, while game elements reduced performance for a few metrics. Importantly, we also found that specific behavioral and demographic profiles predicted individual differences in performance on the game CPT compared to the traditional CPT. Those with more attention difficulties (ADHD symptoms), more reward responsiveness, and younger adults performed better on the game CPT while, conversely, those with fewer ADHD symptoms, less reward responsiveness, and older adults performed better on the traditional CPT.

Discussion

These findings provide insights into how game features can influence attention in different individuals and have important implications for the use of game elements in cognitive tasks and training interventions.

Gray matter volume and within-task verbal fluency performance among older adults

The current study examined the relationship between gray matter volume (GMV) and rate of word generation over the course of three consecutive 20-sec intervals in 60-sec letter and category verbal fluency (VF) tasks. Attenuated rate of within-person word generation in VF provides incremental information beyond total scores and predicts increased risk of incident Mild Cognitive Impairment (MCI). No studies to date, however, have determined the structural neural substrates underlying word generation rate in VF. Participants were 70 community-residing adults ≥ 65 years, who completed the letter and category VF tasks and a 3 T structural MRI scan. Linear mixed effects models (LMEMs) were used to determine the moderating effect of GMV on word generation rate. Whole brain voxel-wise LMEMs, adjusted for age, gender, education, Wide-Range Achievement Test - reading subtest score (WRAT3), and global health score, were run using permutation methods to correct for multiple comparisons. Lower GMV, primarily in frontal regions (superior frontal, rostral middle frontal, frontal pole, medial orbitofrontal, and pars orbitalis), were related to attenuated word generation rate, especially for letter VF. We propose that lower frontal GMV underlies inefficient executive word search processes reflected by attenuated word generation slope in letter VF amongst older adults.

Inhibition Predicts the Course of Depression and Anxiety Symptoms Among Adolescents: The Moderating Role of Familial Risk

ABSTRACT

Numerous theoretical models suggest that inhibition difficulties-the inability to moderate automatic responses-contribute to the onset and/or maintenance of internalizing symptoms. Inhibition deficits and internalizing disorders run in families and share overlapping genetic risk factors, suggesting that inhibition deficits may be particularly prognostic of internalizing symptoms in those with high familial risk. This study tested this hypothesis in a longitudinal sample during the transition from adolescence to early adulthood. As hypothesized, prospective associations between inhibition and anxiety and depressive symptoms 8 years later were moderated by familial risk for depression. Specifically, poorer inhibition prospectively predicted greater anxiety and depressive symptoms in those at high (but not low) familial risk for major depressive disorder. These findings provide preliminary support for impaired inhibition as an indicator of risk for later internalizing symptoms in those at high familial risk.

Intra-individual variability identifies individuals vulnerable to contextually induced executive lapses

Contextual stressors, such as engagement in burdensome emotion regulation known as expressive suppression (ES), can result in transient but clinically meaningful decrement in performance on measures of executive functioning (EF). The goal of the present investigation was to examine whether intra-individual variability (IIV-I), which has been identified as an indicator of cognitive weakness, could serve as a marker of vulnerability to EF decrements due to both naturally-occurring and experimentally-manipulated ES.

In Study 1, 180 cognitively healthy older adults completed the Push-Turn-Taptap (PTT) task to assess IIV-I, four Delis-Kaplan Executive Function System (D-KEFS) subtests to assess EF, and the Burden of State Emotion Regulation Questionnaire (B-SERQ) to assess naturally-occurring ES. In Study 2, a subset (n = 81) of participants underwent experimental manipulation to induce ES, followed by second administration of the D-KEFS to examine ES-induced decrements in EF.

In Study 1, hierarchical linear regression yielded a significant interaction between ES and IIV-I as predictors of EF performance, demonstrating that high ES was associated with low EF only among individuals with high IIV-I. In Study 2, repeated measures ANOVA demonstrated an interaction between time (pre- vs. post- manipulation), group (ES vs. control), and IIV-I (high vs. low), such that only individuals who exhibited high IIV-I were negatively impacted by the ES manipulation.

IIV-I moderates the association between ES and EF, such that only individuals with high IIV-I exhibit vulnerability to the impact of ES. Thus, IIV-I may act as a marker of vulnerability to temporary EF depletion.

The Associations between Results in Different Domains of Cognitive and Psychomotor Abilities Measured in Medical Students

We aimed to investigate the associations between intelligence quotient test scores obtained using the Raven's Advanced Progressive Matrices (APM) and psychomotor testing using the Complex Reactionmeter Drenovac (CRD) test battery, while taking into account previous theoretical approaches recognizing intelligent behavior as the cumulative result of a general biological speed factor reflected in the reaction time for perceptual detections and motor decisions. A total of 224 medical students at the University of Split School of Medicine were recruited. Their IQ scores were assessed using Raven's APM, while the computerized tests of CRD-series were used for testing the reaction time of perception to visual stimulus (CRD311), psychomotor limbs coordination task (CRD411), and solving simple arithmetic operations (CRD11). The total test-solving (TTST) and the minimum single-task-solving (MinT) times were analyzed. On the CRD11 test, task-solving times were shorter in students with higher APM scores (r = -0.48 for TTST and r = -0.44 for MinT; p < 0.001 for both). Negative associations between task-solving times and APM scores were reported on CRD311 (r = -0.30 for TTST and r = -0.33 for MinT, p < 0.001 for both). Negative associations between task-solving times in CRD411 and APM scores (r = -0.40 for TTST and r = -0.30 for MinT, p < 0.001 for both) were found. Faster reaction time in psychomotor limbs coordination tasks, the reaction time of perception to visual stimulus, and the reaction time of solving simple arithmetic operations were associated with a higher APM score in medical students, indicating the importance of mental speed in intelligence test performance. However, executive system functions, such as attention, planning, and goal weighting, might also impact cognitive abilities and should be considered in future research.

Reappraising cognitive reappraisal: The taxing impact of emotion regulation on executive functioning in older adults

OBJECTIVE

Cognitive reappraisal (CR) and expressive suppression (ES) are two common emotion regulation strategies that share similar cognitive and neural underpinnings. Prior research has consistently shown that recent engagement in ES (both self-reported and experimentally manipulated) is associated with subsequent temporary decrements in executive functioning (EF). Thus far, only one study has examined the association between CR and EF, with null results. However, that study was limited by examining only zero-order correlations and by assessing only the speed, not accuracy, of EF performance. The present study examined multivariate relationships among recent CR, recent ES, and EF (both speed and accuracy), as well as the potential impacts of more chronic engagements in, and trait-level preferences between, the two emotion regulation strategies.

METHOD

Participants were 201 community-dwelling older adults aged 60 to 93 who had participated in three separate studies examining the relationship between self-reported emotion regulation and EF.

RESULTS

Recent CR was associated with EF performance accuracy above and beyond chronic CR. Both recent CR and ES contributed to EF performance accuracy uniquely beyond each other and beyond chronic and preferred emotion regulation.

CONCLUSIONS

Both recent ES and CR appear to have a deleterious impact on EF performance accuracy, potentially due to utilization of similar resources; both should be accounted for when assessing emotion regulation and its impacts on EF.

Capturing Cognitive Aging in Vivo: Application of a Neuropsychological Framework for Emerging Digital Tools

As the global burden of dementia continues to plague our healthcare systems, efficient, objective, and sensitive tools to detect neurodegenerative disease and capture meaningful changes in everyday cognition are increasingly needed. Emerging digital tools present a promising option to address many drawbacks of current approaches, with contexts of use that include early detection, risk stratification, prognosis, and outcome measurement. However, conceptual models to guide hypotheses and interpretation of results from digital tools are lacking and are needed to sort and organize the large amount of continuous data from a variety of sensors. In this viewpoint, we propose a neuropsychological framework for use alongside a key emerging approach—digital phenotyping. The Variability in Everyday Behavior (VIBE) model is rooted in established trends from the neuropsychology, neurology, rehabilitation psychology, cognitive neuroscience, and computer science literature and links patterns of intraindividual variability, cognitive abilities, and everyday functioning across clinical stages from healthy to dementia. Based on the VIBE model, we present testable hypotheses to guide the design and interpretation of digital phenotyping studies that capture everyday cognition in vivo. We conclude with methodological considerations and future directions regarding the application of the digital phenotyping approach to improve the efficiency, accessibility, accuracy, and ecological validity of cognitive assessment in older adults.

Global slowness and increased intra-individual variability are key features of attentional deficits and cognitive fluctuations in post COVID-19 patients

Fatigue, attentional deficits and cognitive fluctuations are the most characterizing symptoms of neurological involvement in Post COVID-19 syndrome (PCS). As the intraindividual variability (IIV) in cognitive performances has been recognized as a hallmark of brain-related disorders associated with cognitive deficits, it could be an interesting measure to elucidate the mechanisms subtending both the attentive impairment and the cognitive fluctuations in these patients. By referring to IIV analysis of Reaction Times (RTs), the present study aims to define the attentive impairment and its relation to fluctuations and fatigue, in patients suffering from Post COVID-19 neurological symptoms. 74 patients were enrolled. They underwent an extensive clinical and neuropsychological assessments, as well as computerized Sustained Attention and Stroop tasks. For studying IIV, RTs distributions of performances in computerized tasks were fitted with ex-Gaussian distribution, for obtaining the τ values. Finally, the Resting Motor Threshold (RMT) was also collected to estimate cortical excitability. 29 healthy volunteers served as controls. Patients showed poorer scores in Montreal Cognitive Assessment and higher RMT, in comparison with controls. In Sustained Attention Task, Mean, µ, σ and τ values were significantly higher in PCS patients (p value =  < 0.0001; 0.001; 0.018 and < 0.0001, respectively). Repeated measures ANOVA comparing the RTs mean in Stroop task within-subject and between-subjects revealed significant condition and group effect (p < 0.0001 both) and significant interaction (p = 0.005), indicating worst performances in patients. The mean of the derived interference value was significantly higher in PCS patients than in controls (p = 0.036). Patients suffering from PCS show deficits in attention, both in the sustained and executive components. Both high RTs means and high IIV subtend these deficits and could explain the often-complained cognitive fluctuations in this population.

Variability of Reaction Time as a Marker of Executive Function Impairments in Fibromyalgia

In addition to chronic widespread pain and depression and anxiety symptoms, patients with fibromyalgia frequently experience cognitive problems. This study investigated executive functions in fibromyalgia via a Go/No-Go task. To obtain comprehensive information about performance, traditional and ex-Gaussian parameters of reaction time (RT) variability were used, in addition to speed and accuracy indices. Ex-Gaussian parameters show an excellent fit to empirical RT distributions. Fifty-two female fibromyalgia patients and twenty-eight healthy controls participated. The task included 60 visual stimuli, which participants had to respond to (Go stimuli) or withhold the response to (No-Go stimuli). After 30 trials, the task rule changed, such that previous No-Go stimuli had to be responded to. Performance was indexed by the hit rate, false alarm rate, and mean (M) and intraindividual standard deviation (SD) of RT and the ex-Gaussian parameters mu, sigma, and tau. Mu and sigma indicate the M and SD of the Gaussian distribution; tau reflects the M and SD of the exponential function. Patients exhibited a lower hit rate, higher M RT, and higher tau than controls. Moreover, patients showed greater decrease of the hit rate after the change of task rule. In the entire sample, SD, sigma, and tau were inversely associated with the hit rate and positively associated with the false alarm rate. While the greater decline in hit rate after the change in task rule indicates deficient cognitive flexibility, the lack of any difference in false alarm rate suggests intact response inhibition. Higher M RT reflects reduced cognitive or motor speed. Increased tau in fibromyalgia indicates greater fluctuations in executive control and more frequent temporary lapses of attention. For the first time, this study demonstrated that indices of RT variability, in particular those derived from the ex-Gaussian function, may complement speed and accuracy parameters in the assessment of executive function impairments in fibromyalgia. Optimized assessment may facilitate the personalization of therapies aimed at improving the cognitive function of those with the disorder.

Parameterizing Practice in a Longitudinal Measurement Burst Design to Dissociate Retest Effects From Developmental Change: Implications for Aging Neuroscience

Background: In longitudinal designs, the extraneous influence of retest effects can confound and obscure estimates of developmental change. The current study provides a novel approach to independently parameterize short-term retest effects and long-term developmental change estimates by leveraging a measurement burst design and three-level multilevel modeling. We further employ these short- and long-term slopes as predictors of cognitive status at long-term follow-up assessments.

Methods: Participants included 304 older adults from Project MIND: a longitudinal measurement burst study assessing cognitive performance across both biweekly sessions and annual retests. Participants were classified as either Healthy controls (HC) or Cognitively Impaired, not Demented (CIND) at baseline, the final burst assessment (Year 4), and at an additional four-year follow-up (Year 8). Response time inconsistencies (RTI) were computed at each burst occasion for a simple choice response time (CRT) task and a one-back response time (BRT) task. Three-level multilevel models were employed to simultaneously examine change in RTI for both CRT and BRT across weeks within years, as well as across years, in order to dissociate within-individual retest effects (short-term) from developmental (long-term) change slopes. Individual slopes were then extracted and utilized in a series of multinomial logistic regression equations to contrast short- vs. long-term RTI change as predictors of cognitive status.

Results: Separately parameterizing short- and long-term change estimates yielded distinct patterns of variation. CRT RTI remained stable across short-term weekly assessments, while significantly increasing across years. In contrast, BRT RTI decreased significantly across short-term assessments but showed no change across long-term assessments. After dissociating change estimates, short-term BRT as well as long-term CRT and BRT estimates predicted cognitive status at long-term follow-ups; increases in RTI, suggesting either an inability to benefit from retest or process-based developmental decline, were associated with an increased likelihood of being classified as CIND.

Conclusions: We showcase an innovative approach to dissociate retest effects from developmental change across and within individuals. Accurately parameterizing these distinct change estimates can both reduce systematic bias in longitudinal trend estimates as well as provide a clinically useful tool by utilizing retest effects to predict cognitive health and impairment.

A computational theory of the subjective experience of flow

Flow is a subjective state characterized by immersion and engagement in one's current activity. The benefits of flow for productivity and health are well-documented, but a rigorous description of the flow-generating process remains elusive. Here we develop and empirically test a theory of flow's computational substrates: the informational theory of flow. Our theory draws on the concept of mutual information, a fundamental quantity in information theory that quantifies the strength of association between two variables. We propose that the mutual information between desired end states and means of attaining them - [Formula: see text] - gives rise to flow. We support our theory across five experiments (four preregistered) by showing, across multiple activities, that increasing [Formula: see text] increases flow and has important downstream benefits, including enhanced attention and enjoyment. We rule out alternative constructs including alternative metrics of associative strength, psychological constructs previously shown to predict flow, and various forms of instrumental value.

Intra-Individual Variability in Creativity

Abstract. Individual differences perspectives have dominated the scientific study of creativity since the 1950’s. These perspectives, however, mainly emphasize group-level variations or inter-individual differences, with limited interest in individual-level variations. Yet, (1) group-level findings are often used to make inferences at the person-level, which might not apply consistently across individuals, and (2) a focus on intra-individual variations could supplement knowledge based on inter-individual differences and accurately inform creativity as a dynamic and multifaceted psychological construct. Indeed, when observed at the individual level, creativity can vary from moment to moment, task to task, and even item to item, which is not well reflected in the current understanding of creativity. After introducing the historical context for the study of individual differences in creativity, this article presents and illustrates three fundamental and distinct aspects of intra-individual variability as they apply to creativity, namely (in)consistency (or processing fluctuation), dispersion, and intraindividual change. While doing so, recent developments in apparatus and methods to assess creativity as a more dynamic phenomenon are presented. The article concludes by discussing the promise of accounting for intra-individual variability in creative performance and potential and the new knowledge it may elicit for both creativity research and practice.

Increased Intra-Individual Variability as a Marker of Executive Dysfunction in Generalized Anxiety Disorder

Recent studies suggest that individual difference in intra-individual variability (IIV) of reaction times is an important indicator of attentional executive control. However, there are few existing studies on the executive control of high trait-anxious individuals assessed by using reaction time variability. This study assessed whether executive functions are impaired among clinical and non-clinical trait-anxious individuals indicated by IIV. The cross-reliability and discriminative power of three IIV parameters (raw intra-individual standard deviation, SD; reaction time coefficient of variation, RTCV; and mean absolute deviation, MAD) were compared. Twenty-five non-clinical individuals with low trait anxiety (LTA), 31 non-clinical individuals with high trait anxiety (HTA), and 19 clinical patients diagnosed with generalized anxiety disorder (GAD) finished self-reported measures, an emotional spatial-cuing task, and a non-emotional arrow flanker task. In the emotional task, GAD patients had significantly slower response speed, lower accuracy, and greater IIV parameters than the LTA and HTA groups. In the non-emotional task, the GAD group exhibited poorer processing efficiency, greater SD and RTCV, and intact performance effectiveness. RTCV is suggested to be a better marker of executive dysfunction than SD and MAD due to its good discriminative power and reliability as well as less affected by reaction times.

Fronto-striatal dopamine D2 receptor availability is associated with cognitive variability in older individuals with low dopamine integrity

Within-person, moment-to-moment, variability in behavior increases with advancing adult age, potentially reflecting the influence of reduced structural and neurochemical brain integrity, especially that of the dopaminergic system. We examined the role of dopamine D2 receptor (D2DR) availability, grey-, and white-matter integrity, for between-person differences in cognitive variability in a large sample of healthy older adults (n = 181; 64-68 years) from the Cognition, Brain, and Aging (COBRA) study. Intra-individual variability (IIV) in cognition was measured as across-trial variability in participants' response times for tasks assessing perceptual speed and working memory, as well as for a control task of motor speed. Across the whole sample, no associations of D2DR availability, or grey- and white-matter integrity, to IIV were observed. However, within-person variability in cognition was increased in two subgroups of individuals displaying low mean-level cognitive performance, one of which was characterized by low subcortical and cortical D2DR availability. In this latter group, fronto-striatal D2DR availability correlated negatively with within-person variability in cognition. This finding suggests that the influence of D2DR availability on cognitive variability may be more easily disclosed among individuals with low dopamine-system integrity, highlighting the benefits of large-scale studies for delineating heterogeneity in brain-behavior associations in older age.

Concordance of multiple methods to define resiliency and vulnerability to sleep loss depends on Psychomotor Vigilance Test metric

STUDY OBJECTIVES

Sleep restriction (SR) and total sleep deprivation (TSD) reveal well-established individual differences in Psychomotor Vigilance Test (PVT) performance. While prior studies have used different methods to categorize such resiliency/vulnerability, none have systematically investigated whether these methods categorize individuals similarly.

METHODS

41 adults participated in a 13-day laboratory study consisting of 2 baseline, 5 SR, 4 recovery, and one 36h TSD night. The PVT was administered every 2h during wakefulness. Three approaches (Raw Score [average SR performance], Change from Baseline [average SR minus average baseline performance], and Variance [intraindividual variance of SR performance]), and within each approach, six thresholds (±1 standard deviation and the best/worst performing 12.5%, 20%, 25%, 33%, and 50%) classified Resilient/Vulnerable groups. Kendall's tau-b correlations examined the concordance of group categorizations of approaches within and between PVT lapses and 1/reaction time (RT). Bias-corrected and accelerated bootstrapped t-tests compared group performance.

RESULTS

Correlations comparing the approaches ranged from moderate to perfect for lapses and zero to moderate for 1/RT. Defined by all approaches, the Resilient groups had significantly fewer lapses on nearly all study days. Defined by the Raw Score approach only, the Resilient groups had significantly faster 1/RT on all study days. Between-measures comparisons revealed significant correlations between the Raw Score approach for 1/RT and all approaches for lapses.

CONCLUSION

The three approaches defining vigilant attention resiliency/vulnerability to sleep loss resulted in groups comprised of similar individuals for PVT lapses but not for 1/RT. Thus, both method and metric selection for defining vigilant attention resiliency/vulnerability to sleep loss is critical.

The association between simple reaction time variability and gait variability: The Tasmanian Study of Cognition and Gait

INTRODUCTION

Greater double support time (DST) variability is associated with falls and memory decline. The underlying neurophysiological mechanisms of DST variability are poorly understood. Simple reaction time (SRT) variability, a measure of attention-processing speed is associated with falls and dementia and, may underlie greater DST variability. The aims of this study were to examine the association between SRT and DST variability and if SRT variability mediates the associations between poorer cognition/brain structure and DST variability.

METHODS

Participants (n = 408) were community-dwelling older people without dementia (mean age 72.0 ± 7.0). DST variability was the standard deviation (SD) of DST, assessed with a walkway and averaged across steps of 6 walks. SRT variability was the SD of a button pressing task in response to a visual stimulus. Executive function and processing speed were assessed with neuropsychological tests. Magnetic Resonance Imaging was used to obtain cortical thickness (total and in frontal regions) and cerebral small vessel disease (cSVD). Multivariable linear regression models were used to examine the association between SRT and DST variability and if SRT variability mediated any associations of cognition/brain structure with DST variability.

RESULTS

Greater SRT variability was associated with greater DST variability (p = 0.002). SRT variability partially mediated the association between poorer executive function and greater DST variability. Smaller mean thickness in orbitofrontal regions and greater cSVD burden were only associated with DST variability (p < 0.05), not with SRT variability (p > 0.05).

CONCLUSIONS

Greater SRT variability, which may occur due to inefficient executive functioning, could be an underlying neurophysiological mechanism of greater DST variability.

Multidimensional Interoception and Autistic Traits Across life Stages: Evidence From a Novel Eye-tracking Task

Interoception is believed to underlie socio-cognitive functions which are often impaired in individuals with autism spectrum disorders (ASD). In this study, Experiment 1 examined in a sample of 114 neurotypical college students the associations among autistic traits, alexithymia, and interoceptive accuracy (IA), which was assessed by a novel paradigm "Eye-tracking Interoceptive Accuracy Task (EIAT). In Experiment 2, EIAT and the Autism Spectrum Quotient were administered to 52 preschool children, 50 adolescents, and 50 adults. Experiment 1 supported the association between autistic traits and alexithymia, but failed to support their association with multidimensional interoception. Experiment 2 strongly supported the association between age and IA. We conclude that cardiac IA differs between neurotypical age groups, but shows limited relationship with autistic traits.

Predicting Age From Behavioral Test Performance for Screening Early Onset of Cognitive Decline

Background: Neuronal reactions and cognitive processes slow down during aging. The onset, rate, and extent of changes vary considerably from individual to individual. Assessing the changes throughout the lifespan is a challenging task. No existing test covers all domains, and batteries of tests are administered. The best strategy is to study each functional domain separately by applying different behavioral tasks whereby the tests reflect the conceptual structure of cognition. Such an approach has limitations that are described in the article. Objective: Our aim was to improve the diagnosis of early cognitive decline. We estimated the onset of cognitive decline in a healthy population, using behavioral tests, and predicted the age group of an individual. The comparison between the predicted ("cognitive") and chronological age will contribute to the early diagnosis of accelerated aging. Materials and Methods: We used publicly available datasets (POBA, SSCT) and Pearson correlation coefficients to assess the relationship between age and tests results, Kruskal-Wallis test to compare distribution, clustering methods to find an onset of cognitive decline, feature selection to enhance performance of the clustering algorithms, and classification methods to predict an age group from cognitive tests results. Results: The major results of the psychophysiological tests followed a U-shape function across the lifespan, which reflected the known inverted function of white matter volume changes. Optimal values were observed in those aged over 35 years, with a period of stability and accelerated decline after 55-60 years of age. The shape of the age-related variance of the performance of major cognitive tests was linear, which followed the trend of lifespan gray matter volume changes starting from adolescence. There was no significant sex difference in lifelong dynamics of major tests estimates. The performance of the classification model for identifying subject age groups was high. Conclusions: ML models can be designed and utilized as computer-aided detectors of neurocognitive decline. Our study demonstrated great promise for the utility of classification models to predict age-related changes. These findings encourage further explorations combining several tests from the cognitive and psychophysiological test battery to derive the most reliable set of tests toward the development of a highly-accurate ML model.

Associations Between Control Beliefs and Response Time Inconsistency in Older Adults Vary as a Function of Attentional Task Demands

OBJECTIVE

Control beliefs are established correlates of cognitive aging. Despite recent demonstrations that response time inconsistency (RTI) represents a proxy for cognitive processing efficiency, few investigations have explored links between RTI and psychosocial correlates. We examined associations among RTI and control beliefs (perceived competence and locus of control) for two choice-response time (RT) tasks varying in their attentional demands.

METHOD

Control beliefs and RTI were measured weekly for 5 weeks in a sample of 304 community-dwelling older adults (Mage = 74.11 years, SD = 6.05, range = 64-92, 68.58% female).

RESULTS

Multilevel models revealed that for the attentionally demanding task, reporting higher perceived competence than usual was associated with lower RTI for relatively younger participants and greater RTI for relatively older participants. For the less attentionally demanding task, reporting higher perceived competence than usual was associated with lower RTI for relatively older participants. Links between locus of control and RTI were comparatively scant.

DISCUSSION

Our findings suggest that control beliefs may have adaptive and maladaptive influences on RTI, depending on dimension of control beliefs, individual differences in level of control beliefs and age, as well as attentional task demands. Both for whom and when control beliefs can be leveraged to optimize cognitive aging are discussed.

Reaction time intra-individual variability reveals inhibitory deficits in single- and multiple-domain amnestic mild cognitive impairment

OBJECTIVES

Amnestic mild cognitive impairment (aMCI), a prodromal stage of Alzheimer's disease and other dementias, is characterized by episodic memory impairment. Recent evidence has shown inhibitory control deficits in aMCI, but the extent of these deficits across inhibitory domains (i.e., response inhibition and interference control) and aMCI subtypes (i.e., single- versus multiple-domain) remains unclear. Few studies have included response time intra-individual variability (RT IIV) in these efforts. The aim of this study was to compare response inhibition and interference control between aMCI subtypes using measures of accuracy, mean RT, and RT IIV.

METHOD

We report data from 34 individuals with single-domain aMCI (sdaMCI, 66-86 years), 20 individuals with multiple-domain aMCI (mdaMCI, 68-88 years), and 52 healthy controls (64-88 years) who completed tasks of response inhibition (Go-NoGo) and interference control (Flanker). Group differences in accuracy, mean RT, and RT IIV were examined for both tasks.

RESULTS

Individuals with mdaMCI had higher RT IIV than the other groups on both tasks. In RT IIV, we observed an interference control deficit in mdaMCI and sdaMCI relative to healthy controls, a finding not observed through accuracy or mean RT.

DISCUSSION

RT IIV may detect subtle differences in inhibition deficits between aMCI subtypes that may not be evident with conventional behavioral measures. Findings support the supplementary use of RT IIV when assessing early executive function deficits.

The relationship between neuropsychological dispersion, processing speed and memory after electrical injury

Introduction: Previous studies of neuropsychological performance in electrical injury (EI) patients have produced evidence of deficits in various cognitive domains, but studies have yet to investigate relationships among performance in cognitive domains post-EI. This study examined whether dispersion among neuropsychological test scores was associated with injury parameters and neuropsychological performance in EI patients. Additionally, we examined whether dispersion, processing speed and/or executive abilities explain variance in episodic verbal and visual memory performance among EI patients.Method: Data from 52 post-acute EI patients undergoing outpatient evaluation with objectively-verified valid neuropsychological test performance were examined. Tests included measures of verbal and visual memory, processing speed, and executive functioning. Dispersion was calculated from executive functioning and processing speed scores.Results: Dispersion was not related to mean performance or injury characteristics, but was significantly negatively correlated with performance on a test of processing speed, suggesting that increased dispersion is associated with reduced cognitive efficiency post-EI. Delayed visual memory was related to both dispersion scores and processing speed. Stepwise regression equations predicting delayed memory determined that processing speed most significantly predicted delayed visual memory, even after controlling for immediate visual memory. No significant relationships emerged between verbal memory and non-memory neuropsychological scores.Conclusions: This is the first study to examine neuropsychological dispersion and relationships among domains of cognitive functioning in EI. Current results suggested that neuropsychological dispersion is not a marker of general functioning or severity of injury in EI patients, but may represent more specific processing speed abilities. Processing speed predicts delayed visual memory performance in EI patients, which should be considered in interpreting test scores during evaluations.

Working Memory and Intraindividual Variability in Response Time Mediate Fluid Intelligence Deficits Associated With ADHD Symptomology

Objective: To determine if decreased fluid intelligence was associated with ADHD, and was mediated by deficits in working memory and intraindividual variability in motor responding. Method: The present study tested 142 young adults from the general population on a range of working memory, response time, and fluid intelligence tasks, and an ADHD self-report symptoms questionnaire. Results: Total and hyperactive ADHD symptoms correlated significantly and negatively with fluid intelligence, but this association was fully mediated by both working memory and intraindividual variability in response time. However, inattentive symptoms were not associated with fluid intelligence. Conclusion: These results have important implications for clinicians using speeded psychometric tests as part of their assessment battery, working memory interventions for ADHD patients that focus on performance improvement without controlling for response consistency, and also demonstrate potential differences in the neuropsychological profiles of ADHD subtypes.

Fibrofog in Daily Life: An Examination of Ambulatory Subjective and Objective Cognitive Function in Fibromyalgia

OBJECTIVE

Perceived cognitive dysfunction in fibromyalgia (FM), "fibrofog," is common. Prior laboratory-based studies have limited our understanding of cognitive function in FM in daily life. The objective of this study was to explore levels of subjective and objective cognitive functioning and the association between subjective and objective aspects of cognition in people with and without FM in the lived environment.

METHODS

Participants (n = 50 adults with FM; n = 50 adults without FM, matched for age, sex, and education) completed baseline measures of subjective and objective cognitive functioning (NIH Toolbox). They also completed ecological momentary assessments of cognitive clarity and speed and tests of processing speed and working memory, via a smart phone app, 5×/day for 8 days.

RESULTS

On baseline objective measures, the FM group demonstrated poorer cognitive functioning across 3 NIH Toolbox tests. There were no strong correlations between subjective and objective cognitive functioning in both the FM and control groups. In the lived environment, the FM group demonstrated poorer subjective cognition and objective working memory; groups did not differ on processing speed. Momentary ratings of subjective cognitive dysfunction were significantly related to changes in objective processing speed but not working memory, with no group differences.

CONCLUSION

Findings indicate worse laboratory-based and ambulatory subjective and objective cognitive function for those individuals with FM compared to those without FM. Similar associations between measures of subjective and objective cognitive functioning for the groups suggest that people with FM are not overstating cognitive difficulties. Future research examining contributors to ambulatory fibrofog is warranted.

Brain potentials reveal reduced attention and error-processing during a monetary Go/No-Go task in procrastination

Procrastination is a self-regulatory problem of voluntarily and destructively delaying intended and necessary or personally important tasks. Previous studies showed that procrastination is associated with executive dysfunctions that seem to be particularly strong in punishing contexts. In the present event-related potential (ERP) study a monetary version of the parametric Go/No-Go task was performed by high and low academic procrastinators to verify the influence of motivational context (reward vs. punishment expectation) and task difficulty (easy vs. hard) on procrastination-related executive dysfunctions. The results revealed increased post-error slowing along with reduced P300 and error-related negativity (ERN) amplitudes in high (vs. low) procrastination participants—effects that indicate impaired attention and error-related processing in this group. This pattern of results did not differ as a function of task difficulty and motivation condition. However, when the task got more difficult executive attention deficits became even more apparent at the behavioral level in high procrastinators, as indexed by increased reaction time variability. The findings substantiate prior preliminary evidence that procrastinators show difficulties in certain aspects of executive functioning (in attention and error processing) during execution of task-relevant behavior, which may be more apparent in highly demanding situations.

Intraindividual reaction time variability as an index of attentional control acts as a moderator of the longitudinal relationships between marital quality and children's externalizing problems

The current study investigated whether trial-to-trial intraindividual reaction time variability (IIRTV), which serves as an index of attentional control fluctuations, moderates the effect of marital quality at 7 years of age on the development of children's externalizing problems from 7 to 9 years of age (N = 197). At the first assessment (T1), a flanker task was administered to children for assessing their IIRTV. The Chinese version of a marital quality questionnaire (Evaluating and Nurturing Relationship Issues, Communication, and Happiness [ENRICH]) and the Chinese version of the Child Behavior Checklist (CBCL) were completed by children's mothers to assess marital quality and children's externalizing problems. At the second and third assessments (T2 and T3), children's externalizing problems were reassessed by their mothers. Growth curve analyses showed that boys' externalizing problems were relatively high and significantly decreased over time, whereas girls' externalizing problems were relatively low and stable. Importantly, the results indicated that boys' IIRTV (but not girls' IIRTV) and parental marital quality interactively predict the concurrent and developmental trajectories of externalizing problems. Specifically, boys with greater IIRTV were found to exhibit a relatively persistent high level of externalizing problems in the context of poor parental marital quality, whereas boys with lower IIRTV were found to exhibit a relatively low level of externalizing problems over time regardless of their parental marital quality. The findings suggest that poorer attentional control indexed by greater IIRTV is a robust predictor of boys' externalizing problems and that better attentional control indexed by lower IIRTV may buffer the negative impact of adverse family environment on the development of boys' externalizing problems.

Reversal learning in young and middle-age neurotypicals: Individual difference reaction time considerations

Reversal learning is frequently used to assess components of executive function that contribute to understanding age-related cognitive differences. Reaction time (RT) is less characterized in the reversal learning literature, perhaps due to the daunting task of analyzing the entire RT distribution, but has been deemed a generally sensitive measure of cognitive aging. The current study extends our prior work to further characterize distributional properties of the reversal RT distribution and to distinguish groups of individuals with fractionated profiles of performance, which may be of clinical importance within the context of cognitive aging. Participant sample included young (n = 43) and community-dwelling, healthy, middle-aged (n = 139) adults. To explore individual differences, recursive partitioning analysis achieved a high classification rate by specifying decision tree rules that split participants into young and middle-aged groups. Mu (μ, efficient RT) was the most successful parameter in distinguishing age groups while sigma ( σ ) and tau ( τ , ex-Gaussian indices of intra-individual variability) revealed more subtle individual differences. Accuracy measures did not contribute to separating the groups, suggesting that fractionated components of RT, as opposed to accuracy, can distinguish differences between young and middle-aged participants.

Reliability of P3 Event-Related Potential During Working Memory Across the Spectrum of Cognitive Aging

Event-related potentials (ERPs) offer unparalleled temporal resolution in tracing distinct electrophysiological processes related to normal and pathological cognitive aging. The stability of ERPs in older individuals with a vast range of cognitive ability has not been established. In this test-retest reliability study, 39 older individuals (age 74.10 (5.4) years; 23 (59%) women; 15 non β-amyloid elevated, 16 β-amyloid elevated, 8 cognitively impaired) with scores on the Montreal Cognitive Assessment (MOCA) ranging between 3 and 30 completed a working memory (n-back) test with three levels of difficulty at baseline and 2-week follow-up. The main aim was to evaluate stability of the ERP on grand averaged task effects for both visits in the total sample (n = 39). Secondary aims were to evaluate the effect of age, group (non β-amyloid elevated; β-amyloid elevated, cognitively impaired), cognitive status (MOCA), and task difficulty on ERP reliability. P3 peak amplitude and latency were measured in predetermined channels. P3 peak amplitude at Fz, our main outcome variable, showed excellent reliability in 0-back (intraclass correlation coefficient (ICC), 95% confidence interval = 0.82 (0.67-0.90) and 1-back (ICC = 0.87 (0.76-0.93), however, only fair reliability in 2-back (ICC = 0.53 (0.09-0.75). Reliability of P3 peak latencies was substantially lower, with ICCs ranging between 0.17 for 2-back and 0.54 for 0-back. Generalized linear mixed models showed no confounding effect of age, group, or task difficulty on stability of P3 amplitude and latency of Fz. By contrast, MOCA scores tended to negatively correlate with P3 amplitude of Fz (p = 0.07). We conclude that P3 peak amplitude, and to lesser extent P3 peak latency, provide a stable measure of electrophysiological processes in older individuals.

Age differences in cross-task bleeding

The present study investigated age-related differences in the ability to constrain attention to the current task, without contamination (bleeding) from an upcoming decision. Each experiment included two blocks of trials. During Block 1, participants initially incidentally encoded a list of high- and low-frequency words, after which they pronounced aloud the studied words intermixed with a new set of words during a test phase. Block 2 was identical to Block 1 with the exception that after pronouncing each word aloud, participants made an additional decision (episodic recognition decision in Experiments 1 and 2 and animacy decision in Experiment 3). In the first two experiments, older adults showed disproportionate slowing in their response times to pronounce the words when they additionally had to make a recognition judgment afterward (Block 2) compared to when they only pronounced the words aloud (Block 1). Importantly, the difference between high-frequency and low-frequency words (the word frequency effect) was disproportionately attenuated for older adults in Block 2 compared to Block 1 and compared to younger adults. These results suggest that older adults experience greater cross-task bleeding than younger adults because word frequency has opposing effects in pronunciation and recognition tasks. As predicted, this age modulation of the word frequency effect in pronunciation performance was not replicated in Experiment 3 when participants made an animacy judgment, wherein word frequency effects act in concert with those of the pronunciation task. Discussion focuses on age-related differences in the ability to constrain attention to a current task. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Ex-Gaussian, Frequency and Reward Analyses Reveal Specificity of Reaction Time Fluctuations to ADHD and Not Autism Traits

Both attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) have been linked to increased reaction time variability (RTV), a marker of attentional fluctuation. Here we test whether specificity to either trait emerges when we examine (1) detailed ex-Gaussian and frequency RTV subcomponents, (2) effects while controlling for the other trait and (3) improvement in the RTV measures following rewards or a faster event rate. 1110 children aged 7-10 years from a population-based sample completed a Go/No-Go task under three conditions (slow, fast and incentives). We measured RTV with standard deviation of RT (SDRT), ex-Gaussian distribution measures (Sigma and Tau), RT fluctuations in cycles of ~14-90 s in all conditions (Slow-4 and Slow-5), and RT fluctuations in cycles of 2-14 s in the fast condition (Slow-2 and Slow-3). Parent-rated ADHD and ASD traits were obtained. All refined RTV components were linked to ADHD traits only and not to ASD traits, while Sigma did not relate to either trait. Although both ADHD and ASD social-communication traits were associated with SDRT, the association with social-communication impairments disappeared when controlling for ADHD traits. A reward-induced improvement in RTV measures, indicating malleability, emerged in relation to ADHD traits but not ASD traits. Under closer inspection, specificity emerges of high RTV to ADHD traits. For the clinician, our findings indicate that attentional fluctuation in children with high ASD traits may be due to co-occurring ADHD traits and emphasise how the effectiveness of rewards does not generalise from ADHD to ASD traits.

Aging-Related Changes in the Association between Negative Affect and Response Time Inconsistency in Older Adulthood

Negative affect (NA) and positive affect (PA) are established modifiable psychosocial correlates of cognitive health and have demonstrated capacity for meaningful within-person fluctuations based on person-environment interactions, age, and measurement approach. Previous research has shown NA is associated with increased response time inconsistency (RTI), an early performance-based indicator of cognitive health and aging. It is unclear, however, whether PA is associated with RTI, and whether affect-RTI associations exist within persons over time or change as individuals get older. We utilized data from a measurement burst study (Cognition, Health and Aging Project) to explore within- and between-person associations between affect and RTI in community-dwelling older adults (N=111, M=80.04 years, SD=6.30). Affect and RTI were assessed on six days over a two-week period, every six months for two years. Results revealed a significant association between NA-low arousal and RTI within persons over time. RTI was higher on sessions when NA-low arousal was higher than usual (b=0.21, 95%CI=0.08 to 0.35, p<.01). This association decreased in magnitude over time (b=-0.09, 95%CI=-0.14 to - 0.03, p<.001), ultimately resulting in increased NA-low arousal being associated with decreased RTI two years later (b=-.14, 95%CI=-0.27 to -0.01, p<.05). No PA-RTI associations emerged. The results suggest efforts focused on maximizing resource allocation and personalizing cognitive health efforts should consider for whom and when mitigating NA may be maximally beneficial to daily cognition, whereas additional work is needed to determine influences from PA.

Regular participation in leisure time activities and high cardiovascular fitness improve motor sequence learning in older adults

INTRODUCTION

Older adults show higher interindividual performance variability during the learning of new motor sequences than younger adults. It is largely unknown what factors contribute to this variability. This study aimed to, first, characterize age differences in motor sequence learning and, second, examine influencing factors for interindividual performance differences.

METHOD

30 young adults (age M = 21.89, SD = 2.08, 20 female) and 29 older adults (age M = 69.55, SD = 3.03, 18 female) participated in the study. Motor sequence learning was assessed with a discrete sequence production (DSP) task, requiring key presses to a sequence of visual stimuli. Three DSP practice phases (á 8 blocks × 16 sequences, two six-element sequences) and two transfer blocks (new untrained sequences) were performed. Older participants conducted the Mini-Mental Status Examination and a visuospatial working-memory task. All participants finished a questionnaire on everyday leisure activities and a cardiovascular fitness test.

RESULTS

Performance speed increased with practice in both groups, but young improved more than older adults (significant Group × Time effect for response time, F(1,5) = 4.353, p = 0.004, [Formula: see text] = 0.071). Accuracy did not change in any age group (non-significant Group × Time effect for error rates, F(1,5) = 2.130, p = 0.091, [Formula: see text] = 0.036). Older adults revealed lower transfer costs for performance speed (significant Time × Group effect, e.g., simple sequence, F(1,2) = 10.511, p = 0.002, [Formula: see text] = 0.156). High participation in leisure time activities (β = - 0.58, p = 0.010, R² = 0.45) and high cardiovascular fitness (β = - 0.49, p = 0.011, R² = 0.45) predicted successful motor sequence learning in older adults.

DISCUSSION

Results confirmed impaired motor learning in older adults. Younger adults seem to show a better implicit knowledge of the practiced sequences compared to older adults. Regular participation in leisure time activities and cardiovascular fitness seem to prevent age-related decline and to facilitate motor sequence performance and motor sequence learning in older adults.

Long-term Associations Between Physical Frailty and Performance in Specific Cognitive Domains

OBJECTIVES

No longitudinal epidemiological research has reported associations between physical frailty and performance in specific cognitive domains. Our aim was to investigate whether such associations existed in the absence of accompanying neurodegenerative disorders such as mild cognitive impairment (MCI) and dementia.

METHOD

We addressed this issue in a population-based sample of 896 adults aged 70 years and older over 4 waves of data covering a 12-year period. Physical frailty was assessed and a cognitive battery included measures of processing speed, verbal fluency, face and word recognition, episodic memory and simple and choice reaction time (RT).

RESULTS

Latent growth models showed frailty was associated with poorer baseline performance in processing speed, verbal fluency, simple and choice RT, and choice intraindividual RT variability. However, no significant effects of frailty on slopes of cognition were observed, suggesting that frailty was not associated with cognitive decline. Importantly, when the models took possible dementia into account, significant effects were retained suggesting that differences were not associated with dementia-related neurodegenerative disorders.

DISCUSSION

The findings suggest that frailty-related cognitive deficits may exist independently of mechanisms underpinning neurodegenerative disorders such as MCI and dementia. If confirmed, this finding suggests a new avenue for preventative and therapeutic interventions in clinical and public health contexts for older adults.

Using intraindividual variability as an indicator of cognitive improvement in a physical exercise intervention of older women with mild cognitive impairment

OBJECTIVES

Intervention programs designed to improve cognitive ability in older adults with mild cognitive impairment (MCI) have often focused on physical exercise as a means to improve traditional measures of cognition, with mixed success. Individuals with MCI show high levels of intraindividual variability (IIV) in response speed, and IIV may be sensitive to intervention-related changes. The current study evaluated if participants who participated in a physical activity intervention (aerobic or resistance training) showed a reduction in IIV, compared to a balance and tone control group.

METHOD

This study was a secondary analysis of the EXercise for Cognition and Everyday Living (EXCEL) Study. Women Aged 70-80 years with probable MCI (n = 86) participated in a 6-month randomized controlled trial designed to investigate the effects of different physical exercises on cognitive ability. Participants completed 1-back, task switching, and spatial working memory tasks at baseline, 13 weeks (midpoint) and upon completion of the program.

RESULTS

Analyses were conducted following both the intent-to-treat principle and complier average casual effect (CACE) modeling. Participants in the intervention group who complied with the program showed reduced IIV on task switching in the CACE models. The intent-to-treat analyses were all nonsignificant.

CONCLUSIONS

Physical exercise resulted in improved IIV in older adults with probable MCI, showing that IIV is modifiable by lifestyle engagement. IIV may be a useful complementary index of cognitive plasticity particularly among those with cognitive impairment. (PsycInfo Database Record (c) 2020 APA, all rights reserved).