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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study examined 59 patients who had suffered closed head injuries with respect to their MMPI scores and Category Test scores as assessed shortly post-injury and on subsequent assessment. The number of MMPI scales elevated above t = 70 on the first assessment was negatively correlated with the magnitude of improvement made on the Category Test. Multiple regression analyses showed that the extent of cognitive deficit, as indicated by the Category Test, could be predicted from the degree of psychopathology, with MMPI scales 2 (depression), 7 (psychasthenia) and 8 (schizophrenia) being highly predictive of Category Test performance. These results suggest that patients with better psychological functioning perform at a higher level and make a greater post-traumatic recovery on neurocognitive tests. Although we cannot determine if the emotional impairment is due to neuropathology or is reactive in nature, there are clear implications for rehabilitation.
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PMID:The interplay between emotional and cognitive recovery after closed head injury. 850 80

In order to pursue the hypothesis that the dorsolateral prefrontal cortex is a source of cognitive deficit in schizophrenia, we developed an easily administered pen-and-paper human analogue of a visuospatial working memory task that in non-human primates activates the neurons of Walker area 46 (Goldman-Rakic, 1987). Compared to normal controls, schizophrenic patients made significantly greater errors in identifying where a visuospatial stimulus had been presented to them 30 and 60 seconds earlier, and these differences were significantly greater than in an immediate recall condition. These data suggest that schizophrenic patients have visuospatial working memory deficits that are sensitive to pen-and-paper versions of the tasks that activate the Walker area 46 in non-human primates. The availability of an easily administered test that may be associated with the functioning of the prefrontal cortex may enable more specific assessment of this brain region in humans.
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PMID:A pen-and-paper human analogue of a monkey prefrontal cortex activation task: spatial working memory in patients with schizophrenia. 854 Dec 47

Risk factors promoting the occurrence of neuroleptic-related tardive dyskinesia remain poorly understood. It has been hypothesized that type II schizophrenia, based on Crow's classification, would be more liable to this complication due to cerebral structural abnormalities involved in the pathogenesis of schizophrenia characterized by deficitary symptoms. Association between tardive dyskinesia and cognitive deficit is currently the most firmly established. Data in the literature concerning the association between tardive dyskinesia and the other features of type II schizophrenia are more contradictory.
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PMID:[Schizophrenic deficit syndrome and neurologic tolerance]. 876 42

In this chapter we consider the mechanisms involved in cognitive control-from both a computational and a neurobiological perspective- and how these might be impaired in schizophrenia. By 'control', we mean the ability of the cognitive system to flexibly adapt its behaviour to the demands of particular tasks, favouring the processing of task-relevant information over other sources of competing information, and mediating task-relevant behaviour over habitual, or otherwise prepotent responses. There is a large body of evidence to suggest that the prefrontal cortex (PFC) plays a critical role in cognitive control. In previous work, we have used a computational framework to understand and develop explicit models of this function of PFC, and its impairment in schizophrenia. This work has lead to the hypothesis that PFC houses a mechanism for representing and maintaining context information. We have demonstrated that this mechanism can account for the behavioural inhibition and active memory functions commonly ascribed to PFC, and for human performance in simple attention, language and memory tasks that draw upon these functions for cognitive control. Furthermore, we have used our models to simulate detailed patterns of cognitive deficit observed in schizophrenia, an illness associated with marked disturbances in cognitive control, and well established deficits of PFC. Here, we review results of recent empirical studies that test predictions made by our models regarding schizophrenic performance in tasks designed specifically to probe the processing of context. These results showed selective schizophrenic deficits in tasks conditions that placed the greatest demands on memory and inhibition, both of which we have argued rely on the processing of context. Furthermore, we observed predicted patterns of deterioration in first episode vs multi-episode patients. We also discuss recent developments in our computational work, that have led to refinements of the models that allow us to simulate more detailed aspects of task performance, such as reaction time data and manipulations of task parameters such as interstimulus delay. These refined models make several provocative new predictions, including conditions in which schizophrenics and control subjects are expected to show similar reaction time performance, and we provide preliminary data in support of these predictions. These successes notwithstanding, our theory of PFC function and its impairment in schizophrenia is still in an early stage of development. We conclude by presenting some of the challenges to the theory in its current form, and new directions that we have begun to take to meet these challenges. In particular, we focus on refinements concerning the mechanisms underlying active maintenance of representations within PFC, and the characteristics of these representations that allow them to support the flexibility of cognitive control exhibited by normal human behaviour. Taken in toto, we believe that this work illustrates the value of a computational approach for understanding the mechanisms responsible for cognitive control, at both the neural and psychological levels, and the specific manner in which they break down in schizophrenia.
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PMID:A computational approach to prefrontal cortex, cognitive control and schizophrenia: recent developments and current challenges. 894 63

Discharge of patients from psychiatric institutions has received great attention in recent decades from both the research and clinical points of view. This study identifies and characterizes long-stay, elderly, schizophrenic patients considered candidates for discharge. Of 62 patients aged 60 years and over, residing in open wards of a large public psychiatric hospital for more than a year, 31 fulfilled DSM-3R criteria for schizophrenia. They constituted a "young-old" population, in prolonged, continuous psychiatric hospitalization, who became ill early in life. Their educational and occupational achievements were relatively limited. A mild degree of psychopathology was found, with more negative than positive symptoms of schizophrenia. Their psychiatric symptoms necessitated constant treatment with neuroleptics at moderate to high dosage. Scores on cognitive tests were lower than those of normal age-matched individuals, and indicated a diffuse, cognitive deficit. They fulfilled current criteria for being independent (no need for help in activities of daily living) or "fail" (some help needed). In most there was impaired social and occupational functioning. Suitability for referral to suggested alternatives to psychiatric hospitalization in the community or in the geriatric system is discussed.
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PMID:[Discharge of elderly schizophrenics after prolonged hospitalization]. 904 58

The aim of this study was to evaluate the effects of a new antipsychotic compound on negative symptoms and cognitive deficit in schizophrenia. Psychiatric symptoms and cognition were assessed in 25 patients with schizophrenia, at baseline and after they had taken risperidone for 4 weeks. The Positive and Negative Symptoms Scale (PANSS), the Wisconsin Card Sorting Test (WCST) and two WAIS sub-tests were used to assess the patients. After the study period, both negative and positive symptoms and also measures of cognitive performance improved significantly. The WCST results correlated with negative symptom scores before and after treatment. This suggests that negative symptoms and cognitive deficit have a common underlying substrate which is the target of the risperidone treatment. Our data show that risperidone may have a substantial effect on complex cognitive functions in schizophrenia, and they suggest that certain cognitive deficits are relatively dependent on the negative symptoms of this disorder.
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PMID:Risperidone, negative symptoms and cognitive deficit in schizophrenia: an open study. 905 Nov 59

We investigated the hypothesis that different prefrontal brain systems (i.e., dorsal vs. ventral) and sex contribute differentially to cognitive deficit in schizophrenia. Performance was assessed among clinically stable, chronic schizophrenic outpatients and matched normal control subjects on olfactory identification [on the University of Pennsylvania Smell Identification Test (UPSIT)] and on executive functions [using the Wisconsin Card Sorting Test (WCST)]. Patients were impaired on both tests compared to controls, and male schizophrenics were impaired on the WCST compared to female schizophrenics. The pattern of results suggests that gender differences on the UPSIT are mildly accentuated in schizophrenia. The data support our previous study indicating that UPSIT performance is largely independent of the executive or attentional deficits typically associated with schizophrenia, with the exception of verbal ability. Further research with larger samples is required to test the hypothesis that there is a severely impaired subgroup of male patients with diffuse prefrontal dysfunctions.
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PMID:Sex differences in olfactory identification and Wisconsin Card Sorting performance in schizophrenia: relationship to attention and verbal ability. 920 27

A. Digital EEG is an established substitute for recording, reviewing, and storing a paper EEG record. It is a clear technical advance over previous paper methods. It is highly recommended. (Class III evidence, Type C recommendation). B. EEG brain mapping and other advanced QEEG techniques should be used only by physicians highly skilled in clinical EEG, and only as an adjunct to and in conjunction with traditional EEG interpretation. These tests may be clinically useful only for patients who have been well selected on the basis of their clinical presentation. C. Certain quantitative EEG techniques are considered established as an addition to digital EEG in: C.1. Epilepsy: For screening for possible epileptic spikes or seizures in long-term EEG monitoring or ambulatory recording to facilitate subsequent expert visual EEG interpretation. (Class I and II evidence, Type A recommendation as a practice guideline). C.2. OR and ICU monitoring: For continuous EEG monitoring by frequency-trending to detect early, acute intracranial complications in the OR or ICU, and for screening for possible epileptic seizures in high-risk ICU patients. (Class II evidence, Type B recommendation as a practice option). D. Certain quantitative EEG techniques are considered possibly useful practice options as an addition to digital EEG in: D.1. Epilepsy: For topographic voltage and dipole analysis in presurgical evaluations. (Class II evidence, Type B recommendation). D.2. Cerebrovascular Disease: Based on Class II and III evidence, QEEG in expert hands may possibly be useful in evaluating certain patients with symptoms of cerebrovascular disease whose neuroimaging and routine EEG studies are not conclusive. (Type B recommendation). D.3. Dementia: Routine EEG has long been an established test used in evaluations of dementia and encephalopathy when the diagnosis remains unresolved after initial clinical evaluation. In occasional clinical evaluations, QEEG frequency analysis may be a useful adjunct to interpretation of the routine EEG when used in expert hands. (Class II and III evidence as a possibly useful test, Type B recommendation). E. On the basis of current clinical literature, opinions of most experts, and proposed rationales for their use, QEEG remains investigational for clinical use in postconcussion syndrome, mild or moderate head injury, learning disability, attention disorders, schizophrenia, depression, alcoholism, and drug abuse. (Class II and III evidence, Type D recommendation). F. On the basis of clinical and scientific evidence, opinions of most experts, and the technical and methodologic shortcomings, QEEG is not recommended for use in civil or criminal judicial proceedings. (Strong Class III evidence, Type E recommendation). G. Because of the very substantial risk of erroneous interpretations, it is unacceptable for any EEG brain mapping or other QEEG techniques to be used clinically by those who are not physicians highly skilled in clinical EEG interpretation. (Strong Class III evidence, Type E recommendation).
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PMID:Assessment of digital EEG, quantitative EEG, and EEG brain mapping: report of the American Academy of Neurology and the American Clinical Neurophysiology Society. 922 9

Models of information processing, a part of cognitive psychology, have influenced theories of schizophrenia in the past few years. Study of attention disorders is an original approach of schizophrenics' cognitive disturbances. The authors have reviewed the literature of attention disorders in schizophrenia. Disorders of attention are analysed in different points of view. 'Subtype, syndromic (positive and negative forms) and symptomatic levels of analysis are documented. Subtype approach of attention disorders is not confirmed in the literature. Symptomatic approach of attention disorders in schizophrenia is actually well documented (especially for hallucination and delusion), but very heterogenous. Attention disorders are different in positive and negative syndromes of schizophrenia. Positive patients are more distractible and an early disorder of information processing is a part of cognitive disturbances of negative patients. Some neurobiological and information processing disturbances are discussed in reference of this syndromic approach.
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PMID:[Attention models in evaluating schizophrenia]. 926 30

Impaired cognitive function in schizophrenia, once thought to be a secondary effect of the psychosis, is now seen as an enduring and core feature. It has many manifestations, but the most disruptive element is arguably a fundamental defect in the patient's ability to manipulate available information. The magnitude of the cognitive deficit in schizophrenia is considerable and remains relatively stable despite fluctuations in other symptoms. The degree of dysfunction also has a high predictive value for long-term disability. In recent years, more attention has been directed towards cognitive dysfunction in schizophrenia as a result of which assessment scales and diagnostic systems increasingly incorporate cognitive dysfunction as an independent domain. Good cognitive function depends upon the brain's ability to prioritize tasks and to switch from parallel processing to sequential processing when the processing load is excessive. This requires working executive memory. Neuroimaging and functional analyses suggest that such cognitive function relies upon unimpaired prefrontal activity. In addition, there is increasing evidence that antipsychotic drugs with 5-hydroxytryptamine (5-HT)2A-blocking activity produce better cognitive function in patients with schizophrenia than drugs with predominantly dopamine (D)2-blocking activity (conventional neuroleptics). The development of sophisticated, computer-delivered maze tasks has shown that newer antipsychotics, such as clozapine and risperidone, differ from conventional neuroleptics in their effects on cognitive function. The prospects, therefore, are that patients treated with drugs having 5-HT2A-blocking activity will have better cognitive function and will be better able to function in life's roles than will patients treated with conventional neuroleptics.
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PMID:Cognitive function in schizophrenia. 935 44


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