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Biomedical subjects

W D TenHouten

Publications and source records attributed to W D TenHouten.

13 recordsLinked to original sources
PubMed1992

Are there 'casual users' of cocaine?

Medical and public opinion about cocaine use have shifted dramatically over the past decade. New research methodologies and definitions to evaluate the impact of cocaine are needed. This paper presents a theoretical definition and empirical analysis of the 'casual user' of cocaine. Data have been drawn from a subsample of 58 cocaine users and their cocaine-using contacts in Rotterdam. The methodology of the study presents a novel approach to patterns of cocaine use involving the integration of social network variables with 'snowball' sampling data collection techniques. The theoretical definition is systematically related to two social context variables: (1) the scope of settings where contacts use cocaine; (2) the degree of involvement in social network relations of actual cocaine use. Scope of settings has been defined in terms of the number of cocaine-using social circuits contacts are drawn from: i.e. 'narrow' setting where all contacts originate from one circuit while a 'wide' setting indicates contacts come from two or more circuits. Involvement has been defined in terms of the percentage of contacts where the relation with study participants is characterized by cocaine use most or all of the time. Additional social network variables measuring the mean duration (in years) of contacts' cocaine use and the use of cocaine with contacts in the last six months are subsequently related to the scope and involvement variables. The implications of the analysis for a new cross-classification of cocaine use patterns are discussed with special reference to public health policy issues.

Analysis of Variance↗
PubMed1988

Alexithymia and the split brain: VI. Electroencephalographic correlates of alexithymia.

Electroencephalographic recordings of eight corpus callosotomy patients and eight precision-matched control subjects were obtained as subjects watched a film symbolically depicting death. A content-analytic measure of alexithymia was regressed on eight auto-spectral alpha-band intensity averages and on subsets of alpha-band coherence averages. Results were interpreted on the basis of three possible mechanisms of alexithymia: (1) Alexithymic subjects had more right-temporal alpha-band intensity, suggesting inadequate understanding of the film. (2) A possible lack of inner speech in alexithymics was suggested by their relative alpha abundance of the left frontal and left temporal channels but left parietal alpha desynchronization, and by their lower left frontotemporal but higher left parietofrontal and left parietotemporal coherences. (3) Alexithymic subjects had higher right frontal-left parietal and left frontal-left parietal coherences, suggesting possible interhemispheric inhibition of expression. Expressive subjects had higher right frontal-left temporal (and homologous interhemispheric frontal, parietal, and frontal) coherences, suggesting interhemispheric facilitation of verbal expression.

Adult↗
PubMed1988

Alexithymia and the split brain: VII. Evidence from graphologic signs.

This paper is the seventh report on a single experimental study of alexithymia in corpus callosotomy patients and precision-matched normal controls. This comparison is based on the hypothesis that, insofar as affective verbal expression is enhanced by cortical activities linking the nonverbal representations of emotions (feelings and symbols) of the right hemisphere of the brain to the verbalization capabilities of the left hemisphere, corpus callosotomy patients--lacking the cortical connections to make such interhemispheric exchange possible--would be alexithymic.

Adult↗
PubMed1987

Alexithymia and the split brain. V. EEG alpha-band interhemispheric coherence analysis.

Electroencephalographic (EEG) recordings were obtained while 6 completely commissurotomized patients, 2 partially commissurotomized patients, and 8 precision-matched normal control subjects watched 4 times a film symbolically depicting death. Our hypothesis was that alexithymia--a diminished capability to verbally express moods, symbols, and feelings--would be greater for patients because loss of cerebral commissures reduces interhemispheric communication, separating right-hemisphere-dependent affective understanding and left-hemisphere-dependent verbalization. Path and covariance structure analyses confirmed that callosotomy decreased alpha-band EEG coherences (after adjustment for mean intrahemispheric coherence) between pairs of scalp electrode channels placed homologously over frontal, parietal, and temporal lobes of the brain. This result occurred both for an index of interhemispheric coherence and for a latent variable indicated by the 3 adjusted coherences. Reduced levels of interhemispheric coherence in turn increased alexithymia, for an overall index and for a latent variable indicated by lexical-level content-analytic measures of verbal responses to the filmic stimulus.

Adult↗
PubMed1986

Alexithymia: an experimental study of cerebral commissurotomy patients and normal control subjects.

This study assessed alexithymia in six patients with complete cerebral commissurotomy, two patients with partial commissurotomy, and eight matched control subjects. Comparisons were based on content-analytic measures of the subjects' spoken and written responses to a film that symbolically represented death and loss. The commissurotomized patients were more alexithymic on all four lexical-level variables, all six sentential-level variables, and all six global-level variables. Discriminant function analysis found a linear combination of four variables that effectively discriminated groups of fully commissurotomized, partially commissurotomized, and normal control subjects and correctly classified 15 of the 16 subjects.

Adult↗
PubMed1986

Right hemisphericity of Australian aboriginal children. II: Conjugate lateral eye movements.

Right-handed Aboriginal and White Australian children were compared in Greater Sydney areas having substantial Aboriginal subpopulations. The 45 Aboriginal children showed significantly higher percentages of leftward conjugate lateral eye movements than did the 82 White children for two sets of 17 questions: the WISC-R Similarities test and an original set of questions. A relative right-hemisphericity of the Aboriginal children on the level of hemispheric activation is inferred, which complements the earlier finding of a right-hemisphericity of these same children on the level of performance of lateralized cognitive tests.

Adolescent↗
PubMed1985

Alexithymia and the split brain. I. Lexical-level content analysis.

8 cerebral commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-minute videotaped film symbolically depicting the deaths of a baby and of a boy. After each of 4 showings, all subjects were questioned about the symbolic and emotional contents of the film. Content analyses of the subjects' spoken and written responses were carried out on the lexical level. The commissurotomized patients, in comparison to their normal controls, used a lower percentage of affect-laden words, had a higher percentage of incomplete sentences, used a higher percentage of auxiliary verbs, and used a lower percentage of adjectives. Commissurotomy patients were significantly closer to the alexithymic pole of a factor derived from these 4 variables.

Adult↗
PubMed1985

Alexithymia and the split brain. II. Sentential-level content analysis.

The Hoppe-Bogen finding of alexithymia in 12 commissurotomy patients is examined, using 6 sentential-level items corresponding to 6 of the 8 key alexithymia items in the Beth Israel 'Psychosomatic Questionnaire'. 8 of the same commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-min videotaped film about death. Content analyses of the subjects' spoken and written responses to this film were carried out, with directional support found for all items; however, only 2 of these differences in group means were statistically significant. The items were factor analyzed, and a 1-factor solution obtained. Factor score comparisons replicated the earlier study, as commissurotomy patients were found to be more alexithymic than normal controls.

Affective Symptoms↗
PubMed1985

Alexithymia and the split brain. III. Global-level content analysis of fantasy and symbolization.

8 commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-min videotaped film about death. Content analysis of the subjects' spoken and written responses to this film was carried out on the global, interpretive level, for 2 fantasy and 4 symbolization variables. Commissurotomy patients were found to be significantly more alexithymic than normal controls for 3 of the symbolization variables, for factor-analytic measures of fantasy and symbolization, and for an over-all measure of alexithymia derived from these 2 factors and lexical-level and sentential-level measures of alexithymia.

Affective Symptoms↗
PubMed1985

Alexithymia and the split brain. IV. Gottschalk-Gleser content analysis, an overview.

A structural explanation of psychosomatic personality structure is proposed, that of a functional or physical deconnection of the two cerebral hemispheres. If the affective and symbolic energies of the right hemisphere cannot be externalized through verbal expressions of the left hemisphere (alexithymia), then they are apt to be directed inward, thereby contributing to psychosomatic personality structure. In an experiment, 8 cerebral commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-minute videotaped film symbolically depicting the deaths of a baby and a boy. Gottschalk-Gleser content analysis of the subjects' verbal responses to the film was carried out for anxiety and hostility scales. A complex of shame and total anxiety in combination with hostility directed both inward and outward, was interpreted as an indicator of 'psychosomatic personality structure'. Cerebral commissurotomy patients showed a significantly higher level of psychosomatic personality structure than did normal controls.

Affective Symptoms↗
PubMed1985

Right hemisphericity of Australian aboriginal children: effects of culture, sex, and age on performances of closure and similarities tests.

Right-handed Aboriginal and White Australian urban children were compared in two Greater Sydney areas having substantial Aboriginal subpopulations. The Aboriginal children performed better than their White counterparts on a (right-hemisphere dependent) Closure or Gestalt Completion test, even though they did not do as well on the (left-hemisphere dependent) WISC-R Similarities test. Performance on both tests varied directly with age. Similarities performance as a function of age increased at a greater rate for White than for Aboriginal children. Partition of the Closure items into those containing or not containing one or more parts with elaborated part boundaries showed that items with such elaboration improved with age more than items without elaboration. The sex difference in Closure performance was limited to a male advantage for items without elaborated parts.

Adolescent↗
PubMed1980

Social dominance and cerebral hemisphericity: discriminating race, socioeconomic status, and sex groups by performance on two lateralized tests.

A neurosociological argument is presented which hypothesizes that persons in positions of social subdominance--black racial status, low and middle socioeconomic status (SES), and female sexual status will, in comparison to persons in positions of dominance--white, high SES, and male, be right-hemispheric, i.e., will perform best on a test lateralized to the right cerebral hemisphere and its appositional mode of thought as opposed to a test lateralized to the left hemisphere and its propositional mode of thought. Data from 1058 adults from two probability samples (excluding left-handers, housewives and unemployed persons) are analyzed. Appositional performance is measured by the Street Gestalt-Completion Test (A), propositional performance by the WAIS Similarities Subtest (P), and right-hemisphericity by (A-P)/(A+P). Multigroup discriminant function analysis and three-way analyses of variance produced the following results: (1) blacks are more right-hemispheric than are whites, with lower similarities performance and higher Street performance; (2) SES varies directly with Similarities performance, but not with Street performance; (3) there is a two way interaction between race and SES such that middle SES groups are most right-hemispheric for whites, and low SES groups, most right-hemispheric for blacks; (4) females are more right hemispheric than are males among blacks and lower SES whites, reflecting in part the superior performance of black females on the Street test.

Black or African American↗