Epilepsy in infancy : cognitive & social developmental outcome at 3-5 years

• Main Author: O'Reilly, H. E.
• Published: University College London (University of London) 2012
• Subjects: 612.8
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625789

The present study is the third phase of a longitudinal, population-based study investigating the cognitive and social developmental outcome of children at 3-5 years of age whom developed epilepsy within the first two years of life. These children underwent a neurological and neuropsychological assessment at initial seizure presentation (baseline) and again at 1-year follow-up. The current thesis is an account of the 3-year follow-up phase of this study. Once more these children underwent a neurological assessment and a series of standardised neuropsychological assessments looking at IQ/cognitive score, language, memory, attention and social behaviour. The aim of this study was to establish the neurological factors - structural abnormalities on neuroimaging, abnormal EEG, a history of Infantile Spasms and abnormal neurological examination - that are predictive of later cognitive outcome using regression analysis. Seizure freedom and abnormal EEG predicted IQ/cognitive score, memory and attention performance, baseline cognitive score also predicted IQ/cognitive score at 3-year follow-up. These findings suggest: (a) children who are performing poorly at baseline continue to display delayed development at follow-up, (b) these children are delayed across the range of neuropsychological functions tested and (c) this delay is related to continuing seizure activity. These findings permit earlier identification of those children most at risk for poor developmental outcome with infant-onset epilepsy and suggest that achieving seizure freedom should continue to be the focus of treatment. From examining the literature there are currently no known studies, which, like this study are prospective, longitudinal and focus solely on infant onset epilepsy, and thus these findings make an important new contribution. A second aim of this study was to examine the early natural history of children with infant-onset epilepsy who go on to develop atypical behaviour patterns. Standardised questionnaires and a social observational assessment were used to examine the social and behavioural development of these children, as was an experimental Event Related Potential (ERP) study. 20% of the children assessed demonstrated behaviours associated with Autism Spectrum Disorder (ASD) and poor language functioning at baseline differentiated these children from the non-ASD children. Behaviours associated with Attention Deficit Hyperactivity Disorder were seen in 30.7% of the children in this study and this appeared to be related to structural abnormalities on imaging, however due to the limited group number the significance of this finding could not be investigated. The ERP study was designed to look at the neural correlates of facial emotion and eye gaze perception. By comparing the neural activation in response to these social stimuli in our epilepsy participants and an age-matched group of typically developing children and a younger control group, we could identify differences in face processing and at what stage of the perceptual and cognitive process these occurred. The epilepsy group appeared to have certain delays in the processing of emotional face information and this is proposed to stem from disruption to the neural circuits underlying the subcortical face processing system in these children.