Abstract
This thesis describes the impact of neonatal hypoxic ischaemic encephalopathy (HIE) on child development during the early years of life and evaluates the relationship between developmental outcome measures at two different time-points in children who suffered moderate-severe HIE.Background: Child development is a complex process influenced by both biological and socio-environmental factors. Sequela from hypoxic-ischemic-encephalopathy (HIE) is a leading cause of disability in term born infants. Accurate measurement of developmental outcomes is an essential component of intervention studies and neonatal follow-up. The utility of various developmental outcome measures is reviewed. Developmental outcomes at 18 months and 3:0-5:11 years following HIE is described with evaluation of relationships between measures at two time periods.
Methods: A prospective longitudinal design was used, utilising existing developmental outcome data from intervention groups of the CoolXenon randomised control trial. From 82 term-born infants with moderate-severe HIE 74 survivors completed Bayley Scales of Infant and Toddler Development III (Bayley III) at 18 months and Weschler Preschool and Primary Scale of Intelligence IV and Movement Assessment Battery for Children 2 at 3:0-5:11 years. Six with severe disability were re-tested with Bayley III at 3:0-5:11 years. Maternal education and Indices of deprivation were collected.
Results: Sixty-one children completed testing at both time-periods. A range of developmental outcomes were observable with deficits in cognition, motor, and language skills evident at both time points. Fifty-five children completed age adjusted testing at both time points. Moderate-strong correlations were observed between assessment at 18 months and 3:0-5:11 years; cognition Tb=.419, p<0.001, language Tb=.371, p><0.001, motor Tb=.264, p<0.05. Regression modelling identified significant predictors of full scale intelligence quotient (FSIQ) were Bayley III motor, Bayley III cognition, exact 3:0-5:11year test-age, and maternal education (R2 =.657, p<0.05). Test-age predicted a 5.7-point decrease in FSIQ each year. Gender and deprivation index were not significant predictors. Six with severe disability, showed little change in Bayley III raw scores between time points, corresponding to similar developmental levels Tb=0.50-0.828. Gross Motor Function Classification Scores were unchanged.
Conclusion: Developmental assessments demonstrated a range of developmental outcome for children following HIE in this cohort. Bayley III at 18 months had good outcome prediction in all domains. Significant impairment in cognition and motor skills evident at 18 months is likely to persist into childhood. In those without the most significant impairments age at testing strongly influenced the results. However, gender and deprivation score did not. More complex cognitive impairments may not become evident until school age. Future prospective studies should ideally measure developmental outcome in children at the same age.
| Date of Award | 24 Jan 2023 |
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| Original language | English |
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| Supervisor | Marianne Thoresen (Supervisor) & Sally L Jary (Supervisor) |