Project Summary Caregivers of children with autism spectrum disorders often recall differences in their children as early as infancy, despite most children with autism being diagnosed after age 3. Caregiver recall of behavioral differences in infancy indicates that there is more to learn from the earliest developmental periods of children later diagnosed with autism that could ultimately contribute to earlier screening and earlier interventions. Understanding the prodromal period could identify sources of heterogeneity in autism phenotypes, such as social communication deficits and delayed language, which are highly variable and predictive of long-term outcomes in the autism population. Investigating emerging communication processes is an important domain to focus on in early development. Infant cries are part of the earliest communicative exchanges for humans. Cry characteristics impact caregiver perceptions and responses to their infants and thus may impact early communication development. Differences in cry acoustics associated with later autism diagnoses have been observed as early as 6 months, and caregivers have perceived autism-related differences in cries from infants as young as 1-month of age. These findings support cry acoustics as an early risk marker of autism. Aim 1 will replicate and extend the association between caregiver cry perception and autism outcomes to aid in identification of the objective acoustic features driving the perceptual differences , requiring collection of new caregiver ratings of cries from an existing library. Aim 2 will consist of detailed analysis of existing daylong recordings to capture a phenotype of social contingency development through analysis of caregiver- infant turn-taking involving cry over the first 12 months of life. The project will utilize recordings collected at 1, 3, 6, 9, and 12 months in children with and without autism. In addressing these aims and preparing for a career as an independent investigator, the PI will be trained in three primary areas: 1) the autism spectrum disorder phenotype and clinical knowledge, 2) measurement and data analysis relevant to prospective longitudinal studies of developmental disorders and developmental trajectory phenotypes, and 3) professional development, especially focused on training in grant writing and presenting research to multiple academic disciplines and stakeholders. The research projects and training plan leverage the sponsor and co-sponsor’s existing data (cry recordings and daylong recordings collected longitudinally), expertise in autism and infant cry (sponsor) and statistical analysis (co-sponsor), experience in training and mentoring (sponsor and co-sponsor), and the PIs strong foundation of research experience and commitment to multi- disciplinary research of atypical language acquisition.

PROJECT NARRATIVE Individuals with autism spectrum disorders have persistent deficits in social communication, but prospective studies indicate disruptions in communication are difficult to detect in early infancy. Infants initiate their first social interactions through cry and previous research supports cry acoustics as an early marker of autism. The proposed study utilizes existing longitudinal data to replicate and extend prior findings of caregiver perception differences of cries from infants later diagnosed with autism and investigate patterns of caregiver- infant interactions involving cry to advance understanding of early social communication development in infants with and without autism.