Children were recruited for the study through local birth to age 3 special education programs. Eligible children were (1) age 24 to 42 months at intake, (2) had a mental age divided by chronological age of the Mental Development Index equal to or greater than 35, (3) neurologically within “normal” limits, and (4) diagnosed with autism by an independent child psychiatrist. The parents of all eligible children agreed to participate. Thirteen children entered the study in 1996 and 11 in 1997. Twenty-four children were matched on pretest measures of IQ and randomly assigned to the treatment or comparison condition. One child dropped out of the study, resulting in an analytic sample of 23 children (13 in the treatment group and 10 in the comparison group).
The program was based on the UCLA Lovaas Model, which initially focuses on one-on-one discrete trials and progresses from simpler to more complex skills. The therapist would engage the child in favorite activities, providing brief task instruction, such as “sit down” or making a request. Reinforcements, such as edibles or physical play, were given after each trial; in between, children were encouraged to generalize the lessons into more natural settings and develop social responsiveness. The program was intended to be 40 hours a week of direct treatment, although the averages for years 1 and 2 were 39 and 37 hours a week, respectively. The hours of treatment declined in subsequent years as the children began school. Children received 6 to 10 hours per week of in-home supervision from a senior therapist and weekly consultations with the senior author or clinic supervisor, during which the senior author/clinic supervisor observed the child and recommended appropriate changes to the program.
Children in the comparison group received a parent-directed intervention consistent with the UCLA Lovaas Model. The parents in this group selected how many weekly treatment hours their children received from the therapist, averaging 32 hours in year 1 and 31 hours in year 2, with the exception of one family that chose to have 14 hours of treatment. The children received 6 hours per month of in-home supervision from a senior therapist and consultations every two months with the senior author or clinic supervisor, during which the senior author/clinic supervisor observed the child and recommended appropriate changes to the program.
Communication/language competencies, social-emotional development and behavior, and functional abilities were assessed with the Vineland Adaptive Behavior Scales and the Autism Diagnostic Interview–Revised. Functional abilities also were assessed with the Vineland Adaptive Behavior Scales. For a more detailed description of these outcome measures, see Appendices A2.2–A2.4.
Support for implementation
Therapists had completed at least one year of college and attended 30 hours of training, at least 10 of which were one-on-one training and feedback while working with their assigned child. Therapists attended weekly or biweekly team meetings. Senior therapists had a minimum of a four-year degree, one year of experience as a therapist with two or more children, and a 16-week internship at the UCLA facility.