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PubMedDate not supplied

Peripheral arterial disease and cognitive function.

OBJECTIVE: Peripheral arterial disease (PAD) is associated with comorbid atherosclerosis of the coronary and carotid arteries and is a significant risk factor for stroke. However, cognitive function in PAD patients before clinically evident stroke remains poorly characterized. Here we hypothesized that, on neuropsychological testing, PAD patients would perform more poorly than healthy control subjects, and persons with mild cardiovascular disease (essential hypertension), but better than stroke patients, thus reflecting a continuum of cognitive impairment associated with increased severity of vascular disease. METHOD: The cognitive performance of 38 PAD patients (mean ankle-brachial index=0.67, Fontaine Class II) was contrasted with that of 23 healthy normotensive controls, 20 essential hypertensives, and 26 anterior ischemic stroke patients on twelve neuropsychological tests. RESULTS: PAD patients performed significantly more poorly than hypertensives and normotensives, but better than stroke patients, on seven tests of nonverbal memory, concentration, executive function, perceptuo-motor speed, and manual dexterity. Hypertensives displayed poorer performance than normotensives on tests of nonverbal memory and manual dexterity. These findings were independent of age, education, and depression scores. Higher diastolic blood pressure and plasma glucose levels predicted poorer performance of select cognitive tests by PAD patients. Eight to 67% of PAD patients displayed impaired performance (< 5(th) percentile of normotensive controls) on the seven aforementioned cognitive tests. CONCLUSIONS: PAD patients exhibit diminished performance across a variety of domains of cognitive function. Findings also suggest a continuum of cognitive impairment associated with increasingly severe manifestations of cardiovascular disease, thus emphasizing the need for enhanced preventative measures to avert functional declines.

Aged↗

PubMed1987

[Visual evoked potentials and hemispheric differences: on the functional significance of homologous regions].

A total of 18 right handed subjects participated in an experiment, in which visually evoked potentials were recorded from four scalp electrodes (01, 02 and P3, P4) when words or flashes of diffuse light were presented as stimuli. The evoked potentials were subdivided into three components, an early component (Komp1, 0-150 ms) and two late components (Komp2, 150-300 and Komp3, 300-450 ms). For each of these components and for each subject, correlations were computed between different recording sites. The results show that homologous correlations (01:02, P3:P4) yield values, which are significantly higher than the values of the intra- (01:P3, 02:P4) and diagonal interhemispheric (01:P4, 02:P3) correlations. This result, which holds true for all of the three components in a similar way, is independent from the type of presented stimuli. In contrast to homologous correlations, intra- and diagonal interhemispheric correlations do vary as a function of stimulus type and different components as well. Here, the results show that the degree of correlation between different recording sites is positively related to the degree of cognitive load: with increasing cognitive load, the degree of synchronous neural activity increases. Homologous correlations are independent from the type of stimuli (words and pictures) and from the type of VEP-components (Komp1, 2, and 3) as well. Thus, it can be concluded that homologous correlations reflect attentional rather then cognitive processes.

Adult↗

PubMed2005

Neural correlates of cognitive control in childhood and adolescence: disentangling the contributions of age and executive function.

Dense-array (128-channel) electroencephalography (EEG) was used to record event-related potentials (ERPs) from 33 participants between 7 and 16 years of age while they performed a Go/Nogo task. The frontal (Nogo) N2 component of the ERP was taken as an index of cognitive control, and examined in relation to both age and independent assessments of executive function (EF), including the Iowa Gambling Task (IGT), the Stroop task, a delay discounting task, and backward digit span. Better performance on the IGT and the Stroop task was associated with smaller N2 amplitudes, over and above effects of age. N2 latencies decreased with age but were not predicted by EF. Source modeling of the N2 revealed neural generators in areas suggestive of cingulate cortex and orbitofrontal cortex, and the locations of these generators varied systematically with EF (IGT and Stroop task): the cingulate generator was more anterior for good EF participants at all ages; the orbitofrontal generator was relatively left lateralized for younger and for poorer EF participants. Taken together, these findings suggest that age-related decreases in N2 amplitude, but not N2 latency, reflect the development of cognitive control and cannot be attributed solely to incidental changes that may affect assessments of the N2 (e.g., increases in skull thickness). Functionally relevant decreases in N2 amplitude may reflect changes in the regions of cortex giving rise to the N2.

Adolescent↗

PubMed2002

Parathyroidectomy improves concentration and retentiveness in patients with primary hyperparathyroidism.

BACKGROUND: Many patients with primary hyperparathyroidism (PHPT) show symptoms of hypercalcemia syndrome, including psychologic and psychiatric disorders. The aim of this study was to find out whether parathyroidectomy improves cognitive performance with regard to concentration and retentiveness in patients with PHPT. METHODS: . Twenty patients with PHPT underwent psychologic testing preoperatively as well as 6 and 12 weeks postoperatively. Concentration under stress (timing) was proved by the d2-Test of Attention. To evaluate retentiveness, parts of the Wilde Intelligence Test were used. Patients were tested under identical circumstances with regard to time, location, and tester to minimize exterior influences. RESULTS: The patients' concentration enhanced significantly postoperatively (P <.001). The same applied to the total number of items processed (P <.01). Improvement of patients' ability to memorize numbers reached statistical significance when comparing the preoperative with the postoperative result (P =.0396); furthermore, there was a tendency to perform the tests more carefully and accurately (P =.069). CONCLUSIONS: Parathyroidectomy not only betters physical symptoms of PHPT but can also positively influence the patients' cognitive performance. These findings reflect the clinical observation of the patients' improved mental capacity after parathyroidectomy.

Adult↗

PubMed2004

Peak alpha frequency: an electroencephalographic measure of cognitive preparedness.

OBJECTIVE: Electroencephalographic (EEG) peak alpha frequency (PAF) (measured in Hz) has been correlated to cognitive performance between healthy and clinical individuals, and among healthy individuals. PAF also varies within individuals across developmental stages, among different cognitive tasks, and among physiological states induced by administration of various substances. The present study suggests that, among other things, PAF reflects a trait or state of cognitive preparedness. METHODS: Experiment 1 involved 19-channel EEG recordings from 10 individuals with traumatic brain injury (TBI) and 12 healthy matched controls, before, during, and after tasks of visual and auditory attention. Experiment 2 involved EEG recordings from 19 healthy young adults before and after a working memory task (WAIS-R Digit Span), repeated on 2 different days to measure within-individual differences. RESULTS: Experiment 1 showed significantly lower PAF in individuals with TBI, mostly during post-task rest. Experiment 2 showed PAF during pre-task baseline to be significantly correlated with Digit Span performance of the same day but not with Digit Span performance of another day. Moreover, PAF was significantly increased after Digit Span for those participants whose PAF was lower than the sample median before the task, but not for those who had it higher. Finally, both PAF and Digit Span performance were increased during the second day. CONCLUSIONS: PAF was shown to detect both trait and state differences in cognitive preparedness, as well as to be affected by cognitive tasks. Traits are better reflected during post-task rest, whereas states are better reflected during initial resting baseline recordings.

Adult↗

PubMed2000

Negative symptoms: the 'pathology' of motivation and goal-directed behaviour.

In many neurological and psychiatric disorders, including Alzheimer's disease and schizophrenia, symptoms are present that appear to reflect an essential absence of normal movement, cognition and emotional states. These negative symptoms might reflect fundamental impairments in basic brain mechanisms that underlie goal-directed behaviour. Knowledge of the pathology and pathophysiology of these diseases, combined with evidence from basic science, offers opportunities for understanding the neurobiological basis of goal-directed behaviour, particularly the interaction between limbic structures and striato-thalamo-cortical circuits. The study of patients with negative symptoms also provides opportunities for testing cognitive models of goal-directed behaviour, and eventually to map such models onto the neurobiology of both normal and abnormal behaviour.

Behavior↗

PubMedDate not supplied

Auditory event-related cerebral potentials (P300) in hepatic encephalopathy--topographic distribution and correlation with clinical and psychometric assessment.

BACKGROUND/AIMS: Early cognitive disturbances in patients with cirrhosis (Ci) are difficult to assess. Therefore, we evaluated the role of topographic auditory evoked cerebral potentials (P300-EP). METHODOLOGY: Prospective longitudinal study. SETTING: Tertiary clinical care institution. PARTICIPANTS: 45 patients with cirrhosis were compared to 22 healthy subjects. MAIN OUTCOME MEASURES: Hepatic Encephalopathy (HE) was assessed using the clinical grading, standardized psychometric tests, and auditory evoked P300-EP by multichannel EEG recordings. RESULTS: In the patients, the mean P300 peak latency was significantly increased (386.7 +/- 26.7 versus 318.6 +/- 22.2 ms in controls, p < 0.00001). Even in patients with cirrhosis but no HE (n = 18) the P300 peak latency was abnormally prolonged (> 384 ms) in 8 cases (44%). In addition, P180 peak latency was significantly longer in patients with liver cirrhosis as compared to controls (p = 0.021). The maximal P300 amplitude was significantly lowered in patients with liver cirrhosis in the frontocentral and central cortical regions (FZ: p < 0.008; Cz: p < 0.04). Liver function and etiology of liver disease were not related to the increased peak latencies of the P300 and P180 peaks. CONCLUSIONS: P300-EP is a sensitive measure to detect functional cognitive impairment in cirrhotic patients with subclinical HE and clinically apparent HE. Typical changes include latency prolongation and decreased central peak amplitude. Some 40% of patients with no clinical evidence of HE and normal psychometric tests show abnormal results during P300 testing, which is likely to reflect early impairment of cognitive function. Auditory evoked P300 potentials are more sensitive than psychometric testing alone.

Adult↗

PubMed1993

A comparison of psychiatric symptoms in vascular dementia and Alzheimer's disease.

OBJECTIVE: Psychiatric symptoms account for much of the morbidity of vascular dementia and Alzheimer's disease. The goals of this study were to extend previous observations of the psychopathology and behavioral problems associated with vascular dementia and to compare the profile of symptoms in patients with vascular dementia to that in patients with Alzheimer's disease. METHOD: Twenty-eight pairs of patients (one with vascular dementia and one with Alzheimer's disease) were matched with respect to education, age, and severity of dementia. Their psychiatric symptoms were assessed with the Neurobehavioral Rating Scale, a 28-item observer-rated instrument, and the Hamilton Depression Rating Scale, and the symptoms in the two diagnostic groups were compared. RESULTS: Blunted affect, depressed mood, emotional withdrawal, motor retardation, low motivation, anxiety, unusual thoughts, and somatic concerns occurred in more than one-third of the patients with vascular dementia. There was no significant relation between severity of cognitive impairment and severity of these noncognitive symptoms. The patients with vascular dementia had more impairment than the patients with Alzheimer's disease, as indicated by the Neurobehavioral Rating Scale total scores and scores on the behavioral retardation, anxiety/depression, and verbal output disturbance factors. They also had a higher total score on the Hamilton depression scale and higher scores on 14 of the 17 Hamilton depression items. CONCLUSIONS: Patients with vascular dementia have more severe behavioral retardation, depression, and anxiety than those with Alzheimer's disease when the groups have similar levels of cognitive impairment. This probably reflects the contrasting brain regions typically involved in the two disorders.

Aged↗

PubMed2004

[Cognitive flexibility, an additional symptom of attention deficit hyperactivity disorder. Is it a therapeutically predictive element?].

INTRODUCTION: Cognitive flexibility is a capability acquired during infancy that can be evaluated from the age of 8 onwards. This executive function can affect patients with dorsolateral frontal lesions. Involvement of this function in some children with attention deficit hyperactivity disorder (ADHD) would point to an additional disorder. AIMS: The objective of this study was to report on the involvement of cognitive flexibility in patients with ADHD from the age of 8 years onwards, to establish a correlation with the progressive phenomenon in its development, and to relate the findings from the study of cognitive flexibility with those of the attentional function. PATIENTS AND METHODS: A group of 50 children diagnosed as suffering from ADHD (8 21 years old) and 50 normal children were evaluated. The same subjects were submitted to a study of their attentional functions, their inhibitory control mechanisms as well as their cognitive flexibility. RESULTS: At least 38% of the patients studied showed involvement of cognitive flexibility. No statistically significant relation was observed when data were linked to the age variable, which could point to the absence of the maturation factor, unlike the results observed in the case of sustained attention. Patients with poor cognitive flexibility also present disorders involving attentional discrimination, the control of impulses and interference control. CONCLUSIONS: The group with cognitive rigidity as a symptom added to the attentional disorder could correspond to a complex subtype that does not respond so successfully to stimulants. Consequently, cognitive flexibility studies could reflect an indicator for selecting the type of pharmacological treatment to be employed.

Adolescent↗

PubMed1999

Panmodal processing imprecision as a basis for dysfunction of transient memory storage systems in schizophrenia.

Schizophrenia is a severe mental disorder associated with cognitive disturbances that may reflect underlying deficits in the functioning of brain transient memory storage systems. This study investigates performance in three distinct tasks that require transient memory storage: (1) tone discrimination, (2) object weight discrimination, and (3) "AX"-type visual continuous performance task. The tests used were chosen to investigate the degree to which a similar pattern of performance deficit could be observed across multiple sensory and cognitive domains in schizophrenia. In each of the paradigms, a similar pattern emerged: subjects with schizophrenia showed severe performance deficits whenever performance depended on functioning of transient memory systems. The deficits were apparent at both short and long interstimulus intervals (ISI), however, and schizophrenia subjects were no more affected by increasing ISI than were controls. Moreover, when short ISI performance was matched across groups by manipulating task difficulty, subsequent decay in performance was equivalent across groups. Thus, although schizophrenia subjects show severe performance deficits in memory-dependent tasks, the deficits do not appear to reflect impaired transient memory per se. Rather, they appear to reflect impaired precision of operation of such systems, irrespective of the duration over which representations must be maintained. The severe deficits in processing precision, despite the relatively preserved maintenance of representation, may be relevant to pathophysiological models of schizophrenia.

Adult↗

PubMed1995

Cognitive and biological determinants of P300: an integrative review.

The P300 event-related brain potential (ERP) is thought to reflect neuroelectric activity related to cognitive processes such as attention allocation and activation of immediate memory. However, recent studies have provided evidence that the P300 also is influenced by biological processes such as fluctuations in the arousal state of subjects. The effects of natural (circadian, ultradian, seasonal, menstrual) and environmentally induced (exercise, fatigue, drugs) state variables on the P300 are reviewed. The findings suggest that these factors contribute to P300 measures and are discussed in terms of their theoretical and applied implications.

Brain↗

PubMed2026

Subacute and long-term changes in cognitive functioning after administration of classic psychedelics, MDMA and ketamine: A systematic review of clinical and preclinical evidence.

Psychedelic agents induce a window of heightened neuroplasticity that extends beyond acute intoxication, during which neural circuits are more amenable to change. This period may facilitate changes in cognition relevant to the treatment of psychiatric disorders. This systematic review synthesised clinical and preclinical evidence of subacute and long-term (≥1 day) effects of classic and non-classic psychedelics on cognition. MEDLINE, EMBASE, APA PsycInfo and Web of Science were searched to identify human and animal studies investigating psychedelics and cognition (executive function, attention, decision-making). Sixty-seven (47 clinical, 20 preclinical) articles met inclusion criteria. Psilocybin demonstrated the most consistent evidence of subacute and longer-term cognitive improvement, particularly in cognitive flexibility and attention. Ketamine showed enhancement across cognitive domains, although findings were heterogeneous. LSD and DMT showed no consistent subacute changes, while MDMA was associated with transient cognitive impairments that resolved within days. Risk of bias assessments revealed selective outcome reporting, poor reporting of missing data and inadequate methodological detail, limiting the confidence of findings. Current evidence provides preliminary support for subacute changes in cognition following administration of select psychedelic agents. Cognitive improvements were more frequently seen in psychiatric populations than healthy subjects, which may reflect a remediation of existing cognitive deficit rather than enhancement above normal functioning. Adequately powered, controlled studies with standardised reporting of cognitive outcomes are required to determine the magnitude, durability and clinical relevance of psychedelic-associated cognitive change.

Hallucinogens↗

PubMed1991

Effects of dextroamphetamine on the cognitive and social play of a preschooler with ADHD.

This study investigates how deficits in attention and impulse control are reflected in the social and cognitive play of a 4-year-old boy with attention-deficit hyperactivity disorder. In addition, an A-B-A-B reversal design was employed to evaluate the effectiveness of dextroamphetamine (2.5 mg, twice a day) for treatment of preschool attention-deficit hyperactivity disorder. The most dramatic effects of medication were observed on the level of sustained attention and the pattern of cognitive play. Sustained attention during play and in a structured group activity improved, and play became more sequentially organized and symbolic. Results are discussed with respect to the following: 1) attention-deficit hyperactivity disorder and preschool play; 2) the efficacy of psychostimulant medication; and 3) the adequacy of teacher ratings versus direct observation in measuring medication response.

Attention↗

PubMed2002

[Schizophrenia in childhood and adolescence. Symptomatology, clinical course, etiological and therapeutic aspects].

Schizophrenic psychosis is rare in patients below 15 years of age. Early diagnosis is crucial as the illness is likely to have a poor outcome: indeed, duration of untreated psychosis may exert a negative influence on the prognosis. Thus, it may be highly relevant to recognise premorbid changes of character traits, behaviour and cognitive problems which are reflected in worsening school performance. For example, some 40 to 50% of the children who later develop a psychosis will show social withdrawal, loss of interest in age-appropriate activities, peculiar or immature responsiveness, increasingly suspicious, fearful or depressive states, baseless despair, unusual somatic complaints, concentration problems, cognitive and linguistic disabilities, and peculiar motor movement disorders such as bizarre, ritualistic behaviour, mannerisms, stereotypies, echopraxia. These features are non-specific: they can but need not represent the early signs indicating later development of schizophrenia. They should be evaluated in terms of potential psychosocial, genetic and somatic pre-, peri- and postnatal risk categories. During the child's development these features may build up to constitute vulnerability and stress factors that may lead to psychotic breakdown. Early age of onset correlates with high social disability scores. Complete remission is an extremely rare event in patients with gradual-insidious onset of psychosis.

Adolescent↗

PubMed2006

Chronic treatment with desipramine improves cognitive performance of rats in an attentional set-shifting test.

Alterations in central monoaminergic neurotransmission are important in the actions of many antidepressants. This study tested the hypothesis that tonic elevation of noradrenergic (NA) neurotransmission in medial prefrontal cortex (mPFC) by chronic treatment with the selective norepinephrine (NE) reuptake blocker desipramine (DMI) may contribute to the beneficial cognitive effects of this antidepressant drug (AD). Male Sprague-Dawley rats were treated with DMI acutely (15 mg/kg, i.p.) or chronically for 21 days (7.5 mg/kg/day via osmotic minipump) before assessing performance on an attentional set-shifting test. The extradimensional set-shifting component of this test reflects a process of cognitive flexibility that is dependent upon mPFC, and that we have shown previously to be facilitated by NA activity in mPFC. Microdialysis was performed to measure NE release in mPFC concurrently with behavioral testing. Acute DMI treatment produced an increase in extracellular NE levels in mPFC, and a modest improvement in overall performance across all task stages of the attentional set-shifting test, but failed to produce a significant improvement in any of the individual specific tasks comprising the test sequence. Chronic DMI treatment tonically elevated basal extracellular NE levels in mPFC, associated with a significant improvement in performance specifically on the extradimensional set-shifting component of the test. There was also a significant reduction in set loss errors in rats treated chronically with DMI. Hence, tonic elevation of NA transmission in mPFC by chronic DMI treatment was associated with a time-dependent facilitation of cognitive flexibility that may contribute to the mechanism whereby chronic treatment with ADs, specifically NE reuptake blockers, may exert a beneficial therapeutic effect on cognition in depressed patients.

Adrenergic Uptake Inhibitors↗

PubMedDate not supplied

Platelet monoamine oxidase B activity in dementia. A 4-year follow-up.

Platelet monoamine oxidase B (MAO-B) activity has been found to increase significantly in demented patients. For the first time, a 4-year follow-up of platelet MAO-B activity and Mini-Mental State (MMS) was performed in patients with probable dementia of the Alzheimer type (DAT) and age-matched controls. MAO-B activity of DAT patients increased significantly 2 years after the beginning of the study as compared with controls and remained significantly higher for the entire period of the examinations (p < 0.0001). The decrease of the MMS scores did not correlate with the time course of the increase of platelet MAO-B activity (Spearman rank correlation test). The decline of the MMS scores of DAT patients preceded the elevation of MAO-B activity. Since degenerative processes in brain areas which are responsible for cognitive function and are reflected by the MMS scores rather affect cerebral cholinergic than monoaminergic neurotransmitter systems, degeneration of the latter at late stages of DAT might be reflected by increased platelet MAO-B activity.

Aged↗

PubMed2005

Effect of repeated exposures to cold on cognitive performance in humans.

The effects of repeated exposure to cold temperature on cognitive performance were examined in 10 male subjects who were exposed to control (25 degrees C) and cold (10 degrees C) conditions on 10 successive days. A cognitive test battery (ANAM-ICE) was administered each day to assess complex and simple cognitive functioning accuracy, efficiency and response time. Rectal (T(rect)) and skin temperatures, thermal sensations, metabolic rate (M) and cardiovascular reactivity were also recorded. With the used cold exposure, inducing cold sensations and discomfort, superficial skin cooling (6-7 degrees C) and a slightly lowered T(rect) (0.4 degrees C) we observed three distinct patterns of cognitive performance: 1) negative, reflected in increased response times and decreased accuracy and efficiency; 2) positive, reflected in decreased response time and increased efficiency; and 3) mixed, reflected in a pattern of increases in both accuracy and response time and decreases in efficiency, and a pattern of decreases in both accuracy and response time. T(rect), thermal sensations, diastolic blood pressure (DBP) and heart rate (HR) were independent predictors of decreased accuracy, but also decreased response time. Cognitive performance efficiency was significantly improved and response times shorter over the 10-d period both under control and cold exposures suggesting a learning effect. However, the changes in cognitive performance over the 10-d period did not differ markedly between control and cold, indicating that the changes in the thermal responses did not improve performance. The results suggest that cold affects cognitive performance negatively through the mechanisms of distraction and both positively and negatively through the mechanism of arousal.

Acclimatization↗

PubMed1995

Cognitive dysfunction in systemic lupus erythematosus is independent of active disease.

OBJECTIVE: To determine whether disease activity in organ systems other than the central nervous system (CNS) contributes to impaired neurocognitive functioning in patients with systemic lupus erythematosus (SLE) without current major neuropsychiatric problems. METHODS: A cross sectional study of 90 consecutive female patients with SLE. Neuropsychological status was evaluated with a comprehensive 2.5 h battery of tests. Disease activity was evaluated by the Lupus Activity Criteria Count (LACC) in all patients and the SLE Disease Activity Index (SLEDAI) in a subset of 20. Involvement of particular organ systems was identified with reference to American Rheumatism Association criteria. RESULTS: Sixty-eight of the 90 patients showed no active CNS involvement at the time of testing. Of these 68, 36 (53%) were impaired according to quantitative criteria alone. However, the association between cognitive impairment and disease activity was not significant using either LACC or SLEDAI as the measure of disease activity. Further, the group with active disease did not show generally poorer performance in specific areas of cognitive function than the group with inactive disease at the time of testing. The likelihood of significant cognitive impairment was not increased in the presence of involvement of any of the organ systems reviewed by the LACC. CONCLUSION: These findings substantiate our working hypothesis that cognitive impairment in SLE reflects an immune mediated compromise of an underlying neural substrate, rather than the non-specific effects of chronic illness or its treatment.

Chronic Disease↗