Psychometric Properties of a Flanker Task in a Sample of Patients with Dementia: A Pilot Study

Understanding the human conflict processing network: A review of the literature on direct neural recordings during performance of a modified stroop task

The Stroop Task is a well-known neuropsychological task developed to investigate conflict processing in the human brain. Our group has utilized direct intracranial neural recordings in various brain regions during performance of a modified color-word Stroop Task to gain a mechanistic understanding of non-emotional human conflict processing. The purpose of this review article is to: 1) synthesize our own studies into a model of human conflict processing, 2) review the current literature on the Stroop Task and other conflict tasks to put our research in context, and 3) describe how these studies define a network in conflict processing. The figures presented are reprinted from our prior publications and key publications referenced in the manuscript. We summarize all studies to date that employ invasive intracranial recordings in humans during performance of conflict-inducing tasks. For our own studies, we analyzed local field potentials (LFPs) from patients with implanted stereotactic electroencephalography (SEEG) electrodes, and we observed intracortical oscillation patterns as well as intercortical temporal relationships in the hippocampus, amygdala, and orbitofrontal cortex (OFC) during the cue-processing phase of a modified Stroop Task. Our findings suggest that non-emotional human conflict processing involves modulation across multiple frequency bands within and between brain structures.

Reliability and Validity of Smartphone Cognitive Testing for Frontotemporal Lobar Degeneration

Importance

Frontotemporal lobar degeneration (FTLD) is relatively rare, behavioral and motor symptoms increase travel burden, and standard neuropsychological tests are not sensitive to early-stage disease. Remote smartphone-based cognitive assessments could mitigate these barriers to trial recruitment and success, but no such tools are validated for FTLD.

Objective

To evaluate the reliability and validity of smartphone-based cognitive measures for remote FTLD evaluations.

Design, Setting, and Participants

In this cohort study conducted from January 10, 2019, to July 31, 2023, controls and participants with FTLD performed smartphone application (app)-based executive functioning tasks and an associative memory task 3 times over 2 weeks. Observational research participants were enrolled through 18 centers of a North American FTLD research consortium (ALLFTD) and were asked to complete the tests remotely using their own smartphones. Of 1163 eligible individuals (enrolled in parent studies), 360 were enrolled in the present study; 364 refused and 439 were excluded. Participants were divided into discovery (n = 258) and validation (n = 102) cohorts. Among 329 participants with data available on disease stage, 195 were asymptomatic or had preclinical FTLD (59.3%), 66 had prodromal FTLD (20.1%), and 68 had symptomatic FTLD (20.7%) with a range of clinical syndromes.

Exposure

Participants completed standard in-clinic measures and remotely administered ALLFTD mobile app (app) smartphone tests.

Main Outcomes and Measures

Internal consistency, test-retest reliability, association of smartphone tests with criterion standard clinical measures, and diagnostic accuracy.

Results

In the 360 participants (mean [SD] age, 54.0 [15.4] years; 209 [58.1%] women), smartphone tests showed moderate-to-excellent reliability (intraclass correlation coefficients, 0.77-0.95). Validity was supported by association of smartphones tests with disease severity (r range, 0.38-0.59), criterion-standard neuropsychological tests (r range, 0.40-0.66), and brain volume (standardized β range, 0.34-0.50). Smartphone tests accurately differentiated individuals with dementia from controls (area under the curve [AUC], 0.93 [95% CI, 0.90-0.96]) and were more sensitive to early symptoms (AUC, 0.82 [95% CI, 0.76-0.88]) than the Montreal Cognitive Assessment (AUC, 0.68 [95% CI, 0.59-0.78]) (z of comparison, -2.49 [95% CI, -0.19 to -0.02]; P = .01). Reliability and validity findings were highly similar in the discovery and validation cohorts. Preclinical participants who carried pathogenic variants performed significantly worse than noncarrier family controls on 3 app tasks (eg, 2-back β = -0.49 [95% CI, -0.72 to -0.25]; P < .001) but not a composite of traditional neuropsychological measures (β = -0.14 [95% CI, -0.42 to 0.14]; P = .32).

Conclusions and Relevance

The findings of this cohort study suggest that smartphones could offer a feasible, reliable, valid, and scalable solution for remote evaluations of FTLD and may improve early detection. Smartphone assessments should be considered as a complementary approach to traditional in-person trial designs. Future research should validate these results in diverse populations and evaluate the utility of these tests for longitudinal monitoring.

Do executive functions buffer against COVID-19 stress?: A latent variable approach

Levels of COVID-19 stress have soared worldwide as a result of the pandemic. Given the pernicious psychological and physiological effects of stress, there is an urgent need for us to protect populations against the pandemic's psychological impact. While there exists literature documenting the prevalence of COVID-19 stress among various populations, insufficient research has investigated psychological factors that might mitigate this worrying trend. To address this gap in the literature, the current study seeks to examine executive functions as a potential cognitive buffer against COVID-19 stress. To do so, the study adopted a latent variable approach to examine three latent factors of executive functions and their relation to COVID-19 stress among a sample of 243 young adults. Structural equation models showed differential associations between COVID-19 stress and the latent factors of executive functions. While the latent factor of updating working memory was associated with attenuated COVID-19 stress, task switching and inhibitory control were not significantly associated with COVID-19 stress. These results further our understanding of the critical processes of executive functions and highlight the nuanced link between executive functions and pandemic-related stress.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12144-023-04652-8.

Evaluating the validity of game-based assessments measuring cognitive function among children and adolescents: A systematic review and meta-analysis

Games offer advantages over traditional methods of assessing cognitive function among children and adolescents. However, the validity of game-based assessments has not been systematically evaluated. We conducted a systematic review and meta-analysis to assess the validity of game-based assessments measuring cognitive function among children and adolescents. We systematically searched several databases using pre-defined inclusion criteria. For papers that met the criteria, we extracted and analyzed the cognitive functions measured by each study, the correlation coefficients between game-based and traditional assessments, and factors that could influence the validity of game-based assessments. Our review identified 19 articles featuring 20 studies, 18 games, and 378 unique correlations between game-based and traditional assessments of cognitive function. Game-based assessments yielded significant correlations (n=282, 75%) with traditional assessments, over half of which were in the low to medium range in strength (r=0.3-0.69, n=227, 80%). Factors related to the child, such as age, gender, and prior gaming experience, may influence the validity of game-based assessments by modifying performance on game-based assessments. In addition, we found that game-based assessments that measured cognitive functions across more than one neurocognitive domain and used a prediction model for scoring were more likely to yield significant correlations. In contrast, including a narrative storyline in a game-based assessment was less likely to yield significant correlations. Most studies were of good quality, although the lack of sample size justification was a limiting factor. Further research is needed to elucidate the influence of identified factors on the validity of game-based assessment to justify the wide adoption of game-based assessments of cognitive function among children and adolescents.

Examining the intersection of cognitive and physical function measures: Results from the brain networks and mobility (B-NET) study

Background and objectives

Although evidence exists that measures of mobility and cognition are correlated, it is not known to what extent they overlap, especially across various domains. This study aimed to investigate the intersection of 18 different objective cognitive and physical function measures from a sample of unimpaired adults aged 70 years and older.

Research design and methods

Canonical correlation analysis was utilized to explore the joint cross-sectional relationship between 13 cognitive and 6 physical function measures in the baseline visit of the Brain Networks and Mobility Function (B-NET) Study (n = 192).

Results

Mean age of participants was 76.4 years. Two synthetic functions were identified. Function 1 explained 26.3% of the shared variability between the cognition and physical function variables, whereas Function 2 explained 19.5%. Function 1 termed "cognitive and physical speed" related the expanded Short Physical Performance Battery (eSPPB), 400-m walk speed, and Dual Task gait speed measures of physical function to semantic fluency animals scores, Digit Symbol Coding (DSC), and Trail Making Test B. Function 2 termed "complex motor tasks and cognitive tasks" related the Force Plate Postural Sway Foam Task and Dual Task to the following cognitive variables: MoCA Adjusted Score, Verbal Fluency L words, Craft story immediate and delayed recall, and Trail Making Test B.

Discussion and implications

We identified groups of cognitive and physical functional abilities that were linked in cross-sectional analyses, which may suggest shared underlying neural network pathway(s) related to speed (Function 1) or complexity (Function 2).

Translational significance

Whether such neural processes decline before measurable functional losses or may be important targets for future interventions that aim to prevent disability also remains to be determined.

Cognitive and linguistic abilities and perceptual restoration of missing speech: Evidence from online assessment

When speech is clear, speech understanding is a relatively simple and automatic process. However, when the acoustic signal is degraded, top-down cognitive and linguistic abilities, such as working memory capacity, lexical knowledge (i.e., vocabulary), inhibitory control, and processing speed can often support speech understanding. This study examined whether listeners aged 22-63 (mean age 42 years) with better cognitive and linguistic abilities would be better able to perceptually restore missing speech information than those with poorer scores. Additionally, the role of context and everyday speech was investigated using high-context, low-context, and realistic speech corpi to explore these effects. Sixty-three adult participants with self-reported normal hearing completed a short cognitive and linguistic battery before listening to sentences interrupted by silent gaps or noise bursts. Results indicated that working memory was the most reliable predictor of perceptual restoration ability, followed by lexical knowledge, and inhibitory control and processing speed. Generally, silent gap conditions were related to and predicted by a broader range of cognitive abilities, whereas noise burst conditions were related to working memory capacity and inhibitory control. These findings suggest that higher-order cognitive and linguistic abilities facilitate the top-down restoration of missing speech information and contribute to individual variability in perceptual restoration.

Simultaneous Exercise and Cognitive Training in Virtual Reality Phase 2 Pilot Study: Impact on Brain Health and Cognition in Older Adults

Background:

Aerobic exercise and environmental enrichment have been shown to enhance brain function. Virtual reality (VR) is a promising method for combining these activities in a meaningful and ecologically valid way.

Objective:

The purpose of this Phase 2 pilot study was to calculate relative change and effect sizes to assess the impact of simultaneous exercise and cognitive training in VR on brain health and cognition in older adults.

Methods:

Twelve cognitively normal older adults (64.7±8.8 years old, 8 female) participated in a 12-week intervention, 3 sessions/week for 25–50 minutes/session at 50–80% HR_max. Participants cycled on a custom-built stationary exercise bike while wearing a VR head-mounted display and navigating novel virtual environments to train spatial memory. Brain and cognitive changes were assessed using MRI imaging and a cognitive battery.

Results:

Medium effect size (ES) improvements in cerebral flow and brain structure were observed. Pulsatility, a measure of peripheral vascular resistance, decreased 10.5% (ES(d) = 0.47). Total grey matter volume increased 0.73% (ES(r) = 0.38), while thickness of the superior parietal lobule, a region associated with spatial orientation, increased 0.44% (ES(r) = 0.30). Visual memory discrimination related to pattern separation showed a large improvement of 68% (ES(η_p²) = 0.43). Cognitive flexibility (Trail Making Test B) (ES(r) = 0.42) and response inhibition (ES(W) = 0.54) showed medium improvements of 14% and 34%, respectively.

Conclusions:

Twelve weeks of simultaneous exercise and cognitive training in VR elicits positive changes in brain volume, vascular resistance, memory, and executive function with moderate-to-large effect sizes in our pilot study.

Rethinking cognitive training: The moderating roles of emotional vulnerability and perceived cognitive impact of training in high worriers

Trait worry is a hallmark feature of anxiety and depression, interfering with attentional control and impairing cognitive performance. Previous research has shown the adaptive dual n-back training is effective in improving attentional control and reducing emotional vulnerability, but not for everyone. The current randomised controlled trial explored the role of baseline emotional vulnerability and perceived cognitive impact in training-related cognitive and emotional improvements in 60 high worriers randomly assigned to 10 sessions of the adaptive dual n-back training or non-adaptive 1-back training. Pre-training, post-training and one-month follow-up measures of cognitive performance were assessed using an emotional Flanker task, a cued task-switching task, and the MaRs-IB task. Self-report questionnaires assessed worry, anxiety, depression, somatisation, and self-efficacy, as well as participants' perceived cognitive impact of the training. Participants with higher levels of baseline emotional vulnerability presented the largest improvements in non-verbal reasoning and emotional vulnerability one month after the training, as well as the greatest perceived cognitive impact. Perceived cognitive impact was predicted by working memory improvement on the adaptive n-back training at high baseline levels of anxiety. These results suggest that the adaptive n-back training presents the greatest emotional and cognitive benefits for individuals experiencing severe levels of emotional vulnerability.

Systemic inflammation mediates the negative relationship between visceral adiposity and cognitive control

Elevated visceral adipose tissue (VAT) has been associated with cardiometabolic risk factors including chronic systemic low-grade inflammation. Whereas the cognitive implications of inflammation have been extensively studied in preclinical models, the influence of inflammatory cytokines on cognitive function in humans is unclear. This study aimed to investigate the relations among VAT, inflammatory cytokines, and cognitive control. We hypothesized that inflammatory markers would mediate the negative influence of VAT on selective attention. Participants between 25 and 46 years (N = 115, 43 females) underwent a DXA scan to estimate VAT. A modified Eriksen Flanker task was used to assess attentional inhibitory control while event-related potentials were recorded. ELISA was used to quantify plasma C-reactive protein (CRP) and Interleukin-6 (IL-6) concentrations. Mediation modeling while controlling for diet quality and education level revealed that CRP concentrations significantly mediated the relationship between VAT and incongruent trial accuracy (indirect effect 95% CI {-0.24, -0.01}). Further, IL-6 concentrations had a significant mediation effect on the relationship between VAT and incongruent P3 peak latency (indirect effect 95% CI {0.05, 1.39}). These results suggest that mechanisms by which visceral adiposity exerts a negative influence on cognitive function includes systemic inflammation.

Web-Based Cognitive Testing of Older Adults in Person Versus at Home: Within-Subjects Comparison Study

Background

Web-based research allows cognitive psychologists to collect high-quality data from a diverse pool of participants with fewer resources. However, web-based testing presents unique challenges for researchers and clinicians working with aging populations. Older adults may be less familiar with computer usage than their younger peers, leading to differences in performance when completing web-based tasks in their home versus in the laboratory under the supervision of an experimenter.

Objective

This study aimed to use a within-subjects design to compare the performance of healthy older adults on computerized cognitive tasks completed at home and in the laboratory. Familiarity and attitudes surrounding computer use were also examined.

Methods

In total, 32 community-dwelling healthy adults aged above 65 years completed computerized versions of the word-color Stroop task, paired associates learning, and verbal and matrix reasoning in 2 testing environments: at home (unsupervised) and in the laboratory (supervised). The paper-and-pencil neuropsychological versions of these tasks were also administered, along with questionnaires examining computer attitudes and familiarity. The order of testing environments was counterbalanced across participants.

Results

Analyses of variance conducted on scores from the computerized cognitive tasks revealed no significant effect of the testing environment and no correlation with computer familiarity or attitudes. These null effects were confirmed with follow-up Bayesian analyses. Moreover, performance on the computerized tasks correlated positively with performance on their paper-and-pencil equivalents.

Conclusions

Our findings show comparable performance on computerized cognitive tasks in at-home and laboratory testing environments. These findings have implications for researchers and clinicians wishing to harness web-based testing to collect meaningful data from older adult populations.

The Effects of Alcohol Hangover on Mood and Performance Assessed at Home

The current study evaluated the next day consequences of a social night of drinking compared to a no alcohol night, with standardised mood and portable screen-based performance measures assessed in the morning at participants' homes, and a breathalyser screen for zero alcohol. A mixed sex group (n = 20) took part in the study. Participants reported consuming on average 16.9 units (135 g) alcohol, resulting in a hangover rating of 60 (out of 100) compared to 0.3 following the no alcohol night. Statistical significance comparisons contrasting the hangover with the no alcohol condition revealed an increase in negative mood and irritability during hangover and an (unexpected) increase in risk and thrill seeking. Performance scores showed an overall slowing of responses across measures, but with less impact on errors. The results support the description of hangover as a general state of cognitive impairment, reflected in slower responses and reduced accuracy across a variety of measures of cognitive function. This suggests a general level of impairment due to hangover, as well as increased negative mood. The use of a naturalistic design enabled the impact of more typical levels of alcohol associated with real life social consumption to be assessed, revealing wide ranging neurocognitive impairment with these higher doses. This study has successfully demonstrated the sensitivity of home-based assessment of the impact of alcohol hangover on a range of subjective and objective measures. The observed impairments, which may significantly impair daily activities such as driving a car or job performance, should be further investigated and taken into account by policy makers.