| Summary: | The work described in this thesis aimed to investigate the characteristics and neural correlates of epilepsy and cognitive impairment in preterm children. From a large cohort of preterm children (born at gestational age < 33 weeks), those who had developed epilepsy by age eight years were included in the study. Since the main hypothesis was that in those children with epilepsy and/or cognitive impairment additional undetected grey matter abnormalities are present, preterm control children without epilepsy from the same cohort were selected such that balance was achieved with respect to white matter abnormalities identified on neonatal cranial ultrasound. Conventional structural magnetic resonance (MR) imaging data were analysed qualitatively (visual inspection) for white and grey matter abnormalities. In addition, a quantitative MR imaging analysis method, voxel-based morphometry (VBM), was used for detection of more subtle grey matter abnormalities that may not be detected by purely visual analysis of MR images. Perinatal and neonatal data, data from neurological and psychometric assessments, from the medical history and data obtained from electroencephalography (EEG) were analysed and related to neuroimaging findings. Visual analysis of MR images identified brain abnormalities that had gone undetected on neonatal ultrasound. VBM analysis identified subtle grey matter abnormalities that had not been detected on visual analysis of MR images. VBM-detected grey matter abnormalities were associated with periventricular white matter reduction identified on visual inspection of MR images. The analyses provide evidence for epilepsy and/or cognitive impairment to be related to both reduction of periventricular white matter and subtle VBM-detected grey matter abnormalities. The data suggest that using combined information from visual inspection of MR images and VBM analysis of grey matter improves significantly the prediction of epilepsy and cognitive outcome compared to using findings from clinical variables alone. The data also indicate that in this study group, the extent of brain injury had a stronger effect on cognitive outcome than the presence of epilepsy.
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