Intensive Intervention for Toddlers With Autism (EARLY STEPS)

Composite language measure consisting of an average of the Expressive Language and the Receptive Language age equivalent scores from the Mullen Scales of Early Learning.The Mullen Scales of Early Learning (MSEL) is a developmental test with five subscales: gross motor, visual reception, fine motor, receptive language, and expressive language. The lower the score on this scale, the more immature the ability; the higher the score, the more mature the ability. Measurements were taken at baseline, 6 months, 12 months, and 24 months and a hierarchical longitudinal growth curve approach used to calculate overall rate of growth during the 24 month period.

Overall DQ was calculated by averaging the Time 1 (baseline) age equivalence scores of the two language and two nonverbal subtests from the Mullen Scales of Early Learning (MSEL), dividing by child age in months, and multiplying by 100 to create a quotient score, in order to capture the full range of variability of the sample, since many children fell below the basal standard score. The Mullen Scales of Early Learning (MSEL) is a developmental test with five subscales: gross motor, visual reception, fine motor, receptive language, and expressive language. Gross motor score was not used for the calculations. The lower the score on this scale, the more immature the ability; the higher the score, the more mature the ability. Measurements were taken at baseline, 6 months, 12 months, and 24 months and a hierarchical longitudinal growth curve approach used to calculate overall rate of growth during the 24 month period.

Adaptive behavior age equivalent was characterized by averaging the means of the age equivalents in months of the four domain scores from the Vineland Adaptive Behavior Scales - Second edition (VABS) because the manual does not provide developmental ages corresponding to total scores that could be used to construct quotient scores. Data were provided by parents who were not naïve to group assignment. The Vineland Adaptive Behavior Scales 2 provide a standardized measure of adaptive behavior in four domains: motor, language, social, and activities of daily living. Information is gathered from parents via parent questionnaire. The lower the score on each domain score and the overall score, the more immature the ability; the higher the score, the more mature the ability. Measurements were taken at baseline, 6 months, 12 months, and 24 months and a hierarchical longitudinal growth curve approach used to calculate overall rate of growth during the 24 month period.

Autism severity was calculated using the Calibrated Severity Scores, derived by using tables in publications by Gotham, Pickles, & Lord( 2012) (Esler, Bal, Guthrie, Weismer, and Lord, 2015). We identified the severity score listed in the CSS table that was associated with a subject's ADOS-2 total score for the ADOS module that was administered to each subject at each of four time points - at entry into the project, and 6 months, 12 months, and 24 months after enrollment. The ADOS Calibrated Severity Score scale range is 1-10, with lower scores representing milder and less numerous symptoms and higher scores representing more severe and more numerous systems. Scores 1-3 represent few to no ASD symptoms, scores of 4-5 represent mild to moderate symptoms and concerns related to ASD, and scores of 6-10 represent moderate to severe symptom severity.