Influential factors on cognitive performance in middle-aged cohort: Third National Health and Nutrition Examination Survey-based study

Plasma glucose is not associated with performance on standard cognitive screening tests in a mixed memory clinic cohort-An observational cross-sectional study

BACKGROUND

It has been shown under experimental conditions that cognitive performance, especially working memory, is impaired in patients with type I and type II diabetes mellitus during hyperglycemic and hypoglycemic conditions, perhaps due to altered cerebral glucose metabolism. It is not known if patients with neurodegenerative diseases, who also exhibit pathological cerebral glucose metabolism, are affected in a similar manner by their plasma glucose levels.

OBJECTIVE

We aimed to test if performance on two cognitive screening tests was associated with plasma glucose levels in a memory clinic cohort.

METHODS

We included patients from the Copenhagen Memory Clinic Cohort with an available Mini Mental-State Examination (MMSE) test score and a plasma glucose measurement performed in conjunction with cognitive testing. We built linear regression models with MMSE and Addenbrooke's Cognitive Examination (ACE) test scores as the outcome and plasma glucose as the explaining variable and adjusted models for age, sex, and diabetes (plasma glucose measurement >11.1 mmol/L). We explored non-linear relationships by adding quadratic terms and by fitting a cubic spline regression model.

RESULTS

In total, 2714 patients had an available MMSE score and a plasma glucose measurement. MMSE and ACE total scores were not associated with plasma glucose in a linear or non-linear fashion when we adjusted for age, sex, and diabetes.

CONCLUSION

Plasma glucose levels, predominantly within normal ranges, were not associated with performance on routinely applied cognitive tests and do not need to be taken into consideration when interpreting test results from memory clinic patients.

Meaningful cognitive decline is uncommon in virally suppressed HIV, but sustained impairment, subtle decline and abnormal cognitive aging are not

Background

High antiretroviral therapy (ART) coverage and viral suppression among people with HIV (PWH) in Australia provide a unique context to study individual cognitive trajectories, cognitive aging and factors associated with longitudinal cognitive function during chronic and stable HIV disease.

Methods

Participants from the Predictors of Adherence to Antiretroviral Therapy study (n = 457, recruited between September 2013 and November 2015, median age = 52 years, and all with HIV RNA <50 copies mL) completed a cognitive assessment with CogState Computerized Battery (CCB) at baseline, Month-12, and Month-24. Demographics, psycho-social and socioeconomic factors, healthcare seeking behaviors, HIV disease characteristics and comorbidities were assessed. The CCB data were corrected for age, sex and practice effect and averaged into a global z-score (GZS). Cognitive impairment was defined with the global deficit score method (GDS>0.5). Meaningful cognitive change was statistically defined (decline or improvement versus stability, i.e., 90% CI, that is p < 0.05, 2-tailed) using a novel evidence-based change score: the linear mixed-effect regression (LMER)-based GZS change score. A separate LMER model with a top-down variable selection approach identified the independent effects of age and other demographic, HIV disease characteristics, socioeconomic and health-related factors on the demographically corrected GZS. The combined definitions of change and cross-sectional impairment enabled the identification of cognitive trajectories.

Findings

At Month-12 and Month-24, 6% and 7% showed meaningful cognitive decline and 4% and 3% improved respectively. Only 1% showed sustained decline. Incident impairment due to subtle cognitive decline (i.e., below the threshold of meaningful cognitive decline) was 31% and 25% at Month-12 and Month-24, while 14% showed sustained impairment (i.e., cognitively impaired at all study visits). Older age (≥50 years) and time interaction was associated with lower demographically corrected GZS (β = -0.31, p < 0.001). Having a regular relationship, excellent English proficiency, and perceived stigma (avoidance) were associated with higher GZS (all p < 0.05). Relying on government subsidy, severe depression, and lower belief in ART necessity and higher concerns were associated with lower GZS (all p < 0.05). No HIV disease characteristics had a significant effect.

Interpretations

Meaningful cognitive decline was not different from normal expectation in chronic stable HIV disease. Despite this, subtle cognitive decline, sustained cognitive impairment, and greater than normative-age cognitive aging were evident.

Funding

Funding for the PAART study was provided in part by unrestricted educational grants from Gilead Sciences (www.gilead.com) (Grant Number: IN-AU-264- 0131), the Balnaves Foundation (www.balnavesfoundation.com), the Victorian Department of Health and Human Services (Australia) (www.dhs.vic.gov.au/home), Western Australia Health (www.health.wa.gov.au), the ACT Ministry of Health (Australia) (www.health.act.gov.au), and in-kind support from the Queensland Department of Health (Australia) (www.health.qld.gov.au), and NHMRC Partnership grant APP1058474 (PI: Carr, Andrew).

The neurocognitive implications of depression and socioeconomic status in people with HIV

OBJECTIVE

This cross-sectional study investigates the independent and interactive effects of depression and socioeconomic status (SES) on neurocognition in a diverse sample of people with HIV (PWH).

METHOD

The sample of 119 PWH (71% Latinx, 27% female) completed comprehensive neurocognitive and psychosocial evaluations and were separated into two groups: those with a history of depression diagnosis (n = 47) and those without (n = 72).

RESULTS

The results of regression analyses indicated that lifetime depression was not associated with lower SES nor with worse neurocognitive performance on any neurocognitive outcome. However, a significant main effect of SES was observed on the Hopkins Verbal Learning Test (total), indicating that higher SES was associated with better verbal learning performance (B= .11, SE = .05, p< .02). Lastly, the results revealed an interactive effect of lifetime depression and SES, such that individuals with depression and higher SES performed better on tests of attention/working memory (i.e., WAIS-III Letter-Number Sequencing, B= .08, SE = .04, p< .02; Paced Auditory Serial Addition Test, B= .39, SE = .16, p< .02).

CONCLUSIONS

Depression and SES appear to play an important role in the neurocognitive performance of PWH. Specifically, higher SES appears to have a protective effect on attention/working memory among PWH only if they have co-morbid history of lifetime depression.

A Multivariate Assessment of Age-Related Cognitive Impairment in Octodon degus

Aging is a progressive functional decline characterized by a gradual deterioration in physiological function and behavior. The most important age-related change in cognitive function is decline in cognitive performance (i.e., the processing or transformation of information to make decisions that includes speed of processing, working memory, and learning). The purpose of this study is to outline the changes in age-related cognitive performance (i.e., short-term recognition memory and long-term learning and memory) in long-lived Octodon degus. The strong similarity between degus and humans in social, metabolic, biochemical, and cognitive aspects makes it a unique animal model for exploring the mechanisms underlying the behavioral and cognitive deficits related to natural aging. In this study, we examined young adult female degus (12- and 24-months-old) and aged female degus (38-, 56-, and 75-months-old) that were exposed to a battery of cognitive-behavioral tests. Multivariate analyses of data from the Social Interaction test or Novel Object/Local Recognition (to measure short-term recognition memory), and the Barnes maze test (to measure long-term learning and memory) revealed a consistent pattern. Young animals formed a separate group of aged degus for both short- and long-term memories. The association between the first component of the principal component analysis (PCA) from short-term memory with the first component of the PCA from long-term memory showed a significant negative correlation. This suggests age-dependent differences in both memories, with the aged degus having higher values of long-term memory ability but poor short-term recognition memory, whereas in the young degus an opposite pattern was found. Approximately 5% of the young and 80% of the aged degus showed an impaired short-term recognition memory; whereas for long-term memory about 32% of the young degus and 57% of the aged degus showed decreased performance on the Barnes maze test. Throughout this study, we outlined age-dependent cognitive performance decline during natural aging in degus. Moreover, we also demonstrated that the use of a multivariate approach let us explore and visualize complex behavioral variables, and identified specific behavioral patterns that allowed us to make powerful conclusions that will facilitate further the study on the biology of aging. In addition, this study could help predict the onset of the aging process based on behavioral performance.

Is Obesity Associated with Lower Mini Mental Test Scores among Elderly? A Cross Sectional Study

OBJECTIVES

Obesity leads to many chronic diseases and its association with cognitive impairment is controversial. The objective was to investigate the association between obesity, anthropometric measurements and cognitive functions of elderly.

METHODS

Planned cross-sectionally, community-dwelling Cypriots (aged ≥ 50 years) without any neurological disorders, were included. Cognitive impairment evaluated by Mini Mental State Examination (MMSE) was the dependent variable. Socio-demographic variables, anthropometric measurements and obesity were the independent variables. The data was collected via face-to-face interview. Logistic regression models were constituted to determine the association of anthropometric measurements, obesity and dementia.

RESULTS

The mean age of participants (n = 541) was 60.0 ± 8.7 for women (n = 377) and 61.5 ± 6.0 years for men (n = 164). According to MMSE, 26.0% of women and 11.0% of men had mild-dementia, and the rest scored normal. After adjusted for age and sex, each unit increase in BMI (OR: 1.045, 95%CI: 1.008-1.091), Waist to height ratio (WHtR; OR: 1.030, 95%CI: 1.006-1.055) and Mid upper arm circumference (MUAC; OR: 1.077, 95%CI: 1.016-1.141) increases the risk of mild-dementia. When education, employment and smoking were included in the models, significance of anthropometric measurements was diminished and only sex and education were remained significant for all.

CONCLUSION

After controlled for age and sex, increment in anthropometric measurements increased the risk of dementia but when education was taken into consideration, this significant association was diminished showing that sex and education is more predominant in a heterogeneous group in means of education. Thus, for heterogeneous groups it might be better to revise MMSE. To determine the association between obesity and dementia cohort studies with longer follow-up duration with larger samples are needed.

Cognitive functioning in patients maintained on buprenorphine at peak and trough buprenorphine levels: An experimental study

OBJECTIVES

To assess the cognitive functions in participants maintained on buprenorphine for opioid dependence at peak and trough buprenorphine levels.

METHODS

This was a double-blind, randomized, experimental study. Sixty participants maintained on buprenorphine were matched for age and education and randomly allocated to "peak" group or "trough" group. The "peak" group received buprenorphine two hours before assessment, whereas the trough group received placebo. The cognitive domains of attention, learning and memory, and executive function including fluency, working memory, response inhibition and set shifting were tested.

RESULTS

The two groups were comparable on socio-demographic, substance use profile and opioid agonist treatment-related characteristics. Significant differences in performance of peak and trough group were observed on Wisconsin Card Sorting Test parameters of number of correct responses (U = 289.00, p = 0.03), number of errors (t = 02.26, df = 58, p = 0.03), and perseverative errors (U = 301.50, p = 0.04).

CONCLUSIONS

The time since buprenorphine dose has significant relation on specific cognitive tasks in patients maintained on buprenorphine for opioid dependence.

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 Molar Ratio of Total Branched-chain Amino Acids to Tyrosine Predicts a Digit Symbol Test Abnormality in Cirrhotic Patients

Objective We aimed to investigate the association between the digit symbol test (DST) and clinical characteristics, including the nutritional status of liver cirrhosis patients. Methods Fifty-nine cirrhotic patients without a history of overt hepatic encephalopathy were retrospectively evaluated. We examined neuropsychological abnormalities (NPAs) using the DST. We also estimated the detailed nutritional status using the Food Frequency Questionnaire (FFQ). The patients were divided into two groups according to their DST status: patients with normal DST scores (DST-Nor group, n=45) and those with abnormal DST scores (DST-Abn group, n=14). The clinical and nutritional findings of the two groups were compared. Results Overall, 14 (23.7%) patients had a DST abnormality. There were significant differences between the two groups in serum albumin (Alb; p=0.0043), valine (Val; p=0.0016), leucine (Leu; p=0.0078), isoleucine (Ile; p=0.0022), the molar ratio of total branched-chain amino acids to tyrosine (BTR; p=0.00025), total-bilirubin (T-Bil; p=0.0071), prothrombin time (%) (PT; p=0.028), and serum sodium (Na; p=0.035). A multivariate analysis found the BTR to be the only independent predictor of a DST abnormality (hazard ratio, 9.24; p<0.031). An FFQ analysis, revealed that the nutritional findings of patients with and without a DST abnormality, were similar. Conclusion The BTR was useful for predicting the risk of NPAs, as defined by a DST abnormality. The risk of NPAs may be estimated by monitoring the BTR.