Over a 5 year period infant and baby siblings of children with autism spectrum disorders (ASD) will be recruited to this study and will be randomized into 2 groups. Parents of the intervention group will receive 12 weeks of coaching in how to implement this intervention. Parents randomized to the control group will not receive intervention coaching. Both groups will attend a series of clinic appointments for data collection that occur at 3 month intervals over a 9 month period.

This two-site randomized controlled trail (RCT) will include a sample of 80 siblings of children with ASD (Sibs-ASD) (11 months, 15 days to 18 months, 15 days) who are stratified on initial cumulative-risk status for communication disorder and then randomly assigned to Ingersoll's Improving Parents As Communication Teachers (ImPACT; Ingersoll & Dvortcsak, 2010) treatment or to a business-as-usual (BAU) control condition. The following hypotheses will be tested:

1. Compared to the BAU Control, children assigned to the ImPACT group will show (a) more growth on pivotal skills and language level, and (b) a lesser degree of ASD symptomatology and language delay.
2. Pretreatment, cumulative-risk level will statistically interact with (i.e., moderate) treatment assignment to predict children's (a) change in pivotal skills and language, and (b) severity of autism symptoms and language delay.
3. Compared to the BAU Control, parents in ImPACT will have more optimal parenting stress and parenting efficacy, at least in parents with average or below average depressive symptoms prior to treatment (i.e., depressive symptoms will moderate the effect of ImPACT on parental stress and parenting efficacy).
4. The effect that ImPACT has on growth of pivotal skills and language will be mediated by parents' frequency and fidelity of use of ImPACT strategies at immediate post-treatment.
5. The effect of ImPACT on degree of children's language delay and ASD symptomatology at 6 months post-treatment will be mediated by their pivotal skill level at 3 months post-treatment.

Inclusion Criteria:

Younger sibling of a child with ASD -

1. Age: 11 months, 15 days to 18 months, 15 days
2. Older biological sibling: Must have a diagnosis of Autism from UW or VU, which is confirmed via record review. If the older sibling was not diagnosed at UW or VU, then a diagnostic appointment must be made for the older sibling at the corresponding institution in order to confirm the diagnosis of ASD. Half-siblings are ok.
3. Vision - WNL corrected
4. Hearing - WNL corrected
5. Motor: The child must be able to sit independently while picking up objects and giving them to another person.

Exclusions:

No primary motor impairment. No feeding tubes. No other neurological or genetic conditions. Primary language exposure: The primary parent speak to the child using English 50% of the time, and process.

The assessors and coders are blind to treatment assignment. This will be achieved by using different people to conduct the treatment vs assessment and coding. Additionally, these different staff members have offices on different floors.