Visual Pattern As a Secondary ‘Biologically-Oriented’ Outcome in the Field of Early Intervention of the Autism Spectrum Disorder: Can the Eye-Tracker Provide Useful Suggestions ?

Background: Eye tracking has the potential to characterize autism spectrum disorder at a unique intermediate level, with links 'down' to underlying neurocognitive networks, as well as 'up' to everyday function and dysfunction. Because it is non-invasive and does not require advanced motor responses or language, eye tracking is particularly important for the study of young children and infants (Falck-Ytter et al., 2013).

Objectives: A previously published studies indicated that the early intervention resulted in gains in developmental level, language and adaptive behavior of children with autism spectrum disorder. This work describes a secondary ‘biologically-oriented’ outcome: the visual pattern studied through eye-tracking.

Methods: Twenty 24 to 30 month old children at their first diagnosis of autism spectrum disorder were recruited and their visual pattern, in addition to the standard clinical protocol, was studied at T0 (time of the first diagnosis) and at T1 after 6 months of intervention. The eye-tracking tasks consisted in the presentation of short video sequences involving responding (figure 'a') and two initiating JA tasks (JA1 figure 'b' and JA2 figure 'c'). Gaze accuracy, transitions and fixations were analyzed. Age-matched typical children were also compared at T0 and T1.

Results: In responding JA task children with ASD improved their engagement with target object showing an increased fixation at T1 compared to T0 (p=.02). No significant difference with typical children was found at T0 while a slightly increase in looking at target was discover at T1 (p=.048). In initiating JA1 children with ASD significantly improved their ability of disengage and explore space: increased transitions from non-target object to target object (p=.01), tended to look more to non-target object (p=.06) and decreased fixations at face (p=.01). At T1 their still made more transitions at the target object compared to the non-target one (p=.02) respect to typical children (higher transitions score) while they did not show any more decreased attention at non-target object. As regards IJA2 ASD children did non show significantly improvement in visual pattern and they still made more transitions then typicals between target object and face. From a clinical point of view, at T1 children showed a significantly improved in terms of ADOS-2 comparison score (CS). Also developmental level, language and adaptive behavior showed significant gains.

Conclusions: For our knowledge this was the first trial that used the eye-tracking as out come measure to demonstrate that early intervention was associated with progressive normalized visual pattern and with improvements in social behavior in young children with autism spectrum disorder.