Early Sensory Hyporesponsivity Predicts Later Deficits in Language Understanding in Infants at High Risk for Autism Spectrum Disorder

Background:

Individuals with autism spectrum disorder (ASD) often show atypical responses to sensory stimuli, even as early as infancy. A pattern of hyporesponsivity (characterized by absent or reduced responding to sensory stimuli) in particular seems most prevalent in, and specific to, ASD. It has been proposed that reduced responsivity to sensory stimuli early in life may produce cascading effects on higher level abilities, such as language, in individuals with ASD.  Past work has found that sensory hyporesponsivity covaries with concurrent language in preschool and school-age children with ASD. However, to date no study has evaluated whether hyporesponsivity in infancy predicts future language in younger children with ASD. A primary obstacle to this work is our inability to diagnose ASD in infancy. One way to overcome this challenge is to prospectively study infants who are known to be at high risk for ASD, such as infant siblings of children diagnosed with ASD (Sibs-ASD). 

Objectives:

This pilot project, carried out at Vanderbilt University and the University of Washington, specifically sought to determine (a) whether Sibs-ASD differed from infants with a typically developing older sibling (Sibs-TD) in early sensory hyporesponsivity and (b) whether early hyporesponsivity predicted later language, at least in Sibs-ASD.

Methods:

Sensory hyporesponsivity of 14 Sibs-ASD, as well as 18 Sibs-TD was assessed at 18 months using the Sensory Experiences Questionnaire. Receptive and expressive language was assessed at 24 months using the Vineland Adaptive Behavior Scales. An independent samples t-test was used to evaluate mean differences in early hyporesponsivity between Sibs-ASD and Sibs-TD, and bivariate correlational analyses were used to examine predictive associations between early hyporesponsivity and later language abilities for Sibs-ASD and Sibs-TD.

Results:

We found several anticipated effects, including a trend towards higher hyporesponsivity—reduced responding to sensory stimuli— at 18 months in the Sibs-ASD group relative to the Sibs-TD group (d = .64). Hyporesponsivity at 18 months was strongly predictive of receptive language at 24 months in the Sibs-ASD group (r = -.82), but not the Sibs-TD group (r = -.26). Associations between early hyporesponsivity and later expressive language were non-significant. Further analyses for an expanded sample (anticipated total N = 50) will be presented at IMFAR.

Conclusions:

Results provide increased support for the proposal that early sensory differences may produce cascading effects on higher-level abilities, such as language, in children at high risk for ASD. Findings specifically suggest that sensory hyporesponsivity may be a valuable predictor of later deficits in receptive language in this population. Implications for practice and needs for future research will be discussed.