Parent fidelity mediates the effect of Project ImPACT on vocal complexity

Area of Science:

• Developmental Psychology
• Clinical Psychology
• Speech-Language Pathology

Background:

• Younger siblings of autistic children have a high likelihood of developmental delays.
• Vocal complexity is a key indicator of communication maturity and predicts language outcomes.
• Parent-mediated interventions can support early social communication development.

Purpose of the Study:

• To examine if parent intervention fidelity mediated the effects of Project ImPACT on parent verbal responsiveness and child vocal complexity.
• To assess the impact of a naturalistic developmental behavioral intervention (NDBI) on early communication skills in high-likelihood siblings.
• To understand the mechanisms through which Project ImPACT influences social communication outcomes.

Main Methods:

• A randomized controlled trial comparing Project ImPACT (a 12-week parent-mediated NDBI) to usual care.
• Participants included 54 high-likelihood (HL) child-parent dyads with children aged 12-24 months.
• Intervention fidelity, parent verbal responsiveness, and child vocal complexity were measured post-intervention and at 3-month follow-up.

Main Results:

• Project ImPACT significantly improved parents' verbal responsiveness and children's vocal complexity.
• Parental intervention fidelity to Project ImPACT mediated these improvements.
• The intervention's positive effects were linked to enhanced quality and frequency of strategy use by parents.

Conclusions:

• Project ImPACT effectively enhances early social communication in high-likelihood siblings by improving parent-child interaction strategies.
• Parental engagement and fidelity to NDBIs are crucial for positive developmental outcomes.
• This study highlights the potential of parent-mediated interventions for supporting children at risk for developmental delays.