Exploring Autism Spectrum Disorders: Parental Experiences of Diagnosis and the Behavioural Heterogeneity within the Spectrum

This thesis contains a systematic literature review, and an exploratory research study.
Studies exploring how parents had experienced the process of seeking an autism spectrum disorder (ASD) diagnosis for their child were reviewed (N=28). These indicated that many parents have dissatisfying experiences due to delays, disrespectful interactions with professionals, and a paucity of information. There are issues surrounding clear clinical pathways and communication between services which cause delays in diagnosis and accessing subsequent services.
The research study explored the heterogeneity of behavioural presentations in ASD. Participants were 42 children aged 5 to 17 (25 with ASD and 17 typically developing). Participants contributed demographic, behavioural, cognitive, and neurological data which were explored through cluster and descriptive statistical analyses. The three emergent clusters were strongly influenced by cognitive ability, but also demonstrated a continuum of behavioural presentations and physical and developmental health, with one cluster representing a typically developing group, one representing high-functioning ASD, and one representing low functioning ASD. In contrast to previous research, there were no associations with alpha frontal power recorded with EEG. The social subtypes of ASD identified by Wing and Gould (1979) were strongly correlated with cognitive ability and severity of symptoms.
Overall this research indicates the need to continue improving the diagnosis of ASD. The heterogeneity in symptoms of ASD could be one reason why the diagnostic process is long and complex, and should be explored further. Future research should consider cognitive and behavioural