PubMed Health⌕ Search

Biomedical subjects

G Bomben

Publications and source records attributed to G Bomben.

8 recordsLinked to original sources
PubMed1998

Familial brain wave patterns: study of a 12-sib family.

In the sense of a paradigm for the heritability of complex psychiatric disorders, we compared the brain wave patterns of a 12-sib family with those of 144 unrelated controls and with those of 14 pairs of monozygotic twins. Under constant experimental conditions, electroencephalogram (EEG) parameters generally displayed a broad range of inter-individual differences, but were also remarkably stable over time within each subject, thus suggesting that the variation of EEG parameters forms a continuous phenotypic range rather than discrete phenotype classes. The distributions of all EEG parameters were found to be unimodal but significantly different from a normal distribution. Although an unimodal distribution speaks in favor of a polygenic additive mode of inheritance, this may not necessarily be true. Our findings might reflect the fact that a symmetric environmental distribution is converted through the underlying genotypes' norm of reaction into an asymmetric phenotype distribution. On the other hand, the distributions of the power-related EEG parameters were not that clearly unimodal, and with a larger sample size a trimodal solution might have become significant. With respect to the between-sib EEG similarity, we found the empirically derived value to be approximately half that of the within-subject similarity at 14-day intervals and of the within-pair similarity of monozygotic twins. This finding confirmed earlier results on monozygotic twins brought up together and reared apart, concerning the estimated value of h2. All in all, the EEG paradigm has clearly demonstrated that the methods of quantitative genetics represent a powerful tool once phenotypes designed to assess the variation of a trait are based on dimensional quantities.

Action Potentials↗
PubMed1996

Reliable computer-assisted classification of the EEG: EEG variants in index cases and their first degree relatives.

A method which optimizes on global properties of sample recordings is proposed for the definition of and the discrimination between electroencephalogram (EEG) classes. The sample was drawn from students at the University of Heidelberg from 1974 to 1978 and consists of 15 healthy index cases clinically ascertained as belonging to the low voltage EEG group. In addition, the three clinically defined groups: diffuse beta (18 index cases), borderline alpha (12 index cases) and monomorphous alpha (18 index cases) have been included in the study, as well as the first degree relatives of the index cases, thus providing a clinical classification into four groups. The proposed method provides an automatic and reliable classification algorithm using discriminant and cluster analysis. The relation between such an automatized classification and clinical classification schemes is investigated. In particular, the inheritance of the low voltage EEG, the question on sex differences and the question of a simple Mendelian mechanism had been examined. The method of random splittings had been applied for discriminant and cluster analysis. Our findings can be summarized as follows: (1) except for the monomorphous alpha EEG group, the clinical classification shows rather marginal separation (discriminating performance 60% to 75%), while a new and more reliable grouping scheme improves the discriminating performance up to 87% to 91%. The latter scheme leads to the concept of personal channel pattern (PCP) and was compared to the clinical classification scheme by means of contingency tables; (2) only a weak correlation between the clinically and PCP-based groups could be found (Cramér Index: 0.27). Accordingly, we continued to investigate the extent to which the proposed EEG classification scheme can nevertheless explain the genetic mechanisms apparently involved in the low voltage EEG. We thus considered the role of sex differences manifest in our proposed new grouping scheme; (3) males occurred more frequently in the new group 3 and females more frequently in the new group 1. In this regard, a much better correlation of the new groups between mothers and children than between fathers and children was observed; and (4) with help of our new PCP scheme, we have been able to reproduce a simple two gene Mendelian scheme to explain inheritance of the clinical low voltage EEG group. In this PCP-based scheme, the low voltage property does not occur when dominance of a certain gene (called gene A) is absent.

Adult↗
PubMed1991

Speech characteristics in depression.

This study examined the relationship between speech characteristics and psychopathology throughout the course of affective disturbances. Our sample comprised 20 depressive, hospitalized patients who had been selected according to the following criteria: (1) first admission; (2) long-term patient; (3) early entry into study; (4) late entry into study; (5) low scorer; (6) high scorer, and (7) distinct retarded-depressive symptomatology. Since our principal goal was to model the course of affective disturbances in terms of speech parameters, a total of 6 repeated measurements had been carried out over a 2-week period, including 3 different psychopathological instruments and speech recordings from automatic speech as well as from reading out loud. It turned out that neither applicability nor efficiency of single-parameter models depend in any way on the given, clinically defined subgroups. On the other hand, however, no significant differences between the clinically defined subgroups showed up with regard to basic speech parameters, except for the fact that low scorers seemed to take their time when producing utterances (this in contrast to all other patients who, on the average, had a considerably shorter recording time). As to the relationship between psychopathology and speech parameters over time, we found significant correlations: (1) in 60% of cases between the apathic syndrome and energy/dynamics; (2) in 50% of cases between the retarded-depressive syndrome and energy/dynamics; (3) in 45% of cases between the apathic syndrome and mean vocal pitch, and (4) in 71% of low scores between the somatic-depressive syndrome and time duration of pauses. All in all, single parameter models turned out to cover only specific aspects of the individual courses of affective disturbances, thus speaking against a simple approach which applies in general.

Adult↗
PubMed1988

The within-pair EEG similarity of twins reared apart.

Within the broader context of our investigations into the heredity of the human EEG, we analysed the EEGs of 28 pairs of monozygotic and 21 pairs of dizygotic twins who were separated as infants and reared apart. The principal goal of this study was to determine the degree to which environmental factors possibly influence the development of a person's EEG. Monozygotic twins reared apart were, with respect to their EEGs, only slightly less similar to each other (if there is any difference at all) than the same person is to himself over time. For dizygotic twins reared apart, we verified the findings of our previous study, namely, that the average within-pair similarity of EEGs estimated from a sufficiently representative sample of fraternal twins was significantly higher than the average inter-individual similarity of EEGs obtained from unrelated persons. The results on both monozygotic and dizygotic twins, yielded conclusive proof that the individual EEG pattern is predominantly determined by hereditary factors.

Adult↗
PubMed1988

Genetic determination of the human EEG. Survey of recent results on twins reared together and apart.

In this article, we have discussed recent progress in quantifying the genetically determined component of the resting EEG. This progress has been made possible in particular by the application of advanced information processing techniques such as "supervised learning," and the development of a problem-oriented "similarity" concept. Our work aimed at modeling previous findings regarding the distinct individuality of human brain-wave patterns, the high similarity between the EEGs of monozygotic twins, and the average within-pair similarity of dizygotic twins. Thus, we had three objectives: First, we wanted to improve the quantification of EEG characteristics with respect to reproducibility and specificity by means of adaptive procedures and repeated measurements. Second, we wanted to compare the "typical" within-subject EEG similarity with the "typical" within-pair EEG similarity of monozygotic and dizygotic twins brought up together. Finally, we were interested in the degree to which environmental factors affect the characteristics of human brain-wave patterns. Our investigations were based on the empirical data derived from five different populations: (1) 81 healthy subjects, (2) 24 pairs of monozygotic twins brought up together, (3) 25 pairs of dizygotic twins brought up together, (4) 28 pairs of monozygotic twins reared apart, and (5) 21 pairs of dizygotic twins reared apart. Following our similarity conception, repeated measurements on the set of 81 individuals were used as design samples, and new registrations from the same individuals taken 14 days later were referred to as test samples in order to develop the appropriate method and to determine all required calibration parameters. This specific approach allowed us to construct EEG spectral patterns which, with a specificity and reproducibility of greater than 90% each, largely met the requirements of genetic EEG studies. Hence, we were able systematically to investigate the within-pair EEG similarity of our twin samples.(ABSTRACT TRUNCATED AT 400 WORDS)

Electroencephalography↗
PubMed1987

Genetic aspects of the EEG: an investigation into the within-pair similarity of monozygotic and dizygotic twins with a new method of analysis.

A considerable number of previous studies emphasized the importance of genetic factors in the spontaneous EEG. In this context MZ twins were found to resemble their co-twins as much as they resemble themselves over time, whereas investigations into the within-pair similarity of DZ twins yielded very inconsistent findings. To test these conclusions, we re-analysed the EEGs of an earlier twin study (24 MZ pairs/25 DZ pairs) by means of a new method of analysis. In our study, MZ twins proved to be less like one another than each person is to himself over time. However, this result might be because the EEG data were not optimal for the applied method of analysis, but the existence of true within-pair differences cannot be excluded. Contrary to earlier findings in the literature, the analysis of the EEG of DZ twins showed that, for a sufficiently representative sample, the within-pair similarity is significantly above the inter-individual similarity between unrelated persons.

Adult↗
PubMedDate not supplied

Speaking behavior and speech sound characteristics in acute schizophrenia.

Based on a sample of 45 hospitalized, acute-schizophrenic patients and 45 carefully matched controls, we investigated the non-verbal characteristics of schizophrenic speech by means of an 'acoustic' speech analysis and determined the extent to which speaking behavior and speech sound characteristics had adjusted toward normal values at the time of hospital release. Using a multivariate discriminant function derived from a previous study of chronic schizophrenics, totally 77 (85.6%) individuals of our patient and control sample could be correctly classified by a set of 12 acoustic variables at entry into study. At hospital release, the majority of patients (64.4%) still exhibited speech impairment although acute psychopathology had significantly improved. A configuration of 6 acoustic variables, assessed at the time point of entry into study, predicted at high reliability the severity of the negative syndrome at hospital release. Acute medication effects did not explain these findings, thus underlining the potential diagnostic relevance of the speech analysis method. With respect to the relationship between speech characteristics and acute psychopathology throughout the time course of recovery, our results suggest that changes in speaking behavior and speech sound characteristics may be distinct aspects of schizophrenia that can persist in a subgroup of patients over a long period, mostly beyond the time point of hospital release. Accordingly, the speech analysis method might become very useful in detailing the nature and severity of deficits in patients after remission of positive symptoms.

Acute Disease↗