Project ImPACT Reduces Social Hyporesponsiveness and Translates to More Optimal Expressive Language Outcomes in Some Infants at Increased Likelihood of Autism.

In 30 seconds

This randomized controlled trial tested whether Project ImPACT, a caregiver-implemented naturalistic developmental behavioral intervention, could improve later expressive language in infant siblings of autistic children by reducing social hyporesponsiveness. Infants were assigned to 12 weeks of Project ImPACT or a control group. Social hyporesponsiveness was assessed immediately after intervention, and expressive language three months later. The intervention had an indirect association with expressive language outcomes through reduced social hyporesponsiveness, but this finding was limited to infants whose caregivers had high education levels at study entry.

Key findings

• Project ImPACT indirectly influenced later expressive language through social hyporesponsiveness, but only among infants whose caregivers had high education levels at study entry.
• The trial assigned 23 infants to Project ImPACT and 23 to a non-Project ImPACT control group.

Why it matters

The findings suggest that social responsiveness may be a pathway linking early caregiver-mediated intervention with later expressive language in infants at increased likelihood of autism. The education-related difference also indicates that intervention outcomes may vary across families, an important consideration when interpreting results and evaluating how early interventions work.

What to keep in mind

The reported indirect effect was limited to infants whose caregivers had high education levels at study entry, so the result may not generalize across caregiver education levels.