Sensory Responsiveness in Infants at-Risk for Autism Spectrum Disorders within the First Two Years of Life

Background: Autism Spectrum Disorders (ASDs) are multisystem neurological disorders with primary impairments in the social communication skills as well as the presence of stereotyped/repetitive behaviors (American Psychiatric Association, 2013). Additional comorbidities such as sensory processing dysfunction are reported in more than 90% of the children diagnosed with ASDs (Tomcheck & Dunn, 2007). Parents of infants later diagnosed with ASDs reported early atypicalities in sensory responsiveness to auditory, tactile, and visual stimuli as well as excessive oral exploration of objects (Hoshino et al., 1982; Baranek, 1999; Tomcheck & Dunn, 2007). Early identification of sensory processing issues in infants at-risk for ASDs could help in developing appropriate early interventions. However, few studies have prospectively examined the presence of sensory processing deficits in the at-risk infants.  

Objectives:   The current project examined the sensory processing abilities of infant siblings of children diagnosed with ASDs (AU sibs) within the first 2 years of life by using a parent questionnaire, the Infant/Toddler Sensory Profile (ITSP).

Methods:   This study was part of a larger ongoing longitudinal study comparing the development of AU sibs and typically developing infants within the first 2 years of life. Parents of 13 AU sibs were asked to complete the ITSP at 6,9,12,15,18, and 24 months of age. ITSP assesses the sensory processing abilities from birth to 3 years and its effects on the infant’s daily performance (Dunn, 2002). ITSP scoring was done for 2 sections: (i) response to various sensations, i.e. auditory, visual, tactile, vestibular, and oral sensation and (ii) the neurological threshold of the infant for various sensory behavior such as sensation threshold, seeking behaviors, sensitivity, and avoidance.

Results: 8-54% of the AU sibs showed atypical response - over or under responsiveness to various sensations as well as atypical neurological thresholds between 6 to 24 months. Specifically, 30-50% of the AU sibs showed auditory, oral, and tactile processing deficits early on at 9 months whereas vestibular and visual processing deficits were evident from 12 and 15 months respectively in 30-38% of the group. In terms of neurological thresholds, 50% of AU sibs showed atypical low threshold behaviors early on at 6 months whereas sensation seeking and sensory sensitivity were seen at 12 months and sensation avoiding at 9 months. Currently, we are relating infancy performance to future outcomes and conducting individual item analyses to better understand the sensory processing issues of the AU sibs.  

Conclusions:   Parent questionnaires such as the ITSP are a quick and easy tool for evaluating the sensory processing issues of infants at-risk for ASDs. Our study suggested that almost half of the at-risk infants showed sensory difficulties. However, the incidence is lower than that reported in the previous literature indicating that some of the parents might have over or under estimated the performance of their infants.