Infant Achievements Intervention Improves Caregiver Implementation Fidelity and Infant Social Communication Outcomes: A Preliminary Randomized Clinical Trial

ABSTRACT Randomized controlled trials (RCTs) focused on idiopathic social communication delay (SCD) in the first year of life are rare. We preliminarily tested the efficacy of an 8‐week caregiver‐implemented intervention for infants with idiopathic SCD. Infants (8–12 months) with SCD were block‐randomized with caregivers to the Infant Achievements (IA) ( n = 18) or Caregiver Education (CE) ( n = 20) group in this assessor‐masked RCT. Assessments were completed at baseline, post‐intervention, and 8‐week follow‐up. IA caregivers received reflective, home‐based coaching to implement naturalistic developmental behavioral intervention (NDBI) strategies. Primary outcomes: masked ratings of caregiver implementation fidelity, frequency of infant initiation of joint attention (IJA), and percent of coordination of joint engagement (CJE). Secondary outcomes: masked researcher‐administered and scored Mullen Scales of Early Learning (MSEL) language and Visual Reception scaled scores; nonmasked caregiver‐reported Communication and Symbolic Behavior Scales Caregiver Questionnaire (CSBS CQ) Social, Speech, and Symbolic composite scores and McArthur‐Bates Communication Development Inventories Words Understood and Produced scores. Prespecified analyses followed an intent‐to‐treat approach using Generalized Linear Mixed Models for non‐normally distributed outcomes and linear mixed‐effects models for those with normal distributions. Significant group by time effects favored the IA group relative to the CE group on all primary outcomes at post‐intervention ( p 's ≤ 0.001), and for caregiver fidelity and IJA, at follow‐up (≤ 0.03). Significant IA intervention effects were detected on secondary outcomes of nonverbal cognition (MSEL Visual Reception) and CSBS CQ Speech composite at post‐intervention (< 0.01) and follow‐up (≤ 0.02). IA equips caregivers to learn and generalize the implementation of child‐responsive NDBI strategies and propels pre‐linguistic social communication advances in SCD infants. Trial Registration: ClinicalTrials.gov identifier: NCT03404505.