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PubMed2002

Nicotinic treatment for cognitive dysfunction.

Nicotinic medications may provide beneficial therapeutic treatment for cognitive dysfunction such as Alzheimer's disease, schizophrenia and attention deficit hyperactivity disorder (ADHD). For development of nicotinic treatments we are fortunate to have a well characterized lead compound, nicotine. Transdermal nicotine patches offer a way to deliver measured doses of nicotine in a considerably safer fashion than the more traditional means of administration, tobacco smoking. We have found that transdermal nicotine significantly improves attentional function in people with Alzheimer's disease, schizophrenia or ADHD as well as normal nonsmoking adults. To follow-up on this proof of principal that nicotinic treatment of cognitive dysfunction holds promise, it is important to use animal models to determine the critical neurobehavioral bases for nicotinic involvement in cognitive function so that more selective nicotinic analogues that improve cognitive function with fewer side effects can be developed. We have found with local infusion in rat studies that the hippocampus and amygdala are important substrates for nicotinic effects on working memory function. Both alpha7 and alpha4beta2 nicotinic receptors are involved in working memory. Nicotinic interactions with dopaminergic and glutaminergic systems are also important in the basis of cognitive function. Studies of the neural nicotinic mechanisms underlying cognitive function are key for opening avenues for development of safe and effective nicotinic treatments for cognitive dysfunction.

Alzheimer Disease↗

PubMed2005

[Cognitive dysfunction and electroencephalogram in schizophrenia].

Recent developments in neuroscience, especially in neuropsychology and neuroimaging, have shed light on cognitive dysfunction in schizophrenia. Cognitive dysfunction may be the underlying basis of schizophrenic symptoms and also the vulnerability marker such as an endophenotype used in genetic studies. Among various cognitive functions, attention is currently focused on "social cognition" as a new realm of research which it may determine the social and occupational abilities of patients with schizophrenia. Recent studies indicate that the second-generation antipsychotics may improve some aspects of cognitive dysfunction in schizophrenia. This urges us to reveal whether such drugs also improve the long-term prognosis as well as quality of life of the patients. Although cognitive function has usually been evaluated by neuropsychological tests, it is advisable to employ electroencephalogram especially event-related potential, which has high time resolution, in combination with neuroimaging with high spatial resolution. In this paper, studies with event-related potentials including P50, MMN, Nd, NA, P300, and N400 are reviewed and we propose a pathophysiological model of schizophrenia from the viewpoint of information processing. The model consists of a controlled processing system (e. g., perceptual organization, and semantic integration) and regulatory system which is mainly automatic processing and enables the controlled processing to be efficient. We postulate that both systems will be primarily affected in schizophrenia and that disruptions in the regulatory system from any cause will impose. further burden on the controlled system and lead to psychosis. Finally, comprehensive and sophisticated assessment of these systems will be required in schizophrenia research.

Antipsychotic Agents↗

PubMedDate not supplied

[Schizophrenic disorders--does cognitive dysfunction relate to characteristics of course and psychopathology of the illness?].

AIM: Because of their importance both for pathogenesis or clinical aspects of the disease and for patients' social functioning, cognitive dysfunctions are nowadays often considered as basic characteristics of schizophrenic disorders. This study was aimed at evaluation of the correlation between some indices of disordered cognitive functioning on the one hand and some variables describing course and psychopathology of schizophrenic disorders on the other. METHOD: The study group consisted of 69 inpatients suffering from schizophrenia diagnosed according to both DSM-IV and ICD-10 criteria. Their mental state was rated by two clinical tools (scales: PANSS, KOSS). Also social functioning of patients in the year preceding current hospitalisation was rated by two scales (GAF, scale W). Cognitive dysfunctions were assessed by computer-aided tests from Dr. Schufried's Vienna Test System including measures of reaction time (RT), visual line pursuit (LVT), perseveration (PERSEV), and span of visual-spatial short term memory (CORSI). In statistical analysis simple nonparametric tests and rank correlation measures were applied. RESULTS: Correlations were confirmed between cognitive dysfunctions and social functioning prior to hospitalisation, age, duration of illness and number of previous hospitalizations. Dysfunctions were less severe in first episode patients than in patients during relapses or the residuum stage of illness. Overall assessments of severity of illness do not correlate with cognitive dysfunctions, but detailed analysis of psychopathology revealed correlations of the latter with such psychopathological dimensions as deficit, disorganization and dysphoria. Reality distortion (positive) psychopathological dimension did not have any correlation with cognitive measures. All indices of cognitive dysfunction correlated with poorer outcome of treatment of the current episode. All correlations confirmed were only of weak or moderate level. CONCLUSIONS: Cognitive dysfunctions correlate rather with unfavourable characteristics of the course of the illness. Results of psychopathological assessment hardly correlate with neuropsychological measures--cognitive dysfunctions are related rather to deficit (negative), disorganisation or dysphoria dimensions of a schizophrenic syndrome than to productive (reality distortion, positive) dimension of the syndrome.

Adult↗

PubMed1997

Outcome of delirium: part 2. Clinical features of reversible cognitive dysfunction--are they the same as accepted definitions of delirium?

OBJECTIVE: To describe the clinical features of reversible cognitive dysfunction. DESIGN: Prospective cohort study. SETTING: Acute geriatric inpatient units. PATIENTS: A random sample of consecutive acute admissions of patients over the age of 65 (N = 80). MAIN MEASUREMENTS: Serial assessments of mental state and cognitive function and observational data. OUTCOME MEASURE: Patients with more than five points of 20% improvement in Mini Mental State Examination following the most severely impaired assessment operationally designated 'reversible cognitive dysfunction'. The clinical features of those with RCD are compared with those with non-reversible cognitive dysfunction. MAIN RESULTS: Delusions, hallucinations, aggression, excitement, irritability and other 'active' symptoms were not commoner in RCD than in non-reversible cognitive dysfunction (non-RCD). By contrast, 'quiet' signs, such as plucking at bedclothes, poor attention, incoherent speech, abnormal associations, slow, vague thought and fluctuating mental state were more marked in RCD than in non-RCD. CONCLUSIONS: Reversible cognitive dysfunction is a quiet and unobtrusive disorder.

Acting Out↗

PubMed1991

Visual masking: a reliable measure for the assessment of cognitive dysfunction in the elderly?

Reliable assessment of cognitive dysfunction in the elderly is a prerequisite for the evaluation of treatment of age-related cognitive decline. Psychophysical thresholds are known to be more reliable than psychometric tests, as assessed by stability of performance in visual masking. A backward (Till & Franklin, 1981) and a forward masking study (Coyne, 1981) were replicated. Thereafter, the same volunteers carried out a backward and forward masking task adapted to minimize noncognitive age-related influences: target and mask duration were individually adjusted to control for reduced eye transmissiveness. Attention was assessed with the electrooculogram; a dependent variable insensitive to sporadic decreases of attention was selected. Test-retest stability in the elderly after 2-4 weeks was r = .97 in backward and r = .86 in forward masking. As Alzheimer's disease mainly affects the cortex, backward masking, which is primarily cortical, may be useful to assess aspects of cognitive dysfunction.

Adult↗

PubMed2002

The panorama of opioid-related cognitive dysfunction in patients with cancer: a critical literature appraisal.

BACKGROUND: Opioids have an essential role in the management of pain in cancer patients, particularly those with advanced disease. Cognitive dysfunction is a recognized complication of opioid use. However, misconceptions and controversy surround the nature and prevalence of its occurrence. A projected increase in the aging cancer population highlights the need for a better understanding of this phenomenon. METHODS: A critical appraisal of the literature evidence in relation to the pattern, pathophysiology, assessment, impact, and management of cognitive dysfunction due to opioid use in cancer pain management is given. RESULTS: Studies in cancer patients with less advanced disease reveal subtle evidence of cognitive impairment, largely related to initial dosing or dose increases. In advanced cancer, opioid-induced cognitive dysfunction usually occurs in the form of delirium, a multifactorial syndrome. The presence of both cognitive impairment and delirium frequently is misdiagnosed or missed. Potential risk factors include neuropathic and incidental pain, opioid tolerance, somatization of psychologic distress, and a history of drug or alcohol abuse. Elevation of opioid metabolites with renal impairment may contribute to cognitive dysfunction. Recognition of opioid-related cognitive dysfunction is improved by objective screening. Successful management requires either dose reduction or a change of opioid, in addition to addressing other reversible precipitants such as dehydration or volume depletion. CONCLUSIONS: Opioid-related cognitive dysfunction tends to be subtle in the earlier stages of cancer, whereas delirium, a more florid form with behavioral disturbance is likely to be present in the advanced cancer population. In patients with advanced disease, an optimal management approach requires careful clinical assessment, identification of risk factors, objective monitoring of cognition, maintenance of adequate hydration, and either dose reduction or switching to a different opioid.

Adult↗

PubMed2003

Religion and cognitive dysfunction in an elderly cohort.

OBJECTIVES: This study examines whether attendance at religious services has an inverse association with cognitive dysfunction in an elderly cohort in whom it has already been shown that religious attendance has an inverse association with physical disability and that social engagement has an inverse association with cognitive decline. METHODS: The study population is a racially and religiously diverse sample of 2,812 community-dwelling men and women from New Haven, Connecticut; it was representative of New Haven in 1982, but not of the United States then or now. The primary study hypothesis proposes that attendance at religious services as measured in 1982 contributes to the prediction of lower levels of cognitive dysfunction in 1985 and 1988. A multivariate logistic regression analysis controlling for seven sociodemographic, four behavioral, and seven biomedical covariables is conducted. RESULTS: Study results show an inverse association between religious attendance in 1982 and cognitive dysfunction in 1985 (odds ratio = 0.64; 95% confidence interval = 0.49, 0.85). Religious attendance as measured in 1982 no longer contributes to the prediction of cognitive dysfunction in 1988. DISCUSSION: The short-term nature of the effect is partially explained by differential mortality. Persons with infrequent religious service attendance and with high levels of cognitive dysfunction in 1982 were more likely to die in the period from 1985 to 1988.

Aged↗

PubMed2002

Serum creatinine patterns in coronary bypass surgery patients with and without postoperative cognitive dysfunction.

UNLABELLED: Renal dysfunction is common after coronary artery bypass graft (CABG) surgery. We have previously shown that CABG procedures complicated by stroke have a threefold greater peak serum creatinine level relative to uncomplicated surgery. However, postoperative creatinine patterns for procedures complicated by cognitive dysfunction are unknown. Therefore, we tested the hypothesis that postoperative cognitive dysfunction is associated with acute perioperative renal injury after CABG surgery. Data were prospectively gathered for 282 elective CABG surgery patients. Psychometric tests were performed at baseline and 6 wk after surgery. Cognitive dysfunction was defined both as a dichotomous variable (cognitive deficit [CD]) and as a continuous variable (cognitive index). Forty percent of patients had CD at 6 wk. However, the association between peak percentage change in postoperative creatinine and CD (parameter estimate = -0.41; P = 0.91) or cognitive index (parameter estimate = -1.29; P = 0.46) was not significant. These data indicate that postcardiac surgery cognitive dysfunction, unlike stroke, is not associated with major increases in postoperative renal dysfunction. IMPLICATIONS: We previously noted that patients with postcardiac surgery stroke also have greater acute renal injury than unaffected patients. However, in the same setting, we found no difference in renal injury between patients with and without cognitive dysfunction. Factors responsible for subtle postoperative cognitive dysfunction do not appear to be associated with clinically important renal effects.

Aged↗

PubMed1995

Hypoglycemia-induced cognitive dysfunction in diabetes mellitus: effect of hypoglycemia unawareness.

Hypoglycemia results in cognitive dysfunction. The aim of this study was to assess and compare the degree of cognitive dysfunction experienced by insulin-dependent diabetic patients (IDDM) with hypoglycemia unawareness with patients with normal awareness of hypoglycemia. Cognitive function was examined in 10 patients who had normal awareness of the onset of hypoglycemia and 10 patients who had a history of impaired awareness of hypoglycemia. A hyperinsulinemic glucose clamp was used to manipulate blood glucose concentrations. Cognitive function was assessed using Rapid Visual Information Processing (RVIP), Trial Making B (TMB), Paced Auditory Serial Addition Test (PASAT) and Digit Symbol Substitution Test (DSST). Multivariate analysis of variance demonstrated a significant effect of hypoglycemia on cognitive function (p < 0.01). A trend was observed towards an overall effect of awareness on performance (p = 0.08). There were trends in the effects of awareness on RVIP correct responses across time (p = 0.07) and the interaction of awareness by study by TMB (p = 0.08). During hypoglycemia subjects with impaired awareness were less cautious in their responses (RVIP misses p = 0.03) and on recovery from hypoglycemia, their cognitive function remained abnormal (TMB p = 0.04, RVIP correct responses p = 0.02, RVIP misses p = 0.04). Thus, IDDM patients with hypoglycemia unawareness exhibited more profound cognitive dysfunction during acute hypoglycemia which persisted for longer following blood glucose recovery.

Adult↗

PubMed1996

Cognitive dysfunction after closed head injury: contributions of demographic, injury severity and other factors.

Previous studies have identified a number of variables which help to predict cognitive dysfunction following closed head injury (CHI) The purpose of the current study was to evaluate the predictive utility of a number of risk factors in a large sample of trauma patients who suffered CHI and underwent neuropsychological assessment Risk factors included demographic variables, Glasgow coma scale (GCS), CT scan, loss of consciousness (LOC), and blood alcohol level (BAL) Multiple regression was used to assess the role of these variables in predicting cognitive dysfunction Results suggested that LOC did not predict cognitive dysfunction Demographic factors did emerge as predictors of cognitive dysfunction BAL was correlated with initial GCS, but did not predict cognitive dysfunction once post-traumatic amnesia cleared.

Journal Article↗

PubMed2006

Postoperative cognitive dysfunction: incidence and prevention.

Postoperative cognitive dysfunction (POCD) is a decline in cognitive function for weeks or months after surgery. Due to its subtle nature, neuropsychological testing is necessary for its detection. The interpretation of literature on POCD is difficult because of numerous methodological limitations, particularly the different definitions of POCD and the lack of data from control groups. POCD is common after cardiac surgery, and recent studies have now verified that POCD also exists after major non-cardiac surgery, although at a lower incidence. The risk of POCD increases with age, and the type of surgery is also important because there is a very low incidence associated with minor surgery. Regional anaesthesia does not seem to reduce the incidence of POCD, and cognitive function does not seem to improve after carotid surgery as has previously been suggested.

Aged↗

PubMed2005

Plasma homocysteine levels in L-dopa-treated Parkinson's disease patients with cognitive dysfunctions.

Elevated plasma homocysteine (Hcy) concentrations are associated with Alzheimer's disease and vascular dementia. Several recent reports have indicated that L-dopa treatment is an acquired cause of hyperhomo-cysteinemia. Despite the fact that a large proportion of Parkinson's disease (PD) patients develop cognitive dysfunctions or dementia, particularly in the late stages of the illness and after long-term L-dopa treatment, the relationship between Hcy and dementia in PD has not been fully investigated. The aim of this study was to evaluate plasma Hcy levels in a group of L-dopa-treated PD patients with cognitive impairment and to elucidate a possible role of Hcy in the development of cognitive dysfunctions in PD. We compared Hcy, vitamin B12 and folate levels in 35 parkinsonian patients treated with L-dopa (14 with cognitive dysfunctions, 21 without cognitive impairment). Analysis of the data revealed that mean Hcy levels were significantly higher in the group with cognitive dysfunctions (21.2+/-7.4 vs. 15.8+/-4.4 micromol/L; p=0.0001), while there was no difference in age, sex, B12 and folate levels. In addition, logistic regression analysis showed that the risk of cognitive dysfunction progressively increased according to Hcy levels after correction for age, sex and B-vitamin status (odds ratio, 19.1; 95% CI, 1.5-241.4; p=0.02). Our results raise the possibility of a relationship between Hcy levels and cognitive dysfunctions in this group of L-dopa-treated PD patients. However, prospective studies on large cohorts of patients should be performed to clarify such an association.

Aged↗

PubMed2005

[NQ01 gene polymorphism C609T associated with an increased risk for cognitive dysfunction and sporadic Alzheimer's disease in Chinese].

OBJECTIVE: To investigate the association between the C609T polymorphism of NADP (H): quinoneoxidoreductase 1 (NQ01) gene and decreased cognitive function and sporadic Alzheimer's disease (AD) in a community cohort. METHODS: Polymerase chain reaction (PCR), denaturing high performance liquid chromatography (DHPLC) and sequencing were used to determine the genotype of NQ01 in 110 subjects without cognitive dysfunction, 21 with cognitive dysfunction, and 65 AD patients from a community cohort. RESULTS: Significantly different distributions of C/T and T/T genotypes were found between MMSE normal and abnormal subjects (OR=2.8, 95%CI 0.96-8.18, P=0.024), and between AD patients and healthy controls (OR=3.27, 95% CI 1.54-6.94, P=0.001), respectively. The frequencies of T allele of NQ01 C609T were significantly higher in MMSE abnormal subjects and AD patients (P=0.034 and 0.005) as compared to normal controls. CONCLUSION: The C609T polymorphism of NQ01 gene may be a genetic risk factor for cognitive dysfunction and sporadic AD in Chinese population.

Alzheimer Disease↗

PubMed2002

Relationship between coping, cognitive dysfunction and depression in multiple sclerosis.

Given its relatively high prevalence, one possible source of stress for patients with multiple sclerosis (MS) is cognitive dysfunction. The authors' study was guided by a new theoretical model suggesting that cognitive dysfunction in MS may be most likely to lead to depression when patients use high levels of avoidance coping and/or low levels of active coping. To test this model, 55 patients with definite MS were administered a neuropsychological battery and measures of depression and coping. Consistent with predictions, regression analyses showed that coping significantly moderated the relationship between cognitive dysfunction and depression. Specifically, cognitive dysfunction was most likely to be associated with depression when patients used either high levels of avoidance or low levels of active coping. Implications of these data for clinical applications and for our theoretical conceptualization are discussed and limitations of the model explored.

Adaptation, Psychological↗

PubMed1994

Cognitive dysfunction in early onset parkinsonism.

Cognitive functions of 24 patients with early onset parkinsonism (age of onset before 40 years) and 24 controls were investigated by a battery of neuropsychological tests. Patients were shown to be impaired in performance IQ (PIQ), conceptual ability and regulation behavior, memory, visuospatial perception, and manual dexterity. Patients were also shown to have a higher Zung Depression score. However, analysis of the testing scores appeared to indicate that only a small portion of poor performance on neuropsychological tests are depression related. The results demonstrated that patients with early onset parkinsonism, in whom the factor of aging is not as important, still show cognitive dysfunction and suggested that Parkinson's disease itself can cause cognitive impairment.

Adult↗

PubMed1995

Effect of NE-100, a novel sigma receptor ligand, on phencyclidine- induced delayed cognitive dysfunction in rats.

Phencyclidine (PCP), in a dose of 15 mg/kg, produced delayed cognitive dysfunction (at 24 h) in rats subjected to water maze tasks. At 24 h after PCP administration, ataxia, hyperlocomotion and stereotyped behavior were not induced. NE-100, N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-enthylamine monohydrochloride, a selective and potent sigma receptor ligand, was administered orally 10 min after PCP administration or 15 min before the first trial (24 h after PCP administration). In both cases, NE-100 dose-dependently attenuated the delayed cognitive dysfunction induced by PCP. As these findings show that ingestion of PCP led to delayed cognitive dysfunction similar to the cognitive signs of psychosis seen in humans, NE-100 is being further studied for possible treatment of subjects with schizophrenia.

Animals↗

PubMed2005

Potential mechanisms and markers of critical illness-associated cognitive dysfunction.

PURPOSE OF REVIEW: To review the current understanding of the potential mechanisms of critical illness-associated cognitive dysfunction and to provide insight into markers that could be used to evaluate the influence of specific mechanisms in individual patients. RECENT FINDINGS: Cognitive dysfunction is common in critically ill patients, not only during the acute illness but also long after its resolution. Several pathophysiologic mechanisms are thought to underlie critical illness-associated cognitive dysfunction, including neurotransmitter abnormalities and occult diffuse brain injury. Markers that could be used to evaluate the influence of specific mechanisms in individual patients include serum anticholinergic activity, certain brain proteins, and tissue sodium concentration determination by way of high-resolution three-dimensional magnetic resonance imaging. SUMMARY: Although recent advances in this area are exciting, they are still too immature to influence patient care. Additional research is needed to provide a better understanding of the relative contribution of specific mechanisms to the development of critical illness-associated cognitive dysfunction and to determine whether these mechanisms might be amenable to treatment or prevention.

Biomarkers↗

PubMed1997

Cognitive dysfunction after ventricular fibrillation during implantable cardiovertor/defibrillator procedures is related to duration of the reperfusion interval.

The insertion of implantable cardioverter/defibrillators (ICD) requires induction of repeated episodes of ventricular fibrillation (VF). The neuropsychological repercussions associated with repeated inducement of hypotension and cerebral ischemia are unknown. In this prospective clinical trial, 1 day prior to ICD assessment/implantation and 5 days postprocedure, 14 patients underwent neurological and cognitive screening. Cognitive dysfunction was defined as impaired performance in one of four cognitive domains. Neurological impairment was defined as a decrement of 2 or more points from baseline of a total possible score of 45 points. Intraoperative hemodynamics, including the reperfusion interval (RI; end of preceding fibrillation to beginning of the next), were recorded. Patients underwent an average of 12 +/- 6 episodes of VF with average duration of mean arterial pressure (MAP) <50 mm Hg for 17 +/- 9 s (range 6-39 s) and of MAP <30 mm Hg for 11 +/- 5 s (range 2-22 s). Nine patients, in none of whom the predetermined criteria for neurologic impairment was met, demonstrated a new subtle neurologic finding postoperatively. Ten of 14 patients met the criterion for cognitive dysfunction 5 days postoperatively. The mean RI between episodes of VF was significantly different between those patients demonstrating cognitive dysfunction and the unimpaired patients (3.1 +/- 0.5 min in the group with cognitive dysfunction vs 3.9 +/- 0.8 min in the unimpaired group, P = 0.027). Five patients without cognitive impairment had longer RI between episodes of circulatory arrest than those showing impaired cognition. We conclude that cognitive dysfunction can occur after insertion of ICD and is related to the duration of RI.

Adult↗