Melbourne School of Psychological Sciences - Research Publications

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    Regional white matter microstructure in very preterm infants: Predictors and 7 year outcomes
    Thompson, DK ; Lee, KJ ; Egan, GF ; Warfield, SK ; Doyle, LW ; Anderson, PJ ; Inder, TE (ELSEVIER MASSON, CORPORATION OFFICE, 2014-03)
    The aims of this study were to investigate regional white matter microstructural differences between very preterm (VPT) (<30 weeks' gestational age and/or <1250 g) and full term (FT) (≥37 weeks' gestational age) infants at term corrected age with diffusion tensor imaging, and to explore perinatal predictors of diffusion measures, and the relationship between regional diffusion measures and neurodevelopmental outcomes at age 7 years in VPT children. Mean (MD) (p = .003), axial (AD) (p = .008), and radial diffusivity (RD) (p = .003) in total white matter were increased in VPT compared with FT infants, with similar fractional anisotropy (FA) in the two groups. There was little evidence that group-wise differences were specific to any of the 8 regions studied for each hemisphere. Perinatal white matter abnormality and intraventricular hemorrhage (grade III or IV) were associated with increased diffusivity in the white matter of VPT infants. Higher white matter diffusivity measures of the inferior occipital and cerebellar region at term-equivalent age were associated with increased risk of impairments in motor and executive function at 7 years in VPT children, but there was little evidence for associations with IQ or memory impairment. In conclusion, myelination is likely disrupted or delayed in VPT infants, especially those with perinatal brain abnormality (BA). Altered diffusivity at term-equivalent age helps explain impaired functioning at 7 years. This study defines the nature of microstructural alterations in VPT infant white matter, assists in understanding the associated risk factors, and is the first study to reveal an important link between inferior occipital and cerebellar white matter disorganization in infancy, and executive and motor functioning 7 years later.
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    Volumetric Abnormalities Predating the Onset of Schizophrenia and Affective Psychoses: An MRI Study in Subjects at Ultrahigh Risk of Psychosis
    Dazzan, P ; Soulsby, B ; Mechelli, A ; Wood, SJ ; Velakoulis, D ; Phillips, LJ ; Yung, AR ; Chitnis, X ; Lin, A ; Murray, RM ; McGorry, PD ; McGuire, PK ; Pantelis, C (OXFORD UNIV PRESS, 2012-09)
    It remains unclear whether brain structural abnormalities observed before the onset of psychosis are specific to schizophrenia or are common to all psychotic disorders. This study aimed to measure regional gray matter volume prior to the onset of schizophreniform and of affective psychoses. We investigated 102 subjects at ultrahigh risk (UHR) of developing psychosis recruited from the Personal Assessment and Crisis Evaluation Clinic in Melbourne, Australia. Twenty-eight of these subjects developed psychosis subsequent to scanning: 19 schizophrenia, 7 affective psychoses, and 2 other psychoses. We examined regional gray matter volume using 1.5 mm thick, coronal, 1.5 Tesla magnetic resonance imaging and voxel-based morphometry methods of image analysis. Subjects were scanned at presentation and were followed up clinically for a minimum of 12 months, to detect later transition to psychosis. We found that both groups of subjects who subsequently developed psychosis (schizophrenia and affective psychosis) showed reductions in the frontal cortex relative to UHR subjects who did not develop psychosis. The subgroup that subsequently developed schizophrenia also showed smaller volumes in the parietal cortex and, at trend level, in the temporal cortex, whereas those who developed an affective psychosis had significantly smaller subgenual cingulate volumes. These preliminary findings suggest that volumetric abnormalities in UHR individuals developing schizophrenia vs affective psychoses comprise a combination of features that predate both disorders and others that may be specific to the nature of the subsequent disorder.