SEARCH · PubMed Health

Results for “Cognitive function”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,405 records · Page 78Linked to original sources

PubMed1988

The effects of blood sugar level changes on cognitive function, affective state, and somatic symptoms.

In an attempt to find out whether decreased blood sugar level is associated with impaired cognitive function, adverse emotional changes, or somatic symptoms, 35 subjects who suspected that they had hypoglycemia were given 5-hr glucose tolerance tests (GTTs). Nine blood samples were taken during the GTT, and the subject's mood, Serial Sevens Test (SST) performance, and somatic symptom reports were recorded on each occasion of sampling. The subjects reported significantly more negative affect and somatic symptoms after glucose nadir than before nadir. SST performance deteriorated at glucose nadir. These effects were more pronounced for subjects with high hypoglycemic index scores than for subjects with low index scores. The impairment in SST performance was greater for subjects who showed rapid decreases in blood sugar than for subjects who showed slow decreases. Dividing subjects by high and low nadirs did not reveal any differences in symptomatology.

Adult↗

PubMedDate not supplied

Multiple reproducibility indices for evaluation of cognitive functional MR imaging paradigms.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate a variety of reproducibility indices for cognitive functional MR imaging (fMRI) paradigms that account for both overlapping and extraneous regions of activation. METHODS: Eight right-handed volunteers were imaged with fMRI by using a word-generation paradigm and a forward-backward text-listening paradigm. The paradigms were performed twice in the session and repeated 1 week later. Reproducibility indices for the four repeated studies were determined on the basis of pair-wise computation of the ratio of the probability-weighted intersection volume divided by the union volume of surviving activation clusters. The intersection volume was determined by using several iterations of the morphologic dilatation operator with additional voxels accrued in the intersection weighted by an exponential function. Computed indices included global reproducibility, language area reproducibility, extraneous activation reproducibility, and laterality. RESULTS: The word-generation paradigm had reproducibility values that were significantly greater than those of the forward-backward text-listening paradigm (global reproducibility, 0.75 vs 0.5, P <.005; language area reproducibility, 0.85 vs 0.6, P <.008; mean extraneous activation reproducibility, 0.68 vs 0.41, P <.002). The forward-backward text-listening paradigm demonstrated more focal activations, whereas the word-generation demonstrated larger activations outside the dominant language areas that were highly reproducible. CONCLUSION: For clinically relevant language paradigms, multiple reproducibility indices should be taken into account in selecting an appropriate paradigm. Compared with a forward-backward text-listening task, a word-generation task has higher reproducibility indices at the expense of localizing ability. The forward-backward paradigm demonstrates more focal activations with less extraneous activation.

Adult↗

PubMed2003

Effects of acute tryptophan depletion on cognitive function in Alzheimer's disease and in the healthy elderly.

BACKGROUND: The cholinergic system is profoundly impaired in senile dementia of Alzheimer type (SDAT) and replacement therapy produces only modest clinical benefits. The serotonergic system is also impaired and may contribute both to cognitive and non-cognitive symptoms in SDAT. To investigate this further we assessed the effects of lowering brain serotonin using the technique of acute tryptophan depletion on cognitive function in patients with SDAT and in age matched control subjects. METHOD: Sixteen patients with probable SDAT and 17 healthy elderly subjects received two amino acid drinks in a within subject, double-blind, placebo-controlled, counterbalanced, crossover design. One of the drinks was nutritionally balanced and contained tryptophan (placebo), the other was identical but contained no tryptophan. A battery of detailed neuropsychological tests was performed between 4 and 6 h after the drink. Mood rating scales and other ratings of behavioural and emotional symptoms were also performed on both occasions. RESULTS: Acute tryptophan depletion resulted in impairment on tasks of working memory in both groups. There was no group specific effect. Female SDAT subjects performed better on a task of pattern recognition during acute tryptophan depletion compared with placebo. There were no changes in behavioural symptoms during acute tryptophan depletion in either group. CONCLUSION: Compromised serotonergic function may be an important contributor to cognitive decline in SDAT and in ageing. Strategies targeting specific 5HT receptors may be helpful in SDAT.

Affect↗

PubMed1998

Declining blood lead levels and changes in cognitive function during childhood: the Port Pirie Cohort Study.

CONTEXT: Many studies have found a significant inverse association between early exposure to environmental lead and cognitive function in childhood. Whether these effects are reversible when exposure is reduced is not clear. OBJECTIVE: To assess the reversibility of the apparent effects of lead on cognitive abilities in early childhood by testing whether declines in blood lead concentrations beyond the age of 2 years are associated with improvements in cognition. SETTING: Urban and rural communities surrounding a large lead smelter in Port Pirie, South Australia. PARTICIPANTS: A total of 375 children followed up from birth to the age of 11 to 13 years. DESIGN: Long-term prospective cohort study. MAIN OUTCOME MEASURES: The Bayley Mental Development Index at age 2 years, the McCarthy General Cognitive Index at age 4 years, and IQs from the Wechsler Intelligence Scale (revised version) at ages 7 and 11 to 13 years. RESULTS: Mean blood lead concentrations in the children decreased from 1.02 pmol/L (21 .2 microg/dL) at age 2 years to 0.38 micromol/L (7.9 microg/dL) at age 1 1 to 13 years, but cognitive scores in children whose blood lead concentration declined most were generally not improved relative to the scores of children whose blood lead levels declined least. Changes in IQ and declines in blood lead levels that occurred between the ages of 7 and 11 to 13 years (r= 0.12, P= .09) suggested slightly better cognition among children whose blood lead levels declined most. CONCLUSION: The cognitive deficits associated with exposure to environmental lead in early childhood appear to be only partially reversed by a subsequent decline in blood lead level.

Child↗

PubMed2000

Absence of negative impact of levetiracetam on cognitive function and memory in normal and amygdala-kindled rats.

The effect of the new antiepileptic drug (AED) levetiracetam (LEV, Keppra) on cognitive function was studied in normal and amygdala-kindled rats by using the Morris water maze test. In addition, we investigated the effect of LEV on long-term potentiation (LTP) in rat hippocampal slices. Sodium valproate (VPA) was used as comparator in all studies. Clonazepam (CZP) and carbamazepine (CBZ) were used in normal rats. The results indicated that doses of LEV known to suppress motor seizures did not alter cognitive performance. In contrast, similar doses of the classic AEDs all decreased learning performance of the rats. Likewise, VPA did alter LTP but LEV was inactive. Amygdala-kindled rats were more sensitive than normal rats to the effects of VPA. These results suggest that LEV may be devoid of negative impact on cognition in epileptic patients.

Journal Article↗

PubMed2000

Impairment and recovery of elementary cognitive function induced by hypoglycemia in type-1 diabetic patients and healthy controls.

Although neuroendocrine changes after induction of hypoglycemia, in patients with diabetes and healthy persons, are thoroughly investigated, cognitive adaptation processes are still insufficiently understood. Changes in cognitive functions are mainly investigated by psychometric tests, which represent a summation of different cognitive processes. We aimed at dissecting cognitive adaptation into single components, i.e. stimulus selection, response choice, and reaction speed during a hyperinsulinemic hypoglycemic clamp in patients with type-1 diabetes and matched healthy controls. Using novel neurophysiological analyses, the event-related potentials of early stimulus selection (selection negativity) and response selection (lateralized readiness potential) were studied, in addition to reaction time (RT). A total of 12 diabetic patients and 12 normal volunteers were studied while receiving a hyperinsulinemic hypoglycemic clamp. RTs and the event-related potentials related to stimulus selection and response selection were significantly delayed during hypoglycemia in both groups, whereas early evoked potentials (P100) were unaltered. This suggests that hypoglycemia delays stimulus selection, with the consequence that also central and motor processing are delayed. In addition, patients with diabetes showed an earlier negative shift over the frontal cortex, which, when compared with the controls, reveals better adaptation to hypoglycemia in frontal cortical brain regions. After restoration of euglycemia stimulus selection, response selection and RT returned to baseline level in the type-1 group. In the control group, however, response selection and RTs were still delayed. This suggests that type-1 patients, possibly because of the past occurrence of hypoglycemic events, might be able to better cope with the hypoglycemic state than healthy volunteers who lack such a history. In summary, our data demonstrate, for the first time, that cognitive adaptation processes to an experimental hypoglycemic episode can clearly be dissected into their single components.

Adrenocorticotropic Hormone↗

PubMed1999

Calcium-channel blockers and cognitive function in elderly people: results from the Canadian Study of Health and Aging.

BACKGROUND: Concern has been raised about the potential for adverse cognitive effects associated with the use of calcium-channel blockers (CCBs) in older people. This study was undertaken to examine prospectively the association between the use of these and other antihypertensive drugs and cognitive function. METHODS: The authors examined data from the Canadian Study of Health and Aging (CSHA), a population-based, prospective 5-year investigation of the epidemiology of dementia and other health problems in Canadians 65 years of age and older. The risk of cognitive decline, as indicated by a decline in performance on the Modified Mini-Mental State (3MS) examination over the 5-year period, was assessed in relation to the use of antihypertensive and diuretic drugs by 205 subjects with a history of hypertension and no evidence of dementia at baseline. RESULTS: The proportion of subjects whose cognitive performance declined over the study period was significantly higher in the group using CCBs than in the group using other antihypertensive agents (75% v. 59%). The adjusted odds ratio (OR) for a significant decline in cognitive performance (defined as a decrease in 3MS score of 10 points or more) was 2.28 (95% confidence interval [CI] 1.12-4.66) for subjects using CCBs. The adjusted ORs (and 95% CIs) for cognitive decline in subjects using selected antihypertensive agents or diuretics relative to those exposed to beta-blockers were as follows: angiotensin-converting-enzyme inhibitor, OR 1.36 (95% CI 0.41-4.55); diuretic or other antihypertensive drug, OR 1.45 (95% CI 0.51-4.14); dihydropyridine CCB (nifedipine), OR 1.94 (95% CI 0.52-7.27) and non-dihydropyridine CCB (diltiazem or verapamil), OR 3.72 (95% CI 1.22-11.36). INTERPRETATION: Older people taking CCBs were significantly more likely than those using other agents to experience cognitive decline. These findings are consistent with the results of previous cross-sectional research and emphasize the need for further trials to examine the associations between CCB use, blood pressure and cognitive impairment in elderly patients.

Age Factors↗

PubMed2002

Colour perception among the very elderly related to visual and cognitive function.

Colour perception was studied among a representative sample of 95-year olds and compared with previously examined 80-year olds and a group with Alzheimer's disease (AD), mean age of 80 years. The 95-year olds' results were on a significantly lower level than the other two groups but showed a similar pattern as to colour -discrimination, -naming, -preferences and colour/form recognition. Visual function among 95-year olds had only minor influence on their result in contrast to cognitive function which had a more profound impact. Most interestingly though, the subjects with Alzheimer's diagnosis, younger than the 95-year olds but with a conclusive diagnosis of dementia, performed on an overall higher level than the 95-year olds. This advantage for the Alzheimer group remained even when compared with a sub sample of the 95-year olds with possible dementia diagnosis excluded. On the other hand, only including 95-year olds with a Mini Mental Examination score of >26 in comparison with the Alzheimer group made the differences between the two groups disappear. It is suggested that colour perception as measured in this study is well preserved throughout life. The overall lower colour perception ability in 95-year olds compared with both 80-year olds and subjects with AD may be an expression of the complexity of very high age rather than any isolated concomitant factor.

Aged↗

PubMed1991

Early and long-term effects of electroconvulsive therapy and depression on memory and other cognitive functions.

Twenty-seven medication-free, depressed patients (Research Diagnostic Criteria, endogenous subtype) were administered a comprehensive battery testing memory and other cognitive functions before and after a series of bilateral, brief-pulse electroconvulsive therapy (ECT) administered according to a dosage-titration procedure (8.9 +/- 1.981 treatments). A subset of patients (N = 14) were reexamined at 1 month and 6 months after the conclusion of the treatment. Anterograde (verbal and visuospatial tasks), as well as retrograde (famous and personal events), memory function was significantly impaired at the end of the ECT series. By 1 month follow-up, performance had improved to pre-ECT (depression) levels on both anterograde and retrograde tasks and exceeded these by 6 months. The memory deficits induced by ECT were not a consequence of generalized cognitive impairment. Furthermore, depression and ECT were shown to independently affect memory, and recovery from depression was not a consequence of the amnestic action of the treatment. The results generally confirm previous reports regarding the nature of ECT-induced memory impairment, in a different language and culture. They suggest that long-term effects of the treatment on memory are even less prominent than previously observed.

Adult↗

PubMed1996

Affective reactivity of cognitive functioning and family history in schizophrenia.

This article reports the results of two related studies investigating the association between affective reactivity of cognitive functioning in schizophrenia and family psychiatric history. In Study #1, we examined affective reactivity of positive formal thought disorder symptoms in 29 schizophrenic inpatients. We found that thought disorder was greatly exacerbated by negative affect in those patients with a family history of schizophrenia (SFH) (n = 11), and not in those without the family history (SNFH) (n = 18). In Study #2, we replicated this finding with a stable outpatient sample (n = 10). We also administered dichotic listening tests using affectively neutral and affectively negative stimuli, and found that right-ear advantage was more markedly diminished on the affectively negative task than on the neutral task in the SFH (n = 6) but not the SNFH (n = 4) subjects. These findings support our hypothesis that cognitive symptoms in schizophrenia are exacerbated by negative affect, and that this affective reactivity of symptoms is associated with a familial form of the disorder.

Adult↗

PubMed2006

Cognitive function, fatigue, and menopausal symptoms in breast cancer patients receiving adjuvant chemotherapy: evaluation with patient interview after formal assessment.

BACKGROUND: Women who receive adjuvant chemotherapy for breast cancer report fatigue, menopausal symptoms and cognitive problems. Here we compare assessment of these symptoms using self-report questionnaires and a researcher-administered screen of cognitive function with the experience of women as revealed in a semi-structured interview. METHODS: Twenty-one women who were receiving adjuvant chemotherapy completed the Functional Assessment of Cancer Treatment-General (FACT-G) self-report questionnaire, and sub-scales for fatigue (FACT-F) and endocrine symptoms (FACT-ES). They were evaluated for cognitive dysfunction using the High Sensitivity Cognitive Screen (HSCS). They then completed a semi-structured interview, which explored the nature and severity of these symptoms and their impact on daily function. RESULTS: All patients experienced fatigue and most had menopausal symptoms. There was reasonable correlation of findings in the interview with FACT-F and FACT-ES scores. The HSCS revealed fewer problems than were reported by patients, and correlated with patient experience only for the domain of memory. Most patients noted adverse changes in other cognitive domains, especially concentration, with substantial effects on every-day function. CONCLUSIONS: Women receiving adjuvant chemotherapy for breast cancer have substantial problems with fatigue, menopausal symptoms and cognitive changes. Formal tests such as the HSCS may fail to adequately capture the perceived impact of symptoms.

Activities of Daily Living↗

PubMed2004

Cognitive functioning in humans with mutations of the PAX6 gene.

Fourteen patients with PAX6 gene mutations and previously identified MRI abnormalities were administered tests of cognitive functioning. No deficits were found. A subgroup with agenesis of the anterior commissure performed significantly more poorly on measures of working memory than those without this abnormality, suggesting the anterior commissure may play a role in cognitive processing in addition to an earlier identified role in sensory development and processing.

Adolescent↗

PubMedDate not supplied

Postoperative cognitive function as an outcome of regional anesthesia and analgesia.

BACKGROUND AND OBJECTIVES: It has been suggested that intraoperative neuraxial (spinal, epidural) anesthesia may decrease postoperative cognitive dysfunction when compared with general anesthesia, but the issue remains controversial. We systematically reviewed the data from published studies to determine the effect of intraoperative neuraxial anesthesia versus general anesthesia on postoperative cognitive dysfunction and delirium. METHODS: Studies were identified by searching the PubMed database of the National Library of Medicine (1966 to 2003) for terms related to cognitive dysfunction after surgery. Inclusion criteria were a comparison of intraoperative neuraxial anesthesia versus general anesthesia, and the outcome of postoperative cognitive dysfunction. A total of 196 abstracts were identified, and 24 articles were analyzed. Each article was reviewed, and data were extracted from tables or text or extrapolated from figures as needed. RESULTS: Of the 24 trials obtained, 19 were randomized and 4 were observational (nonrandomized) trials (1 trial was a combination of randomized and observational data). The age of patients studied was typically greater than 60 years, and a wide range of neuropsychometric tests were used to evaluate cognitive function. The majority of trials (23/24 of all trials and 18/19 of randomized trials) did not demonstrate a benefit from neuraxial anesthesia in decreasing the incidence of postoperative cognitive dysfunction. CONCLUSIONS: The use of intraoperative neuraxial anesthesia does not appear to decrease the incidence of postoperative cognitive dysfunction when compared with general anesthesia. There are methodologic and study-design issues present in many studies, and further elucidation of the pathophysiology of postoperative cognitive dysfunction may provide a direction for future studies.

Analgesia, Epidural↗

PubMed2006

Cognitive function in adults with type 2 diabetes and major depression.

The aim of this study was to identify characteristics of neuropsychological functioning among type 2 diabetic adults with and without major depression. Twenty type 2 diabetics with major depression, 20 non-depressed type 2 diabetics and 34 controls without diabetes or depression were compared. A mixed effects repeated measures analysis of covariance indicated significant differences in overall cognitive functioning between diagnostic groups, specifically depressed diabetics demonstrated greater cognitive dysfunction than controls. Further comparisons indicated that depressed diabetics performed significantly worse than non-depressed diabetics in attention/information processing speed. Relative to controls, depressed diabetics performed significantly worse in attention/information processing speed and executive functioning, while there was a trend for non-depressed diabetics to perform worse in executive functioning. These findings suggest that depression negatively impacts cognitive performance among adults with type 2 diabetes, which may have implications for neural circuitry underlying cognitive and mood changes in diabetic patients.

Adult↗

PubMed1996

Executive cognitive functioning predicts reactive aggression in boys at high risk for substance abuse: a prospective study.

This study assessed the ability of executive cognitive functioning (ECF) to predict reactive aggression in boys at high and low risk for substance abuse using a 2-year prospective design. ECF is defined as the self-regulation of goal-directed behavior. Reactive aggression involves impulsive hostile reactions committed with little forethought. ECF was measured using five neuropsychological tests in 198 10- to 12-year-old boys with (SA+) and without (SA-) a paternal history of substance abuse/dependence. Reactive aggression was measured, 2 years later, using a composite index of items derived from two self-report measures. It was hypothesized that ECF would predict reactive aggression, and that this relation would be stronger for the SA+ compared with the SA- boys. SA+ subjects demonstrated lower ECF scores and higher reactive aggression scores, compared with SA- controls. ECF predicted reactive aggression in the SA+ group (beta = 0.37, p = 0.001), but not in the SA- group (beta = 0.09, p = NS). This suggests that compromised ECF may be a risk factor for reactive aggression in SA+ youth. The hypothesis that the relation between ECF and reactive aggression is a manifestation of a mild dysfunction of the prefrontal cortex is discussed.

Aggression↗

PubMed2000

[Neuropsychological aspects of cognitive functioning in epileptic children and adolescents treated with lamotrigine].

The aim of our study was to examine the influence of long term lamotrigine (LTG) add-on therapy on higher nervous function in patients at the developmental age with epilepsy and to analyse the correlation between changes in EEG and cognitive parameters as a consequence of applying LTG in bi- or polytherapy with conventional antiepileptic drugs (AEDs). There were 25 patients (pts), 8-18 years of age with epilepsy stated as "difficult to treat" with partial (12 pts) and generalised (13 pts) seizures. The frequency of seizures was estimated as one or more per month last year (before LTG treatment). The mean age of the patients who had the first seizure was 4.7 yrs. Doses of LTG were adjusted individually (depending on conventional AEDs) according to the recommendation of the producer. The serum levels of conventional AEDs were checked during LTG therapy. Psychological examination was administered three times: before introduction of LTG (as add-on drug) to the therapy, after 3- and after 16 months of the treatment. We measured the level of intelligence, short-term memory, attention, visuomotor integration and abilities of learning. EEG was recorded by Ceegraph (Biologic, USA) after 3 and 12 months of LTG treatment. After the treatment no statistically significant differences in Intelligence Quotient (IQ): global, verbal, nonverbal were noticed. Statistical significance has been stated in parameters of short-term memory. The number of seizures decreased more than 50% in 12 pts. EEG records improved in 6 pts (normalisation of background activity), minimising of epileptform discharges has been noticed in 3 pts. LTG introduced into polytherapy of epilepsy in children and adolescents modified EEG and had minimal influence on cognitive functions.

Adolescent↗

PubMed2001

Associations between apolipoprotein E phenotype, glucose metabolism and cognitive function in men. An explorative study in a population sample.

AIMS: To investigate the associations of the apolipoprotein E phenotype (apoE) and disturbed glucose metabolism with cognitive function in a random population sample. METHODS: A cross-sectional study was conducted, in which 528 men aged 54 or 60 years were recruited randomly from a larger population-based sample of 1516 men. A subject was defined as having abnormal glucose tolerance (AGT), if he had a clinical diagnosis of diabetes, with either dietary or oral antidiabetic treatment or showed impaired glucose tolerance in an oral glucose tolerance test. The subjects were divided into three groups according to apolipoprotein E phenotypes: (a) E2/4, E3/4 or E4/4 (apoE E4); (b) E 3/3 (apoE E3); and (c) E2/2 or E2/3 (apoE E2). Memory function was examined using a word-list learning with Buschke's selective reminding method and test. Executive functions were assessed with the Trail Making Test A and B. RESULTS: Those subjects with apoE E2 and abnormal glucose metabolism demonstrated the worst cognitive executive control compared to other groups. Simple cognitive speed did not differ between the groups. CONCLUSIONS: The exploratory analyses revealed that subjects with apoE E2 allele and AGT had worse glycaemic control and cognitive executive control compared to other groups. Different apolipoprotein phenotypes together with impaired glucose tolerance may have different cumulative adverse effects on age-related cognitive performance. Some subgroups of subjects may be especially vulnerable to cognitive impairment.

Apolipoprotein E3↗

PubMed2005

Insulin and cognitive function in humans: experimental data and therapeutic considerations.

Data from experimental studies in animals and from epidemiological studies in humans suggest a link between insulin and cognitive performance. Do these results translate into clinical and therapeutic benefit for people with cognitive impairment? Insulin injected peripherally can readily cross the blood-brain barrier. Intravenous insulin can improve aspects of cognitive function in healthy adults and in individuals with Alzheimer's dementia. Moreover, intravenous insulin increases concentrations of a long form of beta-amyloid protein, Abeta42. One potential confounding factor with these data, however, is the need for co-administration of glucose with the insulin to maintain euglycaemia as glucose itself can facilitate memory function. Administration of insulin via the intranasal route is scientifically (and therapeutically) more attractive because the insulin goes directly to the cerebrospinal fluid, with minimal systemic absorption; this obviates the need for a glucose infusion. Intranasal insulin may improve some aspects of memory in healthy individuals, but has yet to be studied in people with cognitive impairment. TZDs (thiazolidinediones) reduce peripheral insulin concentrations by enhancing insulin sensitivity. In adults with Type II (non-insulin-dependent) diabetes, TZD therapy improves memory function, but so does sulphonylurea therapy (which elevates peripheral insulin concentrations). Improved memory is linked to lower blood glucose concentrations, rather than altered insulin levels. However, major trials are currently under way examining the impact of TZDs in people with dementia.

Administration, Intranasal↗