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Results for “Cognitive Reflection”

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PubMed2001

Investigating the neurocognitive deficits associated with chronic drug misuse.

Cognitive deficits associated with the chronic abuse of drugs have important theoretical and clinical significance: such deficits reflect changes to the underlying cortical, sub-cortical and neuromodulatory mechanisms that underpin cognition, and also interfere directly with rehabilitative programs. Recent investigations have been made into the neuropsychology of chronic abuse of cannabis, stimulants and opiates. It is suggested that future progress in this area, involving developing advances in brain-imaging and neuropharmacology, will capitalize on experimental demonstrations of specific patterns of impairments in decision-making, attention and memory function.

Animals↗

PubMed1998

Psychotropic drugs in breast milk: no evidence for adverse effects on prepulse modulation of startle reflex or on cognitive level in infants.

Reversals in modulation of the startle reflex probably reflect maturational processes in the central nervous system. This study has investigated the longitudinal changes in prepulse modulation of the blink reflex in three groups of individual infants: (a) breast-fed infants of mentally ill mothers who were prescribed selected psychotropic drugs, (b) bottle-fed infants of similarly ill and medicated mothers, and (c) breast-fed infants of healthy control mothers. The acoustic stimulation paradigm and neurophysiological methods were similar to those used in previous studies and, in addition, the infants' development was simultaneously assessed using the Bayley Scales of Infant Development. All the infants were found to be developing normally and across all three groups we observed a clear transition in prepulse modulation of the eye-blink reflex from small inhibition or facilitation in early infancy (1-4 months) to a robust facilitation in middle infancy (5-8 months). This reversal probably reflects the changing balance of developing neural function in normal infants. There were, therefore, no discernible effects in breast-fed infants of exposure to small doses of antidepressant or neuroleptic drugs.

Acoustic Stimulation↗

PubMed2000

Rivastigmine for Alzheimer's disease: Canadian interpretation of intermediate outcome measures and cost implications.

BACKGROUND: Clinical studies have shown that patients with Alzheimer's disease (AD) who are treated with rivastigmine have statistically significantly better scores on 5 scales used to assess AD than control patients receiving placebo. However, the clinical meaning and cost implications of these differences are not clear. OBJECTIVE: The purpose of this study was to assess the clinical meaning and cost implications of statistically significant results obtained in clinical trials of rivastigmine for the treatment of AD. Potential cost implications for the health care system, caregivers, and society are considered. METHODS: Data on clinical effects of rivastigmine were obtained from published North American and European clinical studies of patients with mild to moderately severe AD receiving rivastigmine 6 to 12 mg/d (n = 828) or placebo (n = 647). Differences in scores on the Alzheimer's Disease Assessment Scale-Cognitive Function, Clinician's Interview-Based Impression of Change with both clinical and caregiver information considered, Progressive Deterioration Scale, Mini-Mental State Examination (MMSE), and Global Deterioration Scale were assessed. A convenience panel of 9 Canadian specialists experienced in the treatment of AD provided their opinions on the clinical importance of the trial results. Chart review was performed to identify specific behaviors that improved, and cost implications of improvements were assessed. RESULTS: The panel determined that statistically significant differences in scores on all scales except the MMSE were likely associated with functional or cognitive differences that were clinically relevant for patients, reflecting stabilization that would have beneficial consequences for caregivers and health care resource use. Subsequent chart review showed that improvement on specific scale items confirmed the physician panel's opinion. Analysis of possible cost implications to society indicated that medication expenditures would be offset largely by delays in the need for paid home care and institutionalization, positive effects on caregiver health, and less time lost from work for the caregiver. CONCLUSIONS: From the perspective of a Canadian specialist panel, rivastigmine treatment for AD produces clinically relevant effects for patients that are beneficial to caregivers. These effects suggest decreased use of caregiver resources and delays in the need for institutionalization, both of which reduce societal costs.

Aged↗

PubMed1999

Impaired K(+) homeostasis and altered electrophysiological properties of post-traumatic hippocampal glia.

Traumatic brain injury (TBI) can be associated with memory impairment, cognitive deficits, or seizures, all of which can reflect altered hippocampal function. Whereas previous studies have focused on the involvement of neuronal loss in post-traumatic hippocampus, there has been relatively little understanding of changes in ionic homeostasis, failure of which can result in neuronal hyperexcitability and abnormal synchronization. Because glia play a crucial role in the homeostasis of the brain microenvironment, we investigated the effects of TBI on rat hippocampal glia. Using a fluid percussion injury (FPI) model and patch-clamp recordings from hippocampal slices, we have found impaired glial physiology 2 d after FPI. Electrophysiologically, we observed reduction in transient outward and inward K(+) currents. To assess the functional consequences of these glial changes, field potentials and extracellular K(+) activity were recorded in area CA3 during antidromic stimulation. An abnormal extracellular K(+) accumulation was observed in the post-traumatic hippocampal slices, accompanied by the appearance of CA3 afterdischarges. After pharmacological blockade of excitatory synapses and of K(+) inward currents, uninjured slices showed the same altered K(+) accumulation in the absence of abnormal neuronal activity. We suggest that TBI causes loss of K(+) conductance in hippocampal glia that results in the failure of glial K(+) homeostasis, which in turn promotes abnormal neuronal function. These findings provide a new potential mechanistic link between traumatic brain injury and subsequent development of disorders such as memory loss, cognitive decline, seizures, and epilepsy.

Animals↗

PubMed2006

The cognitive profile of posterior cortical atrophy.

BACKGROUND: Posterior cortical atrophy (PCA) is a progressive dementia characterized by prominent disorders of higher visual processing, affecting both dorsal and ventral streams to cause Balint's syndrome, alexia, and visual agnosia. OBJECTIVE: To define the cognitive profile of PCA and compare to the typical, primary amnestic dementia of the Alzheimer's type (DAT). METHODS: The authors used standard cognitive tests and a novel battery designed to reflect dysfunction in both ventral (Object, Face & Color Agnosia Screen [OFCAS]) and dorsal (complex pictures and compound stimuli) visual streams. The authors identified 19 patients with PCA and compared their performance to a matched group of patients with DAT and normal controls. RESULTS: Patients with PCA were younger with marked impairment in visuospatial tasks, reading, and writing but relative preservation of memory compared to DAT using standard tests. Dorsal stream signs were most prevalent among the patients with PCA with no pure ventral stream syndromes found. All novel tests distinguished reliably between subjects with complex picture descriptions and processing of compound stimuli showing the most significant differences compared to DAT. CONCLUSIONS: PCA is predominantly a dorsal stream syndrome, distinct from typical DAT, which involves occipitotemporal regions over time.

Aged↗

PubMed2006

Long-term outcomes in epilepsy surgery: antiepileptic drugs, mortality, cognitive and psychosocial aspects.

Assessment of long-term outcomes is essential in brain surgery for epilepsy. Little information exists on long-term non-seizure outcomes after epilepsy surgery. We perform a systematic review and meta-analysis of the evidence on this topic. Our aim was to provide evidence-based estimates of antiepileptic drug, psychosocial, neuropsychological and mortality long-term outcomes following epilepsy surgery, and to identify sources of variation in published results. We searched Medline, Index Medicus, the Cochrane database, bibliographies of reviews, original articles, and book chapters, to identify articles published from 1991 to 2005, containing > or =20 patients of any age, undergoing resective or non-resective epilepsy surgery, and followed for a mean/median of > or =5 years. Two reviewers independently assessed study eligibility and extracted data, resolving disagreements through discussion. Standard meta-analytical techniques were used to pool data. Of the 159 potentially eligible articles reviewed in full-text, 35 (22%) fulfilled eligibility criteria; 6 (17%) were controlled studies; 15 (36%) explored antiepileptic drug outcome; 6 (17%) explored mortality; 11 (31%) reported psychosocial outcomes; and 7 (20%) explored neuropsychological outcomes. On an average, 14% [95% confidence interval (CI(95)) = 11-17] of the patients with temporal lobe surgery achieved long-term antiepileptic drug (AED) discontinuation, 50% (CI(95) = 45-55) achieved monotherapy, and 33% remained on polytherapy (CI(95 =) 29-38). In analyses including all types of surgery, on average, 20% (CI(95) = 18-23) achieved long-term AED discontinuation, while 41% (CI(95) = 37-45) were on monotherapy and 31% (CI(95) = 27-35) remained on polytherapy. Children achieved better AED outcomes than adults. Seizure freedom after surgery was associated with lower mortality, but inconsistent mortality outcomes precluded making strong inferences. Non-controlled studies consistently reported improved long-term psychosocial outcomes, but the effect was less clear in controlled studies. Intelligence was unchanged by surgery, but long-term memory outcomes were associated with seizure freedom and side of temporal lobe resection. Few long-term, controlled studies exist. Longer follow-up was associated with lower rates of AED discontinuation, reflecting lower seizure-free rates over time. Cognitive and psychosocial outcomes were similar to those of short-term studies, and the results were influenced by the presence of controls.

Anticonvulsants↗

PubMedDate not supplied

[Cognitive inhibition and psychopathology: toward a less simplistic conceptualization].

"Cognitive inhibition" is a concept that has found a firm place in the interpretation of performance by normal subjects on tasks involving adherence to a plan and suppression of incorrect responses to distractors. The presence of "negative priming" is the classical indicator of cognitive inhibition. Negative priming occurs when, in a sequence of stimuli each of which is composed of a target and a distractor, the distractor of the first stimulus becomes the target of the second stimulus: reaction time to the second stimulus is slowed because of the inhibition applied to the distractor of the first stimulus. The concept has been extended to the interpretation of pathological behavior and symptoms. Pathological subjects have been found to show deficient negative priming. Thus, negative ideation in depression as well as intrusive paranoid associations in schizophrenia have been related to a deficit in the capacity to inhibit inappropriate representations. In this paper, we briefly review some of the experimental evidence from normal subjects that has contributed to the acceptance of cognitive inhibition as a key process in the control of normal cognition, as well as more recent evidence that has led to a revision of the concept. Negative priming in normal subjects has been found to be dependent upon characteristics of the experimental situation as perceived by the subject. In particular, priming is observed when the subject anticipates difficulty in determining the response and proceeds with caution. Thus, inhibition is not an automatic "brake" applied to irrelevant material, but rather the product of strategic considerations within the experimental situation. This revision of the cognitive inhibition hypothesis leads to a re-interpretation of the apparently deficient cognitive inhibition seen in depressed or schizophrenic subjects. According to this more recent interpretation, deficient cognitive inhibition in pathological subjects can be seen as a less adaptive strategic adjustment to the task. The pathology seems to touch higher-level executive functions rather than a deficient inhibitory "brake". In depressed subjects, abnormal performance in selective attention tasks could be related to the underlying pathology in two ways: some depressed subjects show a marked lack of energy and a psychomotor slowing: these subjects do not exhibit normal negative priming, probably because of a reduction of cognitive resources. Other depressed subjects show abnormal performance as reflected by negative priming greater than normal: this result could be related to an exaggerated tendency to verify a correct response. Schizophrenic subjects show a lack of negative priming that seems most plausibly to be related to an ineffectual integration of the experimental instructions concerning both speed and accuracy in the response. This re-interpretation of the cognitive deficiency in pathological patients provides a better fit with recent experimental results from normal subjects, and with cognitive deficits measured in pathological subjects.

Association Learning↗

PubMed1996

Simultaneously evoked primary and cognitive visual evoked potentials distinguish younger and older patients with Parkinson's disease.

While it is known that both primary visual processes and visuocognitive responses are affected in Parkinson's Disease (PD), their relationship is not known. It is known that both of these measures can be affected by age per se. Our aims were to determine if in non-demented PD patients visual cognitive event-related potential (ERP) changes simply reflect abnormal primary visual processing and to determine the effects of age and disease on their relationship. In order to do so, we introduce a new normalizing procedure for visual ERPs. In addition to the latencies and amplitudes of P100, N140, P200, N200 and P300 components, the P300-P100 latency difference (termed "central processing time"-CPT) were measured. In order to avoid confounding factors of absolute amplitude differences due to say, generally low voltage recordings or poor primary visual responses, P300 responses normalized to P100 responses were also evaluated (P300/P100 amplitude ratio). Visual ERPs were obtained in an "oddball" paradigm in 20 nondemented patients with PD and 20 normal age-matched subjects. The stimuli were horizontal sinusoidal gratings differing only in spatial frequency (0.5 and 1 cycle/degree). While simple ERP latency criteria did not distinguish non-demented PD patients as a group from controls, when younger PD patients were compared to older PD patients and controls CPT acceleratedly increased in younger PD patients. The amplitudes of both N200 and P300 provided significant distinction between patient and control groups. The surprising result emerging from this study is that an individually normalized P300 amplitude provides significant distinction of younger PD patients from age matched normals.

Aged↗

PubMed2001

Informed consent: moral necessity or illusion?

There is a professional and legal consensus about the clinical duty to obtain informed consent from patients before treating them. This duty is a reflection of wider cultural values about the moral importance of respect for individual autonomy. Recent research has raised practical problems about obtaining informed consent. Some patients have cognitive and emotional problems with understanding clinical information and do not apparently wish to participate in making decisions about their treatment. This paper argues that such research does not undermine their potential to provide informed consent. Rather, sufficient resources are required to create better communication skills among clinicians and more effective educational materials for patients. Finally, cognitive and emotional inequality among patients is maintained to be a reflection of wider social and economic inequalities. Researchers who take the right to informed consent seriously should also address these.

Communication↗

PubMed2002

Memory complaints; the association with psycho-affective and health problems and the role of personality characteristics. A 6-year follow-up study.

BACKGROUND: The objective is to investigate whether memory complaints in older persons without manifest cognitive decline are associated with depressive symptoms, anxiety symptoms, physical health and personality characteristics. Furthermore, it is investigated whether personality characteristics have a modifying effect on the association of memory complaints with depressive and anxiety symptoms and physical health. METHODS: The study was carried out using the Longitudinal Aging Study Amsterdam (LASA). Participants were examined during three observation cycles covering a period of 6 years. They were asked about memory complaints, and were examined on cognitive functioning, physical health, depressive and anxiety symptoms, and the personality characteristics: mastery, perceived self-efficacy and neuroticism. The data were analysed by means of Generalised Estimating Equations (GEE). RESULTS: Memory complaints were associated with physical health problems, depressive and anxiety symptoms, low feelings of mastery, low perceived self-efficacy and high neuroticism. The associations between memory complaints and physical health problems, depressive and anxiety symptoms were significantly stronger in people with high mastery, high perceived self-efficacy and low neuroticism. LIMITATIONS: We used a conservative criterion for cognitive decline and therefore we might have included some people with cognitive decline during our follow-up. In order to minimise selection bias we included actual cognitive performance in our regression models. CONCLUSIONS: Our findings suggest that when older persons complain about their memory and do not show actual cognitive decline, one should be aware that these complaints might reflect psycho-affective or health problems.

Aged↗

PubMed2006

Correlations of functional capacity and neuropsychological performance in older patients with schizophrenia: evidence for specificity of relationships?

BACKGROUND: Neuropsychological (NP) performance is a consistent correlate of everyday functioning in schizophrenia, but it is unclear whether relationships between individual NP ability areas and domains of everyday functioning are general or specific. Assessments of real-world everyday functioning may be influenced by environmental and social factors (e.g., social security, disability status, opportunities and restrictions in living situations). This study examined the specificity of the relationships between different NP abilities and performance-based measures of social and living skills. METHODS: 181 ambulatory older (age>50) patients with schizophrenia were examined with NP tests measuring episodic and working memory, executive functioning, verbal fluency, and processing speed. All subjects performed tasks examining social (Social Skills Performance Assessment: SSPA) and everyday living (UCSD Performance Based Skills Assessment: UPSA) skills. RESULTS: Using canonical analysis, the NP variables were used to predict the functional capacity measures. The analysis found that 37% of the variance in the functional capacity and NP measures was shared, X(2) (54)=106.29, p<.001. Two canonical roots described the cognitive variables and the roots were differentially associated with everyday living and social skills. The root loading on processing speed, episodic memory, and executive functions were associated with UPSA scores, while the root loading on working and episodic memory and verbal fluency were associated most strongly with social competence. IMPLICATIONS: Social and everyday living skills deficits in patients with schizophrenia may reflect generally independent domains of functional outcome, linked through cognitive performance. The data suggest that somewhat different cognitive processes are associated with these two domains of functional capacity, although there appears to be some overlap, which may be due to the nature of the NP tests employed.

Activities of Daily Living↗

PubMed1985

An exploratory study of the health decision-making variables of New York and Montana ninth-graders.

The health decision-making dynamics of adolescents in New York and Montana are assessed. Ninth-grade students were asked to make a decision on a hypothetical dilemma scenario. From their choice they were classified as either health-promoting decision makers (HPDM) or health-risky decision makers (HRDM). They were subsequently asked a series of questions dealing with future health choices, degree of reflection, the effect of stress upon choice selection, and type of cognition during decision. Results indicate that HPDM intended not to engage in future, risky sexual behavior or drinking and driving behavior(s). Health-risky decision makers were, however, more reflective in making their initial choice. The variable of stress was not definitive for either group, and significant regional differences were not evident. Implications for the design of school health education program curricula are presented along with suggestions for future investigation.

Adolescent↗

PubMed2004

Reflective thinking in clinical nursing education: a concept analysis.

Over decades nursing had an interest in clarifying and developing its knowledge base and its conceptual foundation. Reflective thinking has become a popular word in nursing education world wide, but its meaning and effective use remains debatable because of lack of clarity in its meaning (Mackintosh, 1998:553). The researcher engaged in the concept analysis of reflective thinking so as to fully understand its meaning and interpretation, hence the research question to be addressed by this article is: "What is the meaning of reflective thinking in clinical nursing education?" This article seeks to explore and describe the conceptual meaning of reflective thinking in clinical nursing education using the method of concept analysis as outlined by Wilson (1963:23-39) and Gift (1997:75,76). Concept analysis of reflective thinking constitutes the first phase of a study to develop a model to facilitate reflective thinking in clinical nursing education, thus ensuring theoretical validity of the model. An extensive examination of domain specific and various disciplines' literature was explored as part of the concept analysis. A selection of information regarding variations and similarities in the use and interpretation of reflective thinking across clinical nursing education was drawn from computerised data bases. This increased the rigor and the findings of the analysis. Through deductive reasoning and drawing of inferences, attributes were clustered in an attempt to identify the apparent essence of the concept. Three categories and the related connotations emerged as follows: Antecedents (Cognitive and affective thinking skills). Process (The three phases of reflective thinking). Outcome ( New insight and changed perspective). Reflective thinking was considered from the result of concept analysis as a cyclic, interactive constructing mental process to improve practice in a specific context. It is recommended that a model to facilitate reflective thinking in clinical nursing education be developed based on the results of this concept analysis.

Cognition↗

PubMed1988

Cognitive function and platelet membrane fluidity in Alzheimer's disease.

Increased platelet membrane fluidity, as reflected by a decrease in the fluorescence anisotropy of diphenylhexatriene in labeled membranes, identifies a clinically distinct subgroup of approximately 50% of patients at our center who meet NINCDS-ADRDA clinical criteria for Alzheimer's disease. In the current study, we compared the cognitive impairments of patients in this subgroup to those observed in the residual subgroup of patients with Alzheimer's disease who had normal platelet membrane fluidity. No significant differences in the number or distribution of deficits in six cognitive domains were observed between the two subgroups. However, in the subgroup with increased platelet membrane fluidity, there were significantly more patients who exhibited dissociation of deficits on tests related to left and right parietal lobe function than in the residual subgroup. Moreover, the cases with dissociation of deficits consisted almost entirely of patients with deficits on tests reflecting left parietal lobe function and no deficit on tests of right parietal lobe function.

Aged↗

PubMed1980

Cerebral lateralization: relation to subject's sex.

Patterns of reflective LEM's have been correlated to a number of cognitive and personality variables, bu the relationship to sex, education, and mental illness is unclear. In this study females produced significantly more R-LEM overall indicating a preferential use of left hemisphere mechanisms when they initiate reflective thought. Females also produced more R-LEM for verbal nonemotional material, suggesting stronger lateralization of language abilities to their left hemisphere. Emotional and spatial stimuli were less well lateralized to the right hemisphere in females, and education was an unimportant variable for both sexes. Schizophrenia was independently associated with increases in total R-LEM indicating increased left hemisphere activity in this group.

Educational Status↗

PubMed2002

Sex hormones and cognitive function in older men.

OBJECTIVES: Recent studies have suggested that estrogen may improve cognitive function or prevent cognitive decline in older women. Little research has been conducted on exogenous or endogenous sex hormones and cognition in older men, yet it has been hypothesized that testosterone, either directly or by conversion to estrogens, may improve cognitive function. We investigated whether serum level of testosterone and estradiol is associated with cognition in older community-dwelling men. DESIGN: A cross-sectional study. SETTING: Population-based listings in the Monongahela Valley near Pittsburgh, Pennsylvania. PARTICIPANTS: Three hundred ten men (mean age +/- standard deviation = 73.0 +/- 7.1) who were part of a cohort study. MEASUREMENTS: We measured cognitive function using the Mini-Mental State Examination (MMSE), Trails B, and Digit Symbol. Sex hormone levels were determined by radioimmunoassay from serum obtained at the time of cognitive testing and analyzed by tertile. RESULTS: No consistent association between total testosterone level and cognitive test scores was observed. However, men with high bioavailable (loosely protein-bound) testosterone had better cognitive test scores on all three tests (P < or =.001). Total estradiol levels were associated with worse cognitive scores on Digit Symbol (P <.001) and Trails B (P =.002), but bioavailable estradiol levels were not associated with cognitive function. Level of sex hormone binding globulin (SHBG) was negatively associated with cognitive scores on all three tests (P < or =.001). After adjusting for age and education, the statistical significance lessened for bioavailable testosterone (MMSE, P =.086; Digit Symbol, P =.047; Trails B, P =.076) and became nonsignificant for SHBG (all cognitive tests P>.10). CONCLUSIONS: Our findings support the hypothesis that higher levels of bioavailable testosterone, but not of bioavailable estradiol, are associated with better cognitive function in older men. In addition, bioavailable measures of testosterone may better reflect hormone levels available to the brain and thus be more closely associated with central nervous system outcomes such as cognition. Future studies, especially randomized trials, should be undertaken to determine whether testosterone may protect against cognitive decline in older men.

Aged↗

PubMed1994

Using multiple risk factors to assess the behavioral, cognitive, and affective effects of learned helplessness.

Rather than examining the effect of the pessimistic explanatory style on an outcome variable reflecting a single domain, I studied the effects of multiple learned-helplessness risk factors on behavioral, cognitive, and affective variables. Undergraduate students completed the Learned Helplessness Scale (Quinless & McDermott-Nelson, 1988) as a measure of their expectation of uncontrollability and the Explanatory Style Questionnaire (Peterson et al., 1982) to determine their explanations for both positive and negative events. Results revealed a significant effect for risk level, with students at greater risk of helplessness reporting significantly more procrastination, lower grade point averages, and more dysphoria. These results support the use of multiple risk factors representing all learned-helplessness precursors and the assessment of learned-helplessness deficits drawn simultaneously from behavioral, cognitive, and affective domains.

Adult↗

PubMed1985

Exercise and its effects on cognition and physiology in older adults.

A total of 114 adults between the ages of 50 and 80 yr. were recruited for a study of fitness. The participants were divided into Structured, Self-imposed, Social, and Nonexercise groups to reflect their levels of physical activity and then were compared on cognitive and physiological variables. Significant differences were noted for fear, assertiveness, depression, and percentage of body fat. Multiple discriminant analyses suggested that group membership could be predicted with 100% success for Structured exercisers compared to Social and Nonexercisers. However, predictability decreased when examining Structured and Self-imposed exercisers. One may infer that people who are more fearful, more assertive, and more depressed participated in exercise. Involvement in a 12-wk. exercise program significantly reduced depression and body-fat concentration.

Adipose Tissue↗