Predictive validity of the factor structure of the Childhood Autism Rating Scale

The purpose of this study was to examine the relations between individual differences in symptom presentation and developmental outcome for young children with autism. Individual differences in symptom presentation were measured with Childhood Autism Rating Scale (CARS). Factor-based scale scores were derived from the CARS ratings of two distinct and independent samples of children with autism: a higher functioning and a lower functioning group. The factor based scales reflected five symptom dimensions: Social Orienting, Social Communication, Emotional Reactivity, Cognitive and Behavioral Consistency, and Odd Sensory Exploration. These measures had been derive from previous factor analytic research on the measurement domains of the CARS (Stella, Mundy, & Tuchman, 2000). The goals of the study were to: (1) examine the stability of CARS factor symptom scales, (2) examine the relations between CARS social symptoms and the potentially related domain of joint attention development, and (3) examine the degree to which initial social symptom status is related to subsequent development on measures of IQ, language, and symbolic play.As expected, children in both groups displayed positive change over time with respect to symptom presentation in that both total CARS and CARS factor scores indicative of behavior problems significantly decreased over a one-year period. Additional observations indicated that significant associations were observed between CARS social symptoms and joint attention skills. Moreover, CARS social symptoms and joint attention were associated with developmental outcome for children in both groups and these variables were related to some aspects of outcome above and beyond variance in language development for the high functioning sample. Finally, an unexpected finding was that the only symptom dimension the higher and lower groups differed on was the Social Orienting factor score of the CARS. These results provide additional support for the potential utility of new factor based scoring of the CARS. They also suggest the dimension of social orienting may be important to consider in understanding developmental differences between higher and lower functioning children with autism