Poster #45 - Emerging Language Comprehension in Toddlers with Significant Developmental Delays: An Item Response Theory Approach

• In Event: 3-159 - Poster Session 12
  In Poster Session: PS 12 Section - Developmental Disabilities

Integrative Statement

Introduction: Language comprehension is critical to a variety of child outcomes. Effective intervention for delayed language comprehension depends on valid, reliable assessment to determine the intensity and techniques that are appropriate for a child. However, assessment of children with developmental delays can be challenging due to comorbid impairments and child difficulty tolerating long assessments. The purpose of this study was to investigate the psychometric properties of several measures of language comprehension in a sample of toddlers with developmental delays using item response theory (IRT) methods. We sought to 1) evaluate the psychometric properties of the measures, 2) determine the appropriateness of the measures for the sample, and 3) examine the relative difficulty of items and the development of comprehension over time.

Methods: The sample consisted of 113 toddlers, ages 24-36 months, with significant developmental delays, which were operationally defined as parent report of fewer than 10 intelligible spoken words and having an age-equivalent score of less than 12 months on the Expressive Language scale of the Mullen Scales of Early Learning (MSEL), who participated in two early language intervention studies. Etiologies of developmental delays included Down syndrome, preterm birth, cerebral palsy, and other conditions. Language comprehension measures included the MSEL, Vineland Adaptive Behavior Scales (Second Edition) (VABS (II)), Clinical Assessment of Language Comprehension (CALC), Sequenced Inventory of Communication Development-Revised (SICD-R), MacArthur-Bates Communicative Development Inventories (CDI), and Peabody Picture Vocabulary Test- Third Edition (Fourth Edition) (PPVT-III (IV)). We used Winsteps to conduct IRT analyses.

Results: In terms of psychometric properties, we found that the aggregate data fit the Rasch model, though each measure also contained items with poor fit (e.g., response to “no”). Additionally, there was some evidence of multidimensionality and local dependence in the data. In terms of measure appropriateness, analyses of the correspondence between item difficulties and participant abilities supported the appropriateness of the measures for our sample, and indicated acceptable measurement precision for most participants. In terms of relative item difficulty, examination of item parameters revealed patterns that were largely consistent with the literature on typically developing children, with a few exceptions (e.g. response to child’s own name was more difficult in our sample). In terms of change over time, investigation of items showing the highest proportions of pre to post intervention improvement indicated that parent-report items of moderate difficulty were most likely to improve.

Discussion: Our findings inform measure development by emphasizing the benefits of integrating IRT methods in order to maximize both measurement precision and testing efficiency. They also add to knowledge about language comprehension development in atypical populations by highlighting a few specific skills that were more difficult for children in our sample than anticipated based on normative data. Finally, they inform clinical practice and research by underscoring the strengths and limitations of currently available measures. Broadly, our impressions support the importance of a multi-method approach in assessment in order to gain a comprehensive and accurate understanding of a child’s language comprehension profile. Limitations include the sample size, which was relatively small among IRT studies.

Authors

• Evelyn L. Fisher, Georgia State University
  Presenting Author

• rose ann sevcik, Georgia state university
  Non-Presenting Author

• MaryAnn Romski, Georgia State University
  Non-Presenting Author