PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Cognitive Dysfunction”

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 703 records · Page 39Linked to original sources

Restitution of neurophysiological functions, performance, and subjective symptoms after moderate insulin-induced hypoglycaemia in non-diabetic men.

The restoration of cognitive function was studied in 10 healthy men aged 26 years (25.5 +/- 1.2 years; mean +/- SD) after insulin-induced hypoglycaemia (arterialized blood glucose 2.5 +/- 0.4 mmol l-1) for 62 +/- 8 min. Another group of six men participated in a single blind sham study for comparison. The hypoglycaemic event caused a significant increase (p = 0.006) in serum adrenaline levels. Ratings of adrenergically mediated symptoms increased during hypoglycaemia (p = 0.006), as did neuroglycopenic symptoms (p = 0.002), although neuroglycopenia ratings increased in both studies. During hypoglycaemia, P300 amplitudes in a relatively demanding visual search task decreased (p = 0.02), whereas easier tasks were unaffected. The amplitudes were restored after 40 min of normoglycaemia. Reaction time deteriorated after restoration of normoglycaemia, suggesting an effect of hypoglycaemia on learning. Thus, hypoglycaemia at a blood glucose level that is common among patients treated with insulin causes clear cognitive dysfunction, although restoration of the cognitive dysfunction to normal was fast.

Adult↗

Correlates of cognitive deficits in first episode schizophrenia.

OBJECTIVE: The presence of cognitive dysfunction in schizophrenia has been well documented, but questions remain about whether there are relationships between this dysfunction and clinical symptomatology. If present, such relationships should be most clearly observable in patients with first episode schizophrenia; that is, before the effects of chronic illness, institutionalization, or treatment might confound them. METHOD: 307 schizophrenia subjects in their first episode of illness were recruited to participate in a clinical trial comparing the long-term efficacy of haloperidol and risperidone. The psychopathology, cognitive functioning, early treatment history, and duration of untreated psychosis of these subjects were assessed prior to their assignment to randomized, double-blind treatment. Approximately two-thirds of the subjects were receiving antipsychotic treatment at the time of assessment; however, the duration of treatment was limited to 12 weeks or less. RESULTS: The severity of negative symptoms at the time of assessment was associated with deficits in memory, verbal fluency, psychomotor speed and executive function. Positive symptoms were not associated with cognitive deficits. Also, the duration of untreated illness (DUI) prior to assessment was not significantly associated with cognitive impairment. CONCLUSIONS: The results of this study of first episode schizophrenia patients suggest that a relationship exists between negative symptoms and cognitive dysfunction. However, that relationship accounts for only a minor portion of the variance (i.e., 10-15%) in the severity of cognitive dysfunction after controlling for a number of potentially confounding factors. This finding provides support for the theory that the neurobiological processes that give rise to symptomatology and cognitive dysfunction in schizophrenia are partially overlapping.

Adolescent↗

A pilot study of visual backward masking performance among affected versus unaffected offspring of parents with bipolar disorder.

BACKGROUND: Cognitive dysfunction is evident in some euthymic patients with established bipolar disorder (BD), including deficits in visual backward masking (VBM) tasks which map to a specific neural pathway. A high-risk paradigm would clarify the temporal relation of cognitive dysfunction to clinical course. METHOD: We compared euthymic offspring (age range: 18-32 years) of lithium-responsive bipolar parents with and without a previous lifetime history of psychiatric illness to healthy comparison subjects with a negative family history, on a VBM task that requires target location. RESULTS: High-risk offspring with no lifetime psychiatric history performed the VBM task at levels of healthy controls. High-risk offspring with a previous history of a mood disorder, in complete remission, made significantly more errors at short target-mask intervals than control or never ill offspring. These higher error rates were not a consequence of faster response times. CONCLUSIONS: There is preliminary evidence of specific cognitive dysfunction early in the course of illness in affected offspring of parents with lithium responsive BD. VBM is ideal for future longitudinal studies addressing whether cognitive dysfunction in BD is a trait marker or a consequence of illness manifestation.

Adolescent↗

Anosognosia in very mild Alzheimer's disease but not in mild cognitive impairment.

OBJECTIVE: To study awareness of cognitive dysfunction in patients with very mild Alzheimer's disease (AD) and subjects with mild cognitive impairment (MCI). METHODS: A complaint interview covering 13 cognitive domains was administered to 82 AD and 79 MCI patients and their caregivers. The patient groups were comparable according to age and education, and Mini Mental State Examination (MMSE) scores were > or =24 in all cases. The discrepancy between the patients' and caregivers' estimations of impairments was taken as a measure of anosognosia. RESULTS: Self-reports of cognitive difficulties were comparable for AD and MCI patients. However, while in comparison to caregivers MCI patients reported significantly more cognitive impairment (p < 0.05), AD patients complained significantly less cognitive dysfunctions (p < 0.001). CONCLUSIONS: While most MCI patients tend to overestimate cognitive deficits when compared to their caregiver's assessment, AD patients in early stages of disease underestimate cognitive dysfunctions. Anosognosia can thus be regarded as a characteristic symptom at a stage of very mild AD (MMSE > or =24) but not MCI. Accordingly, medical history even in mildly affected patients should always include information from both patient and caregiver.

Aged↗

[Longitudinal study of cognitive function in two patients with focal cortical dysplasia].

To clarify the relationship between epileptic attacks and cognitive dysfunction, we examined the serial findings of 123I-IMP single photon emission computed tomography (SPECT) in relation to the intelligence quotient (IQ), assessed by Wechsler Intelligence Scale of Children-Revised, in two female patients with focal cortical dysplasia (FCD) over a 10-year period. The age of patient 1 at the initial assessment was 2 years, and the age of patient 2 was 9 months. They developed complex partial epilepsy in infancy, and were treated with antiepileptic drugs, which remained effective until 11 years of age, when their epileptic attacks recurred. Patient 1, a 14-year-old girl with FCD of the left parietal lobe suffered from dyscalculia, right-left disorientation, and finger agnosia even when she was free of epileptic attacks. Following the recurrence of seizures which occurred every night, she became unable to understand what was said to her. A hypoperfusion area detected by 123I-IMP SPECT was restricted to the left parietal lobe during the seizure-free period, but spread to the temporo-parietal lobes following the recurrence. Her verbal IQ declined from 94 (at 9 years of age) to 63 (at 11 years and 8 months). After her seizures were controlled again (at 14 years and 4 months), the 123I-IMP SPECT findings improved. Patient 2, a 12-year-old girl with FCD of the left frontal lobe, showed cognitive dysfunction. Her verbal IQ declined from 91 (at 7 years and 5 months) to 76 (at 11 years and 8 months) following a recurrence of epileptic attacks. 123I-IMP SPECT showed hypoperfusion in the left frontal lobe, where the accumulation count ratio (left/right ratio) declined from 0.86 (at 3 years) to 0.64 (at 11 years). These findings suggest that epileptic attacks are related to cognitive dysfunction in FCD patients. This cognitive dysfunction appears to correlate with the appearance of hypoperfusion areas, as detected by 123I-IMP SPECT.

Adolescent↗

Age effects on the clinical presentation of alcoholics at a psychiatric hospital.

Little is known about the effects of age on the clinical presentation of alcoholism in various treatment settings, despite the clinical importance of this factor. This study evaluates the effects of age on the clinical profile of 604 alcoholics who presented for initial evaluation and treatment at a psychiatric hospital. Young alcoholics displayed the most prominent substance use, antisocial behavior, depressive symptoms (including suicidality), and impulsivity. Early middle-aged alcoholics displayed the highest levels of drinking. Elderly alcoholics displayed the highest levels of cognitive dysfunction, although some level of cognitive dysfunction was present among even the youngest alcoholics. These findings confirm and clarify the effects of age on the clinical profile of alcoholics presenting for initial evaluation at a psychiatric hospital.

Adult↗

Cognition after major surgery in the elderly: test performance and complaints.

There is evidence that older people in particular have a higher risk of cognitive dysfunction after surgery under general anaesthesia. We have investigated the severity and character of postoperative cognitive dysfunction after major non-cardiac surgery in patients older than 65 yr. Also, cognitive complaints were studied. Cognitive function was assessed using cognitive tests measuring memory and attention, such as ability to shift between two sequences, ability to ward off distractions, simple cognitive speed and speed of general information processing. These tests were performed before, 1 week (short-term) and 3 months (long-term) after surgery. Cognitive performance of the patients was compared with that of healthy subjects not undergoing surgery who were also subjected to repeated cognitive measurements. After 1 week, patients had a poorer performance on tests measuring simple cognitive speed and speed of general information processing. Three months after surgery, patients and controls showed improved cognitive performance compared with the first measurement. These results suggest that major non-cardiac surgery in older patients causes short-term but not long-term cognitive dysfunction. However, after 6 months, 14 of 48 patients (29%) reported having experienced a decline in cognitive abilities after discharge from hospital. Eight of these 14 patients (17%) were still experiencing these cognitive complaints and reported 'not being the same since the operation'. These findings emphasize that cognitive complaints after major surgery may not reflect actual changes in cognitive performance but may be caused by other factors such as depression or awareness of age-related changes.

Aged↗

Validation of the Quick Cognitive Screening Test.

Reports in the literature suggest that 70% to 80% of cognitive deficits with probable organic basis are undetected in patients at risk, especially if symptoms are minimal. Studies have shown that clinically convenient beside screening tests show low sensitivity with a high rate of false-negative results. The purpose of this study was to validate a sensitive mid-range cognitive screening test to detect cognitive deficits, including those not usually identified by bedside mental status examinations. The Quick Cognitive Screening Test (QCST) was initially developed and subsequently adapted from original unpublished work by the late John McFie. The test was designed to detect global cognitive dysfunction and specific areas of cognitive dysfunction. Areas assessed included orientation, attention and concentration, memory, language, construction, perception, spatial ability, and abstract reasoning. Scoring is multidimensional, each subtest having a score, plus summary and global scores. Thirty-eight neurological patients with a cerebrovascular accident, traumatic brain injury, and other miscellaneous diagnoses, were recruited from a tertiary care center for physical rehabilitation. Fifteen residents from a psychiatric rehabilitation center were also recruited. Thirty-two healthy volunteers from the community served as age-matched controls. The Wechsler Adult Intelligence Scale-Revised (WAIS-R) was used to establish reliability and validity of the QCST. The National Adult Reading Test (NART) was used to estimate premorbid intellectual functioning. Results showed that the QCST identified cognitive impairment in all of the neurological and psychiatric patients assessed. Oneway analyses of variance of five summary scores showed significant differences between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Long-latency cerebral event-related potentials in multiple sclerosis.

The objective of this study was to characterize electrophysiologically the basis of the cognitive dysfunction in multiple sclerosis. The cognitive dysfunction experienced by patients with multiple sclerosis has recently become more widely appreciated, but the best means of monitoring such function is unknown. Long-latency cerebral event-related potentials were recorded in a group of patients with relapsing/remitting or secondarily progressive multiple sclerosis and in a group of age-matched normal control subjects. Subjects were presented a series of auditory tones, with one (1,000 Hz) occurring during 86% of the trials (frequent tone) and the other (2,000 Hz) occurring during 14% of the trials (rare tone). Subjects were required to listen to the stimuli and count the occurrence of the rare tones. Cerebral responses recorded from the scalp were averaged separately for the rare and frequent tones. The N1, P2, N2, and P3 components of the long-latency response were all prolonged in latency in patients with MS, as were the N1-N2 and N1-P3 interpeak latencies. In addition, the amplitude of the P2 and P3 peaks was diminished in patients compared with control subjects. Significant correlations were found between the changes in both interpeak latency peak amplitude and the scores on the Mini-Mental State Examination. Electrophysiologic changes occur in MS that are the result of central disease (as opposed to involvement of primary afferent pathways) and correlate with cognitive status. The recording of event-related potentials may thus provide a useful tool, not only as an objective measure of cognitive function in patients with MS, but also as an aid in the evaluation of response to treatment.

Acoustic Stimulation↗

The canine as an animal model of human aging and dementia.

The aged canine displays many features that make it an excellent model for studying the progression of pathology in brain aging and linking these findings to learning, memory and other cognitive functions. Canines develop extensive beta-amyloid deposition within neurons and their synaptic fields, which appears to give rise to senile plaques. These plaques are primarily of the early diffuse subtype. Aged canines also exhibit accumulations of lipofuscin, cerebral vascular changes, dilation of the ventricles, and cytoskeletal changes. Neurofibrillary tangles (NFTs) are not present in the aged canine. Thus, the aged canine brain provides a suitable model for studying early degeneration normally considered to be pre-Alzheimer's. This supposition is also supported by behavioral data. We have found that the extent of beta-amyloid deposition correlates with a decline in select measures of cognitive function. These data provide the first evidence of a correlation between beta-amyloid accumulation and cognitive decline in the absence of NFTs. We summarize four lines of evidence that support using the aged canine as a model of human aging: (a) Aged canines develop aspects of neuropathology similar to that observed in aged humans; (b) Veterinarians have observed that many canines exhibit a clinical syndrome of age-related cognitive dysfunction; (c) Aged canines are deficient on a variety of neuropsychological tests of cognitive function; (d) The level of beta-amyloid accumulation correlates with cognitive dysfunction in the canine. These data indicate that the aged canine is a particularly useful model for studying age-related cognitive dysfunction (ARCD), early neuronal changes associated with aging, and the initial stages of senile plaque formation.

Aging↗

Cognitive outcomes after deep brain stimulation for Parkinson's disease: a review of initial studies and recommendations for future research.

Modern ablative surgery for movement disorders probably results in less frequent and severe cognitive morbidity than seen in early surgical series. Nonetheless, recent studies indicate that neurobehavioral functions commonly compromised in Parkinson's disease (PD) (e.g., executive functions, verbal fluency, and memory) are negatively impacted in some patients by lesion placement. The potential reversibility of cognitive dysfunction after chronic electrical deep brain stimulation (DBS) for PD has lead some to favor this treatment modality over ablation. This paper reviews the initial studies of the cognitive effects of thalamic, pallidal, and subthalamic DBS. These studies suggest that DBS is relatively safe from a cognitive standpoint and that the benefits of motor improvements probably outweigh the cost of minimal cognitive morbidity. This conclusion must be offered with caution, however, given the small numbers of studies to date and their methodological limitations. Neurobehavioral research has yet to adequately address (1) outcome relative to appropriate control groups; (2) effects of electrode placement versus stimulation; (3) laterality- and site-specific effects of DBS; (4) long-term effects of DBS; (5) effects of stimulation parameters; (6) risk factors for cognitive dysfunction with DBS; (7) whether cognitive dysfunction associated with DBS is reversible; and (8) comparative neurobehavioral outcome after DBS and ablation. DBS affords an exciting opportunity to clarify the neurobehavioral role of the basal ganglia.

Brain↗

Effect of cognitive impairment on rehabilitation outcome.

Previous studies examining the relationship between cognition and ability to benefit from inpatient rehabilitation have found cognitive dysfunction to be associated with a poor rehabilitation outcome. To examine whether cognitive dysfunction precluded effective rehabilitation, 52 consecutive admissions to a geriatric rehabilitation unit were assigned Mini Mental State Examination (MMSE) scores. Functional gains were assessed by the change in Functional Independence Measure (FIM) score from admission to discharge. Neither MMSE score alone nor in combination with age was significantly associated with change in FIM (r = 0.10; R = 0.25; P< 0.18). MMSE score alone and in combination with age was correlated with functional status on admission (r = 0.58; R = 0.58; P< 0.0001) and discharge (r = 0.49; R = 0.51; P< 0.0004). Patients evidenced a similar increase in functional status regardless of cognitive ability, but cognitively impaired individuals entered the inpatient unit with a lower functional status, and their level of function at discharge was also impaired relative to cognitively intact cohorts. Low MMSE scores were associated with a greater likelihood of nursing home placement, but a considerable percentage (38%) of individuals with severe cognitive impairment and the majority of individuals with mild to moderate cognitive impairment returned home following discharge. These findings suggest that geriatric patients with cognitive dysfunction should be considered for admission to rehabilitation programs if functional gains will affect quality of life or disposition.

Activities of Daily Living↗

A randomized study of the influence of perfusion technique and pH management strategy in 316 patients undergoing coronary artery bypass surgery. II. Neurologic and cognitive outcomes.

UNLABELLED: This double-blind, randomized comparison of pulsatile or nonpulsatile perfusion and alpha-stat or pH-stat management during cardiopulmonary bypass was designed to assess postoperative central nervous system outcomes. METHODS: Neurologic and cognitive testing was conducted before the operation and 7 days and 2 months after the operation in 316 patients having coronary artery bypass and in a reference cohort of 40 patients having major vascular and thoracic operations. RESULTS: As detailed in part I of this study, mortality in patients having coronary bypass was 2.8%. The incidence of stroke was 2.5% and did not differ among bypass groups. Mortality was 2.5% for the major surgery cohort. The incidence of cognitive (p = 0.003) and either neurologic or cognitive dysfunction (p = 0.0002) was higher at 7 days for the coronary bypass group than for the major surgery cohort. The incidence of neurologic dysfunction remained higher (p = 0.050) at 2 months in the coronary bypass group. Cognitive dysfunction at 2 months was less prevalent after 90 minutes of cardiopulmonary bypass in patients managed with alpha-stat than with pH-stat strategy (27% versus 44%, p = 0.047). CONCLUSIONS: Postoperative central nervous system dysfunction is more prevalent in patients having coronary bypass than in those having major operations. Pulsatility has no effect on central nervous system outcomes, but alpha-stat management is associated with a decreased incidence of cognitive dysfunction in patients undergoing prolonged cardiopulmonary bypass.

Aged↗

Vasoactive intestinal peptide in the brain of a mouse model for Down syndrome.

The most common genetic cause of mental retardation is Down syndrome, trisomy of chromosome 21, which is accompanied by small stature, developmental delays, and mental retardation. In the Ts65Dn segmental trisomy mouse model of Down syndrome, the section of mouse chromosome 16 most homologous to human chromosome 21 is trisomic. This model exhibits aspects of Down syndrome including growth restriction, delay in achieving developmental milestones, and cognitive dysfunction. Recent data link vasoactive intestinal peptide malfunction with developmental delays and cognitive deficits. Blockage of vasoactive intestinal peptide during rodent development results in growth and developmental delays, neuronal dystrophy, and, in adults, cognitive dysfunction. Also, vasoactive intestinal peptide is elevated in the blood of newborn children with autism and Down syndrome. In the current experiments, vasoactive intestinal peptide binding sites were significantly increased in several brain areas of the segmental trisomy mouse, including the olfactory bulb, hippocampus, cortex, caudate/putamen, and cerebellum, compared with wild-type littermates. In situ hybridization for VIP mRNA revealed significantly more dense vasoactive intestinal peptide mRNA in the hippocampus, cortex, raphe nuclei, and vestibular nuclei in the segmental trisomy mouse compared with wild-type littermates. In the segmental trisomy mouse cortex and hippocampus, over three times as many vasoactive intestinal peptide-immunopositive cells were visible than in wild-type mouse cortex. These abnormalities in vasoactive intestinal peptide parameters in the segmental trisomy model of Down syndrome suggest that vasoactive intestinal peptide may have a role in the neuropathology of Down-like cognitive dysfunction.

Animals↗

Relative impact of fatigue and subclinical cognitive brain dysfunction on health-related quality of life in chronic hepatitis C infection.

OBJECTIVES: To assess the relative impact of fatigue and subclinical cognitive brain dysfunction on the impairment of health-related quality of life (HRQL) in hepatitis C virus (HCV) infection. DESIGN AND METHODS: We performed a cross-sectional study in 120 patients with untreated chronic HCV infection to test the hypothesis that the severity of fatigue had an independent effect on HCV-associated impairment of HRQL. Patients were investigated using the short-form-36 questionnaire, the fatigue impact scale, the brief fatigue inventory, and P300 event-related potentials, as an objective correlate of neurocognitive function. Patients with decompensated cirrhosis or clinical depression were excluded. RESULTS: Relative to healthy controls, HCV-infected patients showed significant levels of fatigue (Fatigue Impact Scale, 49 versus 26 points, brief fatigue inventory, 3.0 versus 1.6 points, P < 0.001). Fatigue impact scale and brief fatigue inventory scores were highly correlated (r = 0.77, P < 0.001), demonstrating concurrent validity. Severity of fatigue and age were the only factors independently associated with the impairment of HRQL (P < 0.001). Fatigue was not related to the severity of hepatitis or the degree of subclinical brain dysfunction. CONCLUSION: In untreated patients with chronic HCV infection, fatigue severity and age but not neurocognitive dysfunction or hepatic function are independently associated with impaired HRQL. Both the fatigue impact scale and the brief fatigue inventory are suitable tools to assess the subjective burden of fatigue. Our findings stress the need for effective therapeutic interventions to reduce the burden of fatigue in patients with HCV infection.

Adult↗

Cognitive profile of patients with newly diagnosed Parkinson disease.

OBJECTIVE: To determine the frequency and pattern of cognitive dysfunction in patients with newly diagnosed Parkinson disease (PD) and to identify its demographic and clinical correlates. METHODS: A cohort of 115 consecutive patients with newly diagnosed PD and 70 healthy controls underwent a comprehensive neuropsychological assessment including tests of psychomotor speed, attention, language, memory, executive and visuospatial functions, as well as measures of affective status. Patients also received quantitative ratings of motor symptom severity and functional status. Neuropsychological performance of PD patients was compared with that of healthy controls and with available normative data. Independent demographic and clinical predictors of cognitive impairment were identified with multiple logistic regression analysis. RESULTS: Relative to controls, PD patients performed significantly worse on most cognitive measures. However, further analysis revealed that group differences in cognitive performance could mainly be explained by measures of immediate memory and executive function. Comparison with normative data showed that impairments were most frequent on measures of executive function, memory and psychomotor speed. In all, 24% of PD patients (4% of controls) displayed defective performance on at least three neuropsychological tests and were classified as cognitively impaired. Late onset of disease was an independent predictor of cognitive dysfunction in PD. CONCLUSION: Cognitive impairments are common even in newly diagnosed Parkinson disease patients, with deficits being most prominent in the domains of memory and executive functions. Older age at disease onset is likely to be an important determinant of cognitive dysfunction in Parkinson disease.

Affective Symptoms↗

Executive dysfunction and apathy predict functional impairment in Alzheimer disease.

OBJECTIVE: The purpose of this study was to examine the extent to which executive cognitive dysfunction and frontally-mediated behavioral disturbances are associated with functional impairment in patients with mild-to-moderate Alzheimer disease (AD). METHODS: Patients with AD (N=45) completed the Mattis Dementia Rating Scale, and patients' caregivers completed the Frontal Systems Behavioral Inventory and a modified form of the Lawton and Brody Activities of Daily Living (ADLs) Questionnaire. RESULTS: Multiple-regression analyses revealed that executive cognitive dysfunction and apathy scores accounted for 44% of the variance in instrumental activities of daily living; executive cognitive dysfunction alone explained 17% of the variance in instrumental ADLs, and apathy scores explained an additional 27%. Executive dysfunction and frontal-behavioral impairment explained 28% of the variance in basic ADLs (BADLs), and, after accounting for executive dysfunction, apathy was the only symptom found to explain additional unique variance in BADLs. CONCLUSION: These findings suggest that specific cognitive and behavioral symptoms are associated with functional impairment in patients with AD.

Activities of Daily Living↗

Mood disorders in multiple sclerosis and the effects on cognition.

BACKGROUND: Depression and cognitive dysfunction are common in patients with multiple sclerosis. However, it is unclear whether depression may cause or exacerbate cognitive problems as data remain equivocal. The current review attempts to clarify the relationship between these behavioral disorders. METHOD: The literature pertaining to the influence of depression on cognition in MS patients has been reviewed. RESULTS: Early studies consistently failed to find an association and concluded that cognitive dysfunction in MS patients occurred independently of depression. A more recent literature has found fault with this, citing numerous methodological flaws in the studies undertaken. Newer data now suggests that core symptoms of depression reduce cognitive capacity, in particular exerting an adverse effect on the executive function component of working memory. CONCLUSIONS: Depression may exacerbate cognitive dysfunction in MS patients. Whether treating depression will lead to cognitive improvement is not yet known, but warrants further exploration.

Cognition↗