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0502 SENSORY GATING AND MISMATCH NEGATIVITY IN INDIVIDUALS AT RISK FOR PSYCHOSIS
Posters, Theme 2: Neurobiology of psychosis tivity. We developed a novel MRI technique to measure white matter integrity by assessing myelin-associated water fractions (MWFs), in first-episode psychosis (FEP) patients and healthy volunteers. Methods: Subjects: 46 FEP patients; and 31 controls. Imaging: MR images were acquired on a 1.5 T GE scanner (software version 5.7). A 3D SPGR sequence (for volumetric assessment) and single-slice myelin water data were acquired using a 48-echo CPMG sequence. The myelin water slice was placed transversely to the slice parallel to the AC-PC line. Image Analysis: Genu, minor forceps, anterior and posterior internal capsules, splenium and major forceps were manually selected and averaged over 3 trials. T2 relaxation decay curves were decomposed into an unspecified number of exponentials, and MWFs were extrapolated from these decay curve partitions. Statistics: Omnibus ANOVAs were used to investigate overall group differences and effects of gender and age. As this is preliminary data, exploratory statistics are presented without Bonferroni corrections. Patients had significantly lower MWFs in the left genu, left minor forceps and right major forceps (p-values <0.05). Significant gender effects were observed in some regions. Significant diagnosis x gender effects were also seen. Discussion: FEP patients have bilateral reductions in MWFs, even in the earliest stages of illness, particularly in the frontal regions (responsible for higher order cognitive functioning) suggesting that white matter integrity contributes to psychosis pathogenesis. Significant age and gender effects exist and should be carefully considered in future studies. 0465 A COMPARATIVE FOLLOW UP STUDY OF CORTICAL GREY MATTER CHANGES ASSOCIATED WITH TWO TYPES OF THERAPY IN EARLY COURSE SCHIZOPHRENIA PATIENTS K. Prasad1 *, V. Diwadkar2 , J. Nutche1 , G. Hogarty1 , M. Keshavan2 . Psychiatric Institute and Clinic, Pittsburgh, PA, United States, 2 Wayne State University School of Medicine, Detroit, MI, United States Presenting author contact: [email protected] 1 Western
Early course schizophrenia/schizoaffective disorder patients who received cognitive enhancement therapy (CET) and enriched supportive therapy (EST) have been reported to show better neurocognition and social adjustment at the end of two years compared to those who received only EST. The brain mechanisms underlying such improvements remain unclear. Our goal in this study was to examine the grey matter changes associated with these two types of treatments over two years. Our hypothesis was that the grey matter densities would significantly increase in brain regions involved in social cognition and executive functions in those who received CET (n = 30) compared to those who received EST (n = 24). We obtained structural MRI scans at baseline and at the end of two years of treatment. Using statistical parametric mapping version 5 (SPM5), we performed voxel-based morphometry (VBM) using age and gender as covariates in an ANCOVA model. We observed that CET subjects at the end of two years showed increased grey matter in the ventromedial prefrontal region, Brodmann area 10, lateral parietal area and heteromodal association areas whereas EST subjects showed less robust changes in the hypothesized regions. These observations suggest that the grey matter changes in brain regions mediating social cognition may be related to the treatment related enhancements in cognitive and social functioning.
S77 0502 SENSORY GATING AND MISMATCH NEGATIVITY IN INDIVIDUALS AT RISK FOR PSYCHOSIS A. Brockhaus-Dumke1 *, R. Mueller2 , F. Schulze-Lutter1 , H. Graf von Reventloh1 , H. Picker1 , M. Neumann1 , J. Klosterk¨otter1 , S. Ruhrmann1 . 1 Department of Psychiatry and Psychotherapy, University of Cologne, Cologne, Germany, 2 Center of Applied Informatics, University of Cologne, Cologne, Germany Presenting author contact: [email protected] Within the framework of the European multicenter study (EPOS) the Early Recognition and Intervention Center (FETZ) at the Department of Psychiatry and Psychotherapy of the University of Cologne/Germany aims to evaluate individuals in the prodromal phase (at-risk group) to improve strategies of early recognition and intervention. Abnormalities in auditory information processing are frequently reported in schizophrenia patients. As part of a multidimensional approach to the early recognition of psychosis, P50 and N100 derived sensory gating indices and mismatch negativity (MMN) reflecting early, predominately preattentive aspects of auditory information processing were investigated for their qualification as a neurobiological at-risk indicator of psychosis. We will present auditory evoked ERP/EEG data obtained from individuals at risk (HR), subjects with a first episode of schizophrenia (FE) and subjects with multiple episodes (ME). In addition to the conventional analysis of averaged ERPs, we will present first results based on the single trial analysis of stimulus-associated phase resetting. Our ERP data suggest that deficits in sensory gating (double click paradigm) and echoic memory (mismatch negativity) are most prominent in ME patients. Only a gradual, but non-significant decline was present in HR and FE patients. In contrast to the averaged ERP data, the single trial analysis of the sensory gating data showed significantly reduced phase resettings in individuals at risk and in patients with schizophrenia. These findings suggest that analysis of phase resetting may be superior to the analysis of averaged auditory ERPs in detecting early abnormalities of auditory information processing in individuals at risk for psychosis. The significance of these results for the concept of sensory gating, and the potential role for ERP measures in enhancing risk prediction in clinical high risk subjects will be discussed. 0525 AN MRI STUDY OF NEURODEVELOPMENTAL RISK FACTORS FOR PSYCHOSIS: A RELATIONSHIP BETWEEN DISCORDANT BIRTH WEIGHT AND MORPHOLOGICAL BRAIN DEVELOPMENT IN HEALTHY MONOZYGOTIC TWINS N. Okamoto1 *, O. Saitoh1 , T. Ohnishi1 , K. Anami2 , N. Tatemichi1 . Center of Neurology and Psychiatry, Musashi Hospital, Kodaira, Tokyo, Japan, 2 Takatsuki Hospital, Hachi-oji, Tokyo, Japan Presenting author contact: [email protected] 1 National
Introduction: Schizophrenia and other psychotic disorders that have been reported to demonstrate 50−60% concordance rate in monozygotic twins (MZ) should have neurodevelopmental background for their pathogenesis. It is noted that discordant birth weight and twintwin transfusion syndrome (TTTS) are known as a possible risk factor for the development of psychosis and sometimes give rise to
Early course schizophrenia/schizoaffective disorder patients who received cognitive enhancement therapy (CET) and enriched supportive therapy (EST) have been reported to show better neurocognition and social adjustment at the end of two years compared to those who received only EST. The brain mechanisms underlying such improvements remain unclear. Our goal in this study was to examine the grey matter changes associated with these two types of treatments over two years. Our hypothesis was that the grey matter densities would significantly increase in brain regions involved in social cognition and executive functions in those who received CET (n = 30) compared to those who received EST (n = 24). We obtained structural MRI scans at baseline and at the end of two years of treatment. Using statistical parametric mapping version 5 (SPM5), we performed voxel-based morphometry (VBM) using age and gender as covariates in an ANCOVA model. We observed that CET subjects at the end of two years showed increased grey matter in the ventromedial prefrontal region, Brodmann area 10, lateral parietal area and heteromodal association areas whereas EST subjects showed less robust changes in the hypothesized regions. These observations suggest that the grey matter changes in brain regions mediating social cognition may be related to the treatment related enhancements in cognitive and social functioning.
S77 0502 SENSORY GATING AND MISMATCH NEGATIVITY IN INDIVIDUALS AT RISK FOR PSYCHOSIS A. Brockhaus-Dumke1 *, R. Mueller2 , F. Schulze-Lutter1 , H. Graf von Reventloh1 , H. Picker1 , M. Neumann1 , J. Klosterk¨otter1 , S. Ruhrmann1 . 1 Department of Psychiatry and Psychotherapy, University of Cologne, Cologne, Germany, 2 Center of Applied Informatics, University of Cologne, Cologne, Germany Presenting author contact: [email protected] Within the framework of the European multicenter study (EPOS) the Early Recognition and Intervention Center (FETZ) at the Department of Psychiatry and Psychotherapy of the University of Cologne/Germany aims to evaluate individuals in the prodromal phase (at-risk group) to improve strategies of early recognition and intervention. Abnormalities in auditory information processing are frequently reported in schizophrenia patients. As part of a multidimensional approach to the early recognition of psychosis, P50 and N100 derived sensory gating indices and mismatch negativity (MMN) reflecting early, predominately preattentive aspects of auditory information processing were investigated for their qualification as a neurobiological at-risk indicator of psychosis. We will present auditory evoked ERP/EEG data obtained from individuals at risk (HR), subjects with a first episode of schizophrenia (FE) and subjects with multiple episodes (ME). In addition to the conventional analysis of averaged ERPs, we will present first results based on the single trial analysis of stimulus-associated phase resetting. Our ERP data suggest that deficits in sensory gating (double click paradigm) and echoic memory (mismatch negativity) are most prominent in ME patients. Only a gradual, but non-significant decline was present in HR and FE patients. In contrast to the averaged ERP data, the single trial analysis of the sensory gating data showed significantly reduced phase resettings in individuals at risk and in patients with schizophrenia. These findings suggest that analysis of phase resetting may be superior to the analysis of averaged auditory ERPs in detecting early abnormalities of auditory information processing in individuals at risk for psychosis. The significance of these results for the concept of sensory gating, and the potential role for ERP measures in enhancing risk prediction in clinical high risk subjects will be discussed. 0525 AN MRI STUDY OF NEURODEVELOPMENTAL RISK FACTORS FOR PSYCHOSIS: A RELATIONSHIP BETWEEN DISCORDANT BIRTH WEIGHT AND MORPHOLOGICAL BRAIN DEVELOPMENT IN HEALTHY MONOZYGOTIC TWINS N. Okamoto1 *, O. Saitoh1 , T. Ohnishi1 , K. Anami2 , N. Tatemichi1 . Center of Neurology and Psychiatry, Musashi Hospital, Kodaira, Tokyo, Japan, 2 Takatsuki Hospital, Hachi-oji, Tokyo, Japan Presenting author contact: [email protected] 1 National
Introduction: Schizophrenia and other psychotic disorders that have been reported to demonstrate 50−60% concordance rate in monozygotic twins (MZ) should have neurodevelopmental background for their pathogenesis. It is noted that discordant birth weight and twintwin transfusion syndrome (TTTS) are known as a possible risk factor for the development of psychosis and sometimes give rise to