Impairment In Schizophrenic Patients Research Articles

Effects of Olanzapine and Clozapine on Radial Maze Performance in Naive and MK-801-Treated Mice

Attention, working memory and long-term memory dysfunctions are the most commonly seen cognitive impairments in schizophrenic patients. Conflicting results exist regarding the effects of antipsychotics on cognitive abnormalities. The aim of this study was to investigate the effects of atypical antipsychotic drugs olanzapine (0.4, 0.8 and 1.25 mg/kg, i.p.) and clozapine (0.5 and 1 mg/kg, i.p.) on spatial working memory in naive and MK-801 (0.2 mg/kg, i.p.) treated BALB-c mice in an 8-arm radial arm maze (RAM) task. None of the antipsychotic drugs studied altered number of errors in naive mice, whereas MK-801 significantly increased working memory errors in RAM test. Olanzapine and clozapine potently reversed MK-801 induced increasement of working memory errors. Olanzapine and clozapine prolonged latency of the animals in naive mice. The MK-801-induced enhancement in the speed of mice in performing the RAM task was blocked by olanzapine but not clozapine. Our study shows that atypical antipsychotics olanzapine and clozapine might improve cognitive deficits in schizophrenic patients.

The face and its emotion: Right N170 deficits in structural processing and early emotional discrimination in schizophrenic patients and relatives

Previous studies have reported facial emotion recognition impairments in schizophrenic patients, as well as abnormalities in the N170 component of the event-related potential. Current research on schizophrenia highlights the importance of complexly-inherited brain-based deficits. In order to examine the N170 markers of face structural and emotional processing, DSM-IV diagnosed schizophrenia probands (n=13), unaffected first-degree relatives from multiplex families (n=13), and control subjects (n=13) matched by age, gender and educational level, performed a categorization task which involved words and faces with positive and negative valence. The N170 component, while present in relatives and control subjects, was reduced in patients, not only for faces, but also for face–word differences, suggesting a deficit in structural processing of stimuli. Control subjects showed N170 modulation according to the valence of facial stimuli. However, this discrimination effect was found to be reduced both in patients and relatives. This is the first report showing N170 valence deficits in relatives. Our results suggest a generalized deficit affecting the structural encoding of faces in patients, as well as the emotion discrimination both in patients and relatives. Finally, these findings lend support to the notion that cortical markers of facial discrimination can be validly considered as vulnerability markers.

P03-47 - The differences in producing cognitive deficit between first and second-generation antipsychotics - our experiences

ObjectivesContemporary researches of the cognitive impairment in schizophrenic patients were conducted in three directions: Cognitive declining as a developmental precursor of schizophrenia, evolution of the cognitive deficit during the illness, and at last, impact of pharmacological treatment on cognitive functioning. The main aim of our study is to evaluate differences between first and second-generation antipsychotics in manifestations and course of the cognitive declining, in patients with first episode of paranoid schizophrenia.Material and methodsWe conducted open label, prospective trial, at the sample of 12 patients during first episode of paranoid schizophrenia. Diagnosis was made according to the criteria of the International classification of diseases 10th revision. The sample was divided in two clusters with 6 patients in each one. In the first cluster, patients received first-generation antipsychotics, and in the second one was administered second-generation antipsychotic - risperidone. Cognitive functions was evaluated by Mini Mental State Examination Test which is modified with adding two simple neuropsychological tests: Clock Drawing Test and Test of Verbal Fluency.ResultsWe found more prominent cognitive declining in first cluster patients - particularly mnestic deficit.ConclusionsFirst-generation antipsychotics posses more prominent negative impact on cognitive functioning in comparison to second generation antipsychotic - risperidone.

P03-147 - Subjective cognitive impairment in schizophrenic patients: clinical and neuropsychological correlates

Introduction and objectivesCognitive deficits, in particular that of memory and executive functions, have been linked to functional disability. The treatment with antipsychotic drugs leads to subjective changes in cognitive functioning as well as subjective experience of schizophrenic patients, which both contribute to compliance and treatment outcome. Aim of this study was to evaluate the role of clinical, neurocognitive and pharmacological variables on the subjective perception of cognitive functioning in schizophrenic patients.MethodsThe sample was composed of 78 schizophrenic inpatients (M/F=38/35, mean age 41 + 11.6 years) recruited in the Rehabilitative Centres of two Departments of Mental Health in Italy and treated with typical (n= 15) or atypical antipsychotics (n= 63). Patients were diagnosed according to the DSM-IV TR criteria and evaluated with the Frankfurter Beschwerde Fragebogen (FBF) Scale, the SAPS and SANS (Scales fot the Assessment of Positive and of Negative Symptoms). Neuropsychological functioning was assessed by means of the Wechsler Adult Intelligence Scale (WAIS- R).ResultsThe results showed that the severity of symptoms was correlated positively with a greater impairment on self perception of mental functioning. Neuropsychological functioning also correlated with self perception of cognitive deficits, with an abnormal subjective experience associated with more neuropsychological disturbances. Atypical antipsychotics were associated with a better insight of cognitive dysfunction.ConclusionsThe results of the study underline the importance to investigate the subjective experience of schizophrenic patients treated with antipsychotic drugs in order to improve treatment adherence and efficacy in schizophrenia.

Kognitive Beeinträchtigung und Alltagsfunktion bei an Schizophrenie erkrankten Patienten – Entscheidende Faktoren für den Langzeitverlauf

Kognitive Störungen treten bei schizophren kranken Menschen häufig auf und betreffen vor allem Arbeitsgedächtnis, exekutive Funktionen, Aufmerksamkeitsleistungen und episodisches deklaratives Gedächtnis. Diese kognitiven Störungen haben entscheidende Bedeutung für das Funktionsniveau, den Langzeitverlauf und die Rehabilitation schizophren kranker Menschen. Auf neurobiologischer Ebene sind die kognitiven Störungen schizophren kranker Menschen mit einem dopaminergen Defizit im Bereich des präfrontalen Kortex verbunden.

Verbal learning and memory in schizophrenic and Parkinson's disease patients

The purpose of this study was to investigate the neurofunctional substrate of verbal learning and memory impairments in schizophrenic patients. In this pilot study, our aim was to compare the memory disturbance of schizophrenic patients to the subcortico-frontal memory profile of Parkinson's disease (PD) patients. The California Verbal Learning Test, a verbal episodic memory test, was administered to 60 subjects, 20 patients with schizophrenia, 20 patients with PD and 20 healthy control subjects. All subjects were aged between 50 and 70 years and all patients were in a stable phase. Like the Parkinson patients, the schizophrenic patients showed a major deficit of retrieval characterized by deficit of recalls but contrarily to PD patients, schizophrenic patients’ encoding scores were altered. These impairments in episodic memory could suggest a dysfunction of the subcortico-frontal circuits in schizophrenic patients. However, they demonstrated an additional encoding deficit associated with probable frontal in situ alteration.

Neurological soft signs in schizophrenic patients and their nonpsychotic siblings

Objective: (a) To investigate the prevalence of neurological soft signs (NSS) in schizophrenic patients and their nonpsychotic siblings and (b) to examine the clinical correlates of NSS in the schizophrenic group. Methods: Ninety-nine schizophrenic patients, 80 of their nonpsychotic siblings and 59 healthy controls were included in the study. NSS were assessed with the Neurological Evaluation Scale (NES). Psychiatric assessment of the patients was conducted with the Positive and Negative Syndrome Scale (PANSS). Siblings and the control group were evaluated with Schedules for Clinical Assessment in Neuropsychiatry (SCAN) to determine the presence of any past or current psychotic disorder. Results: Schizophrenic patients had significantly higher scores overall and on each subscale of NES than the sibling and control groups. The sibling group's scores were intermediate between those of the schizophrenic patients and those of the healthy controls. All subscale scores and the total NES scores correlated positively with the negative symptoms subscale scores of PANSS. The general psychopathology subscale scores of PANSS also showed a positive correlation with all subscale scores of NES, except the ‘sequencing of complex motor acts’ subscale. The total NES scores of the patients as well as their scores for the ‘sequencing of complex motor acts’ and ‘others’ subscales were significantly correlated with the respective scores of their own siblings. Conclusions: These results support the findings of previous studies suggesting that there might be common genetic and/or environmental factors in the pathogenesis of neurological impairment in schizophrenic patients and their siblings. They also indicate that neurological soft signs in schizophrenic patients are associated with prominent negative symptoms.

Verbal delayed reactions. A study of prefrontal functional impairments in schizophrenic patients

Verbal delayed reactions. A study of prefrontal functional impairments in schizophrenic patients

Blood–cerebrospinal fluid barrier impairment as indicator for an immune process in schizophrenia

An impairment of the blood–cerebrospinal fluid barrier (BCB) has repeatedly been described in schizophrenic patients. A BCB impairment can be due to vascular leakage during an inflammatory process, or to neuroleptic treatment. The soluble intercellular adhesion molecule-1 (sICAM-1) has been demonstrated to be a reliable marker for an inflammatory process causing an BCB impairment. To clarify the basis of a BCB impairment in schizophrenic patients, we measured the sICAM-1 levels in CSF of 40 schizophrenic patients. High concentrations of sICAM-1 were found to be related to high concentrations of albumin, IgG and total protein in CSF. A BCB impairment was associated with high levels of sICAM-1. Our data indicate an inflammatory mechanism of BCB impairment in schizophrenics and should enrich the discussion on an expanded immunological diagnosis in schizophrenia.

On the distinction between access and store disorders in schizophrenia: a question of deficit severity?

This study documents a severe face naming impairment in schizophrenic patients. A series of twelve patients was examined further to determine whether this deficit conformed to either an access or store disorder as described originally by Warrington and Shallice [45]. This analysis of consistency across time, effects of cueing and familiarity effects revealed heterogeneous performance patterns; pointing to access disorders in some patients and store disorders in others. However, the difference between access-like and store-like patterns of performance was strongly correlated with quantitative differences in patient deficit-severity. Hence, the notion of dichotomous access and store disorders, in schizophrenic patients, may be deceptive; with the naming performance of schizophrenics varying according to the extent of their stored knowledge, rather than any qualitative differences between patients. These findings have implications for our understanding of: cognitive deficits in both schizophrenic and neurological patients; the relationship between psychotic and neurological disorders and perhaps for the underlying neurophysiological dysfunction.

Spatial working memory impairments in schizophrenic patients with the deficit syndrome

Spatial working memory impairments in schizophrenic patients with the deficit syndrome

Clinical correlates of memory in schizophrenia: differential links between depression, positive and negative symptoms, and two types of memory impairment.

This study investigated clinical correlates of memory impairment in schizophrenic patients. In particular, the authors hypothesized that depressive symptoms would be linked to memory efficiency, as found in other clinical populations. In addition, they tested Frith's pathophysiological model predicting links between negative symptoms and failure to respond, as well as between positive symptoms and production of erroneous responses. Thirty-one patients were given several memory tasks: long-term free recall of nonorganizable and organizable lists in immediate and delayed conditions, recognition in immediate and delayed conditions, implicit memory (stem completion task), and short-term memory (digit span). Superficial encoding of information was also assessed by the ability to recall the items sequentially; deep encoding was assessed by the ability to organize the items according to their semantic properties. Two types of memory measures were individualized: measures reflecting memory efficiency and measures reflecting production of erroneous memory responses (intrusions, perseverations, false alarms). Consistent correlations appeared between severity of depressive symptoms and measures reflecting deep but not superficial encoding; none, however, was correlated with negative symptoms. Two of the three types of erroneous memory responses were positively linked to positive symptoms. Efficiency of memory processes relying on deep encoding seemed linked to depressive symptoms. In addition, the two distinct types of impairment predicted by Frith's model were found. The expected link of one with positive symptoms was verified, but the link of the other with negative symptoms was not.

Non-selective impairment of Wisconsin Card Sorting Test performance in patients with schizophrenia

Sixty-two schizophrenic patients and 26 healthy volunteers were administered the Wisconsin Card Sorting Test (WCST) a task putatively specific for frontal functions and the Wechsler Adult Intelligence Scale (WAIS). The purpose of this study was to evaluate the presence of specific frontal lobe deficits in the course of schizophrenia and the capacity of these tasks to discriminate between patients and controls. Schizophrenic patients showed a poorer performance than control subjects in both tests. No evidence emerged to support a higher discriminant power for the WCST in identifying schizophrenic subjects from healthy controls compared with the WAIS. Our data suggest that the deficit in WCST performance is not selective, but rather part of a more generalized neuropsychological impairment in schizophrenic patients.

A Neural Network Simulation of Hallucinated “Voices” and Associated Speech Perception Impairments in Schizophrenic Patients

The mechanism of hallucinated speech, a symptom commonly reported by schizophrenic patients, is unknown. The hypothesis that these hallucinations arise from pathologically altered working memory underlying speech perception was explored. A neural network computer simulation of contextually guided sequential word detection based on Elman (1990a,b) was studied. Pruning anatomic connections or reducing neuronal activation in working memory caused word "percepts" to emerge spontaneously (i.e., in the absence of external "speech inputs"), thereby providing a model of hallucinated speech. These simulations also demonstrated distinct patterns of word detection impairments when inputs were accompanied by varying levels of noise. In a parallel human study, the ability to shadow noisecontaminated, connected speech was assessed. Schizophrenic patients reporting hallucinated speech demonstrated a pattern of speech perception impairments similar to a simulated neural network with reduced anatomic connectivity and enhanced neuronal activation. Schizophrenic patients not reporting this symptom did not demonstrate these speech perception impairments. Neural network simulations and human empirical data, when considered together, suggested that the primary cause of hallucinated "voices" in schizophrenia is reduced neuroanatomic connectivity in verbal working memory.

Cognitive Impairment in Schizophrenia

Neuropsychological impairments in schizophrenic patients are commonly mild to moderate in severity and significantly less severe than those seen in progressive dementia.

Cognitive impairments in schizophrenic patients with hyponatremia

Cognitive impairments in schizophrenic patients with hyponatremia

Negative symptom expression and cognitive impairment in schizophrenic patients and their biological mothers

Negative symptom expression and cognitive impairment in schizophrenic patients and their biological mothers

Memory impairment in schizophrenic patients with tardive dyskinesia

Memory functioning was contrasted in 40 schizophrenic patients with and without tardive dyskinesia (TD). Visual and verbal memory tests were used to investigate specific types of impairments. The presence of TD was ascertained using the Abnormal Involuntary Movement Scale (AIMS). TD patients scored significantly lower than non-TD patients on two measures of visual learning, though no differences were found for verbal learning or immediate recall. These results are consistent with previous reports that schizophrenic patients with TD demonstrate impaired cognitive functioning. They also raise the possibility that the neurochemical and structural changes underlying TD may produce specific deficits in memory for visual materials. In addition, a significant relationship was found between total score on the Brief Psychiatric Rating Scale (BPRS) and performance on all of the test measures included in the cognitive test battery. This demonstrates the importance of attending to the overall level of schizophrenic symptomatology when evaluating results from experimental learning tasks.

Learning capacities during sleep: A preliminary study in a group of schizophrenic inpatients

The relationship between sleep and learning processes is analysed in a sample of schizophrenic patients, starting from more recent hypotheses about the function of REM sleep in learning and memory processes. This is done by means of two experiments: in the first AA. evaluate the possibility to elicit a simple motor conditional reflex acquired during daytime in different sleep stages. With the second experiment daytime learning performances are evaluated with and without a reinforcement administered during REM sleep. Results for the first experiment underline a qualitative difference between REM and nREM sleep in a reflexological perspective. In nREM sleep the conditional response is better maintained than in REM sleep. The second experiment confirms the possibility to improve daytime learning performances after an additional presentation of learning material in REM. The joint study of sleep abnormalities and learning and cognitive impairment in schizophrenic patients is finally suggested.