Cognition and Cerebral Blood Flow After Extracranial Carotid Revascularization for Carotid Atherosclerosis: A Systematic Review.

PURPOSE: Extracranial atherosclerotic carotid stenosis is associated with inadequate cerebral blood flow (CBF) and cognitive dysfunction. The impact of extracranial carotid revascularization on cognition and how any cognitive change relates to changes in CBF are less clear. This review examines the effects of revascularization of extracranial carotid disease by carotid endarterectomy (CEA) or carotid stenting (CAS) on cognition, and how this relates to changes in CBF. METHODS: A systematic review of existing reports in the Medline, Embase, and Cochrane databases was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement recommendations. All original retrospective or prospective studies and clinical trials that compared pre- and postoperative cognitive function and CBF in patients with extracranial carotid stenosis who underwent CEA or CAS versus a control group, published between January 1985 and December 2022, were identified and considered eligible for inclusion in this study. FINDINGS: Seven studies (661 participants; 460 CEA or CAS) were identified. All were observational studies and of moderate to good methodologic quality. Six studies (619 participants; follow-up range 1 month to 2 years) demonstrated improvement in some cognitive domains following CEA or CAS, improvement in CBF following revascularization, and correlated some of these cognitive changes with changes in CBF. One study (42 participants; 3 months follow-up) found cognitive improvement following CEA, but found no improvement in CBF or any correlation between cognitive and CBF change. The literature however represented heterogenous study populations examining asymptomatic and/or symptomatic carotid stenosis, differing in treatment modality and criteria for control groups ranging from healthy volunteers to those with stenosis but not who underwent surgical revascularization, and finally, differing reporting methods. This heterogeneity precluded meta-analysis. IMPLICATIONS: Definitive conclusions are limited by variation in cognitive function assessment, timing of testing, and how these are correlated to CBF. However, research suggests a potential improvement in cognition which may be associated with improvement in CBF, particularly in those patients who have more significant CBF deficit at baseline. Further studies are required to better understand this association and provide a clearer picture of the cognitive effects of carotid revascularization.

Efficacy of probucol on cognitive function in Alzheimer's disease: study protocol for a double-blind, placebo-controlled, randomised phase II trial (PIA study).

INTRODUCTION: Preclinical, clinical and epidemiological studies support the hypothesis that aberrant systemic metabolism of amyloid beta (Aß) in the peripheral circulation is causally related to the development of Alzheimer's disease (AD). Specifically, recent studies suggest that increased plasma concentrations of lipoprotein-Aß compromise the brain microvasculature, resulting in extravasation and retention of the lipoprotein-Aß moiety. The latter results in an inflammatory response and neurodegeneration ensues. Probucol, a historic cholesterol-lowering drug, has been shown in murine models to suppress lipoprotein-Aß secretion, concomitant with maintaining blood-brain-barrier function, suppressing neurovascular inflammation and supporting cognitive function. This protocol details the probucol in Alzheimer's study, a drug intervention trial investigating if probucol has potential to attenuate cognitive decline, delay brain atrophy and reduce cerebral amyloid burden in patients with mild-to-moderate AD. METHODS AND ANALYSIS: The study is a phase II, randomised, placebo-controlled, double-blind single-site clinical trial held in Perth, Australia. The target sample is 314 participants with mild-to-moderate AD. Participants will be recruited and randomised (1:1) to a 104-week intervention consisting of placebo induction for 2 weeks followed by 102 weeks of probucol (Lorelco) or placebo. The primary outcome is changed in cognitive performance determined via the Alzheimer's Disease Assessment Scales-Cognitive Subscale test between baseline and 104 weeks. Secondary outcomes measures will be the change in brain structure and function, cerebral amyloid load, quality of life, and the safety and tolerability of Lorelco, after a 104week intervention. ETHICS AND DISSEMINATION: The study has been approved by the Bellberry Limited Human Research Ethics Committee (approval number: HREC2019-11-1063; Version 4, 6 October 2021). Informed consent will be obtained from participants prior to any study procedures being performed. The investigator group will disseminate study findings through peer-reviewed publications, key conferences and local stakeholder events. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN12621000726853).

Do infants of breast-feeding mothers benefit from additional long-chain PUFA from fish oil? A 6-year follow-up.

Fish-oil supplements are marketed as enhancing intelligence and cognitive performance. However, empirical data concerning the utility of these products in healthy term infants are mixed, particularly with respect to lasting effects into childhood. We evaluated whether fish-oil supplementation during infancy leads to better neurocognitive/behavioural development at 6 years. We conducted a double-blind randomised controlled trial of supplementation with n-3 long-chain PUFA in 420 healthy term infants. Infants received either fish oil (containing at least 250 mg DHA and at least 60 mg EPA) or placebo (olive oil) daily from birth to 6 months of age. Neurodevelopmental follow-up was conducted at a mean age of 6 years (sd 7 months), whereby 335 children were assessed for language, executive functioning, global intelligence quotient and behaviour. No significant differences were observed between the groups for the main neurocognitive outcomes. However in parent-report questionnaire, fish-oil supplementation was associated with negative externalising (P = 0·035, d = 0·24) and oppositional/defiant behaviour (P = 0·006, d = 0·31), particularly in boys (P = 0·01, d = 0·45; P = 0·004, d = 0·40). Our results provide evidence that fish-oil supplementation to predominantly breast-fed infants confers no significant cognitive or behavioural benefit to children at 6 years.

Mechanisms of Change During Attention Training and Mindfulness in High Trait-Anxious Individuals: A Randomized Controlled Study.

The first aim of this study was to compare attention manipulation techniques deriving from metacognitive therapy (the Attention Training Technique; ATT) and mindfulness-based approaches (Mindfulness-Based Progressive Muscle Relaxation, MB-PMR) to a thought wandering control (TWC) condition, in terms of their impact on anxiety and four mechanisms: distancing, present-focused attention, uncontrollability and dangerousness, metacognitive beliefs, and cognitive flexibility (Stroop task). The second aim was to test indirect effects of the techniques on anxiety via the mechanism measures. High trait anxious participants (N = 81, Mage = 23.60, SDage = 7.66, 80% female) were randomized to receive ATT, MB-PMR, or the TWC condition. Measures of cognitive and somatic anxiety, distancing, present-focused attention, metacognitive beliefs, and cognitive flexibility were administered before or after the attention manipulation task. Compared to the TWC group, ATT and MB-PMR were associated with greater changes on cognitive (but not somatic) anxiety, present-focused attention, metacognitive beliefs, and uncorrected errors for threat-related words on the Stroop task. The pattern of means was similar for distancing, but this did not reach statistical significance, and Stroop speed increased equally for all conditions. Indirect effects models revealed significant effects of condition on state anxiety via distancing, metacognitive beliefs, and present-focused attention, but not via Stroop errors. ATT and MB-PMR were associated with changes on anxiety and the mechanism measures, suggesting that the mechanisms of change may be more similar than different across these techniques.

Serum high-density lipoprotein is associated with better cognitive function in a cross-sectional study of aging women.

Purpose/Aim of the study: Poor cardiovascular health, including obesity and altered lipid profiles at mid-life, are linked to increased risk of Alzheimer's disease (AD). The biological mechanisms linking cardiovascular health and cognitive function are unclear though are likely to be multifactorial. This study examined the association between various lipoproteins and cognitive functioning in ageing women. MATERIALS AND METHODS: We investigated the relationship between readily available biomarkers (i.e. serum lipoprotein) and cognitive decline in domains associated with increased risk of AD (e.g. episodic verbal memory performance and subjective memory complaint). We report cross-sectional data investigating the relationship between serum total cholesterol, triglycerides, high-density lipoprotein (HDL-C) and low-density lipoprotein with verbal memory and learning ability in 130 women with and without memory complaints (n = 71 and 59, respectively) drawn from a study investigating cognitively healthy Western Australians (average age 62.5 years old). RESULTS: After statistical modelling that controlled for the effects of age, depression and apolipoprotein E genotype, HDL-C was significantly associated with better verbal learning and memory performance, specifically short and long delay-free recalls (F = 3.062; p < .05 and F = 3.2670; p < .05, respectively). CONCLUSION: Our cross-sectional findings suggest that the positive effect of HDL-C on verbal memory may be present much earlier than previously reported and provide further support for the role of HDL-C in healthy brain ageing. Further exploration of the protective effect of HDL-C on cognitive function in ageing is warranted through follow-up, longitudinal studies.

Impact of Mild Head Injury on Neuropsychological Performance in Healthy Older Adults: Longitudinal Assessment in the AIBL Cohort.

Traumatic brain injury (TBI) is suggested to be a significant risk factor for dementia. However, little research has been conducted into long-term neuropsychological outcomes after head trauma. Participants from the Australian Imaging, Biomarkers and Lifestyle Study of Ageing (AIBL) who had recovered after sustaining a mild TBI involving loss of consciousness more than 5 years previously were compared with matched controls across a 3-year period. Bayesian nested-domain modeling was used to estimate the effect of TBI on neuropsychological performance. There was no evidence for a chronic effect of mild TBI on any neuropsychological domain compared to controls. Within the TBI group, there was some evidence suggesting that the age that the head trauma occurred and the duration of unconsciousness were modulators of episodic memory. However, these findings were not robust. Taken together, these findings indicate that adults who have sustained a TBI resulting in loss of consciousness, but who recover to a healthy level of cognitive functioning, do not experience frank deficits in cognitive ability.

Cerebral Glucose Metabolism is Associated with Verbal but not Visual Memory Performance in Community-Dwelling Older Adults.

Increasing evidence suggests that Alzheimer's disease (AD) sufferers show region-specific reductions in cerebral glucose metabolism, as measured by [18F]-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET). We investigated preclinical disease stage by cross-sectionally examining the association between global cognition, verbal and visual memory, and 18F-FDG PET standardized uptake value ratio (SUVR) in 43 healthy control individuals, subsequently focusing on differences between subjective memory complainers and non-memory complainers. The 18F-FDG PET regions of interest investigated include the hippocampus, amygdala, posterior cingulate, superior parietal, entorhinal cortices, frontal cortex, temporal cortex, and inferior parietal region. In the cohort as a whole, verbal logical memory immediate recall was positively associated with 18F-FDG PET SUVR in both the left hippocampus and right amygdala. There were no associations observed between global cognition, delayed recall in logical memory, or visual reproduction and 18F-FDG PET SUVR. Following stratification of the cohort into subjective memory complainers and non-complainers, verbal logical memory immediate recall was positively associated with 18F-FDG PET SUVR in the right amygdala in those with subjective memory complaints. There were no significant associations observed in non-memory complainers between 18F-FDG PET SUVR in regions of interest and cognitive performance. We observed subjective memory complaint-specific associations between 18F-FDG PET SUVR and immediate verbal memory performance in our cohort, however found no associations between delayed recall of verbal memory performance or visual memory performance. It is here argued that the neural mechanisms underlying verbal and visual memory performance may in fact differ in their pathways, and the characteristic reduction of 18F-FDG PET SUVR observed in this and previous studies likely reflects the pathophysiological changes in specific brain regions that occur in preclinical AD.

Good-quality diet in the early years may have a positive effect on academic achievement.

AIM: The aim of this study was to investigate the associations between early diet and academic performance during childhood. METHODS: Participants were from the Western Australian Pregnancy Cohort (Raine) Study (n = 2287). Frequency of consumption of food and beverages was collected at the one-, two- and three-year follow-ups, using a 24-hour food recall. Diet scores were developed from the number of eating occasions. The Western Australian Literacy and Numeracy Assessment (WALNA) data from grades five (age 10) and seven (age 12) were linked to the Raine study using The Western Australian Data Linkage System. The association between diet scores and WALNA scores was assessed using multivariate linear regression models. RESULTS: A higher (i.e. better quality) diet score at one year of age was associated with significantly higher scores in mathematics, reading, writing and spelling at both grades five and seven. Associations were observed between a higher diet score at two years and academic scores for mathematics, writing and spelling at grade seven. Higher dairy consumption at ages one, two and three, and higher fruit consumption at age one were associated with higher academic scores at all ages. CONCLUSION: Quality of early diet may be a predictor for later academic achievement.

Serum 25-hydroxyvitamin D is associated with reduced verbal episodic memory in healthy, middle-aged and older adults.

BACKGROUND: There is increasing evidence supporting an association of higher serum vitamin D concentration with better cognitive performance in older individuals. However, to date, consideration of the putative association between vitamin D and cognition has been based principally on studies investigating clinical participant samples manifesting vitamin D deficiency, particularly in older people. Moreover, relationships between vitamin D and cognition are typically not considered in the context of counter-regulatory calcium-modulating hormones or calcium homeostasis. OBJECTIVE: Serum vitamin D/bioactive (ionised) calcium/parathyroid hormone homeostasis was considered in the context of cognitive performance in healthy, middle-aged and older individuals. DESIGN: A cross-sectional sample of 179 participants between the ages of 47-84 years was recruited for this study (114 females, 65 males). Participants provided fasting blood samples for analysis of serum 25-hydroxyvitamin D levels, ionised calcium (iCa) and parathyroid hormone (PTH) and completed cognitive measures of verbal episodic learning and memory. RESULTS: Serum 25-hydroxyvitamin D concentrations were negatively associated (with and without covariates of age, gender, depression and NART scores, iCa, and PTH) with measures of verbal episodic learning and memory, in particular with trial 5 of the Rey Auditory Verbal Learning Test (RAVLT) and long-delay free recall on the RAVLT. CONCLUSION: Overall, the findings from this study suggest an association between higher vitamin D status and poorer performance on verbal episodic memory in middle-aged and older individuals with normal vitamin D-calcium-PTH homeostasis. Despite requiring replication in other participant samples, this is a potentially important finding as it indicates that it may not be beneficial from a cognitive perspective to provide vitamin D supplements in individuals with already adequate vitamin D status.

Longitudinal cognitive decline in the AIBL cohort: The role of APOE ε4 status.

The ε4 polymorphism of the APOE gene confers a substantially increased risk of developing Alzheimer's disease. However, the influence of the ε4 allele on age-related cognitive functioning is more contentious. Previously, we demonstrated relatively little evidence for a role of the ε4 allele on baseline cognitive performance in older adults in the Australian Imaging, Biomarkers and Lifestyle (AIBL) Study of Ageing (Foster et al., 2013). We here investigated whether the APOE ε4 allele influenced cognitive status over time when the AIBL cohort was studied longitudinally over a 3-year period. The AIBL neuropsychological test battery was administered at baseline, after 18 months and again after 36 months. Participants comprised 764 Healthy Controls and 131 Mild Cognitively Impaired individuals enrolled in the AIBL Study of Ageing. We compared individuals within each group with and without an ε4 allele. Healthy Controls with an ε4 allele manifested a modest acceleration in cognitive decline over 36 months on measures of verbal episodic memory. By contrast, Mild Cognitively Impaired individuals with an ε4 allele showed increased cognitive decline across a range of cognitive tasks, putatively reflecting early cognitive signs of Alzheimer's disease. Given the long prodromal period that has been noted in late onset Alzheimer's disease, we suggest that these findings are consistent with a prodromal account rather than a phenotypic account of ε4-related cognitive ageing.

The Relationship between Nutrition in Infancy and Cognitive Performance during Adolescence.

OBJECTIVES: In this study, we aimed to investigate the long-term associations between breastfeeding duration during infancy, diet quality as measured by a diet score at 1 year of age, and cognitive performance during adolescence. METHODS: Participants (n = 717) were recruited from the West Australian Pregnancy Cohort (Raine) Study, a prospective longitudinal study of 2868 children and their families based in Perth, WA, Australia. Breastfeeding duration and an early diet score at age 1 year were used as the main predictor variables, while a computerized cognitive battery (CogState) was used to assess adolescents' cognitive performance at 17 years. The diet score, which has seven food group components, was based on a 24-h recall questionnaire completed by the mother at 1 year of age. A higher diet score represents a better, more nutritious eating pattern. Associations between breastfeeding duration, diet score, and cognitive performance were assessed in multivariable regression models. RESULTS: Higher diet scores at 1 year representing better diet quality were significantly associated with faster reaction times in cognitive performance at 17 years [Detection Task (DET): ß = -0.004, 95% CI: -0.008; 0.000, p = 0.036; Identification Task (IDN): ß = -0.004, 95% CI: -0.008; 0.000, p = 0.027]. Breastfeeding duration (≥4 months) was also significantly associated with a shorter reaction time, but only for males (DET: ß = -0.026, 95% CI: -0.046; -0.006, p = 0.010). CONCLUSION: Nutrition in early childhood may have a long-term association with fundamental cognitive processing speed, which is likely to be related to enhanced brain development in the first year of life.

A Western dietary pattern is associated with poor academic performance in Australian adolescents.

The aim of this study was to investigate cross-sectional associations between dietary patterns and academic performance among 14-year-old adolescents. Study participants were from the Western Australian Pregnancy Cohort (Raine) Study. A food frequency questionnaire was administered when the adolescents were 14 years old, and from the dietary data, a 'Healthy' and a 'Western' dietary pattern were identified by factor analysis. The Western Australian Literacy and Numeracy Assessment (WALNA) results from grade nine (age 14) were linked to the Raine Study data by The Western Australian Data Linkage Branch. Associations between the dietary patterns and the WALNA (mathematics, reading and writing scores) were assessed using multivariate linear regression models adjusting for family and socioeconomic characteristics. Complete data on dietary patterns, academic performance and covariates were available for individuals across the different analyses as follows: n = 779 for mathematics, n = 741 for reading and n = 470 for writing. Following adjustment, significant negative associations between the 'Western' dietary pattern and test scores for mathematics (ß = -13.14; 95% CI: -24.57; -1.76); p = 0.024) and reading (ß = -19.16; 95% CI: -29.85; -8.47; p ≤ 0.001) were observed. A similar trend was found with respect to writing (ß = -17.28; 95% CI: -35.74; 1.18; p = 0.066). ANOVA showed significant trends in estimated means of academic scores across quartiles for both the Western and Healthy patterns. Higher scores for the 'Western' dietary pattern are associated with poorer academic performance in adolescence.

Maternal fish oil supplementation in pregnancy: a 12 year follow-up of a randomised controlled trial.

A number of trials have been undertaken to assess whether the intake of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) during pregnancy can influence the neurological development of the offspring, yet no consensus from these trials has been reached. We aimed to investigate the long-term effects (12 years) of fish oil supplementation in pregnancy on neurodevelopment, including cognition, language and fine motor skills. In a follow up of a previously published randomised controlled trial of 98 pregnant women, their children were assessed at 12 years of age using a battery of neurodevelopmental assessments. Fifty participants were assessed at 12 years, with 25 participant's mothers receiving fish oil supplementation, and 25 receiving control capsules. There were no significant differences for any of the assessment measures completed. Our data indicate that fish oil supplementation during pregnancy does not influence the cognition, language or fine motor skills of children in late primary school (12 years of age).

Bone mineral density, adiposity, and cognitive functions.

Cognitive decline and dementia due to Alzheimer's disease (AD) have been associated with genetic, lifestyle, and environmental factors. A number of potentially modifiable risk factors should be taken into account when preventive or ameliorative interventions targeting dementia and its preclinical stages are investigated. Bone mineral density (BMD) and body composition are two such potentially modifiable risk factors, and their association with cognitive decline was investigated in this study. 164 participants, aged 34-87 years old (62.78 ± 9.27), were recruited for this longitudinal study and underwent cognitive and clinical examinations at baseline and after 3 years. Blood samples were collected for apolipoprotein E (APOE) genotyping and dual energy x-ray absorptiometry (DXA) was conducted at the same day as cognitive assessment. Using hierarchical regression analysis, we found that BMD and lean body mass, as measured using DXA were significant predictors of episodic memory. Age, gender, APOE status, and premorbid IQ were controlled for. Specifically, the List A learning from California Verbal Learning Test was significantly associated with BMD and lean mass both at baseline and at follow up assessment. Our findings indicate that there is a significant association between BMD and lean body mass and episodic verbal learning. While the involvement of modifiable lifestyle factors in human cognitive function has been examined in different studies, there is a need for further research to understand the potential underlying mechanisms.

Grey matter changes associated with deficit awareness in mild cognitive impairment: a voxel-based morphometry study.

Reduced awareness of cognitive deficits in mild cognitive impairment (MCI) is associated with poorer outcomes although little is known about the anatomical correlates of this. We examined the association of insight and grey matter volume using a voxel-based morphometry approach in 65 volunteers with MCI and 55 healthy age-matched controls. Participants with MCI had multiple areas of subtle grey matter volume loss compared with controls, although these did not survive correction for multiple comparisons. These were predominantly in the temporal and anterior portions of the brain. Individuals with MCI did not differ from each other on a number of demographic and cognitive variables according to level of insight. Reduced awareness of cognitive deficits was associated with few differences in grey matter volume apart from a subtle loss of grey matter in the medial frontal gyri. Given the modest nature of these findings, the routine assessment of insight in non-clinical populations of individuals with MCI is therefore not supported. Prospective data in larger samples, however, would be helpful to clarify this further and determine if impaired insight predicts brain atrophy and cognitive decline.

Functional Living in Older Adults With Type 2 Diabetes: Executive Functioning, Dual Task Performance, and the Impact on Postural Stability and Motor Control.

OBJECTIVE: Older adults with type 2 diabetes mellitus (DM2) experience accelerated age-related decline in some domains of cognition. The present study sought to investigate executive functioning and dual tasking capacities in this group. METHOD: Older adults with DM2 and age-matched controls completed self-report measures assessing everyday activities, a comprehensive cognitive battery and more specific tasks assessing executive functioning, dual tasking, postural stability, and motor control. RESULTS: Executive abilities were particularly compromised in the participants with DM2. Furthermore, the DM2 group exhibited reduced postural stability under dual task conditions. DISCUSSION: These findings suggest that deficits in more complex cognitive activities underlie the decline in everyday function in DM2.

Brief report: visual acuity in children with autism spectrum disorders.

Recently, there has been heightened interest in suggestions of enhanced visual acuity in autism spectrum disorders (ASD) which was sparked by evidence that was later accepted to be methodologically flawed. However, a recent study that claimed children with ASD have enhanced visual acuity (Brosnan et al. in J Autism Dev Disord 42:2491-2497, 2012) repeated a critical methodological flaw by using an inappropriate viewing distance for a computerised acuity test, placing the findings in doubt. We examined visual acuity in 31 children with ASD and 33 controls using the 2 m 2000 Series Revised Early Treatment Diabetic Retinopathy Study chart placed at twice the conventional distance to better evaluate possible enhanced acuity. Children with ASD did not demonstrate superior acuity. The current findings strengthen the argument that reports of enhanced acuity in ASD are due to methodological flaws and challenges the reported association between visual acuity and systemising type behaviours.

Prospective associations between dietary patterns and cognitive performance during adolescence.

BACKGROUND: The aim of the study was to investigate prospective associations between dietary patterns and cognitive performance during adolescence. METHODS: Participants were sourced from the Western Australian Pregnancy Cohort (Raine) Study that includes 2868 children born between 1989 and 1992 in Perth, Western Australia. When the children were 17 years old (2006-2009), cognitive performance was assessed using a computerized cognitive battery of tests (CogState) that included six tasks. Using a food frequency questionnaire administered when the children were 14 years old (2003-2006), 'Healthy' and 'Western' dietary patterns were identified by factor analysis. Associations between dietary patterns at 14 years of age and cognitive performance at 17 years of age were assessed prospectively using multivariate regression models. RESULTS: Dietary and cognitive performance data were available for 602 participants. Following adjustment for the 'Healthy' dietary pattern, total energy intake, maternal education, family income, father's presence in the family, family functioning and gender, we found that a longer reaction time in the detection task (ß = .016; 95% CI: 0.004; 0.028; p = .009) and a higher number of total errors in the Groton Maze Learning Test - delayed recall task (ß = .060; 95% CI: 0.006; 0.114; p = .029) were significantly associated with higher scores on the 'Western' dietary pattern. The 'Western' dietary pattern was characterized by high intakes of take-away food, red and processed meat, soft drink, fried and refined food. We also found that within the dietary patterns, high intake of fried potato, crisps and red meat had negative associations, while increased fruit and leafy green vegetable intake had positive associations with some aspects of cognitive performance. CONCLUSION: Higher dietary intake of the 'Western' dietary pattern at age 14 is associated with diminished cognitive performance 3 years later, at 17 years.

Neuropsychological performance is positively associated with plasma albumin in healthy adults.

BACKGROUND: Albumin serves a range of physiological functions that are vital to overall brain and cognitive health. Indeed, associations between cognitive performance and albumin have been demonstrated in individuals with chronic liver or kidney disease and in patients with a high urinary excretion of albumin. However, an association of plasma albumin with cognitive performance has not been reported in otherwise healthy participants with clinically acceptable plasma albumin concentrations. METHOD: This study utilized a wide-ranging neuropsychological test battery to investigate the relationship between cognitive performance and plasma albumin homeostasis in 222 healthy participants (143 females) between the ages of 43 and 84 years (mean 65 years). RESULTS: Albumin both with and without the covariates of age, sex and acute-phase proteins was positively associated with enhanced performance on a range of neuropsychological domains including perceptual speed, Stroop and verbal ability. Albumin manifested generally positive but less robust associations with secondary and primary memory. CONCLUSION: The results indicate that there is a positive association between albumin and cognitive performance in physiologically healthy participants free of chronic renal or liver disease.

Does docosahexaenoic acid supplementation in term infants enhance neurocognitive functioning in infancy?

The proposal that dietary docosahexaenoic acid (DHA) enhances neurocognitive functioning in term infants is controversial. Theoretical evidence, laboratory research and human epidemiological studies have convincingly demonstrated that DHA deficiency can negatively impact neurocognitive development. However, the results from randomized controlled trials (RCTs) of DHA supplementation in human term-born infants have been inconsistent. This article will (i) discuss the role of DHA in the human diet, (ii) explore the physiological mechanisms by which DHA plausibly influences neurocognitive capacity, and (iii) seek to characterize the optimal intake of DHA during infancy for neurocognitive functioning, based on existing research that has been undertaken in developed countries (specifically, within Australia). The major observational studies and RCTs that have examined dietary DHA in human infants and animals are presented, and we consider suggestions that DHA requirements vary across individuals according to genetic profile. It is important that the current evidence concerning DHA supplementation is carefully evaluated so that appropriate recommendations can be made and future directions of research can be strategically planned.