Convergent validity of the Mullen Scales of Early Learning and the differential ability scales in children with autism spectrum disorders.

Despite widespread use of the Mullen Scales of Early Learning (MSEL; E. M. Mullen, 1995 ) as a cognitive test for children with autism spectrum disorders and other developmental disabilities, the instrument has not been independently validated for use in these populations. Convergent validity of the MSEL and the Differential Ability Scales (DAS; C. D. Elliott, 1990 , 2007 ) was examined in 53 children with autism spectrum disorder and 19 children with nonspectrum diagnoses. Results showed good convergent validity with respect to nonverbal IQ (NVIQ), verbal IQ (VIQ), and NVIQ-VIQ profiles. These findings provide preliminary support for the practice of using MSEL age-equivalents to generate NVIQ and VIQ scores. Establishing convergent validity of cognitive tests is needed before IQs derived from different tests can be conceptualized as a uniform construct.

The Autism Diagnostic Observation Schedule-toddler module: a new module of a standardized diagnostic measure for autism spectrum disorders.

The Autism Diagnostic Observation Schedule (ADOS; Lord et al., J Autism Dev Disord, 30(3):205-223, 2000) is widely accepted as a "gold standard" diagnostic instrument, but it is of restricted utility with very young children. The purpose of the current project was to modify the ADOS for use in children under 30 months of age. A modified ADOS, the ADOS Toddler Module (or Module T), was used in 360 evaluations. Participants included 182 children with best estimate diagnoses of ASD, non-spectrum developmental delay or typical development. A final set of protocol and algorithm items was selected based on their ability to discriminate the diagnostic groups. The traditional algorithm "cutoffs" approach yielded high sensitivity and specificity, and a new range of concern approach was proposed.