Biomedical subjects

S Grochowski

Publications and source records attributed to S Grochowski.

14 recordsLinked to original sources

PubMed1998

Impaired mismatch negativity (MMN) generation in schizophrenia as a function of stimulus deviance, probability, and interstimulus/interdeviant interval.

Schizophrenia is a severe mental disorder associated with disturbances in perception and cognition. Event-related potentials (ERP) provide a mechanism for evaluating potential mechanisms underlying neurophysiological dysfunction in schizophrenia. Mismatch negativity (MMN) is a short-duration auditory cognitive ERP component that indexes operation of the auditory sensory ('echoic') memory system. Prior studies have demonstrated impaired MMN generation in schizophrenia along with deficits in auditory sensory memory performance. MMN is elicited in an auditory oddball paradigm in which a sequence of repetitive standard tones is interrupted infrequently by a physically deviant ('oddball') stimulus. The present study evaluates MMN generation as a function of deviant stimulus probability, interstimulus interval, interdeviant interval and the degree of pitch separation between the standard and deviant stimuli. The major findings of the present study are first, that MMN amplitude is decreased in schizophrenia across a broad range of stimulus conditions, and second, that the degree of deficit in schizophrenia is largest under conditions when MMN is normally largest. The pattern of deficit observed in schizophrenia differs from the pattern observed in other conditions associated with MMN dysfunction, including Alzheimer's disease, stroke, and alcohol intoxication.

Acoustic Stimulation↗

PubMed1997

Heterogeneity of serotonergic response in treatment-refractory schizophrenia patients.

Oral metachlorophenylpiperazine (m-CPP) as a direct-acting postsynaptic serotonergic agonist was used to study serotonergic dysfunction in treatment-refractory chronic schizophrenia based on the hypothesis that some patients may show central serotonergic hypersensitivity. Seventeen DSM-III-R chronic schizophrenic patients with a history of neuroleptic nonresponse underwent double-blind challenge with oral m-CPP (0.25 mg/kg body weight) and placebo after medication washout: m-CPP significantly elevated both prolactin and cortisol levels as compared to placebo. There was a significant relationship between change in cortisol level and change in psychopathology under m-CPP; a blunted cortisol response was associated with a decrease in total psychopathology, while an increase in cortisol response related to an increase in psychopathology. Similarly, decrease in severity of the activation factor and the hostility factor was associated with a smaller cortisol response in the m-CPP condition. These results point to heterogeneity in central serotonergic sensitivity within the context of different subpopulations of serotonergic receptors.

Adult↗

PubMed1997

Impaired precision, but normal retention, of auditory sensory ("echoic") memory information in schizophrenia.

Working memory is the type of memory that allows one to hold information in mind while working on a task or problem. The present study investigated attention-independent auditory sensory ("echoic") memory in 18 schizophrenic participants and 17 controls. Schizophrenic participants showed impaired delayed tone matching performance in comparison with controls. However, when groups were matched for performance at 1 s by varying the difficulty of the task across groups, schizophrenic participants showed normal retention of information as reflected in normal tone matching performance. These findings demonstrate that schizophrenic may be in the sensitivity of the system rather than the duration for which memory traces were retained.

Adult↗

PubMed1996

Premature disinhibition of P3 generation in schizophrenia.

P300 (P3) is a long-latency cognitive event-related potential (ERP) elicited by relevant target stimuli. P3 was recorded from 11 schizophrenics and 13 normal controls during a cued visual continuous performance task (CPT-AX). Cue-target sequences were presented at short and long interstimulus intervals (ISIs), in order to investigate working memory in schizophrenia. There was no significant between-group difference in P3 amplitude to validly or invalidly cued targets at short ISI. In contrast, P3 amplitude to invalidly cued targets at long ISI was significantly greater in schizophrenics than in controls, suggesting decreased ability to encode or maintain inhibitory representations of stimulus context. P3 amplitude is typically reduced in schizophrenic subjects in the auditory modality, and normal or reduced in the visual modality. This study, which demonstrates a paradoxical P3 increase to targets at long ISI, suggests that P3 impairment in schizophrenia cannot be attributed solely to structural deficits within P3-generator regions.

Adult↗

PubMed1995

Impaired mismatch negativity generation reflects widespread dysfunction of working memory in schizophrenia.

BACKGROUND: Impaired P300 (P3) generation is one of the most robust indices of brain dysfunction in schizophrenia. This study investigates the integrity of cognitive event-related potentials that precede P3 in an "oddball" paradigm to determine the earliest stages at which auditory information processing is impaired in schizophrenia. METHODS: Cognitive event-related potential components including mismatch negativity (MMN), N2, and P3 were recorded from subjects with chronic schizophrenia who were receiving medication (n = 20), from those who were withdrawn from drug treatment (n = 11), and from healthy volunteers (n = 11) during an auditory oddball paradigm. Recordings were made in both passive and active response conditions. The MMN, N2, and P3 amplitudes were compared across groups and the degree of MMN deficit was correlated with the degree of P3 reduction as a function of diagnostic group. RESULTS: Schizophrenic subjects showed severe impairments in the generation of MMN and N2 as well as P3. Across groups, the decrement in MMN amplitude correlated significantly with the decrement in P3 amplitude. There were no significant between-group differences in MMN topography. CONCLUSIONS: The present study demonstrates that the neurophysiological deficits associated with schizophrenia, as reflected in cognitive event-related potential generation, are pervasive, extending even to the level of the sensory cortex. Mismatch negativity indexes the functioning of an automatic alerting mechanism designed to stimulate individuals to explore unexpected environmental events. Dysfunction of this mechanism may contribute to the deficit state associated with schizophrenia.

Adult↗

PubMed1995

Five factor model of schizophrenia: replication across samples.

In order to examine the effect of neuroleptic medication on the factor structure of schizophrenic symptomatology, 517 DSM-III-R schizophrenic in-patients enrolled in a multicenter phase II drug study were evaluated on their pre-existing neuroleptic at screening on the Positive and Negative Syndrome Scale (PANSS) and after a one-week drug-free period. Separate principal components analyses of the PANSS were done at each time point. PANSS total and component scores were assessed for differences utilizing paired t-tests. Both factor analyses confirmed the five factor model (negative, positive, cognitive, excitement and depression components) explaining 51.7 and 56.2% of the variances at each time point. After medication wash-out psychopathology significantly worsened as measured by total PANSS score and by each of the components. The overall worsening of component scores appeared global and uniform, as evidenced by the fact that at washout, the proportion of individual component scores to total psychopathology remained constant for most components. The lack of change of most components in proportion to the psychopathology total is evidence for the stability of these individual psychopathological dimensions of patients while on and off neuroleptics. The results further support the validity of the five-factor model of schizophrenic psychopathology as measured by the PANSS.

Adult↗

PubMed1995

Psychopathology of Schizophrenia: initial validation of a 5-factor model.

Schizophrenic psychopathology is heterogeneous and multidimensional. One of the more fruitful strategies to investigate more homogenous domains of psychopathology has been the positive-negative syndrome approach. However, this approach is unable to address a number of important issues. Most schizophrenics present a mixed syndrome; the criteria for what constitutes a positive and negative syndrome are variable; distinguishing primary from secondary negative symptoms can be difficult. In order to address some of these problems, we propose the introduction of a 5-syndrome model based on a reanalysis of factor-analytic procedures used on 240 schizophrenics assessed with the Positive and Negative Syndrome Scale: A negative, positive, excitement, cognitive and depression/anxiety factor. This 5-factor solution is supported by 4 independent and comparable factor analyses. Data on internal consistency of the 5 factors and on initial validation using demographic and clinical variables are presented.

Adolescent↗

PubMed1994

A new five factor model of schizophrenia.

Schizophrenic psychopathology is heterogeneous and multidimensional. Various strategies have been developed over the past several years to assess and measure more accurately discrete domains of psychopathology. One of the more fruitful strategies to investigate more homogenous domains of psychopathology has been the positive-negative syndrome approach. However, this approach is unable to address a number of important issues. Most schizophrenics present a mixed syndrome; the criteria for what constitutes a positive and negative syndrome are variable; distinguishing primary from secondary negative symptoms can be difficult. In order to address some of these problems, we propose the introduction of a five syndrome model based on a reanalysis of factor analytic procedures used on 240 schizophrenics assessed with the Positive and Negative Syndrome Scale (PANSS). We present data on a 5-factor solution which appears to best fit the psychopathological data and which is supported by three independent and comparable factor analyses; negative, positive, excitement, cognitive and depression/anxiety domains of psychopathology give patients their individual mark. Data on internal consistency of the five factors and on initial validation using demographic and clinical variables are presented.

Adolescent↗

PubMed1994

Five-factor model of schizophrenia. Initial validation.

Schizophrenic psychopathology is heterogeneous and multidimensional. Various strategies have been developed over the past several years to assess and measure more accurately discrete domains of psychopathology. One of the more fruitful strategies to investigate more homogenous domains of psychopathology has been the positive-negative syndrome approach. However, this approach is unable to address a number of important issues. Most schizophrenics present a mixed syndrome; the criteria for what constitutes a positive and negative syndrome are variable; distinguishing primary from secondary negative symptoms can be difficult. In order to address some of these problems, we propose the introduction of a five-syndrome model based on a reanalysis of factor analytic procedures used on 240 schizophrenics assessed with the Positive and Negative Syndrome Scale. We present data on a five-factor solution that appears to best fit the psychopathological data and that is supported by three independent and comparable factor analyses; negative, positive, excitement, cognitive, and depression/anxiety domains of psychopathology give patients their individual mark. Data on internal consistency of the five factors and on initial validation using demographic and clinical variables are presented.

Adolescent↗

PubMed1994

Assessing positive and negative symptoms in children and adolescents.

OBJECTIVE: The purpose of this study was to test the reliability and validity of a new assessment instrument for positive and negative symptoms in severely disturbed children and adolescents (Kiddie-PANSS). METHOD: The Positive and Negative Syndrome Scale for adult schizophrenia was modified through successive field trials on the basis of developmental characteristics of children and adolescents. The scale was then given to 34 inpatients (19 children, mean age = 9.35 years, and 15 adolescents, mean age = 14.33 years) with DSM-III-R diagnoses of schizophrenia, psychosis not otherwise specified, schizoaffective, affective, conduct, personality, and developmental disorders determined independently by child psychiatrists. All patients with schizophrenia were placed in the schizophrenic group, and all others were placed in a general inpatient group. The Kiddie-PANSS ratings were given by three trained child psychiatrists after a 30-35-minute structured interview. The Achenbach Child Behavior Checklist, the Scale for the Assessment of Positive Symptoms, and the Scale for the Assessment of Negative Symptoms were also administered in order to determine criterion-related association. RESULTS: Intraclass correlation coefficients revealed that all subscales and total psychopathology were reliably assessed among raters. The Kiddie-PANSS and Scale for the Assessment of Positive Symptoms/Scale for the Assessment of Negative Symptoms correlated with one another, indicating criterion-related association. Differences on measures of positive, negative, and general psychopathology, as measured by the Kiddie-PANSS, between the patients with schizophrenia and the general inpatient group were highly significant. CONCLUSIONS: The Kiddie-PANSS shows good interrater reliability and criterion-related validity. In a cohort of inpatient children and adolescents the scale successfully differentiated schizophrenic patients from nonschizophrenic patients.

Adolescent↗

PubMed1994

Clozapine effects on positive and negative symptoms: a six-month trial in treatment-refractory schizophrenics.

Fifteen DSM-III-R diagnosed schizophrenics characterized by long-term neuroleptic nonresponse and significant negative symptoms were evaluated with the Positive and Negative Syndrome Scale, a well-operationalized measure of psychopathology, on a baseline neuroleptic and weekly thereafter across 26 weeks of clozapine treatment in order to explore clozapine's effect on other domains of schizophrenic psychopathology beyond its effect on positive symptoms. Mean differences from baseline indicated significant improvement on positive, negative, cognitive, excitement, and depression subscales after 12 weeks. Improvement observed after 12 weeks of clozapine treatment reliably predicted scores observed at week 26. There were no further significant improvements on any symptom profile, including positive and negative symptoms, in this long-term, nonresponder group between weeks 12 and 26. Overall, clozapine proved to affect a broad spectrum of discrete and nonoverlapping domains of psychopathology in this schizophrenic sample.

Adult↗

PubMed1992

Problem solving and suicidality among prison inmates: another look at state versus trait.

This research examines the relationships between means-ends problem solving and suicidality among adult male prison inmates in light of new evidence based on inpatient and college student populations suggesting that state, rather than trait, vulnerabilities may be responsible for problem-solving deficits and differences. Using the Means-Ends Problem-Solving Procedure (MEPS) with 93 state prison inmates, we found that among inmates with a history of parasuicide, current suicidality did not affect problem-solving performance. We further found that among nonsuicidal inmates, parasuicide history had no effect on problem solving or affect-suicidality measures. Although these results support new research suggesting that trait problem-solving deficits are not causally linked to suicidality, they raise questions about the potentially unique relationships among suicidality, problem solving, depression, and hopelessness in incarcerated populations.

Adult↗

PubMedDate not supplied

Schizophrenic patients with depression: psychopathological profiles and relationship with negative symptoms.

This study investigates the occurrence of depression and related psychopathological features in chronic schizophrenics and attempts to examine whether depressive symptoms are independent of negative symptoms. We found that 54% of our sample of 240 chronic schizophrenics exhibited moderate to severe depression. Independent t tests showed that those high in depression tended to exhibit significantly more positive symptoms as defined by the Positive and Negative Syndrome Scale (PANSS). Those with high depression do not exhibit significantly worse negative symptoms compared with low depression, clearly differentiating depression from negative symptoms. Results and the relationship to a previous factor-analytic study of schizophrenic symptoms are discussed.

Adolescent↗

PubMedDate not supplied

Endotracheal intubation-induced upper airway obstruction.

We report a case in which endotracheal intubation performed for acute respiratory distress resulted in respiratory failure that completely resolved on removal of the endotracheal tube, with concomitant expulsion of a latex glove from the mouth. This case serves as a reminder that endotracheal intubation may promote the very complications that it is meant to prevent. Thorough visualization and careful inspection of the larynx before intubation of the trachea is essential.

Airway Obstruction↗