Examining Factors Related to Outcome in Autism Spectrum Disorders

Abstract

Early, comprehensive, behavioural treatments substantially improve outcomes in up to 50% of children with autism spectrum disorders (ASD) while the remainder respond less optimally (Howlin et al., 2009). Understanding this variable treatment response is a priority. Attempts to understand this variability have examined global factors (e.g., IQ, language, age and symptom severity) and their relationship to particular outcomes (e.g., IQ changes; Howlin et al., 2009). The current dissertation adds to a growing body of literature (e.g., Sherer & Schreibman, 2005) moving beyond these immutable factors to examine empirically- and theoretically-determined child characteristics (i.e., toy contact, approach, avoidance, stereotyped and repetitive vocalizations and non-verbal behaviours and affect) hypothesized to predict intervention outcomes for children with ASD. The objective of the current dissertation is to examine the relationship between the six child characteristics at the start of intervention and 12-month language/communication changes for children with ASD enrolled in the Nova Scotia Early Intensive Behavioural Intervention (NS EIBI) program (Bryson et al., 2007). The program is based on Pivotal Response Treatment (Koegel & Koegel, 2006). Study 1 examined 27 children with ASD [mean age = 51.26 months (SD = 9.63); mean cognitive age equivalent = 26.89 months (SD = 9.66)]. Child characteristics were coded from baseline video of the children and therapists during home play interactions. Results indicated that younger baseline age and positive child affect at the start of intervention were related to greater 12-month changes in expressive language. Study 2 examined 39 children with ASD [mean age = 46.95 months (SD = 8.10); mean cognitive age equivalent = 25.03 months (SD = 10.30)]. Child characteristics were coded from baseline video of a standard play task administered by trained research assistants. Results indicated that lower levels of baseline appropriate toy contact and avoidance were related to greater 12-month changes in expressive language. A non-significant trend for positive child affect to be related to greater 12-month changes in expressive language was also found. Results are interpreted in the context of the differences across the two studies and in relation to previous ASD intervention research examining predictors of outcome.