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dc.contributor.advisorChin, Richarden
dc.contributor.advisorBastin, Marken
dc.contributor.authorWoodfield, Julieen
dc.date.accessioned2020-03-31T13:03:37Z
dc.date.available2020-03-31T13:03:37Z
dc.date.issued2020-06-27
dc.identifier.urihttps://hdl.handle.net/1842/36919
dc.identifier.urihttp://dx.doi.org/10.7488/era/220
dc.description.abstractThe human brain can be modelled as a network of interconnected anatomical regions using structural magnetic resonance imaging data. Understanding variations in network structure could help understand variations in higher brain functions such as cognition. This thesis investigates whether brain network structure is associated with cognition in patients investigated for suspected epilepsy and in those undergoing epilepsy surgery. Epilepsy is frequently associated with cognitive impairments and seizures are known to disrupt both structural and functional brain networks. First, a systematic literature review was undertaken to compare structural brain networks in epilepsy with healthy controls. Patients with epilepsy were found to have less efficient networks with increased average path lengths compared to healthy controls. Networks constructed from cortical thickness covariance also showed increased clustering coefficients compared to controls. Second, the association between network structure and cognitive dysfunction in a cohort of children undergoing investigation for suspected epilepsy was analysed. Patients with cognitive dysfunction had networks with longer average path lengths, longer normalised average path lengths, and lower global efficiency, even after controlling for the number and weight of network edges. These findings were consistent across network construction methods. Third, in a cohort of children undergoing resective epilepsy surgery, a post-operative increase in intelligence quotient was associated with increased global efficiency in the structural network within the healthy, contralateral non-operated hemisphere. Although cognition was associated with clinical features such as seizure frequency and age at onset of seizures, differences in network characteristics could not be completely explained by differences in clinical features. Different modelling techniques created different representative models but findings were broadly consistent across model types. This thesis suggests that the widespread alterations in brain structure described in epilepsy may lead to less efficient brain networks which could contribute to cognitive dysfunction. Adequately treating seizures in those with an efficient underlying brain network structure may facilitate cognitive development and allow patients to achieve their cognitive potential.en
dc.language.isoen
dc.publisherThe University of Edinburghen
dc.subjectbrain network structureen
dc.subjectbrain functionen
dc.subjectsystematic reviewen
dc.subjectepilepsyen
dc.subjectlearning difficultiesen
dc.subjectbrain surgeryen
dc.titleAssociation of structural brain networks with cognition in suspected epilepsy and epilepsy surgeryen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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