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At least 865 records · Page 48Linked to original sources

PubMed2006

Environmental influences on energy balance-related behaviors: a dual-process view.

BACKGROUND: Studies on the impact of the 'obesogenic' environment have often used non-theoretical approaches. In this journal's debate and in other papers authors have argued the necessity of formulating conceptual models for differentiating the causal role of environmental influences on behavior. DISCUSSION: The present paper aims to contribute to the debate by presenting a dual-process view on the environment--behavior relationship. This view is conceptualized in the EnRG framework (Environmental Research framework for weight Gain prevention). In the framework, behavior is postulated to be the result of a simultaneous influence of conscious and unconscious processes. Environmental influences are hypothesized to influence behavior both indirectly and directly. The indirect causal mechanism reflects the mediating role of behavior-specific cognitions in the influence of the environment on behavior. A direct influence reflects the automatic, unconscious, influence of the environment on behavior. Specific personal and behavioral factors are postulated to moderate the causal path (i.e., inducing either the automatic or the cognitively mediated environment - behavior relation). In addition, the EnRG framework applies an energy balance-approach, stimulating the integrated study of determinants of diet and physical activity. CONCLUSION: The application of a dual-process view may guide research towards causal mechanisms linking specific environmental features with energy balance-related behaviors in distinct populations. The present paper is hoped to contribute to the evolution of a paradigm that may help to disentangle the role of 'obesogenic' environmental factors.

Journal Article↗

PubMed2006

A comparison of cognitive structure in schizophrenia patients and healthy controls using confirmatory factor analysis.

There is evidence that cognitive task performance breaks down into the same broad domains in schizophrenia as in healthy populations. However, this does not mean that the domains are independent of one another or that the interrelationships among domains are the same between groups. We used confirmatory factor analysis (CFA) to compare the latent structure of a broad neuropsychological battery in schizophrenia patients (n = 148) and healthy controls (n = 157). Main analyses examined the fit of a hierarchical six-factor model, in which associations among the factors were assumed to reflect their strong shared relationship to a general cognitive ability factor. The model incorporated the factors of verbal comprehension, perceptual organization, verbal memory, spatial memory, processing speed, and executive/working memory. The hierarchical model provided a good overall fit to data from both groups. However multiple groups CFA revealed significant differences in factor loadings between groups, reflecting a more generalized latent structure of cognitive ability in schizophrenia. This was also evident in higher bivariate correlations among cognitive domain composite scores calculated from the observed test data. Cognitive ability, as reflected in test performance, appears to be more unitary in schizophrenia than in healthy subjects. This finding may have measurement and treatment implications.

Adult↗

PubMed1987

Magnetic resonance imaging and cognitive functioning in multiple sclerosis.

The relationship between cognitive impairment in multiple sclerosis and brain lesions seen on magnetic resonance imaging (MRI) was studied. Three groups of 11 patients with multiple sclerosis, matched for the variables of disability, duration of illness, age and sex, were included. On the basis of neuropsychological testing, the groups were seen to differ in their level of cognitive impairment. The first group showed no cognitive impairment, the second group a moderate, and the third group a serious cognitive impairment. These differences between the groups were reflected by MRI, which revealed more abnormalities in the groups with cognitive impairment compared with the group with normal cognitive function. However, by MRI it was not possible to distinguish between the groups with moderate and that with serious cognitive impairment.

Adult↗

PubMed2006

Increased amygdala and decreased dorsolateral prefrontal BOLD responses in unipolar depression: related and independent features.

BACKGROUND: Major depressive disorder is characterized by increased and sustained emotional reactivity, which has been linked to sustained amygdala activity. It is also characterized by disruptions in executive control, linked to abnormal dorsolateral prefrontal cortex (DLPFC) function. These mechanisms have been hypothesized to interact in depression. This study explored relationships between amygdala and DLPFC activity during emotional and cognitive information processing in unipolar depression. METHOD: Twenty-seven unmedicated patients with DSM-IV unipolar major depressive disorder and 25 never-depressed healthy control subjects completed tasks requiring executive control (digit sorting) and emotional information processing (personal relevance rating of words) during event-related functional magnetic resonance imaging (fMRI) assessment. RESULTS: Relative to control subjects, depressed subjects displayed sustained amygdala reactivity on the emotional tasks and decreased DLPFC activity on the digit-sorting task. Decreased relationships between the time-series of amygdala and DLPFC activity were observed within tasks in depression, but different depressed individuals showed each type of bias. CONCLUSIONS: Depression is associated with increased limbic activity in response to emotional information processing and decreased DLPFC activity in response to cognitive tasks though these may reflect separate mechanisms. Depressed individuals also display decreased relationships between amygdala and DLPFC activity, potentially signifying decreased functional relationships among these structures.

Adolescent↗

PubMed2005

Lower cognitive test scores observed in alcohol abstainers are associated with demographic, personality, and biological factors: the PATH Through Life Project.

AIMS: To identify variables that explain the association between alcohol abstention and cognitive performance. We hypothesized that demographic and personality variables would be important for explaining the association in all age cohorts, but that health variables would be more important in the older age-cohorts. DESIGN: Three age cohorts (20-24, 40-44, 60-64 years) were sampled randomly, yielding a total of 7485 participants, with data from 602 alcohol abstainers and 4158 light or moderate drinkers used in this study. Setting The sample was drawn from the cities of Canberra and Queanbeyan, Australia. MEASUREMENTS: Scales measuring demographic, health and personality variables and cognitive and physical tests were administered. Participants drinking at hazardous or harmful levels were excluded from the analysis. FINDINGS: A range of demographic and physical function measures were found to explain partially the finding of abstainers having lower cognitive test scores. The effects of independent variables were largest in the 60-64-year-old age group with a trend for physical variables such as lung function and grip strength to become more important in the older age groups. In the 20-24-year-olds, the majority of the effect remained unexplained. CONCLUSION: There is evidence that poorer cognitive test performance by abstainers reflects in part selection effects and poorer physical functioning, but does not appear to be due to mental or physical health conditions or personality.

Adult↗

PubMed1994

Callosal atrophy in patients with lacunar infarction and extensive leukoaraiosis. An indicator of cognitive impairment.

BACKGROUND AND PURPOSE: It is unclear why only some patients with lacunar infarction and radiological evidence of diffuse white matter abnormalities have dementia. The purpose of this study is to investigate the value of callosal atrophy as an indicator of cognitive impairment. METHODS: We used magnetic resonance imaging to evaluate 11 right-handed male patients with lacunar infarction and extensive white matter hypodensities on computed tomography (8 with dementia and 3 without dementia). The midsagittal corpus callosum area on T1-weighted images was compared with the IQ determined by the Wechsler Adult Intelligence Scale. The relation between these parameters and cerebral oxygen metabolism measured with positron emission tomography was also evaluated in the 8 patients with dementia. RESULTS: All patients showed diffuse high-intensity areas in the bilateral hemispheric white matter on T2-weighted images. Compared with 19 age- and sex-matched right-handed normal control subjects, the patients had a significantly smaller callosal area. The severity of callosal atrophy, which varied from mild to severe, was significantly related to the total IQ. In the 8 demented patients, the total callosal area was significantly correlated with the mean level of oxygen metabolism in the cerebral white matter. CONCLUSIONS: In patients with lacunar infarction and diffuse white matter abnormalities, the presence of callosal atrophy may indicate cognitive impairment. Callosal atrophy may reflect the severity and extent of white matter damage associated with a decrease in oxygen metabolism, which may determine the severity of intellectual decline.

Adult↗

PubMedDate not supplied

Chemosensory function and response in idiopathic environmental intolerance.

This chapter reviews the current literature on the possible role of olfactory and trigeminal chemosensory function in idiopathic environmental intolerances (IEI). Two general points emerge from the review. First, studies of chemosensory function in IEI patients indicate that, despite their self-reported "heightened sensitivity" and enhanced responsivity to environmental odors, when compared to healthy controls they generally are found to be equally or even less sensitive to odors as measured by objective psychophysical and electrophysiological measures of olfactory function. These studies point towards alterations in the cognitive processing of olfactory information as the major characteristic of IEI. Second, studies of the role of sensitivity and bias in olfactory and trigeminal chemosensory functioning indicate that nonsensory factors (e.g., attention, bias, personality) can dramatically alter the self-reported impact of exposure to volatile chemicals. Together, these general points suggest a perspective on IEI that views many symptoms of the disorder to primarily reflect the influence of nonsensory, cognitive processes on responses to environmental odors.

Chemoreceptor Cells↗

PubMed1996

Neocortex size and behavioural ecology in primates.

The neocortex is widely held to have been the focus of mammalian brain evolution, but what selection pressures explain the observed diversity in its size and structure? Among primates, comparative studies suggest that neocortical evolution is related to the cognitive demands of sociality, and here I confirm that neocortex size and social group size are positively correlated once phylogenetic associations and overall brain size are taken into account. This association holds within haplorhine but not strepsirhine primates. In addition, the neocortex is larger in diurnal than in nocturnal primates, and among diurnal haplorhines its size is positively correlated with the degree of frugivory. These ecological correlates reflect the diverse sensory-cognitive functions of the neocortex.

Animals↗

PubMed1998

Folate status, vascular disease and cognition in elderly Canadians.

OBJECTIVE: To report on the relationship between serum folate levels and the prevalence of stroke, peripheral vascular disease, cognitive problems and short-term mortality in elderly people. SETTING AND PARTICIPANTS: 1171 subjects whose serum folate was determined as part of their clinical examination in the Canadian Study of Health and Aging, a population study of individuals 65 years and older. METHODS: Cross-sectional analysis compared relationships between serum folate levels and clinical features; longitudinal analysis examined mortality at follow-up by folate status at the time of the clinical examination. RESULTS: Membership in the lowest quartile for serum folate was associated with an increased likelihood of stroke. Those with low folate levels were more likely to be demented, institutionalized and depressed. In the cognitively impaired but not demented group, those with low folate levels scored lower on the Modified Mini Mental State and had more short-term memory problems. CONCLUSIONS: Low folate level was a significant explanatory variable for stroke. Low folate levels were common in all types of dementia and were associated with a history of weight loss, lower body mass index and lower serum albumin concentrations. This may reflect the reduced ability of cognitively impaired individuals to eat adequately.

Aged↗

PubMed2000

A prospective study on circulating insulin-like growth factor I (IGF-I), IGF-binding proteins, and cognitive function in the elderly.

The objective of this study was to investigate the longitudinal relation between the insulin-like growth factor I (IGF-I)/IGF-binding protein (IGFBP) system and cognitive function. The study population consisted of a sample of 186 healthy participants from the population-based Rotterdam Study, aged 55-80 yr. At baseline, we determined fasting blood levels of free and total IGF-I, IGFBP-1, and IGFBP-3. The 30-point Mini-Mental State Examination (MMSE) was used to assess cognitive impairment at baseline (MMSE score of <26; 6% of the sample) and cognitive decline after, on the average, 1.9 yr of follow-up (drop in MMSE score of >1 point/year; 22% of the sample). Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using logistic regression, with adjustment for age, sex, education, body mass index, and fasting insulin levels. Total IGF-I appeared to be inversely related to cognitive impairment, although not significantly. Higher total IGF-I and the total IGF-I/IGFBP-3 ratio were associated with less cognitive decline (OR per SD increase = 0.65; 95% CI = 0.44-0.95 and OR = 0.59; 95% CI = 0.39-0.87, respectively). No relation was observed between free IGF-I and cognitive decline (OR = 0.99; 95% CI = 0.68-1.44). In conclusion, in this prospective study higher serum total IGF-I levels and higher total IGF-I/IGFBP-3 ratios, but not higher free IGF-I levels, were associated with less cognitive decline over the following 2 yr. Circulating total IGF-I levels may reflect an underlying biological process that influences cognitive decline.

Aged↗

PubMed2006

Brain aging in very old men with type 2 diabetes: the Honolulu-Asia Aging Study.

OBJECTIVE: Type 2 diabetes leads to cognitive impairment and dementia, which may reflect microvascular and macrovascular complications as well as neurodegenerative processes. There are few studies on the anatomical basis for loss of cognitive function in type 2 diabetes. The objective of this study was to investigate the association between type 2 diabetes and markers of brain aging on magnetic resonance images, including infarcts, lacunes, and white matter hyperintensities as markers of vascular damage and general and hippocampal atrophy as markers of neurodegeneration in Japanese-American men born between 1900 and 1919 and followed since 1965 in the Honolulu-Asia Aging Study. RESEARCH DESIGN AND METHODS: Prevalent and incident dementia was assessed. Associations between magnetic resonance imaging markers and diabetic status were estimated with logistic regression, controlling for sociodemographic and other vascular factors. RESULTS: The prevalence of type 2 diabetes in the cohort is 38%. Subjects with type 2 diabetes had a moderately elevated risk for lacunes (odds ratio [OR] 1.6 [95% CI 1.0-2.6]) and hippocampal atrophy (1.7 [0.9-2.9]). The risk for both hippocampal atrophy and lacunes/infarcts was twice as high in subjects with compared with those without type 2 diabetes. Among the group with type 2 diabetes, those with the longest duration of diabetes, those taking insulin, and those with complications had relatively more pathologic brain changes. CONCLUSIONS: There is evidence that older individuals with type 2 diabetes have an elevated risk for vascular brain damage and neurodegenerative changes. These pathological changes may be the anatomical basis for an increased risk of cognitive impairment or dementia in type 2 diabetes.

Aged, 80 and over↗

PubMed2006

The impact of normal aging and Parkinson's disease on response preparation in task-switching behavior.

This study investigates the ability to use foreknowledge in preparation of cognitive processes in young and older participants and in PD patients. Additionally, we test the hypothesis that age-associated cognitive deficits in task switching reflect a dopaminergic dysfunction that accompanies healthy aging. To this end, we use a task-switching paradigm that (i) is known to be highly sensitive for dopaminergic dysfunction in the frontostriatal loops and (ii) can be applied with predictable and unpredictable switch and non-switch trials to assess the effect of task foreknowledge. Our results show that young participants benefit from foreknowledge and are thus able to prepare for predictable cognitive processes. Older participants have lost their ability to benefit from foreknowledge, which seems to be an effect of healthy aging. In predictable trials, the performance of PD patients did not differ from that of controls. Thus, PD patients do not show an additional deficit in the preparation of predictable cognitive switches. However, PD patients are specifically impaired in unpredictable trials compared to controls. We suggest that this result can be explained by the uncertainty about the next task in the unpredictable condition which prevents an automatic process and demands more attention. Furthermore, our results of older participants do not resemble the deficits seen in PD patients in task-switching behavior. This argues for different mechanisms that underlie the changes in task-switching behavior in healthy aging and PD.

Adult↗

PubMed1998

Task-related activations in heterotopic brain malformations: a PET study.

Positron emission tomography (PET) studies have shown normal or elevated levels of glucose metabolism in neuronal heterotopia, raising the issue of potential participation of heterotopic neurons in cognitive processing. We studied three patients with heterotopic malformations, using [(15)O]water PET and experimental conditions selected according to the location of the malformations. Task performance was associated with blood flow increases of > 17% within the heterotopia in each patient. In two, these occurred in left frontal heterotopia during sentence generation. In the third patient, activations for facial and visuospatial discrimination and picture naming were found in a right posterior heterotopion. Our findings may reflect participation of heterotopia in cognitive function and suggest that heterotopic neurons synapse with neurons in other brain regions.

Adolescent↗

PubMed1991

Predicting relapse and recovery in alcoholism and addiction: neuropsychology, personality, and cognitive style.

Neuropsychological studies of substance abuse treatment outcome have generally found successful recoverers to show intact functioning on most measures, whereas relapsers do poorly on tests of language, abstract reasoning, planning, and cognitive flexibility. These have been related to involvement of left hemisphere and frontal lobe functions. Personality profiles of successful remitters, with or without formal treatment, include future goal-orientation, frustration-tolerance, and self-efficacy, while relapsers are characterized by impulsivity, antisocial personality, and affective disorders. It is proposed that what these neuropsychological and personality indexes are actually describing in successful recoverers is the neuropsychodynamic trait variable of ego autonomy, which is related to a reflective, nonimpulsive, goal-directed cognitive style. Implications of the neuropsychodynamic model for the evaluation and treatment of substance abusers is discussed.

Alcoholism↗

PubMed1983

Intraoperative nursing activities.

This study was done to describe the behaviors, activities, and cognitive functions of the registered nurse during the intraoperative phase of surgery and to categorize and compare the observed activities with AORN's Statements of basic competency for perioperative nursing. Fifteen randomly selected operating room nurses were observed for more than 210 hours during the intraoperative phase of surgery. Observations were recorded as observed activities and quotations. They were categorized by the coded Statements of basic competency for perioperative nursing. Further categorization was done to determine which basic competencies reflected nursing behaviors, activities, and cognitive functions. Additional data were collected using interviews and questionnaires. This study provided empirical evidence that a small sample of operating room nurses demonstrated most of the basic competencies. It also described the nursing behaviors, activities, and cognitive functions observed during the intraoperative phase of surgery.

Behavior↗

PubMed2001

Preliminary evidence for a cognitive phenotype in Barth syndrome.

Barth syndrome (BTHS) is a rare, X-linked, recessive disorder that affects almost exclusively males. It is characterized by short stature, cardioskeletal myopathy, cyclic neutropenia, increased excretion of 3-methylglutaconic acid in the urine, and moderate hypocholesterolemia. The objective of the present study was to assess whether BTHS presents with a cognitive phenotype. Preliminary data were collected from five kindergarten or first-grade boys with BTHS. An abbreviated psychoeducational test battery was administered to each boy, and parents of each boy completed standardized behavior rating scales. Data from 120 boys of similar age or grade level were used for one comparison group; a subset of this sample comprised a comparison group that was individually matched on age and grade level to one of the five boys with BTHS. Preliminary data reflect a higher incidence of cognitive difficulties in boys with BTHS relative to both comparison groups. Boys with BTHS had significantly lower visual spatial skills, but comparable reading-related skills, when compared with either group. Although based on a small sample size, the preliminary data presented in this work are the first indication of a cognitive phenotype associated with BTHS.

Child↗

PubMed2006

A meta-analysis of cognitive change with haloperidol in clinical trials of atypical antipsychotics: dose effects and comparison to practice effects.

Prospective, double-blind, randomized trials comparing atypical antipsychotic drugs (APDs) to typical APDs, such as haloperidol, indicate that atypical APDs provide a modest benefit to cognitive function in schizophrenia. However, the validity of this inference has been contested by suggestions that the cognitive improvements observed with atypical APDs reflect practice effects associated with repeated testing on the same neuropsychological instruments, or an avoidance of a deleterious effect of haloperidol on cognitive function that might be dose related. These alternate hypotheses were assessed by meta-analyses that 1) examined the relationship between cognitive change and dose of haloperidol within the control arms of prospective atypical vs. typical APD clinical trials; and 2) compared the magnitude of change observed within the haloperidol arms of these studies to estimated practice effects for several commonly used neuropsychological measures. The results indicate that overall cognitive performance improves while on haloperidol. Studies that used a low dose of haloperidol (<10 mg) did not yield larger effect sizes for overall cognitive function or specific neuropsychological measures than studies that used a high dose (>10 mg), although doses greater than 24 mg appear to have deleterious effects. For two of the six neuropsychological tests examined (digit symbol substitution and verbal fluency) the magnitude of change observed was significantly less than practice effects. The results indicate that although haloperidol may cause deleterious effects at very high doses, or in specific cognitive domains, these effects are not likely to explain the broader range of cognitive improvements observed with atypical APDs.

Antipsychotic Agents↗

PubMed1996

The measurement of cognitive function during acute hypoglycaemia: experimental limitations and their effect on the study of hypoglycaemia unawareness.

The risk of hypoglycaemia and the resulting impairment in brain function are major factors preventing those with diabetes achieving normoglycaemia. The need to define these risks more precisely has prompted an increasing research effort to identify which aspects of cerebral function are particularly vulnerable and at which glucose level. Much of the evidence is inconsistent, reflecting not only the wide range of methods for measuring cognitive function and inducing hypoglycaemia, but also the inherent variability of the response. Nevertheless, the data suggest that those mental activities which are relatively undemanding are often unaffected at all levels of experimental hypoglycaemia while the performance of more complex tasks deteriorates at glucose concentrations of around 3 mmol l-1. The relative imprecision of cognitive testing is reflected in the debate which surrounds the pathogenesis of hypoglycaemia unawareness. There is some evidence that the glycaemic threshold for autonomic activation and symptoms can vary while the threshold for cognitive impairment is fixed. This has led to the hypothesis that hypoglycaemia unawareness arises when the autonomic response develops at a blood glucose below that for impaired cognition, thus preventing patients from recognizing or responding to their usual symptoms. However, contradictory data suggest that the threshold for cognitive impairment can alter in line with the autonomic response, a conclusion which falls to fit either the above hypothesis or the clinical description of hypoglycaemia unawareness. These differences may be methodological or relate to the relative imprecision of measurements of cognitive function. Resolution of these discrepancies may have to await the development of advanced technology such as high resolution MRI or PET scanning. In the meantime, progress could be made if all groups agreed on a limited range of cognitive function tests and used them in a standardized manner.

Attention↗