0
selected
-
1.
Omega-3 and its domain-specific effects on cognitive test performance in youths: A meta-analysis.
Emery, S, Häberling, I, Berger, G, Walitza, S, Schmeck, K, Albert, T, Baumgartner, N, Strumberger, M, Albermann, M, Drechsler, R
Neuroscience and biobehavioral reviews. 2020;:420-436
Abstract
Omega-3 fatty acids are vital for brain development. The aim of this meta-analysis was to broaden current knowledge of the effects of omega-3 supplementation on cognitive test performance in youths. Randomized controlled trials (RCTs) meeting selection criteria were identified through two independent literature searches on PubMed, Cochrane Library, PsycARTICLES and PsycINFO (last search June 2019). Twenty-nine out of 1126 studies assessing 4247 participants met all selection criteria. A meta-analysis using random-effects model was performed for eight different cognitive domains. This first analysis revealed no main effect of omega-3 fatty acid supplementation on domain-specific cognitive test performance in youths. Subgroup analyses identified beneficial effects of eicosapentaenoic acid (EPA)-rich but not docosahexaenoic acid (DHA)-rich formulations in the domains of long-term memory, working memory and problem solving and a tendency towards beneficial effects in clinical rather than non-clinical populations. Future research should investigate differential effects of EPA and DHA and consider their baseline levels, other nutritional components and interactions with gene variations as potential predictors of response.
-
2.
Effects of acute caffeine consumption following sleep loss on cognitive, physical, occupational and driving performance: A systematic review and meta-analysis.
Irwin, C, Khalesi, S, Desbrow, B, McCartney, D
Neuroscience and biobehavioral reviews. 2020;:877-888
Abstract
Caffeine is widely used to counteract the effects of sleep loss. This systematic review and meta-analysis examined the impact of acute caffeine consumption on cognitive, physical, occupational and driving performance in sleep deprived/restricted individuals. 45 publications providing 327 effect estimates (EEs) were included in the review. Caffeine improved response time (44 EEs; g = 0.86; 95 % CI: 0.53-0.83) and accuracy (27 EEs; g = 0.68; 95 % CI: 0.48-0.88) on attention tests, improved executive function (38 EEs; g = 0.35; 95 % CI: 0.15-0.55), improved reaction time (12 EEs; g = 1.11; 95 % CI: 0.75-1.47), improved response time (20 EEs; g = 1.95; 95 % CI: 1.39-2.52) and accuracy (34 EEs; g = 0.43; 95 % CI: 0.30-0.55) on information processing tasks, and enhanced lateral (29 EEs; g = 1.67; 95 % CI: 1.32-2.02) and longitudinal (12 EEs; g = 1.60; 95 % CI: 1.16-2.03) measures of vehicular control on driving tests. Studies also typically indicated benefit of caffeine on memory (25 EEs), crystallized intelligence (11 EEs), physical (39 EEs) and occupational (36 EEs) performance. Ingestion of caffeine is an effective counter-measure to the cognitive and physical impairments associated with sleep loss.
-
3.
Iron therapy for improving psychomotor development and cognitive function in children under the age of three with iron deficiency anaemia.
Wang, B, Zhan, S, Gong, T, Lee, L
The Cochrane database of systematic reviews. 2013;(6):CD001444
-
-
Free full text
-
Abstract
BACKGROUND Iron deficiency and iron deficiency anaemia (IDA) are common in young children. It has been suggested that the lack of iron may have deleterious effects on children's psychomotor development and cognitive function. To evaluate the benefits of iron therapy on psychomotor development and cognitive function in children with IDA, a Cochrane review was carried out in 2001. This is an update of that review. OBJECTIVES To determine the effects of iron therapy on psychomotor development and cognitive function in iron deficient anaemic children less than three years of age. SEARCH METHODS We searched the following databases in April 2013: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO, LILACS, ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (ICTRP). We also searched the reference lists of review articles and reports, and ran citation searches in the Science Citation Index for relevant studies identified by the primary search. We also contacted key authors. SELECTION CRITERIA Studies were included if children less than three years of age with evidence of IDA were randomly allocated to iron or iron plus vitamin C versus a placebo or vitamin C alone, and assessment of developmental status or cognitive function was carried out using standardised tests by observers blind to treatment allocation. DATA COLLECTION AND ANALYSIS Two review authors independently screened titles and abstracts retrieved from the searches and assessed full-text copies of all potentially relevant studies against the inclusion criteria. The same review authors independently extracted data and assessed the risk of bias of the eligible studies. Data were analysed separately depending on whether assessments were performed within one month of beginning iron therapy or after one month. MAIN RESULTS We identified one eligible study in the update search that had not been included in the original review. In total, we included eight trials.Six trials, including 225 children with IDA, examined the effects of iron therapy on measures of psychomotor development and cognitive function within 30 days of commencement of therapy. We could pool data from five trials. The pooled difference in pre- to post-treatment change in Bayley Scale Psychomotor Development Index (PDI) between iron and placebo groups was -1.25 (95% confidence interval (CI) -4.56 to 2.06, P value = 0.65; I(2) = 33% for heterogeneity, random-effects meta-analysis; low quality evidence) and in Bayley Scale Mental Development Index (MDI) was 1.04 (95% CI -1.30 to 3.39, P value = 0.79; I(2) = 31% for heterogeneity, random-effects meta-analysis; low quality evidence).Two studies, including 160 randomised children with IDA, examined the effects of iron therapy on measures of psychomotor development and cognitive function more than 30 days after commencement of therapy. One of the studies reported the mean number of skills gained after two months of iron therapy using the Denver Developmental Screening Test. The intervention group gained 0.8 (95% CI -0.18 to 1.78, P value = 0.11, moderate quality of evidence) more skills on average than the control group. The other study reported that the difference in pre- to post-treatment change in Bayley Scale PDI between iron-treated and placebo groups after four months was 18.40 (95% CI 10.16 to 26.64, P value < 0.0001; moderate quality evidence) and in Bayley Scale MDI was 18.80 (95% CI 10.17 to 27.43, P value < 0.0001; moderate quality evidence). AUTHORS' CONCLUSIONS There is no convincing evidence that iron treatment of young children with IDA has an effect on psychomotor development or cognitive function within 30 days after commencement of therapy. The effect of longer-term treatment remains unclear. There is an urgent need for further large randomised controlled trials with long-term follow-up.
-
4.
Neuropsychological speed tests and blood phenylalanine levels in patients with phenylketonuria: a meta-analysis.
Albrecht, J, Garbade, SF, Burgard, P
Neuroscience and biobehavioral reviews. 2009;(3):414-21
Abstract
Although pathogenesis of phenylketonuria is not completely understood, a low phenylalanine diet is effective to prevent severe neurological impairment, mental retardation and behavioural difficulties. Treatment recommendations heavily rely on neuropsychological research; however, single study results are ambiguous, what is reflected in substantial variation of US, British, German, Dutch and French recommendations for blood phenylalanine concentrations for adolescents and adults. We conducted a meta-analysis estimating the influence of age, phenylalanine level, and type of neuropsychological test on effect sizes (standardized differences between controls and patients) of computer-based speed measurements in phenylketonuric patients. The effect of blood phenylalanine level on effect size was more pronounced in children and adolescents than in adults, with choice reaction time being particularly sensitive for phenylalanine concentrations. Results corroborate all recommendations for children. With the exception of the US and Dutch recommendations, all recommendations for adolescents seem to be too liberal. The same effect size is predicted for adult phenylalanine concentrations between 750 and 1500mumol/L not suggesting a preference for any of the published treatment recommendations for adulthood.
-
5.
Performance alterations associated with occupational exposure to manganese--a meta-analysis.
Meyer-Baron, M, Knapp, G, Schäper, M, van Thriel, C
Neurotoxicology. 2009;(4):487-96
Abstract
The review aimed at quantifying the evidence of performance effects resulting from occupational exposure to manganese. Epidemiological studies published between 1987 and 2008 were analyzed. The approach was based on the meta-analytical method of effect size estimates and sought to contribute to the following issues: (1) identification of the affected functions; (2) identification of sensitive neuropsychological tests; (3) analyses of exposure-effect relationships. Thirteen studies examining 958 exposed and 815 unexposed workers were included in the meta-analysis. Mean concentrations of inhalable manganese ranged from 0.05 to 1.59 mg/m(3), mean concentrations of manganese in whole blood ranged from 8.1 to 48.4 microg/L. Nineteen neuropsychological performance variables were analyzed as they were included in at least three of the identified studies. Apart from two outcomes, the overall effects displayed a negative impact of manganese on performance. Significant overall effects were obtained for six test variables; their size ranged from d=-0.23 to -0.36. Four of the variables measured motor speed and two of them speed of information processing. The analysis of exposure-effect relationships showed that larger effect sizes were more consistently associated with higher concentrations of inhalable manganese than with manganese in blood. The evidence of cognitive and motor performance effects is in accordance with the knowledge about accumulation of manganese in the basal ganglia and the effect of manganese on the neurotransmitter dopamine. Inconsistencies in the relationship between effect sizes and the biomarker manganese in blood were discussed in the context of results indicating that the biomarker might not be sufficiently meaningful for the neurobehavioral alterations. Simple motor performance tests with a distinct speed component seem to be highly recommendable for further studies, because they seem to be appropriate for measuring manganese-related changes, seem to provide homogenous results and their outcomes show consistent relations to exposure. The rigorous quantitative approach was especially appropriate for revealing exposure-effect relationships, but information about individual cumulative exposure would enhance the potential for risk assessment of manganese.
-
6.
Effect of iron supplementation on mental and motor development in children: systematic review of randomised controlled trials.
Sachdev, H, Gera, T, Nestel, P
Public health nutrition. 2005;(2):117-32
Abstract
OBJECTIVE To evaluate the effect of iron supplementation on mental and motor development in children through a systematic review of randomised controlled trials (RCTs). DATA SOURCES Electronic databases, personal files, hand search of reviews, bibliographies of books, abstracts and proceedings of international conferences. REVIEW METHODS RCTs with interventions that included oral or parenteral iron supplementation, fortified formula milk or cereals were evaluated. The outcomes studied were mental and motor development scores and various individual development tests employed, including Bayley mental and psychomotor development indices and intelligence quotient. RESULTS The pooled estimate (random effects model) of mental development score standardised mean difference (SMD) was 0.30 (95% confidence interval (CI) 0.15 to 0.46, P<0.001; P<0.001 for heterogeneity). Initial anaemia and iron-deficiency anaemia were significant explanatory variables for heterogeneity. The pooled estimate of Bayley Mental Development Index (weighted mean difference) in younger children (<27 months old) was 0.95 (95% CI -0.56 to 2.46, P=0.22; P=0.016 for heterogeneity). For intelligence quotient scores (> or =8 years age), the pooled SMD was 0.41 (95% CI 0.20 to 0.62, P<0.001; P=0.07 for heterogeneity). There was no effect of iron supplementation on motor development score (SMD 0.09, 95% CI -0.08 to 0.26, P=0.28; P=0.028 for heterogeneity). CONCLUSIONS Iron supplementation improves mental development score modestly. This effect is particularly apparent for intelligence tests above 7 years of age and in initially anaemic or iron-deficient anaemic subjects. There is no convincing evidence that iron treatment has an effect on mental development in children below 27 months of age or on motor development.