How do educational attainment and gender relate to fluid intelligence, crystallized intelligence, and academic skills at ages 22-90 years?

Associations of Circadian Rest-Activity Rhythms With Affect and Cognition in Community-Dwelling Stroke Survivors: An Ambulatory Assessment Study

BACKGROUND

Rest-activity rhythm (RAR) is a modifiable behavioral factor associated with affect and cognition. Identifying RAR characteristics associated with affect and cognition among stroke survivors provides insight into preventing poststroke affective and cognitive impairment.

OBJECTIVE

To examine the associations of RAR characteristics with affect and cognition among community-dwelling stroke survivors.

METHODS

Forty participants with mild stroke (mean age = 52.8; 42.5% female; 55% White) reported their affect and cognitive complaints using ecological momentary assessment and wore an accelerometer for 7 consecutive days and completed the National Institutes of Health Toolbox Cognition Battery. RAR characteristics were extracted using parametric and non-parametric approaches. Multivariable linear regressions were used to identify RAR characteristics associated with affect and cognition.

RESULTS

Later onset of rest (B = 0.45; P = .008) and activity (B = 0.36; P = .041) were positively associated with depressed affect. These associations were reversed for cheerful effect (rest onset: B = -0.42; P = .017; activity onset: B = -0.39; P = .033). Cheerful affect was also positively associated with relative amplitude (ie, distinctions in activity levels between rest and activity; B = .39; P = .030). Intra-daily variability (ie, RAR fragmentation; B = 0.35; P = .042) and later onset of activity (B = .36; P = .048) were positively associated with cognitive complaints. Less erratic RAR was positively associated with fluid cognition (B = 0.29; P = .036); RAR fragmentation was positively associated with crystallized cognition (B = 0.39; P = .015).

CONCLUSIONS

We identified RAR correlates of affect and cognition among stroke survivors, highlighting the value of managing RAR and sleep in stroke rehabilitation. Future studies should test whether advancing the onset of rest and activity, promoting a regular active lifestyle, and improving rest and sleep in the nighttime protect stroke survivors from affective and cognitive impairment.

Effects of age, gender, and education on task performance and prefrontal cortex processing during emotional and non-emotional verbal fluency tests

The emotional semantic fluency test (SFT) is an emerging verbal fluency test that requires controlled access to emotional lexical information. Currently, how demographic variables influence neurocognitive processing during this test remains elusive. The present study compared the effects of age, gender, and education on task performance and prefrontal cortex (PFC) processing during the non-emotional and emotional SFTs. One-hundred and thirty-three Cantonese-speaking adults aged 18-79 performed the non-emotional and emotional SFTs while their PFC activation was measured using functional near-infrared spectroscopy. Results showed that more education predicted better non-emotional SFT performance, whereas younger age, being female, and more education predicted better emotional SFT performance. Only age significantly affected PFC activation during the SFTs, and the effect was comparable between the two SFTs. Thus, compared with its non-emotional analog, the emotional SFT is influenced by overlapping yet distinct demographic variables. There is a similar age-related reorganization of PFC function across SFT performances.

Moderating effects of cognitive reserve on the relationship between brain structure and cognitive abilities in middle-aged and older adults

The cognitive reserve (CR) hypothesis is reinforced by negative moderating effects, suggesting that those with higher CR are less reliant on brain structure for cognitive function. Previous research on CR's moderating effects yielded inconsistent results, motivating our 3 studies using UK Biobank data. Study I examined five CR proxies' moderating effects on global, lobar, and regional brain-cognition models; study II extended study I by using a larger sample size; and study III investigated age-related moderating effects on the hippocampal regions. In study I, most moderating effects were negative and none survived the multiple comparison correction, but study II identified 13 global-level models with significant negative moderating effects that survived correction. Study III showed age influenced CR proxies' moderating effects in hippocampal regions. Our findings suggest that the effects of CR proxies on brain integrity and cognition varied depending on the proxy used, brain integrity indicators, cognitive domain, and age group. This study offers significant insights regarding the importance of CR for brain integrity and cognitive outcomes.

Health literacy mediates the effects of educational attainment on online pharmacy navigation skills in older adults with HIV disease

ObjectiveThe Internet serves an increasingly critical role in health behaviors for older adults with chronic medical conditions. Guided by theories of health behaviors and literacy, this study examined whether the relationship between educational attainment and online pharmacy skills in older persons with HIV disease (PWH) is mediated by health literacy. Design: Participants included 98 PWH age 50 and older who completed the Test of Online Pharmacy Skills (TOPS), which required them to navigate an experimenter-controlled online pharmacy to perform several naturalistic tasks (e.g., refill an existing prescription). Participants also completed the Medication-Management Test-Revised (MMT-R). Results: Mediation analyses revealed a significant indirect effect of education on both online pharmacy accuracy and MMT-R, which was fully mediated by health literacy. In contrast, there was no direct or indirect effect of education on online pharmacy speed when health literacy was included as a mediator. Conclusion: Health literacy plays an important role in the relationship between years of education attained and the ability of older PWH to successfully navigate online pharmacy tasks and manage their medications. Future studies might examine whether interventions to improve electronic health literacy among older PWH who have lower educational attainment have beneficial effects on online health behaviors.

Effects of comorbid posttraumatic stress disorder on cognitive dysfunction in Chinese male methamphetamine patients

OBJECTIVES

Cognitive dysfunction and posttraumatic stress disorder (PTSD) are common in methamphetamine patients. However, few studies have investigated the cognitive performance of methamphetamine patients with PTSD. The purpose of this study was to investigate the impact of comorbid PTSD on cognitive function in Chinese male methamphetamine patients.

METHODS

We analyzed 464 methamphetamine patients and 156 healthy volunteers. The PTSD Screening Scale (PCL-5) was used to assess PTSD and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to assess cognitive function.

RESULTS

Compared with healthy controls, methamphetamine patients had more cognitive dysfunction in immediate memory, visuospatial/constructional, language, attention and delayed memory. Moreover, methamphetamine patients with PTSD had less cognitive dysfunction in immediate memory, attention, and delayed memory than methamphetamine patients without PTSD. Further stepwise regression analysis showed that PTSD alterations in arousal and reactivity cluster were risk predictors for language, and PTSD negative alteration in cognition and mood cluster were risk predictors for delayed memory.

CONCLUSIONS

Our results indicate that methamphetamine patients without PTSD have poorer cognitive dysfunction than those with PTSD. Some demographic and PTSD symptom clusters are protective or risk factors for cognitive dysfunction in methamphetamine patients.

Exploring the Relationships Between Autozygosity, Educational Attainment, and Cognitive Ability in a Contemporary, Trans-Ancestral American Sample

Previous studies have found significant associations between estimated autozygosity - the proportion of an individual's genome contained in homozygous segments due to distant inbreeding - and multiple traits, including educational attainment (EA) and cognitive ability. In one study, estimated autozygosity showed a stronger association with parental EA than the subject's own EA. This was likely driven by parental EA's association with mobility: more educated parents tended to migrate further from their hometown, and because of the strong correlation between ancestry and geography in the Netherlands, these individuals chose partners farther from their ancestry and therefore more different from them genetically. We examined the associations between estimated autozygosity, cognitive ability, and parental EA in a contemporary sub-sample of adolescents from the Adolescent Brain Cognitive Development Study℠ (ABCD Study®) (analytic N = 6,504). We found a negative association between autozygosity and child cognitive ability consistent with previous studies, while the associations between autozygosity and parental EA were in the expected direction of effect (with greater levels of autozygosity being associated with lower EA) but the effect sizes were significantly weaker than those estimated in previous work. We also found a lower mean level of autozygosity in the ABCD sample compared to previous autozygosity studies, which may reflect overall decreasing levels of autozygosity over generations. Variation in spousal similarities in ancestral background in the ABCD study compared to other studies may explain the pattern of associations between estimated autozygosity, EA, and cognitive ability in the current study.

Combination of structural and functional connectivity explains unique variation in specific domains of cognitive function

The relationship between structural and functional brain networks has been characterised as complex: the two networks mirror each other and show mutual influence but they also diverge in their organisation. This work explored whether a combination of structural and functional connectivity can improve the fit of regression models of cognitive performance. Principal Component Analysis (PCA) was first applied to cognitive data from the Human Connectome Project to identify latent cognitive components: Executive Function, Self-regulation, Language, Encoding and Sequence Processing. A Principal Component Regression approach with embedded Step-Wise Regression (SWR-PCR) was then used to fit regression models of each cognitive domain based on structural (SC), functional (FC) or combined structural-functional (CC) connectivity. Executive Function was best explained by the CC model. Self-regulation was equally well explained by SC and FC. Language was equally well explained by CC and FC models. Encoding and Sequence Processing were best explained by SC. Evaluation of out-of-sample models' skill via cross-validation showed that SC, FC and CC produced generalisable models of Language performance. SC models performed most effectively at predicting Language performance in unseen sample. Executive Function was most effectively predicted by SC models, followed only by CC models. Self-regulation was only effectively predicted by CC models and Sequence Processing was only effectively predicted by FC models. The present study demonstrates that integrating structural and functional connectivity can help explaining cognitive performance, but that the added explanatory value (in sample) may be domain-specific and can come at the expense of reduced generalisation performance (out-of-sample).

Do your eye movements reveal your performance on an IQ test? A study linking eye movements and socio-demographic information to fluid intelligence

Understanding the main factors contributing to individual differences in fluid intelligence is one of the main challenges of psychology. A vast body of research has evolved from the theoretical framework put forward by Cattell, who developed the Culture-Fair IQ Test (CFT 20-R) to assess fluid intelligence. In this work, we extend and complement the current state of research by analysing the differential and combined relationship between eye-movement patterns and socio-demographic information and the ability of a participant to correctly solve a CFT item. Our work shows that a participant’s eye movements while solving a CFT item contain discriminative information and can be used to predict whether the participant will succeed in solving the test item. Moreover, the information related to eye movements complements the information provided by socio-demographic data when it comes to success prediction. In combination, both types of information yield a significantly higher predictive performance than each information type individually. To better understand the contributions of features related to eye movements and socio-demographic information to predict a participant’s success in solving a CFT item, we employ state-of-the-art explainability techniques and show that, along with socio-demographic variables, eye-movement data. Especially the number of saccades and the mean pupil diameter, significantly increase the discriminating power. The eye-movement features are likely indicative of processing efficiency and invested mental effort. Beyond the specific contribution to research on how eye movements can serve as a means to uncover mechanisms underlying cognitive processes, the findings presented in this work pave the way for further in-depth investigations of factors predicting individual differences in fluid intelligence.

The Precipitous Decline in Reasoning and Other Key Abilities with Age and Its Implications for Federal Judges

U. S. Supreme Court justices and other federal judges are, effectively, appointed for life, with no built-in check on their cognitive functioning as they approach old age. There is about a century of research on aging and intelligence that shows the vulnerability of processing speed, fluid reasoning, visual-spatial processing, and working memory to normal aging for men and women at all levels of education; even the maintained ability of crystallized knowledge declines in old age. The vulnerable abilities impact a person's decision-making and problem solving; crystallized knowledge, by contrast, measures a person's general knowledge. The aging-IQ data provide a rationale for assessing the key cognitive abilities of anyone who is appointed to the federal judiciary. Theories of multiple cognitive abilities and processes, most notably the Cattell-Horn-Carroll (CHC) model, provide a well-researched blueprint for interpreting the plethora of findings from studies of IQ and aging. Sophisticated technical advances in test construction, especially in item-response theory and computerized-adaptive testing, allow for the development of reliable and valid theory-based tests of cognitive functioning. Such assessments promise to be a potentially useful tool for evaluating federal judges to assess the impact of aging on their ability to perform at a level their positions deserve, perhaps to measure their competency to serve the public intelligently. It is proposed that public funding be made available to appoint a panel of experts to develop and validate an array of computerized cognitive tests to identify those justices who are at risk of cognitive impairment.

A Review of Working Memory Training in the Management of Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders among children. Working memory deficits underlie many of the behavioural symptoms of ADHD. Alongside psychostimulant medications, strategies to improve working memory may play an important adjuvant role in the management of ADHD. In this study, we review the role of working memory deficits in ADHD, the evidence surrounding working memory training strategies in the management of the condition, and the factors affecting the success of these strategies in alleviating ADHD symptoms. More specifically, we review several non-pharmacological interventions that target working memory deficits in ADHD, with special emphasis on cognitive working memory training. We conclude that the development of evidence-based interventions such as computerised cognitive training (CCT) could provide an alternative or adjunct to the use of psychostimulants, especially in cases where side effects are a major issue.

Triangulating multi-method assessments of parental support for early math skills

Past research has examined parental support for math during early childhood using parent-report surveys and observational measures of math talk. However, since most studies only present findings from one of these methods, the construct (parental support for early math) and the method are inextricably linked, and we know little about whether these methods provide similar or unique information about children's exposure to math concepts. This study directly addresses the mono-operation bias operating in past research by collecting and comparing multiple measures of support for number and spatial skills, including math talk during semi-structured observations of parent-child interactions, parent reports on a home math activities questionnaire, and time diaries. Findings from 128 parents of 4-year-old children reveal substantial within-measure variability across all three data sources in the frequency of number and spatial activities and the type and content of parent talk about number and spatial concepts. Convergence in parental math support measures was evident among parent reports from the questionnaire and time diaries, such that scale composites about monthly number activities were related to number activities on the previous work day, and monthly spatial activities were correlated with spatial activities the prior non-work days. However, few parent report measures from the survey or time diary were significantly correlated with observed quantity or type of math talk in the semi-structured observations. Future research implications of these findings are discussed.

Neurotrophins as a reliable biomarker for brain function, structure and cognition: A systematic review and meta-analysis

Neurotrophins are signalling molecules involved in the formation and maintenance of synapses in the brain. They can cross the blood-brain barrier and be detected in peripheral blood, suggesting they may be a potential biomarker for brain health and function. In this review, the available literature was systematically searched for studies comparing peripheral neurotrophins levels with MRI and cognitive measures in healthy adults. Twenty-four studies were identified, six of which included a neuroimaging outcome. Fifteen studies measuring cognition were eligible for meta-analysis. The majority of studies measured levels of brain-derived neurotrophic factor (BDNF), with few assessing other neurotrophins. Results revealed BDNF is related to some neuroimaging outcomes, with some studies suggesting older age may be an important factor. A higher proportion of studies who had older samples observed significant effects between cognition and neurotrophin levels. When cognitive studies were pooled together in a meta-analysis, there was a weak non-significant effect between BDNF and cognitive outcomes. There was also a high level of heterogeneity between cognitive studies. Results indicated that gender was a notable source of the heterogeneity, but additional studies employing relevant covariates are necessary to better characterise the inter-relationship between circulating neurotrophins and cognition.

The Shared Genetic Basis of Educational Attainment and Cerebral Cortical Morphology

Individual differences in educational attainment are linked to differences in intelligence, and predict important social, economic, and health outcomes. Previous studies have found common genetic factors that influence educational achievement, cognitive performance and total brain volume (i.e., brain size). Here, in a large sample of participants from the UK Biobank, we investigate the shared genetic basis between educational attainment and fine-grained cerebral cortical morphological features, and associate this genetic variation with a related aspect of cognitive ability. Importantly, we execute novel statistical methods that enable high-dimensional genetic correlation analysis, and compute high-resolution surface maps for the genetic correlations between educational attainment and vertex-wise morphological measurements. We conduct secondary analyses, using the UK Biobank verbal-numerical reasoning score, to confirm that variation in educational attainment that is genetically correlated with cortical morphology is related to differences in cognitive performance. Our analyses relate the genetic overlap between cognitive ability and cortical thickness measurements to bilateral primary motor cortex as well as predominantly left superior temporal cortex and proximal regions. These findings extend our understanding of the neurobiology that connects genetic variation to individual differences in educational attainment and cognitive performance.

Men and women differ in the neural basis of handwriting

There is an ongoing debate about whether, and to what extent, males differ from females in their language skills. In the case of handwriting, a composite language skill involving language and motor processes, behavioral observations consistently show robust sex differences but the mechanisms underlying the effect are unclear. Using functional magnetic resonance imaging (fMRI) in a copying task, the present study examined the neural basis of sex differences in handwriting in 53 healthy adults (ages 19–28, 27 males). Compared to females, males showed increased activation in the left posterior middle frontal gyrus (Exner's area), a region thought to support the conversion between orthographic and graphomotor codes. Functional connectivity between Exner's area and the right cerebellum was greater in males than in females. Furthermore, sex differences in brain activity related to handwriting were independent of language material. This study identifies a novel neural signature of sex differences in a hallmark of human behavior, and highlights the importance of considering sex as a factor in scientific research and clinical applications involving handwriting.

Sex Hormones as Cognitive Enhancers?

Understanding the differences in the way women and men think has made headway thanks to experiments showing how sex hormones influence cognitive capacities. Masculine and feminine sex hormones (androgens and estrogens, respectively) affect cognition in different ways and may account for some of the gender differences in cognitive abilities, allowing men and women to perform better in certain cognitive tests. In this opinion article, we discuss studies addressing differences in cognitive functions between males and females and the underlying neural substrates, as well as the effects of sex hormone supplementation. Even though some studies on patients receiving exogenous sex hormones showed gender differences that emerge at group levels on a few cognitive tasks, it is not yet clear whether these differences can be partially attributed to hormonal causes. Supplementation of female estrogen can enhance verbal skills, whereas masculine androgen can increase performance in mathematical and visuospatial tasks. Studies of the administration of exogenous sex hormones have allowed further insight into the use of sex hormones as possible cognitive enhancers.

Linear and nonlinear relationships between cognitive subdomains of ability discrepancy and Alzheimer's disease biomarkers

OBJECTIVE

Substantial research indicates that fluid and crystallized abilities are highly correlated throughout the adult life span. However, recent proposals suggest that a large discrepancy between these two abilities, defined as crystallized performance minus fluid performance, indicates heightened risk for Alzheimer's disease (AD).

METHOD

In 266 cognitively healthy older adults, the present study tested linear and quadratic relationships between an ability discrepancy score and early AD neuropathology indexed via in vivo measures of beta-amyloid deposition and cortical thickness in AD-vulnerable regions. We also tested the extent that alternative forms of this ability discrepancy measure (e.g., subdomain discrepancies, verbal-visual discrepancies) and an episodic memory composite might also be sensitive markers of early AD pathology.

RESULTS

An overall ability discrepancy was linearly and positively correlated with beta- amyloid. A quadratic relationship was found between the overall ability discrepancy score and cortical thickness such that a small positive correlation was found at lower discrepancy levels (fluid > crystallized), but at higher discrepancy levels (crystallized > fluid) a negative relationship was found (i.e., an inverted-U pattern). Similar patterns were found across each subdomain of cognition, but the effects were weaker than the overall ability discrepancy score. Importantly, inclusion of episodic memory (the gold standard) did not alter any of the effects, suggesting that an ability discrepancy confers unique predictiveness of AD biomarkers.

CONCLUSIONS

These findings replicate previous findings and increase the confidence in their usefulness to predict AD biomarkers. Longitudinal validation is needed to clearly relate an ability discrepancy to specific stages of preclinical AD. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Cognitive Reserve Capacity: Exploring and Validating a Theoretical Model in Healthy Ageing

OBJECTIVE

Cognitive reserve (CR) capacity can be viewed as the maximum processing potential of neural systems that support adaptive cognitive performance in age-related cognitive decline. CR is a complex construct that can only be measured indirectly. Proxy measures (e.g., psychosocial/lifestyle variables) are traditionally used to reflect CR. However, strong relationships have been observed between these measures and cognitive functions (e.g., executive function [EF], processing resources [PR], fluid/crystallized abilities); therefore, the organizational structure of indicators implicated in CR remains unclear. The objective of this study was to test a hypothetical, theoretical model of CR capacity that includes both traditional CR proxy indicators and measures of cognitive function [Satz et al. (2011). Journal of Clinical and Experimental Neuropsychology, 33(1), 121-130], which remain, as yet, untested.

METHOD

Construct validity of the model was investigated in healthy older adults through exploratory and confirmatory factor analysis (EFA and CFA) using data from the Maastricht Ageing Study (MAAS). A secondary CFA was conducted to validate the model using data from the Irish Longitudinal Study on Ageing (TILDA).

RESULTS

EFA and CFA in MAAS established a two-factor model comprising EF/PR and cumulative cognitive enrichment (CCE), which was further validated in a secondary analysis in TILDA. Convergent and discriminant validity was supported in MAAS (range of R2 = .228-.635; factor correlation confidence interval (CI) = .622, .740) and TILDA (range of R2 = .172-.899; factor correlation CI = .559, .624).

CONCLUSIONS

A dual model of CR elucidated the relationships between hypothesized indicators of CR capacity and revealed a two-factor structure suggesting that both control (EF/PR) and representational processes (CCE) are involved in CR capacity.

Socio-affective and cognitive predictors of social adaptation in vulnerable contexts

People living in vulnerable environments face a harder set of challenges adapting to their context. Nevertheless, an important number of them adapt successfully. However, which cognitive and socio-affective variables are specifically related to these variations in social adaptation in vulnerable contexts has not been fully understood nor directly addressed. Here we evaluated socio-affective variables (anxious attachment style, internal locus of control, self-esteem and stress) and cognitive variables (fluid intelligence, crystallized intelligence, working memory, numeracy, probabilistic reasoning and logical reasoning) to explain variations in social adaptation in a sample of 232 adults living in vulnerable contexts (M = 42.3, SD = 14.9, equal amount of men and women). Our results show that an important amount of variance in social adaptation can be explained by socio-affective variables, principally by self-esteem, while cognitive variables also contributed significantly. As far as we know, this is one of the first steps towards understanding the role of cognitive and socio-affective features on social adaptation. In the long run, this area of research could play an important role on the assignation of resources to ease people's integration into society. Our data and R analysis scripts can be found at: https://osf.io/egxy5/.

Ability emotional intelligence in young people and older adults with and without depressive symptoms, considering gender and educational level

Background

There is little research on differences in Emotional Intelligence (EI) ability at different stages of adult development. The few published studies tend not to use older adult samples. Previous studies on EI ability and age have shown contradictory results. Our main objective was to evaluate results in EI ability across different stages of adult development, taking into account gender, depressive symptoms, and educational level.

Methods

We interviewed 166 participants (108 women), 66 of whom were aged 18–30 years, 53 aged 31–60 years, and 40 aged 61–76 years. All were either working or enrolled in colleges at the time of the study. The assessment tools used were the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT), a test that assesses performance-based EI, and the Centre for Epidemiologic Studies-Depression (CES-D) scale, a tool to evaluate depressive symptoms.

Results

Young people, women, and participants with a higher educational level achieved higher scores on the MSCEIT. Additionally, depressive symptomatology was only partially associated with the MSCEIT (i.e., with the using emotions branch). However, a subsequent joint analysis of the independent effects of variables age, gender, educational level, and depressive symptomatology and their interactions on MSCEIT total suggests that only educational level and depressive symptomatology were associated with EI ability, with the direct relationship between age and gender with MSCEIT disappearing. Additionally, our study indicated an interaction effect between age and depressive symptoms, showing that participants in age cohorts 18–30 and 31–60 and without depressive symptoms have a higher EI ability.

Discussion

Our study suggests that the direct effects of age and gender on EI ability across adult development, using a wide age range, can change or disappear when effects of educational level and depressive symptomatology, and their interactions, are controlled for. Our results also suggest that EI ability is a protective factor against depression in some age cohorts. This novel aspect of our study does not appear in the previous literature. However, prospective studies are needed to verify these findings and examine whether other psychological variables could determine the relations between age, gender and EI ability across adult development.

Intellectual disability and mental disorders in a US population representative sample of adolescents

BACKGROUND

Most research on the prevalence, distribution, and psychiatric comorbidity of intellectual disability (ID) relies on clinical samples, limiting the generalizability and utility of ID assessment in a legal context. This study assessed ID prevalence in a population-representative sample of US adolescents and examined associations of ID with socio-demographic factors and mental disorders.

METHODS

Data were drawn from the National Comorbidity Survey Adolescent Supplement (N = 6256). ID was defined as: (1) IQ ⩽ 76, measured using the Kaufman Brief Intelligence Test; (2) an adaptive behavior score ⩽76, and (3) age of onset ⩽18 measured using a validated scale. The Composite International Diagnostic Interview assessed 15 lifetime mental disorders. The Sheehan disability scale assessed disorder severity. We used logistic regression models to estimate differences in lifetime disorders for adolescents with and without ID.

RESULTS

ID prevalence was 3.2%. Among adolescents with ID, 65.1% met lifetime criteria for a mental disorder. ID status was associated with specific phobia, agoraphobia, and bipolar disorder, but not behavior disorders after adjustment for socio-demographics. Adolescents with ID and mental disorders were significantly more likely to exhibit severe impairment than those without ID.

CONCLUSIONS

These findings highlight how sample selection and overlap between ID and psychopathology symptoms might bias understanding of the mental health consequences of ID. For example, associations between ID and behavior disorders widely reported in clinical samples were not observed in a population-representative sample after adjustment for socio-demographic confounders. Valid assessment and understanding of these constructs may prove influential in the legal system by influencing treatment referrals and capital punishment decisions.General Scientific SummaryCurrent definitions of intellectual disability (ID) are based on three criteria: formal designation of low intelligence through artificial problem-solving tasks, impairment in one's ability to function in his/her social environment, and early age of onset. In a national population sample of adolescents, the majority of those with ID met criteria for a lifetime mental disorder. Phobias and bipolar disorder, but not behavior disorders, were elevated in adolescents with ID. Findings highlight the need to consider how behavioral problems are conceptualized and classified in people with ID.

Fluid reasoning and reading difficulties among children with ADHD

Background: Children with attention-deficit/hyperactivity disorder (ADHD) commonly experience difficulties in reading and in fluid reasoning (Gf). According to Cattell's Investment Theory (1987), Gf is a causal factor in the development of crystallized knowledge (Gc) and academic skills; therefore, the co-occurrence of reading and Gf difficulties within ADHD may not be coincidental. Methods: In the present study with children with both ADHD and reading difficulties (n = 187; 61% male; M_age = 9.2), we utilized mediation analyses to test direct and indirect (through Gc, phonemic awareness, and rapid automatized naming [RAN]) effects of Gf on four basic reading skills: untimed word recognition, untimed phonemic decoding, word reading efficiency, and phonemic decoding efficiency. Results: The direct effect of Gf on all reading skills was nonsignificant; however, significant indirect effects were observed. Specifically, Gf exerted an effect indirectly onto all reading skills through a serial and joint mechanism comprised of Gc and phonemic awareness (i.e., Gf → Gc → phonemic awareness → reading achievement). Gf also exerted an effect indirectly onto untimed word recognition and phonemic decoding through phonemic awareness (i.e., Gf → phonemic awareness → untimed word recognition/untimed phonemic decoding). Conclusion: Results build upon Cattell's Investment Theory by linking Gf with reading difficulties among children with ADHD, suggesting that such difficulties may arise from weaknesses in Gf and insufficient investment of Gf into reading through Gc and phonemic awareness.

Discrepancies between crystallized and fluid ability are associated with frequency of social and physical engagement in community dwelling older adults

OBJECTIVE

Age differences have been noted in the discrepancies between crystallized and fluid ability (Gc-Gf). Larger Gc-Gf discrepancies have also been shown to be associated with Alzheimer's disease biomarkers and clinical severity. However, little is known regarding the relationship between Gc-Gf discrepancies in normal aging and functional outcomes. The aim of the present study was to examine this.

METHOD

Data from 104 adults (M_age = 71.70 years, SD = 9.016) were included in the present study. Measures from the NIH toolbox were used to form the discrepancy scores. Physical, cognitive, and social activities were identified using the Community Healthy Activities Model Program for Seniors activity questionnaire. Linear regression analyses, controlling for age, education, gender, health, and depressive symptoms, were used to examine the association between social, cognitive, and physical activities on Gc-Gf discrepancies.

RESULTS

Results showed that social and physical activity were significantly associated with greater discrepancies between crystallized and fluid ability, independent of covariates. There was no association between cognitive activity and Gc-Gf discrepancies.

CONCLUSIONS

Larger discrepancies between crystallized and fluid ability are related to frequency of social and physical activity. The findings support previous research that discrepancy scores may serve as a marker of cognitive decline. In more highly educated older individuals, Gc-Gf discrepancies may be a more accurate indicator of actual cognitive status.

Impact of IQ on the diagnostic yield of chromosomal microarray in a community sample of adults with schizophrenia

Background

Schizophrenia is a severe psychiatric disorder associated with IQ deficits. Rare copy number variations (CNVs) have been established to play an important role in the etiology of schizophrenia. Several of the large rare CNVs associated with schizophrenia have been shown to negatively affect IQ in population-based controls where no major neuropsychiatric disorder is reported. The aim of this study was to examine the diagnostic yield of microarray testing and the functional impact of genome-wide rare CNVs in a community ascertained cohort of adults with schizophrenia and low (< 85) or average (≥ 85) IQ.

Methods

We recruited 546 adults of European ancestry with schizophrenia from six community psychiatric clinics in Canada. Each individual was assigned to the low or average IQ group based on standardized tests and/or educational attainment. We used rigorous methods to detect genome-wide rare CNVs from high-resolution microarray data. We compared the burden of rare CNVs classified as pathogenic or as a variant of unknown significance (VUS) between each of the IQ groups and the genome-wide burden and functional impact of rare CNVs after excluding individuals with a pathogenic CNV.

Results

There were 39/546 (7.1%; 95% confidence interval [CI] = 5.2–9.7%) schizophrenia participants with at least one pathogenic CNV detected, significantly more of whom were from the low IQ group (odds ratio [OR] = 5.01 [2.28–11.03], p = 0.0001). Secondary analyses revealed that individuals with schizophrenia and average IQ had the lowest yield of pathogenic CNVs (n = 9/325; 2.8%), followed by those with borderline intellectual functioning (n = 9/130; 6.9%), non-verbal learning disability (n = 6/29; 20.7%), and co-morbid intellectual disability (n = 15/62; 24.2%). There was no significant difference in the burden of rare CNVs classified as a VUS between any of the IQ subgroups. There was a significantly (p=0.002) increased burden of rare genic duplications in individuals with schizophrenia and low IQ that persisted after excluding individuals with a pathogenic CNV.

Conclusions

Using high-resolution microarrays we were able to demonstrate for the first time that the burden of pathogenic CNVs in schizophrenia differs significantly between IQ subgroups. The results of this study have implications for clinical practice and may help inform future rare variant studies of schizophrenia using next-generation sequencing technologies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-017-0488-z) contains supplementary material, which is available to authorized users.

Cognitive ability influences on written expression: Evidence for developmental and sex-based differences in school-age children

Some studies have demonstrated that the Cattell-Horn-Carroll (CHC) cognitive abilities influence writing; however, little research has investigated whether CHC cognitive abilities influence writing the same way for males and females across grades. We used multiple group structural equation models to investigate whether CHC cognitive ability influences on written expression differed between grades or sex using the Kaufman Assessment Battery for Children, Second Edition and the Kaufman Tests of Educational Achievement, Second Edition co-normed standardization sample data (N=2117). After testing for consistent measurement of cognitive abilities across grades and sex, we tested whether the cognitive ability influences on written expression were moderated by grade level or sex. An important developmental shift was observed equally across sex groups: Learning Efficiency (Gl) influences decreased whereas Crystallized Ability (Gc) influences increased after fourth grade. Further, Short-Term Memory (Gsm) and Retrieval Fluency (Gr) influences on written expression depended on sex at grades 1-4, with larger Gr influences for females and larger Gsm influences for males. We internally replicated our main findings using two different cognitive explanatory models, adding further support for the developmental and sex-based differential cognitive ability influences on writing. Explanatory cognitive models of writing need to incorporate development, and possibly, sex to provide an expanded understanding of writing development and guard against potential generalizability issues characteristic of special population (i.e., male-female) studies.

Does higher education hone cognitive functioning and learning efficacy? Findings from a large and diverse sample

Attending school is a multifaceted experience. Students are not only exposed to new knowledge but are also immersed in a structured environment in which they need to respond flexibly in accordance with changing task goals, keep relevant information in mind, and constantly tackle novel problems. To quantify the cumulative effect of this experience, we examined retrospectively and prospectively, the relationships between educational attainment and both cognitive performance and learning. We analyzed data from 196,388 subscribers to an online cognitive training program. These subscribers, ages 15–60, had completed eight behavioral assessments of executive functioning and reasoning at least once. Controlling for multiple demographic and engagement variables, we found that higher levels of education predicted better performance across the full age range, and modulated performance in some cognitive domains more than others (e.g., reasoning vs. processing speed). Differences were moderate for Bachelor’s degree vs. High School (d = 0.51), and large between Ph.D. vs. Some High School (d = 0.80). Further, the ages of peak cognitive performance for each educational category closely followed the typical range of ages at graduation. This result is consistent with a cumulative effect of recent educational experiences, as well as a decrement in performance as completion of schooling becomes more distant. To begin to characterize the directionality of the relationship between educational attainment and cognitive performance, we conducted a prospective longitudinal analysis. For a subset of 69,202 subscribers who had completed 100 days of cognitive training, we tested whether the degree of novel learning was associated with their level of education. Higher educational attainment predicted bigger gains, but the differences were small (d = 0.04–0.37). Altogether, these results point to the long-lasting trace of an effect of prior cognitive challenges but suggest that new learning opportunities can reduce performance gaps related to one’s educational history.

Biological Gender Differences in Students’ Errors on Mathematics Achievement Tests

This study investigated developmental gender differences in mathematics achievement, using the child and adolescent portion (ages 6-19 years) of the Kaufman Test of Educational Achievement–Third Edition (KTEA-3). Participants were divided into two age categories: 6 to 11 and 12 to 19. Error categories within the Math Concepts & Applications and Math Computation subtests of the KTEA-3 were factor analyzed and revealed five error factors. Multiple ANOVA of the error factor scores showed that, across both age categories, female and male mean scores were not significantly different across four error factors: math calculation, geometric concepts, basic math concepts, and addition. They were significantly different on the complex math problems error factor, with males performing better at the p < .05 significance level for the 6 to 11 age group and at the p < .001 significance level for the 12 to 19 age group. Implications in light of gender stereotype threat are discussed.

Measuring intellectual ability in cerebral palsy: The comparison of three tests and their neuroimaging correlates

Standard intelligence scales require both verbal and manipulative responses, making it difficult to use in cerebral palsy and leading to underestimate their actual performance. This study aims to compare three intelligence tests suitable for the heterogeneity of cerebral palsy in order to identify which one(s) could be more appropriate to use. Forty-four subjects with bilateral dyskinetic cerebral palsy (26 male, mean age 23 years) conducted the Raven's Coloured Progressive Matrices (RCPM), the Peabody Picture Vocabulary Test-3rd (PPVT-III) and the Wechsler Nonverbal Scale of Ability (WNV). Furthermore, a comprehensive neuropsychological battery and magnetic resonance imaging were assessed. The results show that PPVT-III gives limited information on cognitive performance and brain correlates, getting lower intelligence quotient scores. The WNV provides similar outcomes as RCPM, but cases with severe motor impairment were unable to perform it. Finally, the RCPM gives more comprehensive information on cognitive performance, comprising not only visual but also verbal functions. It is also sensitive to the structural state of the brain, being related to basal ganglia, thalamus and white matter areas such as superior longitudinal fasciculus. So, the RCPM may be considered a standardized easy-to-administer tool with great potential in both clinical and research fields of bilateral cerebral palsy.

Educational attainment influences levels of homozygosity through migration and assortative mating

Individuals with a higher education are more likely to migrate, increasing the chance of meeting a spouse with a different ancestral background. In this context, the presence of strong educational assortment can result in greater ancestry differences within more educated spouse pairs, while less educated individuals are more likely to mate with someone with whom they share more ancestry. We examined the association between educational attainment and F_roh (= the proportion of the genome consisting of runs of homozygosity [ROHs]) in ~2,000 subjects of Dutch ancestry. The subjects’ own educational attainment showed a nominally significant negative association with F_roh (p = .045), while the contribution of parental education to offspring F_roh was highly significant (father: p < 10^-5; mother: p = 9×10^-5), with more educated parents having offspring with fewer ROHs. This association was significantly and fully mediated by the physical distance between parental birthplaces (paternal education: p_mediation = 2.4 × 10^-4; maternal education: p_mediation = 2.3 × 10^-4), which itself was also significantly associated with F_roh (p = 9 × 10^-5). Ancestry-informative principal components from the offspring showed a significantly decreasing association with geography as parental education increased, consistent with the significantly higher migration rates among more educated parents. Parental education also showed a high spouse correlation (Spearman’s ρ = .66, p = 3 × 10^-262). We show that less educated parents are less likely to mate with the more mobile parents with a higher education, creating systematic differences in homozygosity due to ancestry differences not directly captured by ancestry-informative principal components (PCs). Understanding how behaviors influence the genomic structure of a population is highly valuable for studies on the genetic etiology of behavioral, cognitive, and social traits.

Neuropsychological Profiles of Written Expression Learning Disabilities Determined by Concordance-Discordance Model Criteria

Children with specific learning disabilities (SLD) have disparate neuropsychological processing deficits that interfere with academic achievement in spelling, writing fluency, and/or written expression (WE). Although there are multiple potential causes of WE SLD, there is a paucity of research exploring this critical academic skill from a neuropsychological perspective. This study examined the neuropsychological profiles of WE SLD subtypes defined using the concordance-discordance model (C-DM) of SLD identification. Participants were drawn from a sample of 283 children (194 boys, 89 girls) aged 6 years to 16 years old (M(age) = 9.58 years, SD = 2.29 years) referred for comprehensive neuropsychological evaluations in school settings and subsequently selected based on C-DM determined spelling, writing fluency, and WE SLD. WE SLD subtypes differed on several psychomotor, memory, and executive function measures (F range = 2.48-5.07, p range = .049 to <.001), suggesting that these children exhibit distinct patterns of neuropsychological processing strengths and weaknesses. Findings have relevance for differential diagnosis of WE subtypes, discriminating WE SLD subtypes from low WE achievement, and developing differentiated evidence-based instruction and intervention for children with WE SLD. Limitations and future research will be addressed.

How representative is the ACTIVE sample? A statistical comparison of the ACTIVE sample and the HRS sample

OBJECTIVE

This research is designed to examine demographic differences between the ACTIVE sample and the larger, nationally representative Health and Retirement Study (HRS) sample.

METHOD

After describing some relevant demographics (age, education, sex, and race/ethnicity), we use three statistical methods to determine sample differences--logistic regression modeling (LRM), decision tree analysis (DTA), and post-stratification and raking methods. When some differences are found, we create sample weights that other researchers can use to adjust these differences.

RESULTS

The ACTIVE sample is younger, more likely to be female, Black, and more highly educated than the HRS sample. Sample weights were created.

DISCUSSION

By using the resulting sample weights, all results of ACTIVE analyses can be said to be nationally representative based on HRS demographics.

The Brief Repeatable Battery: psychometrics and normative values with age, education and gender corrections in a Serbian population

Cognitive impairment is present in up to 65 % of multiple sclerosis (MS) patients. The Brief Repeatable Battery of neuropsychological tests (BRB) is one of the most used neuropsychological tools for cognitive assessment in MS. However, relative lack of normative data limits its application in research and clinical practice. In order to obtain normative data for a Serbian population, we administered the BRB version A to 140 healthy subjects and assessed the influence of demographic factors such as gender, age, and education on the tests' scores. We also calculated corrections for these factors. Higher education was associated with better performance on all the tests. Age influenced all the tests, except the word list generation, higher age being associated with worse performance on all other tests. Women performed worse on the paced auditory serial addition test 2, no other gender differences were observed. Our data obtained for the Serbian population could further improve use of the BRB in clinical practice and for the research purposes, establishing cognitive evaluation as a part of standard neurological examination of MS patients.

Childhood intelligence and brain white matter hyperintensities predict fluid intelligence age 78-81 years: a 1921 Aberdeen birth cohort study

OBJECTIVES

to evaluate the role of childhood intelligence and white matter hyperintensities (WMH) in the prediction of the trajectory of fluid intelligence in healthy old people from age 78 to 81.

DESIGN

observational follow-up study from 1999 to 2002.

SETTING

a university teaching hospital in Aberdeen, UK.

PARTICIPANTS

a total of 106 volunteers born in 1921, with childhood intelligence records at 11, recruited 1997-98 to a follow-up study.

MEASUREMENTS

participants underwent brain MRI in 1999-2000, to obtain measurements of brain WMH using Scheltens' scale and a test of fluid intelligence (Raven's Progressive Matrices) on three occasions between 1999 and 2002.

RESULTS

in a latent growth model, we found a significant association between childhood intelligence and the intercept, but not the slope, of fluid cognitive ability in late adulthood. Similarly, baseline WMH score was associated with the intercept of late life cognitive ability, but not the slope. Age at imaging was associated with slope but not intercept. There was no significant association between sex and intercept or slope of late life cognitive ability.

CONCLUSIONS

results suggest that brain MRI measures of WMH (attributed to cerebrovascular disease) and childhood intelligence significantly contribute to late life fluid cognitive ability but not to the trajectory of age-related change in fluid intelligence. We also show that age is associated with the cognitive trajectory from 78 to 81 years, even within our narrow age range sample. This may be a consequence of the recruitment pattern, with those having greater WMH burden, and who subsequently declined, being recruited later in the study.

Investigating health-related quality of life, mood and neuropsychological test performance in a homogeneous cohort of Irish female hepatitis C patients

Neurocognitive dysfunction has been reported in individuals with chronic hepatitis C (CHC) infection, but HCV populations investigated have often included participants with numerous potential confounding comorbidities. This pilot study sought to investigate functional capacity and neurocognitive function in a homogeneous state-infected HCV population with histologically defined mild liver disease, free from the comorbid factors typically associated with HCV populations. A further aim was to examine cognitive function in a treatment naive population with a similar history of iatrogenic HCV exposure and spontaneous viral clearance. A convenience sample of 29 women, all of whom were carefully screened to exclude relevant comorbidities, was recruited to the study. Twenty women with a history of iatrogenic HCV exposure were recruited from prospective specialist tertiary care liver clinics. A comparison group of healthy controls (n = 9) was also assessed. Study participants underwent mood, health-related quality of life and neuropsychological assessment. CHC patients reported significantly higher levels of cognitive fatigue than healthy controls (F = 3.4, P = 0.04). On cognitive testing, CHC patients showed impairments compared with healthy controls on estimates of general memory [F(2,25) = 4.1, P = 0.03, partial eta squared = 0.25], delayed auditory recognition [F(2,25) = 4.2, P = 0.03, partial eta squared= 0.22] and sustained attention [F(2,25) = 3.6, P = 0.04, partial eta squared = 0.22]. Increased cognitive fatigue only correlated with delayed auditory memory recall ability (r = 0.724, P = 0.006). In conclusion, these findings appear to support the presence of neurocognitive abnormalities in an iatrogenically infected, homogeneous female HCV population who were carefully screened to eliminate other factors affecting neurocognitive test performance and may indicate underlying neurophysiological causative mechanisms.