Drugs are in development to treat core symptoms of fragile X syndrome (FXS), Down syndrome (DS), and other conditions associated with intellectual disability. Condition-specific behavioral interventions are also being developed. Evaluation of the efficacy of these pharmaceutical and behavioral interventions, however, is being hampered by a lack of psychometrically sound outcome measures. In this presentation, we will outline the requirements for an adequate outcome measure and present the results from two ongoing multi-university consortium projects designed to adapt and evaluate the adequacy of two potential sets of outcome measures, one derived from a broad-based system for assessing cognition (NIH Toolbox Cognitive Battery – NIHTB-CB) and the second a system for assessing language (Expressive Language Sampling -- ELS).
For the project focused on the NIHTB-CB (“A Cognitive Test Battery for Intellectual Disabilities”), results will be presented from a longitudinal study of individuals with FXS, DS, and other IDDs (ages 6-25), examining the reliability, validity, feasibility and sensitivity (to group differences and growth over time) of tests tapping executive function (attention, cognitive flexibility), working memory, processing speed, episodic memory and language. The steps and process by which this work has led to the integration of the NIHTB-CB to several ongoing Phase 2 or 3 clinical trials will be described, including the processes and challenges associated with seeking outcome measure registration with the FDA. Finally, there will be a sneak peek at new cognitive tests being developed by the team targeting numeracy, inhibitory control and concept formation.
For the project on ELS, data will be presented for two standardized procedures for eliciting language samples -- conversation with an examiner and narration of a wordless picture book to an examiner – and two groups of participants – 6- to 23-year-olds diagnosed with either FXS or DS.