Predictors of Improved Adaptive Skills in Children with Autism Spectrum Disorder
Although different modalities and intensity of early intervention services for Autism Spectrum Disorder (ASD) have been well studied, research on other modifiable variables prior to early intervention is limited. In Singapore, regular, long-term early intervention is provided for children with suspected ASD and other developmental disabilities from ages 0 to 7.
The aim of this study was to identify specific modifiable factors prior to early intervention and socioeconomic (SES) factors that are predictors of better outcome in children with ASD.
Consecutive patients with ASD aged 5-year, 0-month to 7-year, 11-month were recruited from a tertiary developmental program in Singapore from August 2016 to July 2018. ASD diagnosis required a psychologist administered Autism Diagnostic Observation Schedule (ADOS) and an Autism Diagnostic Interview- Revised (ADI-R) with consistent clinical history and behavioural observations. The consent rate was 86.3% (N=199). Exclusion criteria were 1. Vision or hearing loss; 2. Significant neurological co-morbidity (cerebral palsy, epilepsy); and 3. Children with genetic syndromes. Parents of these children provided information on demographics, SES indicators and early intervention details (such as wait time and intensity). The primary outcome was the Vineland Adaptive Behaviour Scales (VABS) Adaptive Behaviour Composite (ABC) score completed by a psychologist. Descriptive statistics were used to analyse family SES and early intervention factors. Using adaptive skills as the outcome, linear regression models were applied to determine significant correlates; specifically on variables prior to early intervention.
The sample consisted of 84.0% males, with a racial distribution similar to that of Singapore’s general population (Chinese 67.7%, Malay 18.7% and Indians 4.5%). Mean age of the subjects was 6 years and 3 months (74.4 months, SD 13.1). Mean age at ASD diagnosis was 3 years and 5 months (41.4 months, SD 9.3). Mean VABS ABC standard score (mean 100, SD 15) was 77.8 (SD 15.9). Mean wait time for regular early intervention was 6.3 months (SD 3.0) and mean intensity of early intervention was 8.1 hours/week (SD 4.1). Linear regression showed that wait time for early intervention services was a strong predictor of the VABS ABC score after controlling for other child and parent variables (β=-1.14, p=0.03). Significant covariates also included maternal education (β= 5.39, p=0.04) and total score on the ADOS (β=-1.93, p=0.01).
Wait time for early intervention services is a modifiable risk factor that can predict outcomes in children with ASD. When planning for early intervention services for these children, factors that reduce wait time should be a priority. Children from families with lower maternal education are at risk for poorer outcomes; hence ensuring an appropriate intervention plan for these children is of crucial importance.