Measurement, Stability, and Modification of Prelinguistic Symptoms of Autism in Low-Risk Infants

Background:  

The development of early screeners for symptoms of autism in infancy has experienced a surge in recent years (Bryson, et al., 2007; Pierce et al., 2011; Zwaigenbaum, 2010).  These screeners, however, do not directly address the stability of these symptomatic patterns in early infancy.  Due to the rapidity of development in the first year of life and the implications of early brain plasticity, rigorous measurement of the stability of early signs of autism is paramount.  Consequentially, the identification of infants exhibiting stable early signs of ASD urgently necessitates the investigation of early behavior modification programs for infants less than 18 months of age.  Preliminary studies in our lab show that the use of motivational components of Pivotal Response Treatment (PRT) with infants as young as four months of age exhibiting weaknesses in social engagement can be effective in increasing affect, interaction, orienting to name, and eye contact (Koegel et al., under review). 

Objectives:  

The current study seeks to replicate previous studies measuring early markers of autism, assess whether these early behavior patterns show stability, and examine whether these behaviors can be efficiently and effectively modified.

Methods:  

Fifteen infants were assessed for pre-linguistic signs of autism using parent-report and clinician-observation (Wetherby et al., 2008; Bryson et al., 2008).  Two of these infants exhibited delays in communication and two presented with a lack of interest in social engagement.  A treatment program designed to increase social communication was offered to infants exhibiting delays in both communication and social domains.  The naturalistic treatment involved contingent and natural reinforcement of any communicative behavior.  Treatment occurred three hours a week for six weeks, followed by one hour a week of parent-education for the last six weeks to promote maintenance of gains.  Data from one representative infant is presented here to illustrate the pattern of findings. 

Results:

Baseline observations for one 12-month old infant, showed several early signs of ASD, suggesting that autism symptomology can be measured in infancy.  Additionally, these early signs, including atypical eye contact, no vocalizations, and lack of social engagement, were found to be stable across a one month baseline period.  Despite stability, steady and considerable increases were made in the frequency of vocalizations upon the implementation of treatment.  Further, collateral gains were observed in the area of social engagement with increased positive affect and non-toy play with both the therapist and caregiver.  These gains generalized to the caregiver prior to the implementation of parent-education.

Conclusions:  

The findings from this study lend support for the measurement and stability of early social weaknesses in infancy.  Additionally, the use of a Pivotal Response Treatment for improving early behaviors consistent with ASD, such as low social engagement and vocalizations, is effective.  Taken together, these results suggest optimism in the area of early identification and intervention.  As more infants exhibiting early signs of ASD are identified, empirically-supported methods of measurement and treatment for infants are critical.  Further research with a large sample of infants exhibiting early signs of ASD is warranted.