An investigation of the haemodynamic response and specific factors that impact intervention outcomes for young children on the autism spectrum

Abstract

Autism spectrum disorder is a neurodevelopmental disorder where symptoms are often noticeable in infancy and continue across the life span. It is well established that children on the autism spectrum who receive early intervention have better social and communication outcomes. However, it is less known what factors might impact these outcomes. Moreover, while individuals on the autism spectrum show decreased brain activity in parts of the social brain network compared to typically developed individuals, less is known about how this decrease impacts social and communication outcomes. This thesis aimed to investigate the factors that impact intervention outcomes. Furthermore, the thesis aimed to examine differences in haemodynamic response amongst children on the autism spectrum and typically developing children using fNIRS. Study one examined the impact of factors such as age, intensity and duration of intervention on intervention outcomes using the ESDM. The study utilised standardised measures that assessed adaptive behaviours, social and communication skills, fine motor and domestic skills. The findings showed that younger age at enrolment and a longer duration of intervention were associated with improvements in specific outcomes in language and communication skills. Study two examined variations in initial language abilities of children on the autism spectrum, and how this impacts intervention outcomes. Utilising the same clinical measures, the study showed that differences in initial verbal ability had an impact on specific outcomes after children received the ESDM. Our results suggest that better initial verbal abilities might increase outcomes in language related areas. Study three explores the relationship between patterns of connectivity in parts of the social brain network and subsequent clinical presentations in measures focusing on social skills. The findings suggest that children on the autism spectrum have a different pattern of haemodynamic activity compared to typically developing children during social and non-social tasks. The findings also indicate that social and communication measures are related to haemodynamic outcomes within and between groups. Together, this thesis provides important implications for future clinical practice and research by expanding our understanding of the factors that impact intervention outcomes and how children on the autism spectrum might be processing social information