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Biomedical subjects

M Flaum

Publications and source records attributed to M Flaum.

At least 73 records · Page 4Linked to original sources
PubMed1993

Intelligence and brain structure in normal individuals.

OBJECTIVE: This study was designed to evaluate the relation between intelligence and a variety of measures of brain structure. METHOD: Magnetic resonance imaging scans were used to measure the volume of the intracranial cavity, cerebral hemispheres, lateral ventricles, temporal lobes, hippocampus, caudate, and cerebellum, as well as the overall volume of gray matter, white matter, and CSF, in 67 healthy, normal volunteers. Intelligence was measured with the Wechsler Adult Intelligence Scale--Revised. RESULTS: Full-scale IQ was found to be significantly correlated with intracranial, cerebral, temporal lobe, hippocampal, and cerebellar volume but not with caudate and lateral ventricle volume. There were also significant correlations of full-scale, verbal, and performance IQ with overall gray matter volume but not with white matter or CSF volume. Gender differences were noted in the pattern and number of correlations between the volume of the brain and its subregions and full-scale, verbal, and performance IQ. CONCLUSIONS: The results suggest that the size of some cerebral structures may account for a significant, but modest, proportion of the variance in human intelligence.

Brain↗
PubMed1992

The Comprehensive Assessment of Symptoms and History (CASH). An instrument for assessing diagnosis and psychopathology.

The Comprehensive Assessment of Symptoms and History was developed for research studies of schizophrenia spectrum conditions and affective spectrum conditions. It is designed to provide a comprehensive information base concerning current and past signs and symptoms, premorbid functioning, cognitive functioning, sociodemographic status, treatment, and course of illness. Because the information base is broad, it is not wedded to a specific diagnostic system but rather permits clinicians and investigators to make diagnoses using a wide range of systems, including Research Diagnostic Criteria, DSM-III, DSM-III-R, and the International Classification of Diseases. Given the fact that disorders in psychiatry are not defined at the etiological or pathophysiological level, diagnostic criteria are prone to ongoing revision as our knowledge base changes. Research strategies suggest that investigators should maintain a flexible database to permit them to adapt to changes in diagnostic systems, to do comparative nosological studies, and, ultimately, to develop new diagnostic systems based on knowledge concerning the underlying neurobiological nature of disorders. Because it provides a comprehensive information base, the Comprehensive Assessment of Symptoms and History facilitates research of this type. Extensive developmental work has been done with the Comprehensive Assessment of Symptoms and History, including interrater and test-retest reliability studies, validity studies, training programs, and data entry programs.

Databases, Factual↗
PubMed1992

Hypofrontality in neuroleptic-naive patients and in patients with chronic schizophrenia. Assessment with xenon 133 single-photon emission computed tomography and the Tower of London.

The "hypofrontality hypothesis" has been supported by many neuroimaging studies, but not all, perhaps because of heterogeneity of samples. The present study examined three different samples that permitted assessment of a variety of confounders, such as effects of long-term treatment, chronicity of illness, and presenting phenomenology: (1) 13 neuroleptic-naive schizophrenic patients, (2) 23 nonnaive schizophrenic patients who had been relatively chronically ill but were medication free for at least 3 weeks, and (3) 15 healthy normal volunteers. Regional cerebral blood flow was measured using single-photon emission computed tomography with xenon 133 as the tracer. The control condition consisted of looking at undulating colored shapes on a video monitor, while the experimental task was the Tower of London. We observed the Tower of London to be a relatively specific stimulant of the left mesial frontal cortex (probably including parts of the cingulate gyrus) in healthy normal volunteers. Both the neuroleptic-naive and the nonnaive patients lacked this area of activation, as well as a related one in the right parietal cortex (representing the circuitry specifically activated by the Tower of London). Decreased activation occurred only in the patients with high scores for negative symptoms. These results suggest that hypofrontality is related to negative symptoms and is not a long-term effect of neuroleptic treatment or of chronicity of illness.

Adult↗
PubMed1992

Comorbidity of substance abuse and schizophrenia: the role of pre-morbid adjustment.

Co-morbid substance use and abuse is common in schizophrenic patients, and the role of substance abuse in initiating and maintaining psychosis has important definitional and aetiological implications. We investigated the issue in a cohort of 131 schizophrenic patients. We found non-users (N = 67) were similar to pathological users (N = 64) in current symptomatology and clinical history. The pathological users did, however, have better pre-morbid adjustment levels. Only alcohol use and to some extent cannabis use contributed to this effect; use of stimulants or hallucinogens did not. These results indicate the importance of evaluating the various types of substance used when attempting to explore the significance of co-morbidity. The results also suggest that co-morbidity of substance abuse and schizophrenia may be explained by a common factor antecedent to both: better pre-morbid adjustment. A two-stage model is proposed to explain these findings: increased sociability increases exposure to opportunities of substance use in a subset of patients; subsequent onset of psychotic illness accelerates the use to a pathological level as the individual attempts to cope with the stress of the developing mental illness.

Adaptation, Psychological↗
PubMed1991

Diagnostic criteria for schizophrenia and related disorders: options for DSM-IV.

Five alternative sets of diagnostic criteria for schizophrenia and related psychotic disorders are presented in the appendix following this report. They include the DSM-III-R criteria, the most recent version of the ICD-10 research criteria, and three new sets that have been proposed as options for DSM-IV. A multicenter field trial is currently gathering data that will allow researchers to compare the performance characteristics of each set of criteria, including dimensions such as classification rates, reliability, and user-friendliness. In this report, the rationale behind the proposed modifications and the methods and goals of the field trials are summarized.

Affective Symptoms↗
PubMed1991

Schizophrenia: the characteristic symptoms.

The specific symptoms that have been felt to characterize schizophrenia have varied widely over time and across cultures, as has the diagnostic and prognostic importance placed on these symptoms. In this report, the historical concepts of what constitutes the "characteristic symptoms" of schizophrenia are reviewed in the context of the development of DSM-IV. Through the existing literatures as well as through previously unpublished data sets, the dimensions of reliability, specificity, validity, and descriptive value of the various signs and symptoms used to classify schizophrenia are explored. In addition, the structure of the DSM-III-R definition of schizophrenia with that of the proposed revisions of the International Classification of Diseases (ICD-10) are contrasted, demonstrating several potentially meaningful differences. It is concluded that a comprehensive description of the signs and symptoms of schizophrenia should place a strong emphasis on both positive and negative symptoms. Principles and approaches to guide the development of DSM-IV are suggested.

Humans↗
PubMed1990

Positive and negative symptoms in schizophrenia. A critical reappraisal.

We reexamined the validity of subdividing schizophrenia into categorical subtypes using the predominance of positive and negative symptoms as the characteristic defining features. Using diagnostic criteria proposed in 1982, we again found that the negative subtype may be characterized by a variety of hypothesized correlates of structural brain abnormality, including poor premorbid adjustment, early age at onset, lower educational achievement, poor performance on cognitive testing, and poor response to treatment; a preponderance were also male and unemployed. The patients with negative symptoms did not have a significantly larger ventricular-brain ratio than did those with mixed or positive symptoms, however. As an alternative approach, patients were also classified by ventricle size (large and small); this classification had less predictive validity, with the use of hypothesized indexes of structural brain abnormality, than did the classification based on phenomenology.

Achievement↗
PubMed1990

Ventricular enlargement in schizophrenia evaluated with computed tomographic scanning. Effects of gender, age, and stage of illness.

We evaluated ventricular-brain ratio with computed tomographic scanning in a sample of 108 DSM-III-diagnosed schizophrenic patients and 75 healthy normal volunteers. Significant differences were noted between the patients and controls, but our large sample size also permitted us to determine that the statistically significant difference was contributed primarily through the male patients. Ventricular enlargement occurs only in some schizophrenic patients. In this particular sample, only 6% of schizophrenics had ventricular-brain ratios greater than 2 SDs from the control mean, and 28% were 1 SD greater than the control mean. However, the corresponding figures for male schizophrenics were 19% and 43%, indicating that there is much less overlap between normal individuals and ill subjects in the male population. First-admission schizophrenic patients also had significantly greater ventricular enlargement than did their age-equivalent normal controls, suggesting that ventricular enlargement in schizophrenia may antedate the onset of symptoms. Examination of ventricular size in schizophrenics and normal subjects from a broad age range suggests that ventricular enlargement does not progress over time at a greater rate in schizophrenic patients than in normal subjects.

Adult↗
PubMed1990

Malignant fibrous histiocytoma arising from descending thoracic aorta.

Cases of malignant fibrous histiocytoma arising from the aorta are rare and have a dismal outlook despite treatment. The longest reported survival period following resection is only 28 months. A patient with malignant fibrous histiocytoma of the descending thoracic aorta was successfully treated with resection and reconstruction with a prosthetic graft. The patient developed metastatic disease eight months postoperatively. With aggressive triple regimen chemotherapy, complete remission has been obtained. The patient is alive and free of disease six years postoperatively.

Aged↗
PubMed1990

The role of gender in studies of ventricle enlargement in schizophrenia: a predominantly male effect.

Two previously reported neuroimaging studies from the authors' laboratory demonstrated larger lateral ventricles in schizophrenic patients than in normal control subjects. This diagnostic effect was accounted for almost entirely by the male subjects. In this report the role of gender is further explored through reexamining these data sets and those of two earlier studies. Although Gender by Diagnosis effects were not demonstrated, in three of the four studies male schizophrenic subjects had significantly larger ventricles than their control counterparts; there were no differences among the female subjects. One study suggested the opposite effect, but this may be attributable to a non-representative control group.

Anthropometry↗
PubMed1990

Ventricular abnormalities in affective disorder: clinical and demographic correlates.

Ventricle-brain ratio was measured by CT scan in 24 bipolar patients, 27 unipolar patients with major depression, 108 schizophrenic patients, and 75 normal control subjects. The male bipolar patients had significantly larger ventricles, but the depressive patients did not. The findings suggest the possibility that ventricular enlargement in bipolar patients is independent of age, as it appears to be in schizophrenia, whereas in depressed patients it may be related to the aging process. Ventricular enlargement in bipolar patients was not related to relevant clinical correlates, such as response to treatment, history of substance abuse, history of ECT, or cognitive impairment.

Adult↗
PubMedDate not supplied

The reliability of "bizarre" delusions.

The concept of bizarre delusions figures prominently in the diagnosis of schizophrenia under DSM-III-R criteria. Yet this concept may be difficult to apply in the clinical world. The interrater reliability of distinguishing bizarre versus non-bizarre delusions was estimated by compiling a sample of 40 delusional ideas and asking a group of psychiatrists (ranging from experts in the field to residents) to identify them as bizarre or non-bizarre. The interrater reliability of the 45 respondents was consistently low as measured by kappa statistic (kappa less than 0.40) within and across groups of raters, and regardless of whether or not a structured definition was applied. Implications for DSM-IV are discussed.

Delusions↗
PubMedDate not supplied

Symptom dimensions and brain morphology in schizophrenia and related psychotic disorders.

The heterogeneity of symptoms in schizophrenia may reflect heterogeneity of underlying pathophysiological mechanisms. Factor analytic studies have consistently identified three symptom factors, psychotic, negative and disorganized, as independent dimensions of schizophrenic psychopathology. This study examined the relationship of these symptom dimensions with volumes of specific brain regions. One-hundred and sixty-six schizophrenia spectrum patients were clinically evaluated with the Comprehensive Assessment of Symptoms and History (CASH) and scanned with a 1.5 Tesla magnetic resonance imaging scanner. Regions of interest (ROIs) were manually traced on 5 mm and 3 mm coronal slices by a single technician, blind to all aspects of subject identity. Correlations between ROI volumes and indices of symptom severity were determined. Analyses of covariance were then used to test for specific relationships between each of the three symptom dimensions and ROI volumes. Tests were made of each dimension, controlling for all others. Overall symptom severity was significantly correlated with larger ventricle volumes (lateral, third and temporal horns) and smaller temporal lobe, hippocampal and superior temporal gyral volumes. Both psychotic and negative symptom severity predicted increased third ventricular volume. Psychotic symptom severity uniquely predicted decreased superior temporal gyral volume as well as increased temporal horn volume. Within the psychotic symptom dimension, hallucinations alone predicted left superior temporal gyral volume. No significant associations between disorganized symptoms and any ROIs were demonstrated. These results provide clues to the localization of specific brain regions underlying symptom clusters in schizophrenia, and provide further validating evidence for the construct of independent dimensions of psychopathology within schizophrenia and related psychotic disorders.

Adolescent↗
PubMedDate not supplied

Effects of errors in a multicenter medical study: preventing misinterpreted data.

Large research projects offer significant advantages for research, but they pose special data quality problems. Data gathered in such projects may contain a greater absolute number of mistakes because of the people collecting data, the complexity of data processing, and the collation required. We wanted to learn from the types and frequencies of errors encroaching on data in a multicenter field trial, and to assess the effects of these errors had they passed through. We used extensive error trapping while processing 688 forms from seven sites in the field trial. Snapshots of the dataset were taken at several points in the process, before and after checking and correcting. We discovered 2.4% of the received data to be mistaken. These errors would have affected the data's reliability, decisions based on the study, and possibly the choice of analysis. Almost all of the mistakes were made at the time of measurement and may be related to raters' perceived importance of the variables. We found that communication and education effectively reduced the number of mistakes and their impact on the study over the course of the field trial. While an estimate of the overall error rate is important, the number of mistakes, in general, is only imperfectly related to the errors' effects on the study's results. Our results also suggest that statistical models that treat mistakes as simple independent events can be misleading.

Bias↗
PubMedDate not supplied

The reliability of distinguishing primary versus secondary negative symptoms.

The objective appearance of negative symptoms in schizophrenia and other psychotic disorders may be a direct reflection of a primary neural abnormality or may be secondary to a variety of factors such as neuroleptic side effects, depression, positive symptoms, or environmental understimulation. Although there is a consensus that it is important to be able to disentangle "primary" versus "secondary" negative symptoms, optimal strategies for doing so remain unclear. Concerns have been raised about making this distinction based on clinical judgment because of potential low reliability in the absence of extensive training and/or highly specialized rating scales. This is particularly important in terms of the application of DSM-IV criteria for schizophrenia, in which negative symptoms play a prominent role. In the context of the DSM-IV schizophrenia field trial project, we examined the reliability of making the primary versus secondary distinction in a multicenter sample of 462 subjects with nonorganic psychotic disorders. Each subject was assessed by two raters, half in an interrater design (i.e., conjoint interviews) and half in a test-retest design (i.e., independent interviews by two raters conducted 1 day apart). All raters used the same semistructured interview instrument, which included an abbreviated version of the Scale for the Assessment of Negative Symptoms (SANS). In addition to the usual SANS ratings, raters were asked to indicate their judgment as to whether the symptom was primary, secondary, or unknown (inadequate information to assess). No formal training was provided. Reliability, as quantified by kapp, indicated only a fair degree of agreement ranging from 0.48 to 0.68 for interrater reliability (median, 0.50) and 0.34 to 0.66 for test-retest reliability (median, 0.38). Negative symptoms were rated as primary approximately twice as often as secondary, and raters believed they had adequate information to make this distinction based only on cross-sectional evaluation in all but 10% of the cases. These data suggest that the primary versus secondary distinction should not be incorporated into the application of operationalized diagnostic criteria. Implications are discussed in terms of balancing reliability and validity in the assessment of negative symptoms.

Adult↗