Chinese Children with Autism Spectrum Disorder Show a Preference for Dynamic Geometric Compared with Social Images Which Is Also Associated with Symptom Severity

Background: Simple behavioral paradigms quantifying differential attention towards social vs non-social stimuli using eye-tracking measures may be potential markers for young children with autism spectrum disorder (ASD). One promising paradigm is where fixation on dynamic geometrical images (DGI) is compared to dynamic social images (DSI) with ASD children showing greater interest in the geometric patterns¹. However, other paradigms showing reduced attention towards biological as opposed to non-biological motion have also generated some positive findings². It is also unclear the extent to which these measures are effective in Asian as well as Caucasian cultures.

Objectives: In this preliminary study on Chinese children diagnosed with ASD compared with age- and gender-matched typically developing (TD) children, we have investigated whether there is a similar bias attention towards DGI and away from biological motion, and if this is associated with symptom severity.

Methods: 40 children were recruited for the study. The ASD group consisted of 22 children diagnosed with autism (DSM-V) while the TD group consisted of 18 children (ASD mean±SD age = 4.47±2.05years; TD =4.18±0.45 years, t=.600, p=.552). All ASD children were assessed using the Autism Diagnostic Observation Schedule-2 (ADOS-2). Additionally, parents of children in each group completed the Social Responsivity Scale 2 (SRS-2), Caregiver Strain Questionnaire (CSQ), Social Communication Questionnaire (SCQ), and Repetitive Behavior Scale Revised (RBS-R). Data from 4 children were excluded due to parental interference, spending <50% time looking at the images or technical issues. A Tobii T120 Eye Tracker (Tobii, Stockholm, Sweden; www.tobii.com) was used to measure eye fixations during two paradigms: (1) a DGI vs DSI visual preference paradigm where 30 different pairs of videos were presented simultaneously side by side, each for 2 s. (2) a non-biological vs biological motion paradigm with pairs of videos with point-light displays depicting animate (cat or human) vs scrambled control inanimate images (cat or human control)(8, 10s trials).

Results: Fixation count and duration for DGI vs DSI stimuli in the two groups was analyzed using a one-way analysis of covariance (ANCOVA) in ASD and TD groups with age as a covariate. A significant difference was found for both fixation count [F_{2, 33}=6.01 p=.02] and total duration [F_{2, 33}=6.85, p=.013]. Post hoc analysis with Bonferroni correction showed that children in the ASD group had a significantly greater proportion of fixations (p<.020, Cohen’s d=0.89) and total duration (p<.013, Cohen’s d=0.96) on DGI than TD children. Pearson correlation showed that fixation number and total fixation duration to DGI in ASD subjects were significantly associated with the social affect (SA) score on ADOS-2 (r = 0.60, p=.007; r=0.57, p=.011). On the other hand, no significant difference was found between the ASD and TD groups in the biological motion paradigm.

Conclusions: Our results demonstrate that eye tracking measures showing greater attention towards DGI may be a sensitive marker for ASD and ASD symptom severity in Chinese subjects.

References:

1. Pierce K et al (2016) Biol Psychiatry 79:657-666.
2. Annaz D et al (2012) J Autism Dev Disorders 42:401.