Preliminary Results of the Sensory Project in Infant Siblings: Early Sensory Responsiveness Is Linked with Communication Development in Infants at Risk for Autism

Background:

Children with autism spectrum disorder (ASD) show a broad range of differences in their patterns of responding to sensory stimuli (i.e., sensory responsiveness). It has been proposed that differences in sensory responsiveness, especially in infancy, may produce cascading effects on communication/language development in children with ASD. This theory proves arduous to evaluate given the challenge of reliably diagnosing ASD in infancy and toddlerhood. The Sensory Project in Infant Siblings (Project SPIS) is prospectively following infants at heightened risk for ASD (infant siblings of children with ASD; Sibs-ASD) to test the “cascading effects” theory.

Objectives:

NIDCD-funded Project SPIS aims to evaluate (a) whether sensory responsiveness differs in Sibs-ASD versus infants at relatively lower, general population-level risk for ASD (infant siblings of typically developing children; Sibs-TD), (b) whether early sensory responsiveness is associated with communication and language skill, and (c) whether associations between sensory responsiveness and communication/language skill vary according to risk group.

Methods:

Preliminary analyses were conducted on 28 infants 11-18 months of age (11 Sibs-ASD, 17 Sibs-TD) for whom Project SPIS data has been collected and scored/coded to date. Sensory responsiveness was measured with two previously developed and validated measures of early sensory responsiveness – the Sensory Experiences Questionnaire (SEQ) and Sensory Processing Assessment (SPA). Parents reported on infants’ concurrent communication and language skill via the Vineland Adaptive Behavior Scales (VABS) and MacArthur-Bates Communicative Development Inventories: Words and Gestures (MCDI) checklist. Infants’ prelinguistic skill was additionally assessed using the Communication and Symbolic Behavior Scales (CSBS). A partial interval coding system was utilized to code CSBS samples for presence/absence of communication acts, vocalizations including canonical syllables, and selected consonants. Two metrics of prelinguistic vocal complexity were derived: (a) canonical syllabic communication and (b) consonant inventory.

Results:

Preliminary results indicate that Sibs-ASD do not significantly differ from Sibs-TD in sensory responsiveness between 11-18 months of age: sensory seeking (d = 0.42, t = 1.07, p = 0.30), hyporesponsiveness (d = 0.11, t = 0.28, p = 0.78) and hyperresponsiveness (d = –0.34, t = 0.88, p = 0.39). Effect sizes for between-group differences are small in magnitude. However, individual differences in sensory responsiveness are associated with indices of communication and language ability across risk groups. For example, more hyporesponsive symptoms were associated with decreased communication skill (e.g., zero-order correlation = –0.45), decreased vocabulary size (zero-order correlations with expressive and receptive vocabulary = –0.40 and –0.36, respectively), and decreased canonical syllabic communication and consonant inventory (–0.44 and –0.35, respectively). These associations do not vary according to group. Final analyses, including results from observational measures of sensory responsiveness, will be presented at INSAR.

Conclusions:

Findings suggest that individual differences in early sensory responsiveness are linked with communication and language development across infants at high and low risk for ASD, providing increased support for the cascading effects theory. Infants are being followed longitudinally to assess the extent to which early sensory responsiveness may be useful for predicting future language and communication skill and to evaluate putative mechanisms by which sensory responsiveness may influence development.