Eye-Tracking Methodology to Detect Differences in Attention to Faces Between Developmental Language Disorder and Autism.

Purpose: Developmental language disorder (DLD) and autism sometimes appear as overlapping conditions in behavioral tests. There is much literature on the visual scanning pattern (VSP) of faces in autistic children, but this is scarce regarding those with DLD. The purpose of this study was to compare the VSP of faces in young children with DLD, those with autism, and typically developing peers, assessing the effect of three variables.

Method: Two eye-tracking experiments were designed to assess the effect of the emotion and the poser's gender (Experiment 1) and the poser's age (Experiment 2) on the VSP of participants (Experiment 1: N = 59, age range: 32-74 months; Experiment 2: N = 58, age range: 32-74 months). We operationalized the VSP in terms of attentional orientation, visual preference, and depth of processing of each sort of face. We developed two paired preference tasks in which pairs of images of faces showing different emotions were displayed simultaneously to compete for children's attention.

Results: Data analysis revealed two VSP markers common to both disorders: (a) superficial processing of faces and (b) late orientation to angry and child faces. Moreover, one specific marker for each condition was also found: typical preference for child faces in children with DLD versus diminished preference for them in autistic children.

Conclusions: Considering the similarities found between children with DLD and those with autism, difficulties of children with DLD in attention to faces have been systematically underestimated. Thus, more effort must be made to identify and respond to the needs of this population. Clinical practice may benefit from the potential of eye-tracking methodology and the analysis of the VSP to assess attention to faces in both conditions. This would also contribute to the improvement of early differential diagnosis in the long run.