Analysis of Crying during the Separation Phase of the Strange Situation Procedure in Infant Siblings at High Risk for ASD

Background: To better understand social communication during early development, a growing literature is assessing the vocal production of children with Autism Spectrum Disorders (ASD). Previous studies have provided preliminary evidence that disruptions in cry acoustics may be part of an atypical vocal signature of autism early in life. In the current research we investigate the acoustic characteristics of cries elicited in a standardized social interaction context, the Strange Situation Procedure (SSP). The SSP is a gold-standard measure of infant attachment security that consists of a series of separations and reunions with the caregiver designed to activate the infant’s attachment behavioral system. Infants often become distressed during separations from the caregiver, and the SSP has been used to assess infant affect and emotional reactivity. The SSP is a standardized yet naturalistic way to study distress reactions both in typical populations and in at-risk populations such as toddlers at high risk for ASD.

Objectives:  Test whether the acoustic signature of the cries of HR toddlers differ from those of LR toddlers during the standardized separation from the parent during the SSP.

Methods:  We examined the acoustic characteristics of cries extracted from the separation phase of the strange situation procedure in a sample of toddler of younger siblings of a child with autism spectrum disorder-autism spectrum disorders (ASD) (high risk, HR) and a low risk (LR) group. Cry samples derived from vocal recordings of 15-month-old HR (n = 13) and LR infants (n = 14) were subjected to acoustic analyses.

Results: HR toddlers, compared to those with LR, produced cries that were shorter (HR: M = 22.1, SD = 22.7; LR: M = 45.6, SD = 27.9; F = 7.9 p < .05) and had a higher fundamental frequency (F0) (HR: M = 370.1, SD = 30.5; LR: M = 330.0, SD = 26.8; F = 16.8 p < .05). Three HR toddlers later classified with an ASD at 36 months (autistic disorder in all cases) produced cries that had among the highest F0 and shortest durations.

Conclusions:  Using a standardized social elicitor, we found that 15-month-olds at high risk for ASD had shorter cry utterances that had higher fundamental frequencies than low-risk toddlers. Strikingly, those HR toddlers later diagnosed with ASD had amongst the most extreme values in the sample. This concordance between the risk group and diagnosed children suggest that disturbed cry patterns, although not a core communication deficit in children with ASD, may provide an early marker of risk for later autism. Understanding the stability of these cry characteristics and their potential impact on the parent–child relationship will require continued longitudinal follow-up of high risk siblings in their family context beyond the age of first diagnosis.