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PubMed1995

Cognitive function during insulin-induced hypoglycemia in humans: short-term cerebral adaptation does not occur.

It has been suggested that cerebral adaptation may occur in response to short-term hypoglycemia. This was examined in the present study by measuring serial changes in cognitive function and symptoms after 60 min of continuous hypoglycemia. Hypoglycemia was induced with a hyperinsulinemic glucose clamp on two separate occasions in 24 non-diabetic human subjects. Cognitive function was assessed using the following cognitive test battery: Paced Auditory Serial Addition Test (PASAT), Rapid Visual Information Processing (RVIP), Trail-Making B (TMB), Digit Symbol Substitution Test (DSST) and Four Choice Reaction Time (CRT). In condition A the blood glucose was maintained at 4.5 mmol/l throughout. On two separate occasions (condition B and condition C) the blood glucose was stabilised at 4.5 mmol/l for 30 min, lowered to 2.5 mmol/l for 60 min and restored to 4.5 mmol/l for 30 min. In each condition the cognitive test battery was performed immediately after stabilisation of blood glucose at 4.5 mmol/l and the subsequent battery was repeated at different time intervals: condition A--after a further 40 min of euglycemia; condition B--after 5 min of hypoglycemia; condition C--after 40 min of hypoglycemia. Acute hypoglycemia induced a significant deterioration in cognitive function which was manifest in all tests except TMB (P < 0.05), but performance ability did not differ between conditions B and C. Symptom scores, assessed by a scaled questionnaire, increased significantly during hypoglycemia (P < 0.001) but no differences were detected between the scores at 30 min and 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2001

The effects of short-term blood pressure variability and nighttime blood pressure levels on cognitive function.

We investigated the relationship between 24-h blood pressure (BP) and cognitive function. We performed the Hasegawa Dementia Scale Revised (HDSR), the Mini-Mental State Examination (MMSE), and the Raven's Coloured Progressive Matrices Test (RCPM) in 88 subjects (71+/-9 years) with no history of stroke. Ambulatory BP was non-invasively measured using a TM2421 for 24 h in all patients. Whereas 90% of the scores converged into a narrow range between 25 and 30 points in the HDSR and the MMSE tests, the RCPM score was widely distributed, ranging from 9 to 36 points. The subjects were therefore divided into three groups of > or =25, 26-30, and 31-36 according to their RCPM scores. Subjects with lower scores were significantly associated with increased short-term BP variability during the daytime (p<0.05) and had a tendency toward higher nighttime SBP (p=0.05) compared with those with higher scores. Increased short-term variability of daytime BP and high nighttime systolic BP were associated with cognitive impairment as assessed by the RCPM. The RCPM, which can assess the capacity for judgment through visual information processing, may detect earlier stages of cognitive impairment related to high BP. To prevent a deterioration of cognitive function, strict control of nighttime BP and suppression of short-term BP variability are thus necessary.

Aged↗

PubMed1992

Toward an understanding of cognitive functioning in geriatric depression.

This paper addresses the questions of whether depression compromises cognition in the elderly and whether discernable patterns of cognitive performances could be differentiated between patients with severe depression and those with organic dementia. Published data on geriatric depression and cognitive functioning are divided in demonstrating a depression effect. Further examination and external validation by new data show that the depression effect on discrete cognitive tasks is (1) small, and (2) sensitive to the confounding of sampling and task variables. Future research must take these factors into account. Patterns of cognitive functioning in depression and dementia are different and can be differentiated using a variety of measures. This review finds the term pseudodementia inappropriate and misleading and recommends that it be abandoned.

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PubMed1995

Transient fluctuations in cognitive functioning in schizophrenia based on single-case study methods.

The stability of cognitive performance in four schizophrenia patients was examined over a short time period. A cognitive battery highly sensitive to organismic state (the Repeatable Cognitive-Perceptual-Motor Battery, RCPM) was utilized. Single-case statistical methods tested for within-individual change across five assessments at two week intervals. All four subjects showed statistically significant post-baseline variation in a global measure of impairment (average impairment rating score) and in at least 50% of the individual tests having adequate test-retest reliability. Data are interpreted as providing suggestive evidence of transient fluctuations in performance within a stable window of impaired cognitive functioning. These fluctuations appear substantial enough to influence both research and clinical outcomes. The benefits of the single-case methodology employed are discussed. The data suggest that significant transient fluctuations in cognitive performance can be observed in schizophrenia in domains purported to represent vulnerability markers of the disorder. The importance of accounting for these transient fluctuations in the attempt to identify enduring, trait-like characteristics of cognitive functioning in schizophrenia is discussed.

Adult↗

PubMed1998

Noise stress impairs prefrontal cortical cognitive function in monkeys: evidence for a hyperdopaminergic mechanism.

BACKGROUND: Stress can exacerbate a number of psychiatric disorders, many of which are associated with prefrontal cortical (PFC) cognitive deficits. Biochemical studies demonstrate that mild stress preferentially increases dopamine turnover in the PFC. Our study examined the effects of acute, mild stress exposure on higher cognitive function in monkeys and the role of dopaminergic mechanisms in the stress response. METHODS: The effects of loud (105-dB) noise stress were examined on a spatial working memory task (delayed response) dependent on the PFC, and on a reference memory task with similar motor and motivational demands (visual pattern discrimination) dependent on the inferior temporal cortex. The role of dopamine mechanisms was tested by challenging the stress response with agents that decrease dopamine receptor stimulation. RESULTS: Exposure to noise stress significantly impaired delayed-response performance. Stress did not impair performance on "0-second" delay control trials and did not alter visual pattern discrimination performance, which is consistent with impaired PFC cognitive function rather than nonspecific changes in performance. Stress-induced deficits in delayed-response performance were ameliorated by pretreatment with drugs that block dopamine receptors (haloperidol, SCH 23390) or reduce stress-induced PFC dopamine turnover in rodents (clonidine, naloxone hydrochloride). CONCLUSIONS: These results indicate that stress impairs PFC cognitive function through a hyperdopaminergic mechanism. Stress may take the PFC "off-line" to allow more habitual responses mediated by posterior cortical and subcortical structures to regulate behavior. This mechanism may have survival value, but may often be maladaptive in human society, contributing to the vulnerability of the PFC in many neuropsychiatric disorders.

Animals↗

PubMed2006

Role of cognitive function in assessing informed consent for endoscopy.

BACKGROUND: Patient understanding of the consent process is often suboptimal and the reasons for this are poorly understood. In particular the role of cognitive function in assessing the level of understanding of consent has not been evaluated. AIMS: This study aims to assess the level of patient understanding of the informed consent process and the role of cognitive function in those with low levels of understanding. METHODS: The study was prospective, interviewing patients immediately after they had given consent but before undergoing their procedure. Understanding of the reason for the procedure, the risks attendant upon it, details of the procedure itself and post procedure care was scored with the total representing overall level of understanding. A mini mental state examination (MMSE) was then performed with the score recorded. RESULTS: 100 patients were interviewed. A low level of understanding was shown in 36%. Ninety two patients had a MMSE score greater than 24. All patients with a high level of understanding had MMSE scores greater then 24 compared with 78% of those with a low level of understanding. All patients (n = 8) who displayed a MMSE score less than 24 had a low level of understanding. Men displayed poorer levels of understanding than women. A subnormal MMSE only identified 22% of those with low levels of understanding. CONCLUSIONS: Understanding of the consent process is suboptimal. Adequate cognitive function does not predict a high level of understanding of the informed consent process while cognitive impairment precludes it. It is evident, however that factors other than cognitive dysfunction are at play when attempting to explain low levels of understanding.

Adult↗

PubMed1995

Ultradian rhythms in performance on tests of specialized cognitive function.

Performance on cognitive tasks cycled at ultradian frequencies for 24 males over a test period of eight hours. The verbal task of written word production cycled at 80 minutes; the spatial task of locating points in space cycled at 96 minutes. Multiple cycles were seen for a perceptual speed task that factor loads on both the verbal and spatial task. Replication of the results for the first 12 and second 12 subjects demonstrated their robustness. The verbal and spatial tasks were chosen to reflect specialized functions of the left and right cerebral hemispheres, respectively. Accordingly, the results are interpreted as evidence that specialized task performances are associated with independent neurochemical systems. In addition, blood samples were taken at task performance to assess cyclicity of hormone levels. Luteinizing hormone had a period of 120 minutes, testosterone and cortisol were inconsistent and none seemed to be related to the cognitive tasks. However when subjects were divided according to a winter or summer testing schedule, the spatial periodicity was absent for the summer group and the verbal periodicity was absent for the winter peak.

Activity Cycles↗

PubMedDate not supplied

The effects of mild diastolic hypertension on the results of tests of cognitive function in adults 22 to 59 years of age.

OBJECTIVE: To test the hypothesis that mild diastolic hypertension (90 to 104 mm Hg) may induce asymptomatic impairment of cognitive function. DESIGN: Cross-sectional. SETTING: Community participants recruited to a university-based ambulatory care center. PARTICIPANTS: Three hundred twelve men and women with untreated essential hypertension and 47 normotensive subjects, 22 to 59 years of age. MEASUREMENTS AND MAIN RESULTS: Cognitive function tests measured reaction time to and accuracy in interpreting predetermined visual stimuli, the ability to acquire, reproduce, and change a set of arbitrary stimulus-response associations, and memory and learning of verbal information. These tests were selected to detect subtle differences in performances as opposed to differentiating neurologically normal persons from brain-damaged persons. After controlling for age, gender, and education, results showed that there was no significant difference between the normotensive and hypertensive subjects in two measures of reaction time to and four measures of accuracy in interpreting predetermined visual stimuli, in the measure of arbitrary stimulus-response associations, or in seven memory and learning variables. Although confidence intervals for the differences between means were wide, clinically significant differences were not likely to be present. Younger age was associated with faster reaction times, fewer errors, and better performance on memory and learning tasks, independent of diastolic blood pressure. CONCLUSIONS: The few detectable effects of untreated mild hypertension on cognitive function reported in the literature may be due to chance and are of questionable clinical significance.

Adult↗

PubMed1981

Medical status and cognitive functioning in alcoholic women.

The prevalence of physical health disorders and measures of cognitive functioning were compared for 100 alcoholic and 100 nonalcoholic women matched on age and education. Alcoholic women were less healthy and more impaired on visual-spatial tasks than nonalcoholic women, and there were no relationships between health and cognitive functioning for either group.

Adult↗

PubMed1989

Impact of iron supplementation on cognitive functions in preschool and school-aged children: the Indian experience.

Four studies examined impacts of iron supplementation on school children of various ages and both sexes. The first study investigated impact of iron-folic acid supplements for 60 d on cognition in 94 boys and girls aged 5-8 y. Improvement in total scores of the anemics was significantly higher than the nonanemics in 7-8-y-old children only. The second study assessed impacts of supplementation on cognition in 14 pairs of 5-6-y-old anemic boys, with clear beneficial effects on cognitive function. The third study investigated effects of varying dosages of elemental iron on cognitive function in 48 boys aged 8-15 y, with different levels of improvement. The fourth study investigated impacts of iron supplementation on 163 anemic girls aged 8-15 y with treatment and evaluations at 4 and 8 mo, with significantly improved scores in cognitive function after the eighth month.

Adolescent↗

PubMed2000

Cognitive function in breast cancer patients receiving adjuvant chemotherapy.

PURPOSE: Breast cancer patients receiving chemotherapy have complained of difficulties in their ability to remember, think, and concentrate. This study assessed whether there are differences in cognitive function between breast cancer patients treated with standard-dose adjuvant chemotherapy compared with healthy controls. PATIENTS AND METHODS: The High Sensitivity Cognitive Screen and the Profile of Mood States (POMS) were used to assess cognitive function and mood in a group of 107 women. The women consisted of 31 breast cancer patients receiving adjuvant chemotherapy (group A), 40 breast cancer patients who had completed adjuvant chemotherapy a median of 2 years earlier (group B), and 36 healthy controls (group C). RESULTS: Univariate analysis showed statistically significant differences (P =.009) in overall cognitive function scores between groups A and C, with poorer function in patients receiving adjuvant chemotherapy. These differences remained significant (P =.046) when controlling for age, education level, and menopausal status. More patients had moderate or severe cognitive impairment in groups A and B than in controls (P </=.002). There were no significant differences in POMS scores between the groups, suggesting that the differences seen in cognitive scores were unlikely to be because of mood disturbance. CONCLUSION: Cognitive differences were observed in breast cancer patients receiving adjuvant chemotherapy compared with healthy controls. These differences did not seem to be caused by significant differences in mood disturbance between the two groups. If confirmed, these results have substantial implications for informed consent, counseling, and psychosocial support of patients receiving adjuvant chemotherapy for breast cancer.

Adult↗

PubMed2006

Post-call cognitive function and satisfaction in medical students on different call schedules: a prospective observational pilot study.

OBJECTIVE: The purpose of this study was to evaluate the effects of 2 different call schedules on post-call cognitive function and satisfaction. STUDY DESIGN: This is a prospective observational pilot study of 20 third-year medical students. A computerized cognitive function test was administered to students with call every fourth night or a week of 12-hour "night float" shifts. Questionnaires were completed to assess satisfaction on different call schedules. RESULTS: There was no significant difference in cognitive functioning scores for students on either call schedule. Responses on questionnaires indicate that night float allows students to feel more alert for clinical duties (P = .03). CONCLUSION: There is no significant impact of sleep deprivation on cognitive scores; however, night float allows students to feel subjectively more alert for clinical duties.

Clinical Clerkship↗

PubMed2005

Attachment behaviours and parent fixation in people with dementia: the role of cognitive functioning and pre-morbid attachment style.

This study replicates and extends exploratory research into the occurrence of attachment behaviours and parent fixation amongst people with dementia. Relationships between cognitive functioning, pre-morbid attachment style, attachment behaviours and parent fixation were examined. Fifty-three people with dementia, living in residential or nursing homes, completed the Standardised Mini-Mental State Examination and were interviewed about their parents. A family member or friend rated pre-morbid attachment style and care staff made observations of attachment behaviour. Results indicated that parent fixation occurred more often in participants with lower levels of cognitive functioning. Parent fixation was not related to pre-morbid attachment style. The occurrence of overt attachment behaviour was inconsistently associated with both high and low levels of cognitive functioning, at different times of the day. Participants with an avoidant attachment style exhibited more overt attachment behaviour than participants with a secure attachment style. Findings are interpreted in terms of attachment theory and the clinical and research implications of the study are discussed.

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PubMed1996

Is the cognitive function of older patients affected by antihypertensive treatment? Results from 54 months of the Medical Research Council's trial of hypertension in older adults.

OBJECTIVE: To establish whether initiation of treatment with diuretic or beta blocker is associated over 54 months with change in cognitive function. DESIGN: A cognitive substudy, nested within a randomised, placebo controlled, single blind trial. SETTING: 226 general practices from the Medical Research Council's general practice research framework. SUBJECTS: A subset of 2584 subjects sequentially recruited from among the 4396 participants aged 65-74 in the trial of treatment of hypertension in older adults. The 4396 subjects were randomised to receive diuretic, beta blocker, or placebo. Subjects had mean systolic pressures of 160-209 mm Hg and mean diastolic pressures <115 mm Hg during an eight week run in. OUTCOME MEASURES: The rate of change in paired associate learning test (PALT) and trail making test part A (TMT) scores (administered at entry and at 1, 9, 21, and 54 months) over time. RESULTS: There was no difference in the mean learning test coefficients (rate of change of score over time) between the three treatments: diuretic -0.31 (95% confidence interval -0.23 to -0.39), beta blocker -0.33 (-0.25 to -0.41), placebo -0.30, (-0.24 to -0.36). There was also no difference in the mean trail making coefficients (rate of change in time taken to complete over time) between the three groups: diuretic -2.73 (95% confidence interval -3.57 to -1.88), beta blocker -2.08 (-3.29 to -0.87), placebo -3.01, (-3.69 to -2.32). A less conservative protocol analysis confirmed this negative finding. CONCLUSION: Treating moderate hypertension in older people is unlikely to influence, for better or for worse, subsequent cognitive function.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

Cognitive function in euthymic bipolar patients, stabilized schizophrenic patients, and healthy controls.

Studies on cognitive function in bipolar disorder have led to contrasting results and few data are available on affected subjects during the euthymic phase. In the present study we investigated the cognitive function of a cohort of bipolar (n=40) and schizophrenic (n=66) patients compared to healthy controls (n=64). Patients were evaluated in the outpatient setting over at least 3 months using a computerized version of Wisconsin Card Sorting Test. Schizophrenic patients showed the worst performance while that of the bipolar patients was somewhere between schizophrenic and controls. A discriminant analysis was able to classify correctly 60.59% of the subjects (schizophrenics 48.5%, bipolars 40%; healthy controls 85. 9%). The scores of the Wisconsin Card Sorting Test were entered into a principal component analysis, which yielded a 2-factor solution. Even in that analysis bipolar patients showed intermediate features in comparison with the other groups. These data indicate that bipolar patients have subtle neurocognitive deficits even after the resolution of an affective disorder. As well as observing quantitative differences between groups, the results show different dimensions of cognitive performance within groups suggesting that the deficit of euthymic bipolars could be a dishomogeneous entity, probably more heterogeneous than that in schizophrenia. Studies administering a more complete neuropsychological battery could further clarify the nature and meaning of the cognitive deficits in schizophrenia and bipolar disorder.

Adult↗

PubMed2002

[Cognitive functions and driving ability of older drivers].

INTRODUCTION: The aim of the study was to test older drivers applying for a renewal of their driver's license for cognitive impairment and to examine the outcome of a subsequent driving test. MATERIAL AND METHODS: Patients registered with general practitioners (GPs) in the County of Southern Jutland, who applied for a renewal of their driver's license because of age, participated in the study. Data were collected from a questionnaire sent to GPs and from driving license certificates. The test used m-mini mental state (m-MMSE) for registration of cognitive functioning was a short version of MMSE. The number of recommended driving tests and the results of the driving test were compared during a period before and after the test was used, and compared with the result of the m-MMSE. A total of 6,091 elderly participated in the study, 2,631 before and 3,460 after the introduction of the test. In addition a semi-structured telephone interview with a random sample of the participating GPs was carried out. RESULTS: The use of m-MMSE resulted in significantly more older drivers being recommended a driving test and significantly fewer having their driver's license renewed. Of the older drivers who were recommended a driving test and did not have their driver's license renewed, 83% and 60% had impaired cognitive functioning. The majority (95%) of the GPs considered the test to be a useful tool in general practice. DISCUSSION: The results show that the use of m-MMSE when older drivers apply for renewal of their driver's license because of age, led to fewer older drivers having their driver's license renewed, and that most of them have impaired cognitive functioning. The test is suitable for general practice.

Accidents, Traffic↗

PubMedDate not supplied

Cognitive function in patients with chronic granulomatous disease: a preliminary report.

Chronic granulomatous disease is an inherited immunodeficiency in which phagocytes fail to generate superoxide and its metabolites, resulting in severe recurrent infections and frequent hospitalizations. Chronic illness and frequent hospitalizations can affect growth and development as well as social and educational opportunities. Since no data have been reported on cognitive functioning in patients with this illness, the authors sought to examine cognitive function in a group of patients with chronic granulomatous disease. A retrospective chart review of 26 patients seen and followed at the National Institutes of Health who had received cognitive testing at the request of parent or staff was performed. Demographic information including medical, psychiatric, and developmental histories was gathered. Six patients (23%) were found to have an IQ of 70 or below, indicative of cognitive deficits, and all of those patients had defects in the membrane-linked cytochrome b558. The prevalence of cognitive deficits in this selected population of chronic granulomatous disease patients was high. The determination of the true distribution of cognitive functioning in the general chronic granulomatous disease population is important, since cognitive deficits have implications for educational planning and potential therapies such as transplantation and gene therapy in children.

Adolescent↗

PubMed2004

Does carotid endarterectomy lead to a decline in cognitive function or health related quality of life?

Carotid endarterectomy has been shown to reduce the long-term risk of stroke in selected patients. The present study was designed to examine cognitive function and health related quality of life in a series of carotid endarterectomy patients. One hundred and nine patients undergoing carotid endarterectomy were assessed before surgery and at 6 months post op (n = 100) on standard cognitive function tests and quality of life surveys. Microembolisation was detected using transcranial Doppler ultrasonography. Multivariate repeated measures analysis if variance identified evidences of significant impairments on some tests. Further analysis revealed that particulate Microembolisation detected during the procedure was a significant risk factor associated with declining cognitive function. Patients' self-reported health related quality of life had not deteriorated at 6 month following surgery.

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