EEG differences in monozygotic twins discordant and concordant for schizophrenia

Stassen, Hans H.; Coppola, Richard; Gottesman, Irving I.; Torrey, Ε. Fuller; Kuny, Stephan; Rickler, Kenneth C.; Hell, Daniel

doi:10.1017/s0048577299970713

Cited by 27 publications

(15 citation statements)

References 7 publications

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“…Yet EEG parameters were not only stable over time, but also exhibited a broad range of inter-individual differences, thus underlining the trait-like qualities of these quantities [cf. Stassen et al, 1999].Due to differences in EEG recording equipment between the earlier studies and this present investigation the correlations presented below were, in terms of absolute size, not fully compatible with previous results (systematically smaller). Given these incompatibilities, Frequency bands were chosen to be compatible with a major portion of the literature, although these frequency bands are not optimal with respect to reproducibility and specificity of EEG characteristics.…”

contrasting

confidence: 89%

“…In a recent study of the within-pair EEG differences in monozygotic (mz) twins discordant or concordant for schizophrenia, Stassen et al [1999] found that discordant as well as the concordant pairs exhibited a much lower within-pair EEG concordance than healthy mz control twins. Most notably, the underlying electrocortical anomalies were differently manifested in the cotwins concordant for schizophrenia, thus giving rise to the intriguing question of the extent to which nongenetic, pathologic processes are involved in the pathogenesis of the twins' illness.…”

Section: Introductionmentioning

confidence: 99%

“…The respective normative samples included repeated assessments on healthy volunteers at 14-day and 5-year intervals [Stassen et al, 1999], and assessments on healthy mz and dizygotic twins brought up together and reared apart [Stassen et al, , 1988a. Data calibration was accomplished using the 'Computerized Recognition of Persons by multivariate EEG patterns' as optimization criterion which led to recognition rates of >92% correctly identified individuals under comparable experimental conditions [Stassen, 1980].…”

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confidence: 99%

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Nongenetic pathologic developments of brain‐wave patterns in monozygotic twins discordant and concordant for schizophrenia

Weisbrod

Hill

Sauer

et al. 2003

American J of Med Genetics Pt B

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Evidence from previous studies has suggested that the inter-individual differences in human brain-wave patterns (EEG) are predominantly determined by genetic factors. In particular, the within-pair EEG concordance of monozygotic (mz) twins was found to be typically as high as r = 0.81 across channels and frequency bands, thus being comparable to that between repeated assessments on the same individual with typically r = 0.83. Yet our investigations into mz twins discordant and concordant for schizophrenia yielded a significantly reduced within-pair EEG concordance for both, the pairs discordant for schizophrenia and the pairs concordant for schizophrenia (with concordance for schizophrenia assessed through a syndrome-oriented approach). A multivariate discriminant function of EEG parameters distinguished in a reproducible way between affected and unaffected subjects at an overall performance of >75% correctly classified subjects, while the severity of illness, as derived from EEG-differences between affected and unaffected subjects, was closely related to the severity of illness as provided by psychopathology syndrome scores. Consequently, EEG anomalies associated with schizophrenia and manifested differently in the mz co-twins concordant for schizophrenia are likely the effect of nongenetic, pathologic processes that evolved independently in the co-twins' genetically identical brains once the illness began to progress. The existence of such nongenetic processes would suggest a modification of the standard phenotype-to-genotype search strategies of molecular-genetic studies that aim to link the schizophrenia phenotype to genetic vulnerability factors.

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confidence: 89%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Nongenetic pathologic developments of brain‐wave patterns in monozygotic twins discordant and concordant for schizophrenia

Weisbrod

Hill

Sauer

et al. 2003

American J of Med Genetics Pt B

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“…It was noted that the test-retest stability of power in the waking EEG of individuals was comparable to values of monozygotic twins (MZ) (van Beijsterveldt et al 1996;Stassen et al 1999). However, EEG topography was not examined.…”

Section: Discussionmentioning

confidence: 98%

Individual 'Fingerprints' in Human Sleep EEG Topography

Finelli

Achermann

Borbély

2001

Neuropsychopharmacology

172

129

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The sleep EEG of eight healthy young men was recorded from 27 derivations during a baseline night and a recovery night after 40 h of waking. Individual power maps of the nonREM sleep EEG were calculated for the delta, theta, alpha, sigma and beta range. The comparison of the normalized individual maps for baseline and recovery sleep revealed very similar individual patterns within each frequency band. This high correspondence was quantified and statistically confirmed by calculating the Manhattan distance between all pairs of maps within and between individuals. Although prolonged waking enhanced power inthe low-frequency range and reduced power in the high-frequency range Sleep is generally regarded as a global brain process. Recently, regional aspects of sleep have gained increasing attention. Early reports that the location of the recording electrodes affects the pattern of the sleep EEG (Findji et al. 1981;Buchsbaum et al. 1982;Hori 1985) were reexamined by using contemporary methods of quantitative EEG analysis. Power spectra along the antero-posterior axis were shown to exhibit frequencyspecific and state-dependent gradients (Werth et al. 1996(Werth et al. , 1997) with a frontal predominance in the 2-Hz band during the initial part of sleep. This hyperfrontality of low-frequency activity was accentuated by sleep deprivation (Cajochen et al. 1999). It may be associated with the reduction of regional cerebral blood flow which is known to occur during slow wave sleep (Finelli et al. 2000b; for a review see Maquet 2000) as well as in the course of prolonged waking (Thomas et al. 1998(Thomas et al. , 2000. These findings support the hypothesis that sleep has a local, use-dependent, facet and that cerebral structures that had been particularly active during waking may exhibit more intensive signs of sleep (Horne 1993;Krueger and Obál 1993;Kattler et al. 1994;Benington and Heller 1995;Borbély and Achermann 2000).Studies on regional differences in the sleep EEG are typically based on the statistical analysis of the records from several subjects. This approach emphasizes the changes common to all subjects, and tends to disregard individual differences. However, individual features may be important. This was recently demonstrated in a study where the relationship between the waking and sleep EEG was investigated (Finelli et al. 2000a). Examining the individual time course of theta power in the waking EEG in the course of a 40-h sleep deprivation period revealed a correlation with the change in delta power in the nonREM sleep EEG. The results suggested that a common regulatory process might control specific parts of the waking and sleep EEG. The aim of the present analysis was to investigate the individual topographic distribution of power in non-REM sleep before and after sleep deprivation, a manipulation known to cause massive changes in the sleep EEG. SUBJECTS AND METHODSEight right-handed healthy male subjects (mean age 23 y Ϯ 0.46 SEM, range 21-25 years) participated in the study. They were selected on the bas...

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“…MZ twins discordant for schizophrenia reportedly exhibit much lower within-pair electroencephalographic (EEG) concordance than healthy MZ twins. These results prompted us to hypothesize that EEG abnormalities associated with schizophrenia reflect non-genetic, pathological developments affecting genetically identical brains (Stassen et al 1996). However, this hypothesis was not confirmed.…”

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confidence: 98%

Psychophysiological Differences in Identical Twins Discordant for Schizophrenia: A Critical Index for the Onset of Schizophrenia

Yoshida

Numachi

Fukushima

et al. 2006

Tohoku J. Exp. Med.

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It has been hypothesized that not only genetic but also environmental factors contribute to the onset of schizophrenia. We therefore conducted psychophysiological studies on a pair of identical twins discordant for schizophrenia, to differentiate non-genetic from genetic indexes possibly associated with this disease. The affected and unaffected twins were 28 year-old females. The affected twin was diagnosed as having schizophrenia based on the Diagnosis and Statistical Manual of Mental Disorders, third edition revised (DMS-III-R), whereas the unaffected twin had no psychiatric disorders. The brain potentials evoked by visual stimulation (visual event-related potential [visual ERP]) were recorded. The components of the visual ERP, which are believed to reflect pattern cognition, semantic processing and the failure to use preceding word information, were compared with normal subjects. Both twins showed abnormal semantic processing and similar failure to use preceding word information. Abnormality of semantic processing was marked in the affected twin. These results indicate that failure to use preceding word information might reflect only genetic factors, whereas abnormal semantic processing might reflect both genetic and non-genetic factors because the affected twin was considered to show accelerated deterioration after the disease onset. However, only the affected twin showed abnormal pattern cognition, which might be attributable to nongenetic factors such as an acquired vulnerability to schizophrenia. We suggest that the impairment of pattern cognition evaluated by visual ERP may be a critical index for the onset of schizophrenia. acquired vulnerability; visual event related potential; discordant identical twins; schizophrenia

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EEG differences in monozygotic twins discordant and concordant for schizophrenia

Cited by 27 publications

References 7 publications

Nongenetic pathologic developments of brain‐wave patterns in monozygotic twins discordant and concordant for schizophrenia

Nongenetic pathologic developments of brain‐wave patterns in monozygotic twins discordant and concordant for schizophrenia

Individual 'Fingerprints' in Human Sleep EEG Topography

Psychophysiological Differences in Identical Twins Discordant for Schizophrenia: A Critical Index for the Onset of Schizophrenia

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