PROJECT SUMMARY / ABSTRACT: Children with neurodevelopmental disorders (NDDs) typically have severe deficits in domains of daily functioning like communication, which families consistently list as one of their top clinical priorities. However, existing clinical outcome assessments (COAs) have major limitations, including the inability to discriminate among individuals with low communication ability and/or are primarily nonverbal. Further, there are no current caregiver-reported measures designed for clinical trials that have high quality validity evidence for individuals with NDDs. To address this critical need, our team designed the Observer-Reported Communication Ability (ORCA) measure to assess expressive, receptive, and pragmatic forms of communication, regardless of the modalities used by a child (e.g., vocalizations, gestures, assistive devices). Qualitative and quantitative evidence support its validity for individuals with Angelman syndrome, and excitingly, the ORCA is likely to be generalizable to other NDD populations. This proposed study will allow us to use rigorous development methods to expand the ORCA measure to a broad range of NDD populations and, using existing COAs, provide investigators with a comprehensive set of tools to evaluate changes in communication ability in NDD populations in pediatric clinical trials. Our study team includes experts in COA development, communication, clinical trials, and neuropsychology. Importantly, the team also includes a Stakeholder Engagement Group (SEG) consisting of 16 leaders in the field; 12 parents/patient advocates and 4 clinicians who will provide access to 13 distinct NDD populations for the studies planned in this proposal. An External Technical Advisory Committee (ETAC) will provide additional guidance and consists of clinicians, methodologists, speech-language pathologists, industry experts, and patient advocates. In the 2-year UG3 planning phase, we will conduct qualitative interviews with 8-12 parents for each of our 13 NDDs and with 8-12 communication experts to identify the core concepts of communication for each of the NDDs (Aim 1). We will use the results from the qualitative interviews and data collected in seven ongoing natural history studies to develop targeted plans for the UH3 implementation phase to expand and validate the ORCA measure for each of the 13 NDDs (Aim 2). In the 3-year UH3 phase, we will expand the ORCA measure and conduct, as needed, additional qualitative interviews and longitudinal quantitative studies to evaluate the reliability, validity and responsiveness of the ORCA measure alongside other communication COAs (Aim 3). Finally, we will have approximately 1500 caregivers of typically developing children from birth to <6 years of age complete the expanded ORCA measure twice (6-months apart) to estimate age-based norm scores and examine responsiveness of the ORCA measure over time. With constant feedback from the SEG and the ETAC, we will provide an expand...