Patterns of cerebral gray and white matter alterations in preterm subjects by magnetic resonance imaging
[eng] Preterm birth is frequently associated with an increased risk of neurodevelopmental difficulties and of cognitive, behavioural and emotional problems during childhood. The present thesis comprises two MRI studies that demonstrated patterns of cerebral gray matter (GM) and white matter (WM) alt...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2009 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/42279 |
| Acceso en línea: | https://hdl.handle.net/2445/42279 http://www.tdx.cat/TDX-0629110-112345 http://hdl.handle.net/10803/2294 |
| Access Level: | acceso abierto |
| Palabra clave: | Encèfal Cognició Neuroanatomia Imatges per ressonància magnètica Infants prematurs Encephalon Cognition Neuroanatomy Magnetic resonance imaging Premature infants |
| Sumario: | [eng] Preterm birth is frequently associated with an increased risk of neurodevelopmental difficulties and of cognitive, behavioural and emotional problems during childhood. The present thesis comprises two MRI studies that demonstrated patterns of cerebral gray matter (GM) and white matter (WM) alterations and their cognitive correlates in children and adolescents who were born preterm.Our first study provided evidence of the persistence of diffuse WM abnormalities in adolescents who were born very preterm, and underlines their high frequency. The individual voxel-based morphometry analysis approach demonstrated that 80% of preterm subjects had WM abnormalities, the most frequently affected areas being the centrum semiovale and the posterior periventricular regions. These results suggest that WM reductions are common, even in those preterm subjects without motor impairment and who receive normal schooling. Volumetric and MRI-related cognitive outcomes suggest that cognitive processing speed is persistently impaired following early brain damage, despite the existence of developmental plasticity. Although the nature of the relationship between diffuse WM injury and cognitive/behavioural deficits is complex and not entirely understood, the results of our first study suggest that WM abnormalities are related with worse Performance IQ scores and slower processing speed. So, we can affirm that diffuse WM loss in preterm children plays an important role in long-term cognitive impairment. Our second study focussed on the investigation of preterm children with a low risk either of neurological deficit or of developmental difficulties. While the neurodevelopmental and cognitive outcome of high-risk preterm samples is well known, little research has been conducted into low-risk preterms, such as those born between 30-34 weeks of GA, with uncomplicated perinatal histories, normal cranial ultrasound scans and no obvious neurodevelopmental deficits. To our knowledge, this is the first study to investigate the brain volume characteristics of a low-risk preterm sample in childhood using an MRI approach and the first attempt to relate these measures to cognitive performance. This study demonstrated that low-risk preterm children are characterized by the presence of regional cortical GM volume reductions in the parietal and temporal lobes which correlate strongly with IQ. Moreover, preterm children also showed WM volume reductions that were concomitant with the GM loss in the parietal and temporal regions compared to full-terms.In summary, the body of results derived from this thesis provides evidence that preterm birth is associated with brain abnormalities and cognitive impairment in middle childhood and adolescence. Future studies are required to assess the impact of cognitive and behavioural function in middle childhood on later outcomes in preterm samples with low risk of neurodevelopmental deficits. |
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