PROJECT SUMMARY For infants, mobility is a primary driver for exploration, communication, and interaction with caregivers that support learning and general development. From early in life, infants with DS exhibit developmental delays across these domains. There is widespread agreement that cost effective, caregiver-implemented early interventions during infancy are needed to address these delays. A candidate approach to such an intervention involves body weight supported harness systems that allow infants to move freely at a time when they are not yet independently mobile. Harness systems have been widely used in children of all ages with mobility impairments but have not been systematically studied in DS. Movement and mobility support infant participation in the everyday interactions with objects and people in their homes that are foundational for early learning. Early motor delays and mobility challenges represent an obstacle to participation in these key contexts for infants with DS. The proposed work will set the stage for the first clinical trial of a home-based mobility-related intervention specifically tailored for infants with DS by developing and refining procedures for collecting data longitudinally in the home. Aim 1 is to examine the feasibility and acceptability of the harness system, longitudinal study visit schedule, data collection methods (in person vs. virtual), and in-home standardized assessment procedures for infants with DS and their families. To achieve this aim, we will implement a detailed survey focused on assessing caregiver attitudes toward the harness system and study participation, gather data on study enrollment, retention, the effectiveness of in-person and virtual methods of data collection, rates of data completion, and home administration of standardized measures. Aim 2 is to identify observational variables best suited to serve as primary outcome measures in future clinical trials evaluating the effectiveness of the harness intervention for infants with DS. To achieve this aim, we will gather observational data on infant posture and locomotion, object exploration, communication, and caregiver-infant joint object engagement during everyday play at home. Both aims will be addressed through a longitudinal study of 15 infants with DS and their caregivers carried out over a 6-month period, during which we will document the natural history of these behaviors and examine their relations with INCLUDE DCC-recommended standardized assessments of development, social communication, and language. This approach, based on our team’s previous work, will allow us to design a home-based body weight supported harness intervention whose effectiveness can be evaluated in a subsequent clinical trial. Home-based intervention will enhance accessibility to intervention research for families who face barriers to laboratory-based research participation and thereby increase sample diversity and representation. Upon completion of this project, we will have developed the feasible and acceptable procedures for harness system setup, longitudinal in-home data collection, and assessment administration with infants with DS and their families necessary to conduct a future high-impact phase 1 clinical trial.

PROJECT NARRATIVE The emergence of crawling and walking is significantly delayed in infants with Down syndrome (DS), but the development of independent mobility provides infants with new opportunities for exploring the environment and interacting with objects and people that are important foundations for early learning. Increasing infant mobility early in development with body weight supported harness systems may support infant exploration, communication, and social interaction. This project will set the stage for the first clinical trial of a mobility-related intervention specifically tailored for infants with DS by developing and refining procedures for collecting data longitudinally in the home, allowing us to deliver a home-based intervention that will be accessible to all families with infants with DS.