Relations between short-term memory deficits, semantic processing, and executive function

Research has demonstrated that better value-based decision making (e.g., waiting or working for rewards) relates to greater executive function (EF) ability. However, EF is not a static ability, but is influenced by the emotional content of the task. As such, EF ability in emotional contexts may have unique associations with value-based decision making, in which costs and benefits are explicit. Participants (N = 229) completed an EF task (with both negative and neutral task conditions) and two value-based decision-making tasks. Willingness to wait and to work were evaluated in separate path models relating the waiting and working conditions to the EF conditions. Willingness to wait and willingness to work showed distinct relationships with EF ability: Greater EF ability on a negative, but not on a neutral, EF task was related to a willingness to wait for a reward, whereas greater EF ability across both EF tasks was related to a greater willingness to work for a reward. EF ability on a negative EF task showed an inverted-U relationship to willingness to wait for reward, and was most related to willingness to wait at a 6-month delay. Greater EF, regardless of whether the task was negative or neutral, was related to a greater willingness to work when reward was uncertain (50%) or was likely (88%), but not when reward was unlikely (12%). This study suggests that the emotional content of value-based decisions impacts the relationship between EF ability and willingness to wait or to work for reward.

Executive function deficits in depression implicate involvement of frontal-striatal circuits. However, studies of hypothalamic-pituitary-axis (HPA) function suggest that stress-related brain changes of hippocampus may also implicate prefrontal-hippocampal circuits, which may explain the profile of both executive dysfunction and memory deficits. In this study we examined the performance of patients with major depressive disorder (MDD) on tasks of memory and executive function in relation to melancholic features and to cortisol levels. Our hypothesis was that raised cortisol levels in melancholic patients would correlate with these deficits. Forty female MDD patients, 20 having melancholic features (MEL vs. Non-MEL), and 20 sex-age- and education-matched normal controls were investigated using the Cambridge neuropsychological test automated battery (CANTAB), to assess memory (paired associative learning, PAL; short-term recognition memory, SRM) and executive (intradimensional/extradimensional set-shifting, ID/ED; Stockings of Cambridge, SOC) functions. Plasma and salivary cortisol levels were measured. The MDD patients performed worse than controls on PAL and both executive tasks. The MEL group differed from controls on all tests, and differed from the non-MEL only at the ED stage of the ID/ED task. Patient cortisol levels were within the normal range and did not correlate with neuropsychological performance for any group. MDD patients showed neuropsychological deficits on tasks of executive function and memory, supporting the model of frontal-temporal dysfunction. MEL vs. non-MEL performed worse overall and demonstrated a qualitative difference in set shifting, perhaps implicating more extensive prefrontal involvement. Cortisol levels did not correlate with depression severity or the observed deficits.

Many studies show a link between social cognition, a set of cognitive and emotional abilities applied to social situations, and executive functions in typical developing children. Children with Down syndrome (DS) show deficits both in social cognition and in some subcomponents of executive functions. However this link has barely been studied in this population. The aim of this study is to investigate the links between social cognition and executive functions among children with DS. We administered a battery of social cognition and executive function tasks (six theory of mind tasks, a test of emotion comprehension, and three executive function tasks) to a group of 30 participants with DS between 4 and 12 years of age. The same tasks were administered to a chronological-age control group and to a control group with the same linguistic development level. Results showed that apart from deficits in social cognition and executive function abilities, children with DS displayed a slight improvement with increasing chronological age and language development in those abilities. Correlational analysis suggested that working memory was the only component that remained constant in the relation patterns of the three groups of participants, being the relation patterns similar among participants with DS and the language development control group. A multiple linear regression showed that working memory explained above 50% of the variability of social cognition in DS participants and in language development control group, whereas in the chronological-age control group this component only explained 31% of the variability. These findings, and specifically the link between working memory and social cognition, are discussed on the basis of their theoretical and practical implications for children with DS. We discuss the possibility to use a working memory training to improve social cognition in this population.

Virtual Reality Learning Environments (VLE) are a promising approach for the 21st century classroom. Therefore, it is important to identify the best way that these learning environments will enhance students’ cognitive functions. In this paper, we investigate the effect of lighting conditions, within a VLE, on several cognitive functions while we introduce the novel idea of transformable luminance conditions. We have been inspired by evidence from cognitive and environmental studies, from real environments, that lighting conditions affect people’s memory, attention and executive functions. Our transformable luminance approach, when applied in a virtual university amphitheatre, is benchmarked against the conventional approach of a single luminance VLE (either high or low). The first main outcome of our study is that traditional single luminance lighting conditions exert the same effect in both real and virtual learning environments. That is, high luminance enhances sustained attention and short term memory, while low luminance enhances long term memory. The results also indicate that our novel transformable luminance approach enhances student performance in executive tasks, compared to any single luminance condition (i.e. low or high).

Executive functions and theory of mind development in preschoolers: Insights from NIRS data

Alcohol abuse and/or dependence (AA/D) and mood disturbance are co-occurring conditions among patients who have had a traumatic brain injury (TBI). However, the relationship between these disorders has not been extensively studied. To examine the relationship of AA/D and post-TBI mood disorders and the effect of these conditions on psychosocial outcome. Prospective, case-control surveillance study conducted during the first year following trauma. Settings University hospital level I trauma centers and specialized rehabilitation units. Patients One hundred fifty-eight TBI patients with closed head injury with and without a history of AA/D. We prospectively compared psychiatric, neuropsychological, and psychosocial outcomes among the patients, who were evaluated at baseline and at 3, 6, and 12 months after trauma. Psychiatric diagnosis was made using a structured clinical interview and DSM-IV criteria. Neuropsychological testing results and quantitative magnetic resonance images were obtained at the 3-month follow-up. A history of AA/D was significantly more frequent among patients who developed mood disorders during the first year following TBI. There was also a significantly higher frequency of mood disorders among patients with alcohol abuse relapse. Patients with a history of AA/D had significantly reduced frontal gray matter volumes than did patients without a history of alcohol abuse. In addition, patients who resumed alcohol abuse had decreased medial frontal gray matter volumes and impaired performance in executive tasks. Both AA/D and mood disorders following TBI were associated with a poor vocational outcome. Previous alcohol abuse increases the risk of developing mood disorders after TBI, and emotional disturbance, in turn, increases the risk of alcohol abuse relapse. Alcohol's neurotoxic effects and TBI likely interact to produce greater disruption of the neural circuits that modulate reward, mood, and executive function. Patients with a history of AA/D who also developed mood disorders following TBI had major difficulties resuming a productive life.

We compared the performance of patients with Alzheimer’s disease to that of patients with subcortical vascular dementia (s-IVD) in a set of tasks assessing categorization abilities, sustained and selective attention, and set-shifting and set-maintaining skills. Only the measures of naming and categorization abilities on the Test of Classification and Recall of Pictures (TCRP) proved useful in differentiating AD from s-IVD patients. s-IVD patients showed worse performance than AD on the TCRP categorization measures, while both AD and s-IVD patients were equally impaired in other tasks assessing executive functions (EF). With respect to the naming task, s-IVD patients made significantly more perseverative and unrelated errors than AD patients. Moreover, in the s-IVD group, we found a strong correlation between categorization ability and an attentional test score (Attentional Matrices), while no such correlation emerged in the AD group. These results suggest a dissociated impairment of EF in the 2 dementia groups. In our view, the lack of inhibition and the inability to manipulate complex information are responsible for a greater executive dysfunction in s-IVD patients in comparison with AD patients. The capacity to build up strategies appears more preserved in AD patients, whose impaired performance in executive tasks seems to be related to an impairment of attentional shifting and working memory.

BackgroundThe earliest cognitive manifestations of asymptomatic and prodromal familial frontotemporal dementia (f‐FTD) mutation carriers are still being characterized. Patients with symptomatic FTD are known to be error prone, particularly on tasks of executive function, but little is known about the frequency or predictive utility of these errors in the earliest stages of f‐FTD. The current study compared error rates on executive functioning tasks in controls and asymptomatic and prodromal mutation carriers and investigated whether errors predict worsening clinical status as follow up.MethodThis study included 90 participants (mean age = 48.57, SD = 13.30; 51.1% female; 86.67% white) with pathogenic FTD mutations (C9orf72, n = 45; GRN, n = 30; or MAPT, n = 15) who were asymptomatic or prodromal (Clinical Dementia Rating plus FTLD; CDR®+NACC‐FTLD ≤ 0.5). Propensity score matching identified (CDR®+NACC‐FTLD = 0) who did not carry pathogenic mutation but were matched on age, education, and sex. Regressions were used to compare controls and mutation carriers on error scores (rule violations and/or repetitions) from three executive functioning tasks: design fluency, lexical fluency, and Stroop inhibition. Mutation carriers with longitudinal data within 1.5 years were binarized as stable (n = 35) or progressors (n = 13) based on whether their CDR®+NACC‐FTLD sum of boxes score was worse at follow up (mean follow up = 1.07 years). Regressions were fit to evaluate the relationship between baseline error scores and group (i.e., stable vs. progressor).ResultMutation carriers committed significantly more errors than controls on the Stroop task (β = 0.67, p = 0.03) and lexical fluency (repetitions: β = 0.27, p = 0.02). The groups did not significantly differ in errors on the remaining tasks. A greater number of Stroop errors predicted mutation carriers who progressed at follow up (β = 1.04, p<0.001). When introducing the primary outcome from each task as a covariate (e.g., correct responses), the fluency task (repetitions: β = 0.10, p = 0.03) and Stroop task (errors: β = 0.82, p<0.001) were significantly associated with progression.ConclusionErrors on executive tasks may be early cognitive features in familial FTD. Importantly, errors were uniquely predictive above and beyond total scores. Research in larger samples will enable investigations of genetic differences in error rates.

Subclinical manic symptoms predict social cognitive impairment mediated by deficits in executive functioning in older adults with mood disorders

ABSTRACTObjectives: Unusually high engagement in expressive suppression (i.e., purposeful regulation of overt affect) has been associated with poorer performance on executive functioning (EF) and motor-sequence learning tasks. As such, expressive suppression represents one possible source of fluctuations in executive test performance. However, the relationship between expressive suppression and EF and motor performance has not yet been examined in older adults, who are more prone to EF and motor fluctuations than are younger adults. The purpose of this study was to test whether greater self-reported, naturally occurring expressive suppression is related to poorer EF performance and motor-sequence learning in older adults.Method: One hundred and ten community-dwelling older adults completed a self-report measure of expressive suppression, a battery of EF tests, and a computer-based measure of motor-sequence learning.Results: As expected, higher self-reported burden of expressive suppression in the 24 hours prior to testing was related to poorer performance on EF tests and on multiple aspects of motor-sequence learning (action planning latencies and sequencing errors) even after accounting for age, depressive symptoms, and component processes (e.g., processing speed).Conclusions: The current results suggest that naturally occurring expressive suppression depletes EF, which builds on previous findings from experimental studies that show that expressive suppression leads to reduced EF performance. Furthermore, this effect can be captured using self-report methods. These findings highlight expressive suppression as one source of intraindividual fluctuations in executive and motor functioning, which likely place older adults at risk for both functional and motor lapses (e.g., medication mistakes, falls).

Background. Understanding the factors that influence language recovery in aphasia is important for improving prognosis and treatment. Chronic comprehension impairments in Wernicke’s aphasia (WA) are associated with impairments in auditory and phonological processing, compounded by semantic and executive difficulties. This study investigated whether the recovery of auditory, phonological, semantic, or executive factors underpins the recovery from WA comprehension impairments by charting changes in the neuropsychological profile from the subacute to the chronic phase. Method. This study used a prospective, longitudinal observational design. Twelve WA participants with superior temporal lobe lesions were recruited 2 months post–stroke onset (2 MPO). Language comprehension was measured alongside a neuropsychological profile of auditory, phonological, and semantic processing and phonological short-term memory and nonverbal reasoning at 3 poststroke time points: 2.5, 5, and 9 MPO. Results. Language comprehension displayed a strong and consistent recovery between 2.5 and 9 MPO. Improvements were also seen for slow auditory temporal processing, phonological short-term memory, and semantic processing but not for rapid auditory temporal, spectrotemporal, and phonological processing. Despite their lack of improvement, rapid auditory temporal processing at 2.5 MPO and phonological processing at 5 MPO predicated comprehension outcomes at 9 MPO. Conclusions. These results indicate that recovery of language comprehension in WA can be predicted from fixed auditory processing in the subacute stage. This suggests that speech comprehension recovery in WA results from reorganization of the remaining language comprehension network to enable the residual speech signal to be processed more efficiently, rather than partial recovery of underlying auditory, phonological, or semantic processing abilities.

Age-related neurodegeneration associated with Alzheimer’s (AD) disease begins in middle age, well before the onset of symptoms. Therefore, translational models to identify modifiable risk factors in middle-age are needed to understand etiology and identify therapeutic targets. Vervet monkeys (Chlorocebus aethiops sabaeus), like humans, naturally develop several risk factors for AD with age, including obesity, prediabetes, and hypertension. Furthermore, older vervets exhibit accumulation of amyloid and tauopathies, decreased brain volumes, and physical declines in gait speed, suggesting that these NHPs may be useful models of early AD-like neuropathology. Currently, we are investigating the extent to which cognitive and physical decline co-occur in 20 elder (mean age=23 years, ~equivalent to a human age of 80 years) and 10 middle-aged (mean age=11 years) females through assessments of physical performance, executive function, social cognition, and short-term memory. These measures are part of a larger study to integrate physical, social, and cognitive function with measures of body composition, metabolic profiles, CSF, blood, neuroimages, and neuropathology. While tests of social cognition and short-term memory are ongoing, assessments of executive function indicate that performance declines with age (N=26; p<0.05; R-squared=0.23). Furthermore, animals that exhibit slower gait speed also perform poorly on the executive function task (N=26, p<0.05; R-squared=0.25). These preliminary results suggest that accelerated aging co-occurs in multiple systems in vervets. This study will enable examination of temporal relationships between physical and cognitive declines. Ultimately, this comprehensive, integrative whole-body approach will help clarify the mechanisms underlying divergent aging trajectories and inspire interventions that promote multi-system healthy aging.

Two studies were conducted to investigate the specificity of the relationship between preschoolers' emerging executive functioning skills and false belief understanding. Study 1 (N=44) showed that 3- to 5-year-olds' performance on an executive functioning task that required selective suppression of actions predicted performance on false belief tasks, but not on false photograph tasks. Study 2 (N=54) replicated the finding from Study 1 and showed that performance on the executive functioning task also predicted 3- to 5-year-olds' performance on false sign tasks. These findings show that executive functioning is required to reason only about representations that are intended to reflect a true state of affairs. Results are discussed with respect to theories of preschoolers' theory-of-mind development.

A growing body of evidence suggests that patients with bipolar disorder (BD) have cognitive impairments even during euthymic periods. The main cognitive domains affected are verbal memory, attention, and executive function. Nevertheless, some studies suggest that at least a subgroup of euthymic patients demonstrates intact executive functioning in classic neuropsychological tests, which could be due to the lack of real-life, or ecological validity. In this study, we highlight the usefulness of incorporating more ecological tests of executive function in assessment batteries in order to detect specific cognitive deficits in BD patients with otherwise normal performance in standard executive tests. Nineteen euthymic BD patients and 15 healthy controls completed a standard neuropsychological battery assessment and two experimental tasks (the Multiple Errands Test-Hospital Version and the Hotel Task) to measure executive functioning in highly demanding cognitive settings that mimic real-life scenarios. No significant differences were found between the groups' demographic variables. We found, as predicted, that the group of euthymic BD patients who had control-comparable performance in classic executive tasks showed important deficits in more ecological tasks of executive functioning of the type that mimic real-life scenarios. Together, these data suggest that the inclusion of ecological tests in the assessment of BD patients can contribute to providing a more realistic cognitive profile of this patient population, which will undoubtedly allow for a better design of therapeutic and rehabilitation strategies that can help patients to minimize impact in real-life settings.

BackgroundSubjective Cognitive Decline (SCD) refers to a self‐perceived decline in cognitive ability despite normal performance on objective tests. SCD has been conceptualized as a marker of preclinical Alzheimer’s disease (AD) but research has uncovered considerable heterogeneity in symptoms and outcomes. Therefore, it is likely that SCD encompasses distinct subtypes, similarly to Mild Cognitive Impairment (MCI). Here we sought to identify and characterize subgroups based on patterns of subjective cognitive symptoms.MethodsCommunity‐dwelling participants aged ≥50 years (n = 483), located within the United States, were recruited via a crowdsourcing website, and completed a survey consisting of the following: SCD Questionnaire‐MyCog, PROMIS depression scale, and demographic questions. The SCD‐Q includes 24 items assessing self‐perceived recent decline on memory, language, and executive functioning tasks with a yes or no format. Two‐step cluster analysis using AIC was performed on all SCD‐Q items.ResultsThe analysis yielded a 3‐cluster solution with fair cohesion and separation (silhouette measure = 0.46). Cluster 1 (No Subjective Decline) included 36% of participants reporting no decline except for sporadic endorsement (≤2%) on a few memory tasks. Cluster 2 (Mild Subjective Decline) consisted of 42% of participants who frequently (≤50%) endorsed decline on select memory and language tasks, and less frequently on executive functioning tasks (≤25%). Cluster 3 (Moderate Subjective Decline) included 22% of participants who almost unanimously (≥80%) reported decline on a wide range of memory and language tasks, and frequently (≥60%) on executive functioning tasks. Clusters differed on total SCD‐Q scores (1&lt;2&lt;3, M = 0.1, 3.5, 13.7), percent below the SCD cutoff of 7/24 (1 and 2&lt;3, 0%, 8.4%, 100%), depression score (1&lt;2&lt;3, M = 10.9, 13.0, 16.7), gender (percent women 1&lt;2 and 3, 58.7%, 71.0%, 704%) and AD family history (percent with history 1&lt;2 and 3, 20%, 29%, 34.9%) but not on age.ConclusionWe identified three distinct subgroups in our community sample, defined by escalating subjective symptom burden, growing involvement of language and executive functioning domains and increasing prevalence of AD risk factors (female gender/AD family history). All Moderate‐Subjective‐Decline subgroup members but none/very few of the others, scored above the published SCD cut‐off. Longitudinal outcomes are needed to establish subgroup validity.