Early Intervention and Its Effects on the Development of Infant Siblings of Children with Autism

Background:  Early intervention can scaffold improvement in abilities of autistic children (Rogers, 1996).  Improvements following intervention led to an assertion that intervention can help children “recover” from autism (Lovaas, 1987).  Stability of diagnosis within the first two years of life may be low in high-risk populations (Ozonoff et al., 2011). Some infant siblings meet criteria for autism early in development, but no longer meet criteria later, though infant characteristics seemingly do not predict such change (Kleinman et al., 2008; Sutera et al., 2007). Only one study has examined the interventions infant siblings receive (Regehr & Feldman, 2009) and none has examined the impact of intervention on their development.

Objectives:  1) Determine whether infant siblings who met criteria for ASD on the ADOS by 24 months, but not at 36 months, received more intervention than infants who met criteria at 36 months, and those who never met criteria.  2) Determine whether early intervention yields increases in scores on the Mullen Scales of Early Learning (MSEL) in infant siblings.

Methods:  Twenty low-risk infants (LR) and 57 high-risk infant siblings (HR) were assessed at 6, 12, 18, 24, and 36 months.  At each time point, parents were interviewed about therapy and enrichment activities (e.g., “Mommy and Me”) their child participated in since the previous assessment.  Intensity of therapy and enrichment activities was calculated by multiplying total hours of participation by the teacher/child ratio.  The MSEL were administered at each assessment.  Administration of the ADOS began at 18 months.  Infants who met criteria for ASD on the ADOS at 18 or 24 months, but not 36 months, were classified as “false-positive” (FP). Four LR and 4 HR infants were classified as FP.  One LR and 8 HR infants were classified as “ASD” at 36 months.  The remaining 45 infant siblings were classified as “HR-Non-ASD”.

Variables for intensity of therapy and enrichment activities, as well as change in MSEL scores, were calculated from 6 to 18 months and from 18 to 36 months.  Gender, income, and outcome grouping (LR, HR-Non-ASD, FP, ASD) were entered into all univariate analyses.

Results:  ASD infants received more therapy, but not more enrichment, than FP, HR-Non-ASD, and LR infants from 18 to 36 months (p<.001).  There were no such group differences from 6 to 18 months.

From 6 to 18 months: No effects of intervention on change in MSEL scores were apparent. From 18 to 36 months: Therapy predicted change in Receptive Language scores(p=.006).  Therapy (p<.001) and outcome grouping (p<.001) predicted change in Expressive Language scores.  Enrichment (p=.016) predicted change in Fine Motor scores. There were no relationships between intervention and change in Visual Reception scores.

Conclusions:  While early therapy scaffolds the linguistic development of infant siblings, it does not appear to help infants move off the spectrum by 36 months of age.  Infants who met criteria for ASD at 36 months received more intervention than “False-Positive” infants and infants who never met criteria for ASD.  Infants later diagnosed with autism are being targeted early for intervention.  Therapy and enrichment activities differentially improve developmental trajectories.