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Biomedical subjects

D L Braff

Publications and source records attributed to D L Braff.

At least 109 records · Page 6Linked to original sources
PubMed1986

Information-processing abnormalities: trait- and state-dependent components.

Schizophrenics were compared to schizoaffective, bipolar, and nonpsychotic depressed patients in a visual masking paradigm in which an informational target stimulus was followed at varying intervals by a noninformational masking stimulus. In limiting the availability of the sensory signal provided by the target stimulus, the mask was used to probe how information from the environment enters and is processed by the central nervous system. The use of the masking paradigm was originally based on the hypothesis that thought disorder is a result of a more primary dysfunction in the processes that precede and result in thought. Results confirmed previous findings of a performance deficit in the schizophrenics when compared to nonpsychotic controls. Schizoaffective and bipolar patients also showed evidence of impaired processing, however. Results were interpreted in terms of a trait/state formulation in which impaired information processing is seen as a fundamental trait of schizophrenia spectrum disorders and as a state that can covary with psychotic illness in general. A unifying concept centers on the effects of psychopathological conditions on an individual's processing resources that results in either underprovision or overprovision of information from sensory input to complex cognitive operations dependent on the cerebral cortex. Findings from a variety of paradigms are consistent with those of the masking paradigm in revealing that the processing deficits of schizophrenics are time dependent and occur in the 500 ms following stimulus input.

Adult↗
PubMed1986

On the consistency of the MMPI in borderline personality disorder.

14 patients diagnosed as having Borderline Personality Disorder were examined on two separate occasions with the MMPI. Results strongly suggest that, as a group, borderline patients are quite consistent responders on the MMPI under test-retest conditions (1 to 58 mo.). The frequency distribution of scale elevations and code types was also examined which showed the often-noted heterogeneity of profile code types within this population. Thus, a note of caution is advised for those investigators who assume that a prototypical borderline MMPI profile exists. Specifically, considerable heterogeneity is seen among this sample of patients with respect to a two-point coding strategy, and individual codes change over time.

Adult↗
PubMed1986

Delirium: recognition and management in the older patient.

The EEG can be an enormous aid in distinguishing between organic and "functional" problems and between acute drug intoxication and other forms of delirium. The characteristic EEG finding in delirium is bilateral diffuse slowing that parallels the severity of the syndrome. The vulnerability of the elderly cannot be overstressed. Their health and nutritional status, borderline cerebral changes, and sensory deprivation due to impaired vision or hearing are all predisposing factors for delirium.

Aged↗
PubMed1985

Information processing in borderline patients.

An experiment was conducted to determine whether depressed borderline patients could be distinguished from normal controls and psychotic patients on the basis of a visual backward masking task that measures speed of information processing. Results showed that a) borderline patients could not be distinguished from normal controls on the information-processing task; b) both the borderline patients and the normal controls were superior to psychotic patients with diagnoses of major depressive, schizoaffective, and manic disorders; and c) among the three psychotic groups, the schizoaffective subjects were the most impaired. The data support the idea that borderline patients have normal-range information-processing functions. In distinction, all three psychotic groups showed disruption of this fundamental ego function by which information is processed. The results of related experiments indicate that schizotypal patients (in distinction to borderline patients) are abnormal information processors. Taken together, these findings support the contention that the schizotypal/borderline distinction is valid.

Adult↗
PubMed1985

The time course of information-processing deficits in schizophrenia.

A visual backward masking task was used to specify the time course of the information-processing dysfunction in 19 schizophrenic patients and 15 matched control patients using novel interstimulus intervals. The authors found that the information-processing deficit in schizophrenic subjects occurred at interstimulus intervals of greater than 60 msec and less than 500 msec. These data are compared with the results of evoked-potential and other psychophysiological studies. The visual-processing impairment is specific and time-linked rather than a reflection of the effects of gross psychopathology or medication in schizophrenic individuals.

Adult↗
PubMed1985

Interhemispheric visual masking.

Backward masking functions were evaluated in a paradigm in which target and masking stimuli were presented to opposite cerebral hemispheres using separate peripheral pathways. Backward masking occurred dichoptically when the target and mask were projected to opposite hemispheres. These findings indicated that some effective masking mechanisms are mediated by interhemispheric interactions independent of retinal phenomena.

Adult↗
PubMed1985

Monoamine oxidase inhibitors in the treatment of atypical depression.

In a 6-week, double-blind study outpatients diagnosed as suffering from atypical depression were treated with either isocarboxazid or placebo. Selection criteria were purposely broad so as to capture the entire range of patients so diagnosed. Patients were then subclassified along several symptomatic, syndromal, phenomenological, and diagnostic categories in order to identify clinical characteristics specifically responsive to isocarboxazid. Although isocarboxazid was clearly superior to placebo for the overall group of atypical depressives, the authors were by and large unable to identify subgroups specifically responsive to the monoamine oxidase inhibitor. A few factors correlated with better response to both isocarboxazid and placebo: no family history of alcoholism or sociopathy, lack of self-pity, and not meeting Research Diagnostic Criteria for major depressive disorder. The single item that was associated with a statistically significant advantage of isocarboxazid over placebo was loss of anticipatory pleasure. Clinical implications and suggestions for further research are discussed.

Adjustment Disorders↗
PubMed1984

The schizophrenia spectrum: a study of the relationship among the Rorschach, MMPI, and visual backward masking.

Compared 20 Ss within the schizophrenia spectrum and 20 non-schizophrenia spectrum controls in terms of their MMPI and Rorschach performance. Ss also were studied in terms of their ability to identify a briefly exposed visual stimulus when it was followed by a noninformational mask stimulus and when it was not. Ss did not differ on the MMPI or on their ability to identify an unmasked target stimulus. They differed significantly in the number of deviant verbalizations, a special scoring category of the Rorschach. Ss also differed in their ability to identify the briefly exposed stimulus when it was followed by the noninformational mask. Results indicated a relationship among the deviant verbalization, the masking procedure, and the schizophrenia spectrum.

Adult↗
PubMed1984

MMPI characteristics of borderline personality inpatients.

MMPI (Form R) profiles of psychiatric inpatients (N = 45) meeting DSM-III criteria for borderline personality disorder were compared with chronic schizophrenic inpatients (N = 48) and with inpatients with acute psychotic illness (N = 20). Profile shape was similar among the three groups, although the borderline sample showed significantly higher elevations on four of the 10 clinical scales--Depression, Hysteria, Psychopathic Deviate, and Psychasthenia--when compared to the chronic schizophrenic cohorts. The borderline sample showed only one significant deviation on the clinical scales when compared to the acute psychotic sample as evidenced by a higher elevation on the Psychopathic Deviate scale. Clinically, the borderline MMPI responses suggest features of irritability, hostility, and resentfulness. On the validity scales, the borderline sample showed a significantly lower score on the L scale when compared to both comparison groups, although all of the groups' L scale scores were within conventional limits. While significant differences between groups did not emerge on the F scale, the borderline sample attained a clinically elevated score suggestive of weakened ego defenses and unconventional thinking. Analysis was also performed of a composite measure of psychoticism probability (the Goldberg Index) between groups. While the borderline and acute psychotic samples showed Goldberg indices suggestive of increasing likelihood for psychotic illness, the chronic schizophrenic group yielded a Goldberg Index significantly greater than both of the other groups, thus confirming the validity of the hypothesis. Finally, the MMPI borderline profiles were also compared to previously published norms of borderline outpatients and veteran borderline inpatients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

The relationship of depression and thought disorder in pain patients.

In the recent literature, the presence of thought disorder occurring with depression has been both supported and contradicted. In order to clarify the relationship of thought disorder and depression this study examined three areas of cognitive function in depressed and non-depressed groups drawn from pain patients and normals. Subjectively, depressed subjects had significant deficits in abstraction, associative tightness, and speed of information processing. Across all subjects, increasing cognitive impairment in all three dimensions correlated significantly with increasing severity of depression. Pain per se and analgesics did not account for the results. There were several significant correlations between the cognitive measures, suggesting a general process mediating the thought disorder associated with increasing levels of depression. The results support and extend the known relationship of thought disorder and depression.

Adolescent↗
PubMed1983

Luminance level and onset sequence of a pre- and post-exposure adapting field affects recognition of masked and unmasked stimuli.

Three experiments were conducted to evaluate the effects of the luminance level of a pre-/post-exposure field and onset sequence of a post-exposure field on briefly exposed visual stimuli for 13 male and 13 female undergraduate college students. Results showed that identification of a briefly exposed informational test stimulus as well as masking effects (the minimum interval between an informational test stimulus and non-informational backward visual noise mask) were both influenced by the luminance of the pre-exposure field and onset sequence of the post-exposure field.

Adolescent↗
PubMed1982

The effect of mental retardation and schizophrenia on information processing.

Research Diagnostic Criteria-diagnosed schizophrenic persons with average intelligence and dual diagnosis mentally retarded schizophrenic persons were tested in a forced-choice letter discrimination task in order to examine the relationship between schizophrenia and retardation from the standpoint of information-processing theory. The subjects consisted of eight schizophrenic persons of average or better intelligence, eight mentally retarded schizophrenic persons, and a control group of eight Research Diagnostic Criteria-diagnosed minor depressive individuals who were matched with the nonretarded schizophrenic group for intelligence. The groups did not differ significantly on the minimum exposure duration needed to identify an unmasked target stimulus at criterion levels of accuracy. When masked stimuli were employed, however, the depressive group obtained significantly more correct detections than both schizophrenic groups. More importantly, the performance of the two schizophrenic groups did not differ significantly. Our data indicated that schizophrenic deficits in information processing are independent of intellectual factors. Thus, vulnerability to a masking stimulus in schizophrenic persons can be attributed to the pathology of schizophrenia. This vulnerability indicates that schizophrenic patients are slow information processors.

Adult↗
PubMed1982

Effect of antipsychotic medication on speed of information processing in schizophrenic patients.

The authors evaluated the effects of antipsychotic medication and schizophrenia on speed of information processing. Medicated (N - 20) as well as unmedicated (N = 16) schizophrenic patients showed more evidence of slow information processing than did depressed control subjects (N = 20). The medicated schizophrenic patients had higher levels of general psychopathology but also showed superior information processing speed compared with the unmedicated schizophrenic patients. These data confirm that the schizophrenic patients are slow information processors and that antipsychotic medication probably does not cause, and may actually reverse, slowness of information processing in schizophrenic patients.

Adult↗
PubMed1981

Early information processing deficit in schizophrenia. New findings using schizophrenic subgroups and manic control subjects.

In recent years, the idea that schizophrenia involves a primary disturbance of the higher cognitive (ie, cortical) thinking processes has been challenged by investigators who have shown that there may be a primary disturbance in schizophrenia in the early stages of information processing that occurs during the first few hundred milliseconds after the stimulus reaches the sense organs. Among the hypothesized early information processing deficits are deficiencies in iconic storage (a brief peripheral memory store) and slowness of processing from iconic storage to a more permanent memory system. Three experiments were conducted using tachistoscopically presented stimuli in order to evaluate these two stages of information processing (iconic storage and speed of processing) in schizophrenic and control subjects. Results converged in supporting the hypothesis, that independent of iconic storage and sensory registration, slow information processing is a relatively stable deficit of schizophrenic patients with a poor prognosis. The schizophrenic patients with a good prognosis had a similar deficit, which was reversible. Results are discussed as they relate to the early information processing deficit theories of schizophrenia.

Adult↗