This project will look at Milieu Teaching (i.e., a language intervention) that encourages looking to audiovisual speech cues (Milieu Teaching-AV) for infants with autistic older siblings (Baby Sibs), who are highly likely be diagnosed with autism or developmental language disorder (DLD), compared to Milieu Teaching alone (Milieu Teaching-NoAV). This study will specifically look at whether Milieu Teaching-AV (compared to Milieu Teaching-NoAV) results in (a) increased looking towards caregivers' faces, (b) increased communicative behaviors and language skill, and (c) increased engagement with the caregiver during play. We will also look at caregiver factors, such as their use of strategies and their attitudes toward the intervention they received.

Language outcomes are highly heterogenous in autism and can impact long-term psychosocial, educational, and vocational outcomes for children on the autism spectrum. Thus, there is a pressing need to identify novel approaches to language intervention, ideally those that can be implemented in early stages of development, when brain and behavior are most plastic. Many have begun to consider "pre-emptive" interventions for infants with autistic older siblings (Baby Sibs), who are highly likely be diagnosed with autism or developmental language disorder (DLD) themselves.

I hypothesize that a targeted pre-emptive intervention that encourages Sibs-autism to look to the mouth of a speaker (i.e., by moving a referent, or the item about which an adult is talking, near the mouth) during an evidence-based intervention for language may yield more optimal language outcomes than traditional therapy alone. This strategy has already been shown to boost word learning in autistic preschoolers, at least for proximal targets (i.e., for words that were specifically taught using the strategy in a short-term training context).

This study represents a preliminary systematic test of this strategy in Sibs-autism. I will evaluate the effects of an intervention that encourages looking to audiovisual speech by moving the referent of interventionist talk near the mouth (Milieu Teaching-AV) compared to Milieu Teaching-NoAV in a total of 60 Baby Sibs within the context of a pilot randomized controlled trial (RCT). This pilot RCT will allow me to estimate effect sizes for (a) direct effects on word learning, both for trained words and broader language, (b) moderated effects (i.e., determining for whom the intervention yields optimal outcomes), and (c) mediated effects (i.e., determining the mechanisms by which the intervention works).

Inclusion Criteria:

1. chronological age of 6-12 months at study entry (±30 days);
2. an older sibling with an autism diagnosis, confirmed by a detailed developmental interview and administration of the Autism Diagnostic Observation Schedule (ADOS-2); and
3. monolingual English-speaking household.

Exclusion Criteria:

1. adverse neurological history;
2. known genetic condition;
3. pre-term birth (gestation < 37 weeks); and
4. caregiver report of a diagnosed vision impairment or hearing loss

Raw clinical data will utilize standard codes from the National Institute of Mental Health (NIMH) Data Archive format, which is utilized for National Database for Autism Research (NDAR) and National Database for Clinical Trials Related to Mental Illness (NDCT) data, whenever possible. All raw clinical data that cannot be made to meet this format will be archived in a separate Open Science Framework (OSF) database along with a data dictionary.

Qualitative data (e.g., redacted transcripts, coded redacted transcripts, and data sheets) will be uploaded to the Qualitative Data Repository (QDR; hosted by Syracuse University) as Word and Excel files, as relevant.

All clinical trial data will be uploaded when the clinical trial is complete.

Data shared in OSF with individual papers and the QDR will be shared for general use. Broader data pulls in NDAR/NDCT will require application and approval by the NIMH for data use.

Due to the nature of the behavioral intervention, we can only mask the outcomes assessor for non-caregiver report outcomes