The Characters Of Visual Dynamic Attention Of Autism Children In Smooth Pursuit Eye Movement

Autism spectrum disorders(ASD)are a group of neurodevelopmental disorders with pathogenic heterogeneity,which seriously influence physical and mental health development of children.Clinically,they are characterized by impairments in social interactions and abnormity of interests and behaviors.Visual processing failing in external motion stimuli in ASD patients were reported in some early studies.Smooth pursuit eye movement(SPEM)is evoked by visual stimuli moving smoothly.It can be used for conducting research on how people perceive and use the motion information to predict the direction of the target's movement.In addition,it also plays an important part on measuring the visual attention mechanism.In order to explore the feature of ASD children's visual dynamic attention,we selected 3-5 years olds' ASD children and the age-matched typical developing children.In current studies,all children were asked to finish tasks of tracking a series of oscillation,and their eye tracking data would be collected during the experiment,after then we obtain and compare the index of RMSE representing the accumulation errors between positions of fixation points and their corresponding positions of targets at the same time for these two groups of children.In the first study,we asked subjects to pursuit a single stimulus doing sinusoidal motion with different horizontal velocity and amplitude.The results showed that ASD children tracking the large amplitude motion is superior to small amplitude motion.With the target's speeding up,their tracking ability decreased.But overall,the visual sensitivity to the motion features of ASD children are significantly weaker than TD children,and their deviation of eye position to the target trajectory in the tracking process are significantly greater than TD children,which suggest the defects that ASD children might have in visual motion tracking.To explore the relationship between smooth pursuit eye movement and the attention distribution of ASD children,we tried to add distraction to the original oscillation task paradigm in the second study.Then we found that all children's pursuit performance influenced by distracting attention at the same time.ASD children were the first to show,by contrast,their tracking maintenance insufficient in the second half of the motion in small amplitude by larger deviation degree of eye position to the target trajectory,indicating that ASD children's limited attention resource allocation might be hindered during smooth pursuit eye-movement tracking.Based on the results of second study,we employed flashing cues into the target motion process in the final study,aiming at measuring whether the cues exert influence on ASD children's smooth pursuit eye movement.The results showed that ASD children can pay attention on capturing target with flashing cues.The RMSE in the half part motion with cues was significantly less than those without any cues.It seems to illustrate that the cues through motion can help ASD children maintain their attention in the smooth pursuit process.This research summarizes that children with autism have some defects in smooth pursuit eye movement.The dynamic attentional factors such as the impairments of attention distribution and maintenance in motion tracking may be contributed to this kind of visual tracking dysfunction.It also revealed that ASD children have more difficulties in integrating the dynamic information processing during visual motion tracking.