31580
Joint Attention in Typical and Atypical Early Development: An Eye-Tracking Study
Joint attention (JA) is defined as the ability to share interest about an object or an event, by following (“response to joint attention (RJA)”) or directing (“initiation of joint attention (IJA)”) the gaze of a social partner. In Autism Spectrum Disorders (ASD), a deficit in the JA skills represents one of the core and earliest symptoms and a specific target of early treatments. Younger siblings of children with ASD have around the 20% of risk of developing ASD themselves and, even if they don’t receive a clinical diagnosis, they might show subclinical developmental problems, commonly related to the Broader Autism Phenotype (BAP).
Objectives:
The aim of this eye-tracking study was to evaluate the visual patterns during tasks eliciting initiating joint attention in High Risk – non ASD (HR-nASD) subjects as compared to ASD and typical development (TD) children, to correlate these eye-tracking data with clinical measures, and finally to describe the clinical phenotype of these HR-nASD toddlers.
Methods:
This was a prospective multicenter observational study. Fifty-two children participated in the study: 17 ASD, 19 HR-nASD and 16 TD. The sample age range was 18-33 months. All subjects underwent a comprehensive clinical assessment and eye tracking experiments, composed by two video-task eliciting IJA (IJA1 and IJA2 respectively) and RJA. Fixations, Transitions and alternating gaze were analyzed.
Results:
In the RJA task no differences were found between groups. In the IJA1 task alternating gaze between target object and the model’s face was statistically different between HR-nASD and ASD subjects (p<0,001) as well as between TD and ASD subjects (p= 0,029). Alternating gaze between the non-target object and the model’s face and between non-target object and target object differed significantly between the HR-nASD and TD groups (p= 0,012 and p= 0,003, respectively) with lower values for the HR- nASD population. In the IJA2 task alternating gaze between face and target object differed significantly between HR-nASD and ASD subjects (p <0,001) as well as between the TD and ASD groups (p= 0,004). Moreover, in ASD group the rate of alternating gaze between the face and the target object was associated with more core ASD symptoms (p=0,004), in particular social and communicative impairment (p= 0,015).
Conclusions:
High risk subjects who do not develop ASD at 36 months show lower non-verbal cognitive skills than typical development children and similar levels of restricted and repetitive behaviors and better social and communicative skills as compared to ASD children. During initiating joint attention tasks, HR-nASD toddlers exhibit visual patterns similar to TD in terms of target-object-to-face gaze alternations, while their looking behavior was similar to ASD toddlers regarding not-target-object-to-face gaze alternations. Furthermore, as shown in the literature, IJA seems to be more useful to capturing differences between ASD and TD infants. The study of alternating gaze in typical and atypical development can shed light on how children begin to visually explore the world around them and how they share interest in objects and/or events with other people.