Dimensions Of Cognitive Function Research Articles

A change in social participation affects cognitive function in middle-aged and older Chinese adults: analysis of a Chinese longitudinal study on aging (2011-2018).

One of the biggest challenges facing older adults is cognitive decline and social participation has always been considered a protective factor. However, it is not clear whether social participation predicts cognitive function in this population, rather than depressive symptoms, self-reported health, and activities of daily life, with sufficient capacity to detect unique effects. This study included adults aged 45 and above in China (N = 5,258) who participated in a large national older adult health survey and provided data from 2011, 2013, 2015, and 2018. The unique associations between the predictors of social participation and cognitive function over time and context were evaluated in the Latent Growth Model (LGM). Among the 5,258 participants in our study, an overall cognitive decline was observed. Social participation predicts two dimensions of cognitive function, with a degree of impact comparable to depressive symptoms, self-reported health, and activities of daily life. Among them, social participation exhibits a noteworthy prognostic impact on episodic memory during the same period. The regression coefficient is approximately 0.1 (p < 0.05) after controlling other mixed variables (depressive symptoms, self-reported health, and activities of daily life). In contrast, social participation is also a significant predictor of mental intactness in the same period, with a regression coefficient of 0.06 (p < 0.05), even if all mixed variables are controlled. Over time, the correlation strength of social participation is comparable to other recognized cognitive function prediction indicators, indicating that promoting social participation among middle-aged and older Chinese adults is a meaningful way to improve cognitive function degradation, which has important policy and practical significance.

Relationship Between Hearing Loss and Cognitive Function in Elderly Chinese People: A Study Based on Propensity Score Matching

To explore the relationship between hearing loss and cognitive function in the elderly population through propensity score matching method. We analyzed the data of 7605 participants aged 60 and above who were included in the 2018 China Health and Retirement Longitudinal Study (CHARLS). The non-substitutable 1∶1 nearest neighbor matching method without caliper value was used for propensity score matching and G-computation was used to estimate the average treatment effect (ATE) of hearing loss on all dimensions of cognitive function. Before matching, there were 3626 (47.68%) women, with 1409 (18.53%) of whom suffering from hearing loss and 3031 (39.86%) of whom suffering from cognitive impairment. After matching, 1409 subjects were included in the hearing loss group and 1409, in the normal hearing group, with both groups sharing similar distribution of basic demographic characteristics. The results for the average treatment effect of the population indicated that the cognitive function scores of the hearing loss group were lower than those of the normal hearing group, with the overall cognitive function being 0.593 points lower (95% confidence intervel [CI]: －0.916-－0.257, P<0.001), orientation being 0.183 points lower (95% CI: －0.302-－0.055, P=0.004), immediate memory being 0.150 points lower (95% CI: －0.218-－0.085, P<0.001), and language skills being 0.178 points lower (95% CI: －0.303-－0.058, P=0.006). The prevalence of cognitive impairment of the hearing loss group was 4.2% higher than that of the normal hearing group (95% CI: 0.007-0.077, P=0.020). Hearing loss adversely affects the orientation, memory, and language skills of the elderly population and forms a potential risk factor for cognitive impairment in the elderly population.

Resting state EEG complexity as a predictor of cognitive performance

Sustained spontaneous activity in the resting state brain represents the intrinsic state of the brain during most cognitive tasks. Electroencephalogram (EEG) measures of the resting state have shown potential as biomarkers for the evaluation of cognitive performance, but there is a lack of validation across health and different diseased populations. This study aims to decode cognitive function from resting-state EEG activity, and demonstrates that nonlinear dynamic features of EEG signals can be used to predict cognitive performance in healthy young adults, elderly adults with mild cognitive impairment (MCI), and patients with major depressive disorder (MDD) using the extreme gradient boosting (XGBoost) prediction model. In particular, the results showed that performance in cognitive task can be predicted by the resting-state EEG-based measures in these three populations (correlation coefficients between predicted values and observed true values were: r=0.39, p < 0.01; r=0.76, p < 0.001; and r=0.40, p < 0.001; respectively). Furthermore, we observed a U-shaped or inverted U-shaped distribution of multiscale fuzzy entropy index (MFEI) in healthy, aging and diseased populations, which symbolizes the law of complexity and health. The results suggest that the dynamic complexity of resting state EEG oscillations can predict certain dimensions of cognitive function in both health and mental illness, and highlights the nonlinear relationship between neurological measures and cognitive health status. These findings may provide insights into the development of treatments to improve cognition.

Workplace learning and development of people with limited work capacity

AbstractWorkplace learning and development is crucial for sustained employability, especially for people with limited work capacity (LWC). We explored the development in cognitive functioning and work behaviour of people with LWC and to which extent this is moderated by workplace acceptance and support. As suggested in literature, acceptance and support concern pre‐conditions for development. Therefore, we expected them to influence the development of our target group. In total, 182 people with LWC and 172 workplace mentors provided data on dimensions of cognitive functioning and work behaviour on three time‐points over 4 months. Furthermore, people with LWC provided data on workplace acceptance and support.Results showed significant development over time for both, self‐ and observer‐rated cognitive functioning, such as planning and organising, learning and memory, problem solving, and for self‐rated adaptability and concentration. Development over time emerged for the self‐rated work pace, a work behaviour dimension. Moreover, the growth curves on self‐rated variables such as learning and memory, work accuracy, social behaviour and work pace were moderated by workplace acceptance and support. This study provides initial insight into growth patterns of cognitive functioning and work behaviour of people with LWC and illustrates the relevance of a supportive climate for development.

Cognitive Impairment Mediates the Association between Dietary Inflammation and Depressive Symptoms in the Elderly

The underlying mechanism in both cognitive impairment and depression was chronic inflammation, which could be reflected by the dietary inflammatory index (DII). However, the effect of cognitive impairment on the association between DII and depression was not clear. Therefore, in this study, we hypothesized that cognitive impairment could mediate the association between dietary inflammation and depressive symptoms. A total of 2550 participants aged ≥60 from the National Health and Nutrition Examination Survey (NHANES) in 2011-2014 were involved in the serial, cross-sectional study. Proinflammatory and anti-inflammatory diets were measured by DII. Cognitive impairment was measured by four dimensions, CERAD-immediate, CERAN-delayed, animal fluency test, and DSST. Depressive symptoms were measured by PHQ-9 scores. We found that a proinflammatory diet and cognitive impairment were both risk factors for depressive symptoms. An interaction between an inflammatory diet and cognitive impairment was detected (P-interaction = 0.060). In addition, all four dimensions of cognition mediated the association between DII and depressive symptom scores. Part of the association between DII and depressive symptoms scores could be explained by different dimensions of cognitive function, and the proportion of mediation ranged from 10.0% to 36.7%. In conclusion, cognitive impairment levels partly mediated the association between DII and depressive symptoms.

Correlating Ocular Physiology and Visual Function with Mild Cognitive Loss in Senior Citizens in Taiwan.

Purpose: The transition of Taiwan from an aging to a super-aging society has come with a cost as more elderly now suffer from cognitive impairment. The main purpose of our study was to investigate if early detection can be developed so that timely intervention can be instituted. We analyzed the correlation of cognitive function with ocular physiology and visual functions between senior citizens aged 60 years or older in Taiwan. Methods: Thirty-six healthy subjects were recruited for the study. Addenbrooke’s cognitive examination III (ACE-III), binocular functions (including objective and subjective refraction, distance and near dissociated phoria, stereopsis, contrast sensitivity, adult developmental eye movement (ADEM), and ocular physiology (by using optical coherence tomography, OCT, and macular pigment measurement, MPS) were performed, and the data were analyzed via independent t-test, chi-square test, Pearson correlation, linear regression, and ROC (receiver operating characteristic) curve. Results: Data analysis showed that (1) patients with poor eye movement had a strong correlation with the total score and all dimensions of cognitive functions, (2) the thickness of the macula had a strong correlation with attention and memory, and (3) patients with poor eye movement and poor stereopsis in combination with thinner inferior macula appeared to have lower cognitive abilities. Discussion and Conclusions: Cognitive dysfunction is not readily identified during the early stage of cognitive decline. The use of simple and inexpensive ADEM or stereopsis test and comparing the OCT results that are popular in optometry clinics for reference can be diagnostic in identifying patients with mild cognitive impairments. With the combined use of macular pigment density or retinal thickness measurements, it was possible to effectively predict the early degradation of cognition.

Dynamic latent variable models for the analysis of cognitive abilities in the elderly population.

Cognitive functioning is a key indicator of overall individual health. Identifying factors related to cognitive status, especially in later life, is of major importance. We concentrate on the analysis of the temporal evolution of cognitive abilities in the elderly population. We propose to model the individual cognitive functioning as a multidimensional latent process that accounts also for the effects of individual-specific characteristics (gender, age, and years of education). The proposed model is specified within the generalized linear latent variable framework, and its efficient estimation is obtained using a recent approximation technique, called dimensionwise quadrature. It provides a fast and streamlined approximate inference for complex models, with better or no degradation in accuracy compared with standard techniques. The methodology is applied to the cognitive assessment data from the Health and Retirement Study combined with the Asset and Health Dynamic study in the years between 2006 and 2010. We evaluate the temporal relationship between two dimensions of cognitive functioning, that is, episodic memory and general mental status. We find a substantial influence of the former on the evolution of the latter, as well as evidence of severe consequences on both cognitive abilities among less-educated and older individuals.

Resting-state brain oscillations predict cognitive function in psychiatric disorders: A transdiagnostic machine learning approach

BackgroundCognitive dysfunction is widespread in psychiatric disorders and can significantly impact quality of life. Deficits cut across traditional diagnostic boundaries, necessitating new approaches to understand how cognitive function relates to large-scale brain activity and psychiatric symptoms across the diagnostic spectrum. ObjectiveUsing random forest regression, we aimed to identify transdiagnostic patterns linking cognitive function to resting-state EEG oscillations. Methods216 participants recruited through an outpatient psychiatric clinic completed the Cambridge Neuropsychological Test Automated Battery and underwent a 5-minute eyes-closed resting state EEG recording. We built random forest regression models to predict performance on each cognitive test using the resting-state EEG power spectrum as input, and we compared model performance to a sampling distribution constructed with random permutations. For models that performed significantly better than chance, we used feature importance estimates to identify features of the EEG power spectrum that are predictive of cognitive functioning. ResultsRandom forest models successfully predicted performance on measures of episodic memory and associative learning (Paired Associates Learning, PAL), information processing speed (Choice Reaction Time, CRT), and attentional set-shifting and executive function (Intra-Extra Dimensional Set Shift, IED). Oscillatory power in the upper alpha range was associated with better performance on PAL and CRT, while low alpha power was associated with worse CRT performance. Beta power predicted poor performance on all three tests. Theta power was associated with good performance on PAL, and delta and theta oscillations were identified as predictors of good performance on IED. No differences in cognitive performance were found between diagnostic categories. ConclusionResting oscillations are predictive of certain dimensions of cognitive function across various psychiatric disorders. These findings may inform treatment development to improve cognition.

Association between social participation and cognitive function among middle- and old-aged Chinese: A fixed-effects analysis

BackgroundSocial Participation (SP) is known to benefit cognitive function. However, whether the positive relationship holds across different types of SP and dimensions of cognitive function, and whether the statement stays true in middle- and old-aged Chinese have not been investigated. The present study aimed to understand the current patterns of SP and cognitive function in China’s context, and therefore, explore the associations between cognitive function and SP at different levels from various aspects.MethodsA total of 7973 community residents aged 45 years and older were selected from the China Health and Retirement Longitudinal Study (CHARLS, 2011-2015). A fixed-effects analysis was used to explore the association between changes in SP (diversity, frequency, and type) and that in cognitive function (memory and mental status) over a four-year period.ResultsChanging from no SP to more variety (β = 0.377, 95% confidence interval (CI) = 0.192-0.562 for 1 type, β = 0.703, 95% CI = 0.470-0.937 for ≥2 types) or higher frequency (β = 0.235, 95% CI = 0.007-0.462 for not regularly, β = 0.604, 95% CI = 0.411-0.798) of SP was associated with improvements in cognitive function. Playing mah-jong and using Internet were associated with improved memory but not with mental status. Sports and volunteering were associated with improved mental status but not with memory. The same pattern was observed in men and in women.ConclusionsThe study confirmed that more diversity and higher frequency of SP was associated with improved cognitive function, whereas reminded policymakers to consider cultural context when developing target strategies to improve cognitive function.

Investigating whether depressed youth exhibiting elevated C reactive protein perform worse on measures of executive functioning, verbal fluency and episodic memory in a large, population based sample of Dutch adolescents

Cognitive functioning is disrupted during a depressive episode and cognitive dysfunction persists when depression is in remission. A subtype of depressed individuals who exhibit elevated inflammatory biomarkers may be at particular risk for cognitive dysfunction. We examined whether an elevated inflammatory biomarker (C-reactive protein: CRP) in acute and/or remitted depression was associated with specific deficits in executive functioning, episodic memory, and verbal fluency. Data were drawn from a population-based sample of Dutch adolescents (N = 1066; 46% male) recruited at the age of 11 and followed over the course of eight years. We tested whether adolescents with either, (i) a history of depression (Wave 1–3) or (ii) current depression (Wave 4), and elevated levels of C-reactive protein measured in blood at Wave 3 performed worse on cognitive assessments at Wave 4. Eight measures of cognitive functioning were hypothesized to load on to one of three dimensions of cognitive functioning (executive functioning, episodic memory, and verbal fluency) within a structural equation model framework. Higher levels of CRP were associated with worse future executive functioning in adolescents with and without current/prior depression. A current depression diagnosis also was associated with worse executive functioning. There was consistent evidence linking low socioeconomic status and health-related covariates (high body mass index/sedentary behavior) with worse performance across multiple measures of cognitive functioning and, importantly, the association of depression/CRP and executive functioning was no longer significant when controlling for these covariates. Future studies may benefit from investigating whether specific depressogenic behaviors (e.g., sedentary behavior/substance use) mediate a relationship between depression and worse executive functioning, potentially via a prospective pathway through elevated inflammation.

Acute neurocognitive deficits in active duty service members following subconcussive blast exposure

Military service members are frequently subjected to subconcussive blast events during training and deployment. Emerging evidence suggests blast exposures of these magnitudes may have long-term consequences for dimensions of cognitive function. Less is known about cognitive sequelae acutely following deployment-related subconcussive blast events. The current study addressed this knowledge gap by assessing the extent to which subconcussive blast exposure affected performance on the Automated Neuropsychological Assessment Metrics 4 TBI-MIL (ANAM). Baseline-referenced and normative comparisons of archival ANAM data were analyzed for a cohort of personnel who were exposed to blast (blast group; n = 27) and personnel who were not exposed to blast (no-blast group; n = 36) that were otherwise asymptomatic for a concussion. The blast group exhibited statistically significant lower scores compared to the no-blast group (between-subjects), baseline assessments (within-subjects), and an age-matched normative population. Normative comparisons revealed that the scores for the reaction time subtests (i.e., procedural and both simple reaction time tasks) were outside the range of normal functioning (1 SD) and reliable change indices revealed clinically meaningful change only for simple reaction time. The results highlight covert effects of subconcussive blast exposure that may warrant further monitoring in the immediate aftermath of a blast event.

Associations of Skeletal Muscle Mass, Lower-Extremity Functioning, and Cognitive Impairment in Community-Dwelling Older People in Japan.

We examined whether skeletal muscle mass and lower extremity functioning are closely associated with multiple cognitive domains, including global cognition, memory, attention, executive functioning, and processing speed, in community-dwelling older Japanese adults. A cross-sectional, population-based community study. This study was conducted among community-living older people enrolled in the Obu Study of Health Promotion for the Elderly. Participants comprised 5,104 adults (≥ 65 years, mean age: 71 years). Data from 4273 participants were analyzed. Appendicular skeletal muscle mass was estimated from bioelectrical impedance analysis and expressed as appendicular skeletal muscle mass index (ASMI). Lower-extremity functioning was assessed by the Five-Times-Sit-to-Stand test (FTSS) and Timed Up and Go test (TUG). Cognitive functions were assessed by the Mini Mental State Examination, word list memory, Trail Making Test parts A and B, and Symbol Digit Substitution Task. Logistic regression analysis were performed to calculate odds ratios (ORs) of cognitive impairment in various domains among skeletal muscle mass, lower-extremity functioning levels adjusted for important demographic variables, and comorbidities. Participants with lower ASMI and slower FTSS and TUG groups had lower cognitive functioning scores than did participants with higher ASMI and faster FTSS and TUG. The slowest quartiles (Q4) of FTSS and TUG were significantly associated with impaired global functioning (MMSE score < 24) compared to the fastest quartile (Q1) after multivariate adjustment (FTSS, OR = 1.46, 95% confidence interval (CI) = 1.12-1.90; TUG, OR = 1.65, 95% CI = 1.25-2.17). In other dimensions of cognitive functioning, FTSS and TUG were significantly associated with all cognitive impairment in the full adjustment model. Lower-extremity functioning, rather than skeletal muscle mass, is closely related to multiple cognitive domains. This study suggests that maintaining lower-extremity functioning, rather than skeletal muscle mass, may be required for detecting and preventing cognitive impairment.

Adult Body Height Is a Good Predictor of Different Dimensions of Cognitive Function in Aged Individuals: A Cross-Sectional Study.

Background: Adult height, weight, and adiposity measures have been suggested by some studies to be predictors of depression, cognitive impairment, and dementia. However, the presence of confounding factors and the lack of a thorough neuropsychological evaluation in many of these studies have precluded a definitive conclusion about the influence of anthropometric measures in cognition and depression. In this study we aimed to assess the value of height, weight, and abdominal perimeter to predict cognitive impairment and depressive symptoms in aged individuals.Methods and Findings: Cross-sectional study performed between 2010 and 2012 in the Portuguese general community. A total of 1050 participants were included in the study and randomly selected from local area health authority registries. The cohort was representative of the general Portuguese population with respect to age (above 50 years of age) and gender. Cognitive function was assessed using a battery of tests grouped in two dimensions: general executive function and memory. Two-step hierarchical multiple linear regression models were conducted to determine the predictive value of anthropometric measures in cognitive performance and mood before and after correction for possible confounding factors (gender, age, school years, physical activity, alcohol consumption, and smoking habits). We found single associations of weight, height, body mass index, abdominal perimeter, and age with executive function, memory and depressive symptoms. However, when included in a predictive model adjusted for gender, age, school years, and lifestyle factors only height prevailed as a significant predictor of general executive function (β = 0.139; p < 0.001) and memory (β = 0.099; p < 0.05). No relation was found between mood and any of the anthropometric measures studied.Conclusions and Relevance: Height is an independent predictor of cognitive function in late-life and its effects on the general and executive function and memory are independent of age, weight, education level, gender, and lifestyle factors. Altogether, our data suggests that modulators of adult height during childhood may irreversibly contribute to cognitive function in adult life and that height should be used in models to predict cognitive performance.

Schizophrenia and subsequent neighborhood deprivation: revisiting the social drift hypothesis using population, twin and molecular genetic data.

Neighborhood influences in the etiology of schizophrenia have been emphasized in a number of systematic reviews, but causality remains uncertain. To test the social drift hypothesis, we used three complementary genetically informed Swedish cohorts. First, we used nationwide Swedish data on approximately 760 000 full- and half-sibling pairs born between 1951 and 1974 and quantitative genetic models to study genetic and environmental influences on the overlap between schizophrenia in young adulthood and subsequent residence in socioeconomically deprived neighborhoods. Schizophrenia diagnoses were ascertained using the National Patient Registry. Second, we tested the overlap between childhood psychotic experiences and neighborhood deprivation in early adulthood in the longitudinal Twin Study of Child and Adolescent Development (TCHAD; n=2960). Third, we investigated to what extent polygenic risk scores for schizophrenia predicted residence in deprived neighborhoods during late adulthood using the TwinGene sample (n=6796). Sibling data suggested that living in deprived neighborhoods was substantially heritable; 65% (95% confidence interval (95% CI): 60–71%) of the variance was attributed to genetic influences. Although the correlation between schizophrenia and neighborhood deprivation was moderate in magnitude (r=0.22; 95% CI: 0.20–0.24), it was entirely explained by genetic influences. We replicated these findings in the TCHAD sample. Moreover, the association between polygenic risk for schizophrenia and neighborhood deprivation was statistically significant (R2=0.15%, P=0.002). Our findings are primarily consistent with a genetic selection interpretation where genetic liability for schizophrenia also predicts subsequent residence in socioeconomically deprived neighborhoods. Previous studies may have overemphasized the relative importance of environmental influences in the social drift of schizophrenia patients. Clinical and policy interventions will therefore benefit from the future identification of potentially causal pathways between different dimensions of cognitive functions and socioeconomic trajectories derived from studies adopting family-based research designs.

TASER® Exposure and Cognitive Impairment

Research SummaryThis study reports findings from a randomized controlled trial that examined the effects of the TASER® (a conducted energy weapon sold by TASER International, Scottsdale, Arizona) on several dimensions of cognitive functioning. The research demonstrated that in a sample of healthy human volunteer participants, TASER exposure led to significant and substantial reductions in (a) short‐term auditory recall and (b) abilities to assimilate new information through auditory processes. The effects lasted up to 1 hour for most subjects, almost all of whom returned to baseline 60 minutes postexposure.Policy ImplicationsThe study applies the findings of reduced cognitive functioning among healthy participants in a laboratory setting to criminal suspects in field settings and questions the abilities of “average” suspects to waive their Miranda rights knowingly, intelligently, and voluntarily within 60 minutes of a TASER exposure. The study poses the question: What would it cost police to wait 60 minutes after a TASER deployment before engaging suspects in custodial interrogations?

Association of Dynapenia, Sarcopenia, and Cognitive Impairment Among Community-Dwelling Older Taiwanese.

A decline in physical and/or cognitive function is a common feature of aging, and frailty has been shown to be associated with cognitive impairment and dementia. This study aimed to evaluate the association between dynapenia, sarcopenia, and cognitive impairment among community-dwelling older people in Taiwan. Data from the I-Lan Longitudinal Aging Study (ILAS) were retrieved for study. Global cognitive function was assessed by Mini-Mental State Examination (MMSE), whereas the Chinese Version Verbal Learning Test, Boston Naming Test, Verbal Fluency Test, Taylor Complex Figure Test, Digits Backward Test, and Clock Drawing Test were used to assess different domains of cognitive function. Association between sarcopenia and global cognitive function as well as all different dimensions of cognitive function were evaluated. Data from 731 elderly participants (mean age 73.4 ± 5.4 years, 53.8% males) were used for study analysis. The overall prevalence of sarcopenia was 6.8%, which was significantly higher in men (9.3% versus 4.1%, p < 0.05). The mean MMSE score was 23.4 ± 4.4 for all participants, and 10.3% of the study participants were cognitively impaired. Sarcopenia was not significantly associated with global cognitive function (odds ratio [OR] = 1.55, p = 0.317), but global cognitive impairment was significantly associated with low physical performance (OR = 2.31, p = 0.003) and low muscle strength (OR = 2.59, p = 0.011). Nonetheless, sarcopenia was significantly associated with impairment in the verbal fluency test (OR = 3.96, p = 0.006) after adjustment for potential confounders. Dynapenia was significantly associated with cognitive impairment in multiple dimensions and global cognitive function, but sarcopenia was only associated with an impaired verbal fluency test. Reduced muscle strength and/or physical performance related to non-muscle etiology were strongly associated with cognitive impairment. More longitudinal studies are needed.

Examining Cognitive Functioning Following TASER Exposure: A Randomized Controlled Trial

SummaryIndividuals who experience electrical injury suffer significant, sometimes long‐term deficits in neuropsychological functioning. The TASER, an electrical device used by thousands of police departments, generates a high‐voltage (up to 50 000 V), low‐amperage (2.1 mA) current of electricity that is designed to disable a resistive criminal suspect. Questions have emerged regarding the potential for TASER exposure to cause impairment in cognitive functioning. In the current study, healthy human volunteers were randomly assigned to four groups, two of which received a TASER exposure. Participants completed a battery of cognitive tests before and after receiving their assigned treatment. Participants who received a TASER exposure experienced statistically meaningful declines in measures of verbal learning and memory, although deficits lasted less than 1 hour. After TASER exposure, participants also self‐reported significant difficulties with concentration, anxiety, and feeling overwhelmed. Other dimensions of cognitive functioning were not affected. Our findings show that the effects of TASER exposure on brain functioning are not well understood. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Long-Chain Omega-3 Fatty Acids and Optimization of Cognitive Performance

Low consumption of the omega-3 fatty acids, eicosapentaenoic and docosahexaenonic acids, is linked to delayed brain development and, in late life, increased risk for Alzheimer's disease. The current review focuses on cognitive functioning during midlife and summarizes available scientific evidence relevant to the hypothesis that adequate dietary consumption of the long-chain omega-3 fatty acids is necessary for optimal cognitive performance. Taken together, the findings suggest that raising the currently low consumption among healthy adults may improve some aspects of cognitive performance. Nonetheless, evidence from randomized clinical trials is comparatively sparse and leaves unclear: (a) whether such effects are clinically significant, (b) whether effects of eicosapentaenoic acid and DHA differ, (c) which dimensions of cognitive function are affected, (d) the dose-response relationships, or (e) the time course of the response. Clarification of these issues through both laboratory and clinical investigations is a priority given the broad implications for public health, as well as for military personnel and other positions of high performance demand and responsibility.

Chimpanzee Intelligence Is Heritable

The role that genes play in human intelligence or IQ has remained a point of significant scientific debate dating back to the time of Galton [1]. It has now become increasingly clear that IQ is heritable in humans, but these effects can be modified by nongenetic mechanisms [2-4]. In contrast to human IQ, until recently, views of learning and cognition in animals have largely been dominated by the behaviorist school of thought, originally championed by Watson [5] and Skinner [6]. A large body of accumulated research now demonstrates a variety of cognitive abilities in nonhuman animals and challenges traditional behaviorist interpretations of performance [7, 8]. This, in turn, has led to a renewed interest in the role that social and biological factors might play in explaining individual and phylogenetic differences in cognition [9]. Specifically, aside from early attempts to selectively breed for learning skills in rodents [10-12], studies examining the role that genetic factors might play in individual variation in cognitive abilities in nonhuman animals, particularly nonhuman primates, are scarce. Here, we utilized a modified Primate Cognitive Test Battery [13] in conjunction with quantitative genetic analyses to examine whether cognitive performance is heritable in chimpanzees. We found that some but not all cognitive traits were significantly heritable in chimpanzees. We further found significant genetic correlations between different dimensions of cognitive functioning, suggesting that the genes that explain the variability of one cognitive trait might also explain that of other cognitive traits.

Anxiety symptoms and cognitive performance in later life: Results from the longitudinal aging study Amsterdam

Objectives: This study investigates whether, and if so how, anxiety symptoms are related to cognitive decline in elderly persons and whether anxiety symptoms precede cognitive decline. Method: Data were obtained from the Longitudinal Aging Study Amsterdam. Anxiety symptoms were measured with the Hospital Anxiety and Depression Scale. General cognitive functioning was measured with the Mini-Mental State Examination, episodic memory with the Auditory Verbal Learning Test, fluid intelligence with the Raven's Coloured Progressive Matrices and information processing speed with the coding task. Multilevel analyses were performed to investigate the relationship between anxiety symptoms and cognitive decline over 9 years, taking into account confounding variables. Results: Although not consistent across all dimensions of cognitive functioning, a curvilinear effect of anxiety on cognitive performance was found. Furthermore, we found that previous measurement of anxiety symptoms were not predictive of cognitive decline at a later time-point. Conclusion: This study suggests that the effect of anxiety on cognition depends on the severity of the present anxiety symptoms with mild anxiety associated with better cognition, whereas more severe anxiety is associated with worse cognition. The effect of anxiety symptoms on cognitive functioning seems to be a temporary effect, anxiety is not predictive of cognitive decline.