Recent publications have shown behavioral differences from 6 to 9 months between siblings of older children with ASD (high risk-HR) and siblings of children with typical development (low risk-LR) (see Elsabbagh et al. 2009, 2012; Ozonoff et al., 2008 for a review). Previous works have demonstrated that children with autism have deficits in attentional (dis-)engagement mechanisms (gap effect, Van der Geest et al., 2001) and in processing of social information, particularly faces (Dawson, 2005). Furthermore, young children with autism can differentially process direct and averted gaze when viewing faces (Grice et al., 2006).
The aim is testing newborns to detect the earliest developmental atypicalities that may be associated with autism or the broader autism phenotype (BAP). We compare at low and at high risk newborns by using behavioral marker tasks, designed to assess attention to social and non-social stimuli; offering some support to previous behavioral studies with older individuals with ASD, and suggesting the presence of social attention processing abnormalities very early in the development.
Attentional tasks are tested at birth in both groups (HR and LR) using the following established paradigms: the “gap effect” task with face-like stimuli (Farroni et al., 1999) and the “eye contact” task (Farroni et al., 2002) with faces showing direct and averted gaze. Eight 2 to 5–day–old newborn infants (siblings of an individual with ASD) have been tested so far, using the gap-overlap experimental paradigm and a spontaneous preference between mutual and averted gaze. The first task measures the “cost” of disengaging from a central stimulus in order to fixate a peripheral target. This task measures the latency of orienting towards peripheral cues depending on the temporal gap between a central stimulus and the peripheral target and depending, in the case of newborns, on the kind of peripheral target (upright vs inverted face). A second task tests the ability to discriminate between direct and averted gaze as demonstrated in previous studies.
From the behavioral pattern in both experiments emerges a remarkable variability on attentional and visual responses in the HR sample compared with the LR sample. ASD-sibling newborns have shown atypical patterns in engagement and disengagement behavior in both tasks. The HR group shows a lack of the typical gap effect and in particular is slower to orient when a face appears in the periphery. In the case of eye contact task the HR group shows the same trend as the LR group (preference for direct gaze) but they have a lower number of orientation towards direct gaze with a very lower fixation time during the exploration of the stimuli.
Our results confirm the possibility of identifying early behavioral risk-markers. A longitudinal design could make more clear the developmental trajectory of these abilities and the connection with the ASD attentional phenotype, in order to timely categorize possible predictors of the core deficits in autism.
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