Breast-feeding and cognitive development: a meta-analysis.
(25/1670)
BACKGROUND: Although the results of many clinical studies suggest that breast-fed children score higher on tests of cognitive function than do formula-fed children, some investigators have suggested that these differences are related to confounding covariables such as socioeconomic status or maternal education. OBJECTIVE: Our objective was to conduct a meta-analysis of observed differences in cognitive development between breast-fed and formula-fed children. DESIGN: In this meta-analysis we defined the effect estimate as the mean difference in cognitive function between breast-fed and formula-fed groups and calculated average effects using fixed-effects and random-effects models. RESULTS: Of 20 studies meeting initial inclusion criteria, 11 studies controlled for >/=5 covariates and presented unadjusted and adjusted results. An unadjusted benefit of 5.32 (95% CI: 4.51, 6.14) points in cognitive function was observed for breast-fed compared with formula-fed children. After adjustment for covariates, the increment in cognitive function was 3.16 (95% CI: 2.35, 3.98) points. This adjusted difference was significant and homogeneous. Significantly higher levels of cognitive function were seen in breast-fed than in formula-fed children at 6-23 mo of age and these differences were stable across successive ages. Low-birth-weight infants showed larger differences (5.18 points; 95% CI: 3.59, 6.77) than did normal-birth-weight infants (2.66 points; 95% CI: 2.15, 3.17) suggesting that premature infants derive more benefits in cognitive development from breast milk than do full-term infants. Finally, the cognitive developmental benefits of breast-feeding increased with duration. CONCLUSION: This meta-analysis indicated that, after adjustment for appropriate key cofactors, breast-feeding was associated with significantly higher scores for cognitive development than was formula feeding. (+info)
Neuropsychological impairment in stroke, carotid stenosis, and peripheral vascular disease, A comparison with healthy community residents.
(26/1670)
BACKGROUND AND PURPOSE: An increasing body of literature suggests a role for clinically "silent" cerebrovascular disease in the pathogenesis of cognitive impairment. Such pathology commonly occurs in the absence of stroke. The main aim of the study was to examine neuropsychological impairment associated with cerebrovascular and peripheral vascular disease (PVD) and to compare cognitive deficits with a nonvascular control group. The main hypothesis was that older people with both transient ischemic attack (TIA) and PVD would demonstrate greater cognitive impairment than controls. METHODS: A battery of neuropsychological tests was administered to 4 groups of community residents older than 65 years. The groups comprised 25 patients with carotid stenosis and TIA, 25 nonamputees with PVD, 25 patients with stroke, and 25 matched (with the stroke group) controls. RESULTS: Stroke patients showed greater impairment than controls in all tests. PVD patients did not perform significantly worse (P<0.05 after Bonferroni correction) than control subjects on any of the neuropsychological tests. However, 25% of PVD patients had scores lying within the bottom 5% of control group scores for attention, calculation, and 1 test of frontal lobe function. TIA patients were more impaired in general intellectual impairment and frontal lobe function than controls. Frontal lobe impairment, suicidal thinking, and age were all independent predictors of global cognitive impairment in the TIA group. Frontal lobe impairment was the only predictor of global cognitive impairment in the PVD group. CONCLUSIONS: TIA and PVD patients showed similar patterns of neuropsychological impairment, but TIA may result in more prolonged cognitive impairment, particularly in frontal lobe function. This group may be at increased risk of vascular dementia as well as impulsivity and suicide. (+info)
Memory deficits in patients with schizophrenia: preliminary data from the Wechsler Memory Scale-Third Edition support earlier findings.
(27/1670)
OBJECTIVE: To determine whether memory data presented for a schizophrenia sample in the Technical Manual of the Wechsler Memory Scale-Third Edition support trends identified in a previously published review of studies employing an earlier version of the instrument, the Wechsler Memory Scale-Revised. DESIGN: Archival: reformulation of published data. PATIENTS: Patients with schizophrenia, Alzheimer's disease, Korsakoff's syndrome or traumatic brain injury (TBI) for whom intelligence and memory data were reported in the Technical Manual of the Wechsler Adult Intelligence Scale-Third Edition Wechsler Memory Scale-Third Edition (WAIS-III WMS-III). OUTCOME MEASURES: Mean Full Scale, Verbal, and Performance Intelligence Quotients of the WAIS-III and mean WMS-III Immediate and General Memory Indexes. Single-trial learning and learning slope data were also culled from the WAIS-III WMS-III Technical Manual. RESULTS: Memory indexes for patients with Alzheimer's disease or Korsakoff's syndrome were substantially lower than those for patients with schizophrenia or TBI. In tests of learning processes, patients with schizophrenia had an inferior ability to repeat material presented just once, in comparison with the standardization sample. However, they did relatively better with repeated presentations than patients with Alzheimer's disease or Korsakoff's syndrome. The learning slope for patients with schizophrenia demonstrated an ability to absorb and consolidate increasing amounts of material with repeated exposure that is inconsistent with pronounced memory impairment. CONCLUSIONS: Although patients with schizophrenia exhibit new learning deficiencies, their memory capabilities are not substantially weaker than their general intellectual abilities, and do not approach the memory impairment exhibited by patients with Alzheimer's disease or Korsakoff's syndrome. (+info)
Correlation between magnetic resonance imaging and clinical profiles of periventricular leukomalacia.
(28/1670)
Magnetic resonance imaging (MRI) findings of 70 children with periventricular leukomalacia (PVL), examined between 1 year 2 months and 8 years of age (mean: 2 years 4 months of age), were analysed. Neurological assessments were made between 1 year 3 months and 15 years (mean: 4 years 9 months). The possible correlations between MRI findings and clinical profiles of PVL were investigated using three parameters of the MRI findings. The grade of ventriculomegaly correlated well with the severity of cerebral palsy (CP) but not with the severity of mental impairment. The grade of reduction of periventricular white matter correlated well with the severity of CP and mental impairment, and is the most reliable parameter for neurological prognosis. The degree of periventricular hyperintensity on T2-weighted images did not correlate well with severity of CP, but correlated to some degree with mental impairment. There was a significantly lower degree of periventricular hyperintensity in children at less than 28 weeks of gestation than at 28 or more weeks of gestation, but no significant difference in other parameters. The periventricular hyperintensity should be evaluated in view of the gestational age. (+info)
The genetic basis of cognition.
(29/1670)
The molecular characterization of single-gene disorders or chromosomal abnormalities that result in a cognitive abnormality (predominantly mental retardation) and of the genetic variants responsible for variation in intellectual abilities (such as IQ, language impairment and dyslexia) is expected to provide new insights into the biology of human cognitive processes. To date this hope has not been realized. Success in finding mutations that give rise to mental retardation has not been matched by advances in our understanding of how genes influence cognition. In contrast, the use of engineered mutations in mice to study models of learning and memory has cast new light on the molecular basis of memory. A comparison of studies of human and mouse mutations indicates the limitations of current genetic approaches to the understanding of human cognition. It is essential to interpret a mutation's effect within a well-characterized neural system; mutations can be used to define gene function only when the mutation has an effect on a system whose constituents form a serial causal chain, such as the molecular components of a signal transduction pathway. Typically, however, genetic mutations with a cognitive and behavioural phenotype are characterized by specific effects on different systems whose inter-relationships are unknown. Genetic approaches are currently limited to exploring neuronal function; it is not yet clear whether they will throw light on how neuronal connections give rise to cognitive processes. We need a much greater integration of different levels of understanding of cognition in order to exploit the genetic discoveries. In short, a rapprochement between molecular and systems neuroscience is required. (+info)
Second-order belief attribution in Williams syndrome: intact or impaired?
(30/1670)
Second-order mental state attribution in a group of children with Williams syndrome was investigated. The children were compared to age, IQ, and language-matched groups of children with Prader-Willi syndrome or nonspecific mental retardation. Participants were given two trials of a second-order reasoning task. No significant differences between the Williams syndrome and Prader-Willi or mentally retarded groups on any of the test questions were found. Results contrast with the view that individuals with Williams syndrome have an intact theory of mind and suggest that in their attributions of second-order mental states, children with Williams syndrome perform no better than do other groups of children with mental retardation. (+info)
Everyday cognition: age and intellectual ability correlates.
(31/1670)
The primary aim of this study was to examine the relationship between a new battery of everyday cognition measures, which assessed 4 cognitive abilities within 3 familiar real-world domains, and traditional psychometric tests of the same basic cognitive abilities. Several theoreticians have argued that everyday cognition measures are somewhat distinct from traditional cognitive assessment approaches, and the authors investigated this assertion correlationally in the present study. The sample consisted of 174 community-dwelling older adults from the Detroit metropolitan area, who had an average age of 73 years. Major results of the study showed that (a) each everyday cognitive test was strongly correlated with the basic cognitive abilities; (b) several basic abilities, as well as measures of domain-specific knowledge, predicted everyday cognitive performance; and (c) everyday and basic measures were similarly related to age. The results suggest that everyday cognition is not unrelated to traditional measures, nor is it less sensitive to age-related differences. (+info)
Cognitive and academic outcome following cranial irradiation and chemotherapy in children: a longitudinal study.
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Cranial irradiation therapy (CRT) and chemotherapy are associated with neurobehavioural deficits. Many studies have investigated late effects of these treatments, but few have evaluated changes in abilities over time. This study employed a longitudinal design to map abilities following these treatments. Three groups of children were studied: Group 1 (n = 35): children treated with CRT (18 Gy) + chemotherapy, aged 5 years or less at time of diagnosis; Group 2 (n = 19): children treated with chemotherapy alone, aged 5 years or less at time of diagnosis; Group 3 (n = 35): healthy children. All children were aged 7-13 years at time of initial assessment, with no pre-diagnosis history of neurologic, developmental, or psychiatric disorder. Intellectual and educational abilities were evaluated twice: T1, not less than 2 years post-treatment, and T2, 3 years later. Group 1 achieved poorest results at T1, with comparison groups performing similarly. At T2 group differences were maintained. For verbal skills differences remained stable. Group 1 exhibited deterioration on non-verbal and processing tasks, while comparison groups showed improved abilities. Group 1 exhibited increases in literacy skills, with educational intervention predicting progress. Results suggest cumulative deficits in non-verbal and information processing skills for children treated with CRT + chemotherapy, with other deficits remaining relatively stable over time. Improved literacy skills suggest that gains can occur with remediation. (+info)