Executive functioning and the metabolic syndrome: a project FRONTIER study

Metabolic syndrome and cognitive deficits in the Greek cohort of Epirus Health Study

BACKGROUND

Metabolic syndrome is considered an important risk factor for cognitive decline and dementia. However, the evidence in middle-aged individuals is still conflicting. The aim of the study was to explore the association between metabolic syndrome and its individual components with cognitive function and to investigate possible interaction between sex, age and genetic predisposition for metabolic syndrome and Alzheimer's disease in a middle-aged Greek cohort.

METHODS

A total of 2,077 healthy adults (mean age: 46.7 years) were included in the primary cross-sectional analysis and 305 of them in secondary prospective analyses. Metabolic syndrome was defined by the revised National Cholesterol Education-Adult Treatment Panel III and the International Diabetes Federation criteria. Cognitive function was measured primarily with the Trail Making, Verbal fluency and Logical Memory test, and in secondary prospective analyses with online versions of Posner cueing task, an emotional recognition task, Corsi block-tapping task and Stroop task.

RESULTS

Multivariable linear regressions showed an association of metabolic syndrome with lower performance in attention (β=1.62 seconds, 95% CI=0.20, 3.04) and memory (β=-0.62 words, 95% CI=-1.19, -0.05) that could be driven by associations with elevated fasting glucose and abdominal obesity. Similar associations were observed in the secondary prospective analyses.

CONCLUSION

In summary, metabolic syndrome was associated with cognitive deficits in domains related with the cognitive profile of vascular cognitive impairment.

Neuroprotection in metabolic syndrome by environmental enrichment. A lifespan perspective

Metabolic syndrome (MetS) is defined by the concurrence of different metabolic conditions: obesity, hypertension, dyslipidemia, and hyperglycemia. Its incidence has been increasingly rising over the past decades and has become a global health problem. MetS has deleterious consequences on the central nervous system (CNS) and neurological development. MetS can last several years or be lifelong, affecting the CNS in different ways and treatments can help manage condition, though there is no known cure. The early childhood years are extremely important in neurodevelopment, which extends beyond, encompassing a lifetime. Neuroplastic changes take place all life through - childhood, adolescence, adulthood, and old age - are highly sensitive to environmental input. Environmental factors have an important role in the etiopathogenesis and treatment of MetS, so environmental enrichment (EE) stands as a promising non-invasive therapeutic approach. While the EE paradigm has been designed for animal housing, its principles can be and actually are applied in cognitive, sensory, social, and physical stimulation programs for humans. Here, we briefly review the central milestones in neurodevelopment at each life stage, along with the research studies carried out on how MetS affects neurodevelopment at each life stage and the contributions that EE models can provide to improve health over the lifespan.

Increased pulse wave velocity is related to impaired working memory and executive function in older adults with metabolic syndrome

Age-related vascular alterations promote the pathogenesis of vascular cognitive impairment (VCI). Cardiovascular risk factors that accelerate vascular aging exacerbate VCI. Metabolic syndrome (MetS) constitutes a cluster of critical cardiovascular risk factors (abdominal obesity, hypertension, elevated triglycerides, elevated fasting glucose, reduced HDL cholesterol), which affects nearly 37% of the adult US population. The present study was designed to test the hypotheses that MetS exacerbates cognitive impairment and that arterial stiffening moderates the association between cognitive dysfunction and MetS in older adults. MetS was defined by the NCEP ATP III guidelines. Cognitive function (digit span and trail-making tests) and brachial-ankle pulse wave velocity (baPWV; a non-invasive clinical measurement of arterial stiffness) were assessed in older adults with MetS and age- and sex-matched controls. Multiple linear regression models were applied to test for the main effects of MetS, baPWV, and their interaction on cognitive performance. Fifty-three participants with MetS (age: 68 ± 8 years) and 39 age-matched individuals without MetS (age: 66 ± 9 years) were enrolled into the study. In adjusted multivariable regression analyses of the digit span backward length score, both MetS (ß = 1.97, p = 0.048) and MetS by baPWV interaction (ß =  - 0.001, p = 0.026) were significant predictors. In participants with MetS, higher baPWV was associated with poorer performance on digit span backward length score, a test of working memory (R =  - 0.44, p = 0.0012), but there was no association in those without MetS (R = 0.035, p = 0.83). MetS was negatively associated with performance on the digit span backward length score, baPWV was negatively associated with multiple neuropsychological outcomes, and baPWV moderated the association between digit span backward length score and MetS, as individuals with both MetS and higher baPWV had the most impaired cognitive function. Our findings add to the growing body of evidence that individuals with MetS and higher baPWV may be prone to VCI.

Depression is differentially related to cognitive and biomarker outcomes among Mexican Americans

Introduction

Despite tremendous advancements in the research of Alzheimer's disease (AD), Mexican Americans, who reflect 65% of the US Hispanic community, remain severely underrepresented in research. Our data demonstrate that risk factors for, and biomarkers of, AD are different among Mexican Americans as compared with non-Hispanic whites. Here, we examined the impact of depressive symptoms on cognitive and AD-relevant biomarker outcomes among the Mexican Americans.

Methods

Data were examined from 1,633 (852 Mexican Americans and 781 non-Hispanic whites) of the Health and Aging Brain Study-Health Disparities (HABS-HD). Depression was assessed using the Geriatric Depression Scale while cognition was measured using detailed neuropsychological testing. Plasma biomarkers of Aβ40, Aβ42, total tau, and NfL were examined in addition to MRI-based neurodegeneration. PET amyloid data were available in a subset of participants.

Results

Depressive symptoms were significantly associated with cognitive testing results among both Mexican Americans and non-Hispanic whites. However, depression was only significantly associated with cognitive outcomes and plasma biomarkers among the Mexican American APOEε4 non-carriers.

Discussion

Depressive symptoms are more commonly endorsed by Mexican Americans and these symptoms are more strongly associated with cognitive and AD-biomarker outcomes among this ethnic group. However, depression scores were only related to AD outcomes among APOEε4 non-carriers within the Mexican American group. These findings can aid in the development of a population-informed precision medicine for treating and preventing cognitive loss among the Mexican Americans.

Metabolic Syndrome and Cognitive Function in Midlife

OBJECTIVE

Metabolic syndrome (MetS) is a cluster of cardiovascular risk factors associated with cognitive decline. We investigated the relationship between MetS and cognition in middle-aged adults. We hypothesized that higher numbers of MetS components will relate to poorer performance on executive function (EF) tasks as frontal lobe regions critical to EF are particularly vulnerable to cardiovascular disease.

METHODS

197 adults (ages 40-60) participated. MetS was evaluated using established criteria. Composite scores for cognitive domains were computed as follows: Global cognitive function (subtests from the Wechsler Abbreviated Scale of Intelligence, 2nd Edition), EF (Stroop Color Word, Digit Span Backward, and Trails A and B), and memory (California Verbal Learning Test, 2 Edition).

RESULTS

Higher number of MetS components was related to weaker EF-F(4, 191) = 3.94, p = .004, MetS components ß = -.14, p = .044. A similar relationship was detected for tests of memory-F(4, 192) = 7.86, p < .001, MetS components ß = -.15, p = .032. Diagnosis of MetS was not significantly associated with EF domain score (ß = -.05, p = .506) but was significantly associated with memory scores-F(4, 189) = 8.81, p < .001, MetS diagnosis ß = -.19, p = .006.

CONCLUSIONS

Our findings support prior research linking MetS components at midlife to executive dysfunction and demonstrate that MetS, and its components are also associated with poorer memory function. This suggests that cognitive vulnerability can be detected at midlife. Interventions for MetS at midlife could alter cognitive outcomes.

Relationship between Puberty and Inhibitory Control: Computational Modeling of the Drift-diffusion Process

Previous work relies largely on the simple reaction time measures in inhibitory control tasks. The goal of the current study was to provide a better understanding the relationship between puberty, sex, and inhibitory control utilizing and contrasting two popular drift diffusion models. A sample of 103 adolescents (M_age = 14.49, SD = 1.69) self-reported their pubertal development and completed a flanker task. Utilizing Bayesian regressions, we found that the interaction between puberty and sex were significant predictors of the A/B parameter, conceptualized as the amount of information considered for a decision during the task.

Network Modeling Sex Differences in Brain Integrity and Metabolic Health

Hypothesis-driven studies have demonstrated that sex moderates many of the relationships between brain health and cardiometabolic disease, which impacts risk for later-life cognitive decline. In the present study, we sought to further our understanding of the associations between multiple markers of brain integrity and cardiovascular risk in a midlife sample of 266 individuals by using network analysis, a technique specifically designed to examine complex associations among multiple systems at once. Separate network models were constructed for male and female participants to investigate sex differences in the biomarkers of interest, selected based on evidence linking them with risk for late-life cognitive decline: all components of metabolic syndrome (obesity, hypertension, dyslipidemia, and hyperglycemia); neuroimaging-derived brain-predicted age minus chronological age; ratio of white matter hyperintensities to whole brain volume; seed-based resting state functional connectivity in the Default Mode Network, and ratios of N-acetyl aspartate, glutamate and myo-inositol to creatine, measured through proton magnetic resonance spectroscopy. Males had a sparse network (87.2% edges = 0) relative to females (69.2% edges = 0), indicating fewer relationships between measures of cardiometabolic risk and brain integrity. The edges in the female network provide meaningful information about potential mechanisms between brain integrity and cardiometabolic health. Additionally, Apolipoprotein ϵ4 (ApoE ϵ4) status and waist circumference emerged as central nodes in the female model. Our study demonstrates that network analysis is a promising technique for examining relationships between risk factors for cognitive decline in a midlife population and that investigating sex differences may help optimize risk prediction and tailor individualized treatments in the future.

Contribution of Components of Metabolic Syndrome to Cognitive Performance in Middle-Aged Adults

Introduction

Metabolic syndrome (MetS) has been associated with impaired cognition in different cognitive domains. This study investigated the association between MetS and cognitive functioning in middle-aged Bulgarians across different definitions of MetS severity.

Material and Methods

Our cross-sectional sample included 112 participants (67 free of MetS and 45 with MetS) with a mean age of 50.04 ± 3.31 years. The following MetS variables were considered—presence of MetS, continuously measured MetS components, dichotomized MetS components, number of MetS components present, and Metabolic Syndrome Severity Score (MSSS). Participants’ cognitive performance was assessed using the Consortium to Establish a Registry for Alzheimer’s Disease Neuropsychological Battery (CERAD-NB). We employed multivariate regression models to investigate the associations between different measures of MetS severity and CERAD-NB total and subtest scores.

Results

Bivariate analyses showed that the CERAD-NB total score was significantly higher in women, participants with a university degree, those with normal blood pressure, normal waist circumference, and low triglyceride levels, compared with their counterparts. MetS participants had lower CERAD-NB total score (78.87 ± 6.89 vs. 84.97 ± 7.84) and specifically performed poorer on the subtest Word List Recall (7.16 ± 1.52 vs. 7.99 ± 1.52). These findings persisted after controlling for age, gender, and education. Next, generalized linear regression indicated that the CERAD-NB total score was lower in participants with MetS (β = −4.86; 95% confidence interval [CI]: −7.60, −2.11), those with more MetS components (β = −8.31; 95% CI: −14.13, −2.50 for fours vs. 0 components) and with an increase in MSSS (β = −3.19; 95% CI: −4.67, −1.71). Hypertension independently contributed to lower CERAD-NB total score (β = −4.00; 95% CI: −6.81, −1.19).

Conclusions

Across several definitions, MetS was associated with lower cognitive functioning, and MetS severity appeared to be a better predictor than most MetS components. Recognizing and reducing severity of MetS components might be helpful in supporting cognitive functioning. Further longitudinal research is needed to shed more light on the relationship between MetS and cognitive functioning across the life span.

Metabolic syndrome and cognitive performance across the adult lifespan

Metabolic Syndrome (MetS) is associated with increased rates of mortality and increased risk for developing dementia. Changes in brain structure and cognitive functioning have been reported within the literature. However, research examining cognitive performance in individuals with MetS is limited, inconclusive, and focuses primarily on older cohorts. As such, the effect of MetS on cognitive functioning earlier in the lifespan is unclear. This study aimed to investigate cognitive performance in young, middle-aged, and older adults with multiple metabolic and vascular risk factors in a sample of community dwelling participants (N = 128). Participants were administered a comprehensive neuropsychological battery and self-report measures. As expected, older adults performed more poorly than young and middle-aged adults across most assessments. Relative to controls, individuals with MetS reported greater hunger and disinhibited eating. MetS participants performed more poorly on Color-Word Interference: Inhibition. Additionally, when weight was accounted for, there was a significant relationship between MetS and select executive functioning tasks in middle-aged adults. These findings suggest that aspects of executive functioning may be impaired in MetS and could be further impacted by excess weight in middle-age. Future studies aimed at investigating potential causal relationships between metabolic and vascular risk factors, disinhibited eating, and executive dysfunction may provide insight into effective intervention targets to prevent MetS.

Metabolic Syndrome and Physical Performance: The Moderating Role of Cognition among Middle-to-Older-Aged Adults

OBJECTIVE

Mobility limitation and cognitive decline are related. Metabolic syndrome (MetS), the clustering of three or more cardiovascular risk factors, is associated with decline in both mobility and cognition. However, the interrelationship among MetS, mobility, and cognition is unknown. This study investigated a proposed pathway where cognition moderates the relationship between MetS and Mobility.

METHOD

Adults ages 45-90 years were recruited. MetS risk factors and mobility performance (Short Physical Performance Battery (SPPB) and gait speed) were evaluated. Cognition was assessed using a comprehensive neuropsychological battery. A factor analysis of neuropsychological test scores yielded three factors: executive function, explicit memory, and semantic/contextual memory. Multivariable linear regression models were used to examine the relationship among MetS, mobility, and cognition.

RESULTS

Of the 74 participants (average age 61 ± 9 years; 41% female; 69% White), 27 (36%) participants manifested MetS. Mean SPPB score was 10.9 ± 1.2 out of 12 and gait speed was 1.0 ± 0.2 m/s. There were no statistically significant differences in mobility by MetS status. However, increase in any one of the MetS risk factors was associated with decreased mobility performance after adjusting for age and gender (SPPB score: β (SE) -.17 (0.08), p < .05; gait speed: -.03 (.01), p < .01). Further adjusting for cognitive factors (SPPB score: explicit memory .31 (.14), p = .03; executive function 0.45 (0.13), p < .01; gait speed: explicit memory 0.04 (0.02), p = .03; executive function 0.06 (0.02), p < .01) moderated the relationships between number of metabolic risk factors and mobility.

CONCLUSION

The relationship between metabolic risk factors and mobility may be moderated by cognitive performance, specifically through executive function and explicit memory.

Metabolic syndrome components moderate the association between executive function and functional connectivity in the default mode network

Middle aged individuals with Metabolic Syndrome are at high risk for cognitive decline. Dyssynchrony in the resting state Default Mode Network is one early indicator of brain vulnerability. We set out to explore the relationship between default mode resting state functional connectivity and cognitive performance in both memory and executive domains at midlife in the presence of Metabolic Syndrome components. Seed-based Correlation Analyses were performed between the seed voxel in the posterior cingulate cortex and the medial prefrontal cortex on 200 participants (ages 40-61). Executive domain scores were significantly predicted by the interaction between number of Metabolic Syndrome components and resting state connectivity in the Default Mode Network (p = .004) such that connectivity was negatively related to executive function at higher numbers of Metabolic Syndrome components. Results were not significant for memory. Our findings indicate that clusters of cardiovascular disease risk factors alter functional relationships in the brain and highlights the need to continue exploring how compensatory techniques might operate to support cognitive performance at midlife.

Cognitive performance in relation to metabolic disturbances in patients with COPD

BACKGROUND & AIMS

Cognitive impairment (CI) and metabolic abnormalities, including the metabolic syndrome (MetS) and sarcopenia, are more prevalent in COPD patients compared to controls without diagnosed lung disease. Because earlier studies have shown these metabolic abnormalities may affect cognitive performance, this study investigated whether cognitive performance is more impaired in subgroups of COPD patients with MetS or sarcopenia.

METHODS

Cognitive performance patterns of 170 COPD patients referred for pulmonary rehabilitation (53.5% male, 63.4 ± 9.4 years, FEV₁ 54.5 ± 22.7% predicted) were compared between COPD subgroups stratified by presence of MetS and sarcopenia. Cognitive performance was assessed using a detailed neuropsychological test battery, which measured psychomotor speed (Stroop Color-Word Test, Concept Shifting Test, Letter-Digit Substitution Test), planning (Behavioral Assessment of the Dysexecutive Syndrome), working memory (Visual-Verbal Learning Test, Digit Span), verbal memory (Visual-Verbal Learning Test) and cognitive flexibility (Stroop Color-Word Test, Concept Shifting Test). MetS was determined according to the NCEP ATP-III criteria. Sarcopenia was determined based on decreased appendicular lean mass by dual-energy x-ray absorptiometry and impaired physical performance by 6-min walking distance.

RESULTS

MetS was observed in 54.7% and sarcopenia in 30.0% of COPD patients. The prevalence of general CI was not different between patients with and without MetS (30.4% and 39.0%, respectively) or those with and without sarcopenia (34.0% and 34.5%, respectively, both p > 0.05). Domain-specific cognitive performance was not different between metabolic subgroups, but those with sarcopenia displayed a lower prevalence of CI on verbal memory than those without (21.7% and 29.7%, respectively, p = 0.011). Only the digit span (working memory) subtest was significantly different between metabolic subgroups, in favor of those without MetS (p = 0.017).

CONCLUSION

Cognitive performance was not affected more in COPD patients with sarcopenia or MetS.

Metabolic syndrome is associated with cognitive impairment after transient ischemic attack/mild stroke, but does not affect cognitive recovery in short term

The metabolic syndrome (MetS) is a cluster of risk factors for cognitive impairment. We aimed to investigate the association between MetS and risk of persistent cognitive impairment in patients with a transient ischemic attack (TIA) or mild ischemic stroke. This is a prospective and observational study in consecutive patients with first-ever TIA or mild stroke (National Institutes of Health Stroke Scale score ≤ 6). Patients underwent Montreal cognitive assessment (MoCA) at hospital admission and day 30 after discharge. We defined cognitive impairment as a MoCA score of ≤26. Persistent cognitive impairment was defined as baseline cognitive impairment and an increase of <2 point or decrease in MoCA score at 1 month after discharge. Three hundred eleven eligible patients were enrolled, aged 21-80 years, and mean age was 61.87 ± 9.643 years and 211 patients were males (70.1%). Cognitive impairments were present in 166 (53.4%) patients at admission. The cognitive impairment rate was significantly higher in MetS patients than those without MetS both at admission and day 30 after discharge (66.1% vs 33.6%, P < 0.001 and 56.6% vs 27.9%, P < 0.001). In logistic regression analysis, MetS, hyperglycemia, hypertension, dyslipidemia, and obesity had no significant interaction with persistent cognitive impairment. However, hypertension had a tendency to be a predictor of persistent cognitive impairment, although this tendency had no statistical significance (odds ratio = 2.545, 95% confidence interval 0.872, 7.430, P = 0.0874). Baseline MetS is associated with the risk of cognitive impairment, but MetS does not affect short-term cognitive recovery from cognitively impaired in patients with TIA/mild stroke.

Association of HIV serostatus and metabolic syndrome with neurobehavioral disturbances

Metabolic syndrome (MetS), a constellation of related metabolic risk factors, is a common comorbidity associated with cognitive difficulty in people living with HIV (PLWH). Neurobehavioral disturbances (e.g., behavioral manifestations of frontal-subcortical dysfunction) are also prevalent in HIV, yet the role MetS might play in HIV-associated neurobehavioral disturbances is unknown. Thus, we examined the link between MetS and neurobehavioral disturbances in PLWH. Participants included 215 adults (117 PLWH, 98 HIV-uninfected), aged 36 to 65 years, from a cohort study at the University of California San Diego. Using the Frontal Systems Behavior Scale, we captured neurobehavioral disturbances (apathy, disinhibition, and executive dysfunction). MetS was defined by the National Cholesterol Education Program's Adult Treatment Panel-III criteria. Covariates examined included demographic, neurocognitive impairment, and psychiatric characteristics. When controlling for relevant covariates, both HIV serostatus and MetS were independently associated with greater apathy and executive dysfunction. HIV, but not MetS, was associated with greater disinhibition. The present findings suggest an additive effect of HIV and MetS on specific neurobehavioral disturbances (apathy and executive dysfunction), underscoring the importance of identifying and treating both HIV and MetS to lessen central nervous system burden among PLWH.

Physical activity is associated with better global cognition and frontal function in overweight/obese older adults with metabolic syndrome

Background

There is epidemiological evidence of an association between the metabolic syndrome (MetS), a cluster of cardiovascular risk factors related to central adiposity and insulin resistance, and cognitive impairment and dementia. On the other hand, there is evidence for a beneficial effect of physical activity on cognitive outcomes in older adult populations. In a cross-sectional study, we evaluated the relationship between aerobic physical activity and cognition in a cohort of overweight/obese older adults with MetS at risk for dementia. Cognitive function was assessed in a subsample of 82 subjects (men 55-75 y; women 60-75 y), with MetS and a BMI ≥27 to < 40 kg/m² enrolled in the PREDIMED-PLUS study, a trial of diet and exercise in individuals with MetS with outcomes of cardiovascular prevention. Domain Z scores were calculated for the different cognitive domains. Aerobic physical activity was determined with the Rapid Assessment of Physical Activity questionnaire.

Results

Adjusted covariance analyses revealed that, compared to sedentary participants, those physically active obtained higher scores in mean global cognitive scores, with mean adjusted difference 0.254 (95% CI 0.032 to 0.477, p = 0.026) and frontal composites, with mean adjusted difference 0.375 (95% CI 0.110 to 0.639, p = 0.006).

Conclusions

Our findings indicate that aerobic physical activity is associated with better global cognition and frontal function in overweight/obese older individuals with MetS, suggesting that physical activity could be a therapeutic strategy to reduce the risk of developing cognitive impairment or dementia in this population.

The Effect of an Education Program Based on Illness Perception on the Lifestyle of Patients with Metabolic Syndrome: A Randomized Controlled Clinical Trial

Background:

This study aimed to examine the effects of an education program based on illness perceptions on the lifestyle of patients with metabolic syndrome.

Methods:

This is a randomized controlled clinical trial on 80 patients with metabolic syndrome referred to diabetic clinic affiliated to Shiraz University of Medical Sciences from August to November 2016. The patients were assigned to two control and intervention groups using a simple randomization method. The intervention group received education based on illness perceptions, using face-to-face and telephone follow up sessions in five weeks. The lifestyle questionnaire, brief illness perception questionnaire and demographic information questionnaire were used for data collection. The patients’ lifestyle was examined before and at the end of the eighth week from the beginning of the intervention. Descriptive and inferential statistics were used for data analysis.

Results:

After the intervention, the total lifestyle score in the intervention group significantly increased, as compared to the control group (14.60±6.85 vs 6.15±5.80) (P<0.001). Of all the lifestyle dimensions, only stress management after the intervention showed no significant changes (P>0.001).

Conclusion:

Education based on illness perceptions affected the lifestyle of patients with metabolic syndrome. Therefore, nurses and healthcare providers can use this program for improving the lifestyle of patients with metabolic syndrome.

Trial Registration Number: IRCT2016020826437N1

Exergaming Improves Executive Functions in Patients With Metabolic Syndrome: Randomized Controlled Trial

BACKGROUND

Recent studies indicate that participation in exercise-related games can improve executive function, attention processing, and visuospatial skills.

OBJECTIVE

The aim of this study was to investigate whether exercise via exergaming (EXG) can improve executive function in patients with metabolic syndrome (MetS).

METHODS

A total of 22 MetS patients were recruited and randomly assigned to an EXG group or a treadmill exercise (TE) group. The reaction time (RT) and electrophysiological signals from the frontal (Fz), central (Cz), and parietal (Pz) cortices were collected during a Stroop task after 12 weeks of exercise.

RESULTS

During the Stroop congruence (facilitation) judgment task, both the EXG and TE groups showed significantly faster RT after 12 weeks of exercise training. For N200 amplitude, the EXG group demonstrated significantly increased electrophysiological signals from the Fz and Cz cortices. These changes were significantly larger in the EXG group than in the TE group. Separately, for the P300 amplitude, the EXG groups presented significantly increased electrophysiological signals from the Fz, Cz, and Pz cortices, whereas the TE group showed significantly increased electrophysiological signals from the Cz and Pz cortices only. During the Stroop incongruence (interference) judgment task, both the EXG and TE groups showed significantly faster RT. For P300 amplitude, the EXG group had significantly increased electrophysiological signals from the Fz and Cz cortices only, whereas the TE group had significantly increased electrophysiological signals from the Fz, Cz, and Pz cortices.

CONCLUSIONS

EXG improves executive function in patients with MetS as much as normal aerobic exercise does. In particular, a unique benefit of EXG beyond increased aerobic capacity is the improved selective attention among cognitive functions. Thus, EXG could be recommended to someone who needs to improve their brain responses of concentration and judgment as well as physical fitness.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04015583; https://clinicaltrials.gov/ct2/show/NCT04015583.

Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis

OBJECTIVE

To systematically review the literature relating to the impact of multiple co-occurring modifiable risk factors for cognitive decline and dementia.

DESIGN

A systematic review and meta-analysis of the literature relating to the impact of co-occurring key risk factors for incident cognitive decline and dementia. All abstracts and full text were screened independently by two reviewers and each article assessed for bias using a standard checklist. A fixed effects meta-analysis was undertaken.

DATA SOURCES

Databases Medline, Embase and PsycINFO were searched from 1999 to 2017.

ELIGIBILITY CRITERIA

For inclusion articles were required to report longitudinal data from participants free of cognitive decline at baseline, with formal assessment of cognitive function or dementia during follow-up, and an aim to examine the impact of additive or clustered comorbid risk factor burden in with two or more core modifiable risk factors.

RESULTS

Seventy-nine full-text articles were examined. Twenty-two articles (18 studies) were included reporting data on >40 000 participants. Included studies consistently reported an increased risk associated with greater numbers of intraindividual risk factors or unhealthy behaviours and the opposite for healthy or protective behaviours. A meta-analysis of studies with dementia outcomes resulted in a pooled relative risk for dementia of 1.20 (95% CI 1.04 to 1.39) for one risk factor, 1.65 (95% CI 1.40 to 1.94) for two and 2.21 (95% CI 1.78 to 2.73) for three or more, relative to no risk factors. Limitations include dependence on published results and variations in study outcome, cognitive assessment, length of follow-up and definition of risk factor exposure.

CONCLUSIONS

The strength of the reported associations, the consistency across studies and the suggestion of a dose response supports a need to keep modifiable risk factor exposure to a minimum and to avoid exposure to additional modifiable risks. Further research is needed to establish whether particular combinations of risk factors confer greater risk than others.

PROSPERO REGISTRATION NUMBER

42016052914.

Texas Mexican American adult normative studies: Normative data for commonly used clinical neuropsychological measures for English- and Spanish-speakers

This study aimed to provide normative references for Mexican Americans on neuropsychological measures of cognitive functioning. Data were analyzed from a total of 797 Mexican-Americans recruited across three Texas-based studies with approximately one-half of the participants tested in Spanish. Normative tables include: MMSE, AMNART, WMS-III (Logical Memory I, II; Visual Reproduction I, II; Digit Span), CERAD, RAVLT, Exit25, CLOX 1 & 2, Trail Making Test- A&B, BNT, COWA, and Animal Naming. The norms were stratified by education then age. Normative references were generated for Texas-based Mexican Americans and data may be limited to the population sampled.

Diagnostic value of imaging in infective endocarditis: a systematic review

Sensitivity and specificity of the modified Duke criteria for native valve endocarditis are both suboptimal, at approximately 80%. Diagnostic accuracy for intracardiac prosthetic material-related infection is even lower. Non-invasive imaging modalities could potentially improve diagnosis of infective endocarditis; however, their diagnostic value is unclear. We did a systematic literature review to critically appraise the evidence for the diagnostic performance of these imaging modalities, according to PRISMA and GRADE criteria. We searched PubMed, Embase, and Cochrane databases. 31 studies were included that presented original data on the performance of electrocardiogram (ECG)-gated multidetector CT angiography (MDCTA), ECG-gated MRI, ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT, and leucocyte scintigraphy in diagnosis of native valve endocarditis, intracardiac prosthetic material-related infection, and extracardiac foci in adults. We consistently found positive albeit weak evidence for the diagnostic benefit of ¹⁸F-FDG PET/CT and MDCTA. We conclude that additional imaging techniques should be considered if infective endocarditis is suspected. We propose an evidence-based diagnostic work-up for infective endocarditis including these non-invasive techniques.

Metabolic syndrome correlates poorly with cognitive performance in stroke-free community-dwelling older adults: a population-based, cross-sectional study in rural Ecuador

BACKGROUND

Studies investigating a possible correlation between metabolic syndrome and cognitive decline have been inconsistent.

AIMS

To determine whether metabolic syndrome or each of its components correlate with cognitive performance in community-dwelling older adults in rural Ecuador.

METHODS

Stroke-free Atahualpa residents aged ≥60 years were identified during a door-to-door survey. Metabolic syndrome was defined according to the International Diabetes Federation criteria. Cognition was evaluated by the use of the Montreal Cognitive Assessment (MoCA). Multivariate logistic regression models estimated the association between metabolic syndrome and each of its components with cognitive performance.

RESULTS

A total of 212 persons (mean age: 69.2 ± 7.2 years, 64 % women) were enrolled. Of these, 120 (57 %) had metabolic syndrome. Mean scores in the MoCA were 18.2 ± 4.6 for persons with and 19 ± 4.7 for those without metabolic syndrome. In fully adjusted logistic models, MoCA scores were not associated with metabolic syndrome (p = 0.101). After testing individual components of metabolic syndrome with the MoCA score, we found that only hypertriglyceridemia was independently associated with the MoCA score (p = 0.009).

CONCLUSIONS

This population-based study showed a poor correlation of metabolic syndrome with cognitive performance after adjusting for relevant confounders. Of the individual components of metabolic syndrome, only hypertriglyceridemia correlated with worse cognitive performance.

Increased attrition of leukocyte telomere length in young adults is associated with poorer cognitive function in midlife

Evidence for an association of leukocyte telomere length (LTL) with cognitive function, predominantly in older adults, is inconsistent. No report has examined the association of LTL dynamics (age-specific LTL and its attrition rate) with cognitive function. We aimed to examine the association of LTL dynamics over 13 years in young adulthood with cognitive function in midlife. 497 individuals who had LTL measured at ages 28-32 and 41-46 years were assessed at ages 48-52 for global cognitive function and its five specific component domains with a NeuroTrax computerized test battery. Multivariable regression and logistic models were applied for cognition treated as a continuous and categorical variable, respectively. We found that LTL attrition (adjusted for sex, baseline LTL and potential confounders including socioeconomic variables) was inversely associated with global cognition (standardized β = -.119, p = .004) and its component domains: information processing speed (β = -.102, p = .024), visual-spatial function (β = -.102, p = .017) and memory (β = -.093, p = .045), but less so for the attention and executive domains. The multivariable-adjusted odds ratio for low global cognition comparing the upper versus lower thirds of LTL attrition was 2.12 (95 % CI 1.11-4.08, p for trend = .023). There was no association of baseline or follow-up LTL with cognition. No effect modification was evident for sex, smoking or inflammatory markers. In conclusion, faster LTL attrition in young adulthood was associated with poorer global and domain-specific cognitive function in midlife, suggesting that more rapid LTL attrition may be predictive of cognitive aging in healthy young adults.

Executive dysfunction assessed by Clock-Drawing Test in older non-demented subjects with metabolic syndrome is not mediated by white matter lesions

AIMS

Metabolic syndrome (MetS) has been associated with greater occurrence of white matter hyperintensities (WMH). It remains uncertain whether MetS as a construct is associated with poorer cognitive performances. This study explores whether MetS is associated with poorer performances in global and domain-specific cognitive tests in older non-demented subjects independently of its individual components, WMH severity and other variables.

METHODS

MetS was diagnosed according to the National Cholesterol Education Program Adult Treatment Panel III definition. Brain magnetic resonance studies (1.5T) were performed. Deep and periventricular WMH were graded using the Fazekas scale. Subjects underwent the Mini-Mental State Examination, the Babcock Short Story Recall test and the Clock-Drawing Test (CDT).

RESULTS

Eighty community-dwellers aged 67-91 years were studied. Subjects with MetS (n = 35) had more severe WMH, and poorer performances on the CDT (P = 0.003) and the Babcock Short Story Recall test (P = 0.027). After multiple adjustment, MetS was inversely associated with CDT scores (B = -1.285; 95% confidence interval = -1.996--0.575; P = 0.001) but not with episodic memory. Results were not affected by WMH severity. Interestingly, none of the individual components of MetS predicted poorer cognitive performances.

CONCLUSIONS

Impairment in executive functions assessed by CDT may represent an early and specific sign of cognitive decline in older individuals with MetS. Future longitudinal studies are needed to better establish the predictive role of MetS on dementia and to demonstrate the possibility of dementia prevention by targeting MetS.

Advancing understanding of executive function impairments and psychopathology: bridging the gap between clinical and cognitive approaches

Executive function (EF) is essential for successfully navigating nearly all of our daily activities. Of critical importance for clinical psychological science, EF impairments are associated with most forms of psychopathology. However, despite the proliferation of research on EF in clinical populations, with notable exceptions clinical and cognitive approaches to EF have remained largely independent, leading to failures to apply theoretical and methodological advances in one field to the other field and hindering progress. First, we review the current state of knowledge of EF impairments associated with psychopathology and limitations to the previous research in light of recent advances in understanding and measuring EF. Next, we offer concrete suggestions for improving EF assessment. Last, we suggest future directions, including integrating modern models of EF with state of the art, hierarchical models of dimensional psychopathology as well as translational implications of EF-informed research on clinical science.

Cognitive profiles in patients with multi-infarct dementia: an omani study

Background

Studies on neurocognitive impairment among patients presenting with multi-infarct dementia (MID) have received little attention from non-Western societies, and the Arab world is no exception. To our knowledge, this is the first study to characterize neurocognitive, affective and vegetative functioning in patients with MID in Oman.

Methods

In this study, we recruited 20 Omani patients presenting with MID and age- and gender-matched controls at the outpatient clinic of the Department of Behavioral Medicine, Sultan Qaboos University Hospital, Sultan Qaboos University, Muscat, Oman. In addition to the collection of clinical and demographic information, various cognitive batteries were administered to the consenting participants, including those indexing nonverbal reasoning abilities, working memory (attention, concentration and recall) and executive functioning. Questionnaires that elicit the affective range and the quality of sleep were also administered.

Results

Compared with the matched healthy subjects, the patients diagnosed with MID significantly differed in the presently operationalized indices of visuospatial function, semantic memory and affective and vegetative functioning. In contrast, episodic memory and some attentional capacities were not significantly different compared with the control subjects.

Conclusions

The present study was explorative and clinically designed to describe neurocognitive functioning in patients with MID seeking consultation at a tertiary care center in Oman. Our data are necessary for planning and setting up community services and health care programs for demented patients in a society where dementia is a growing silent epidemic.