[Visual fixation patterns during basic facial emotion recognition and its correlation with social impairment among...

Objective: To explore the visual fixation patterns during facial emotion recognition and the association between fixation duration percentage (FDP) of eye region with social impairment among high-functioning autism spectrum disorders (HFASD). Methods: Children were recruited from the Child and Adolescent Behavior Research Center of Sun Yat-sen University, Guangzhou, between July and December 2019 for case control study. A total of 42 children with HFASD and 23 age-and gender-matched typical development (TD) children were enrolled. Based on their performance during the facial emotion recognition task, HFASD children were further divided into ASD-1 group (correctly recognized both happy and fear emotions) and ASD-2 group (recognized happy emotions only). During the free viewing task, an infrared eye tracker was used to record the gazing data of children in the three groups. The social responsiveness scales (SRS) was utilized to evaluate HFASD children's social impairment, with the cutoff score of 75 to differentiate those from mild and severe social impairment. The differences of FDP among the three groups were analyzed by the Analysis of Variance (ANOVA) model. Mixed linear regression model was conducted to evaluate the associations between social impairment and FDP of eye region among HFASD children. Results: The final sample consists of 25 ASD-1 (20 males, aged (7.9±1.0) years), 17 ASD-2(14 males, aged (7.2±1.2) years), and 23 TD (12 males, aged (7.7±1.3) years) children. There were no significant differences in age and gender among three groups (F=2.05, χ²=10.08, P=0.14 and 0.07, respectively). For the happy emotion, there are significant differences in eye FDP among the three groups (TD: 0.37±0.20, ASD-1: 0.35±0.20, ASD-2: 0.47±0.24, F=3.97, P=0.02). Mixed linear regression model revealed that, adjusting for emotion, gender, age and intelligence quotient, ASD children's eye FDP negatively associates with social impairment (OR=0.15, 95%CI: 0.06-0.35, P<0.01). Conclusions: Longer FDP is associated with milder social impairment among HFASD children. HFASD children with facial emotion recognition difficulties require longer fixation to recognize happy emotions.