title: Eye movements characteristics of Chinese dyslexic children in picture searching.
abstract: BACKGROUND
  Reading Chinese, a kind of ideogram, relies more on visual cognition. The visuospatial cognitive deficit of Chinese dyslexia is an interesting topic that has received much attention. The purpose of current research was to explore the visuopatial cognitive characteristics of Chinese dyslexic children by studying their eye movements via a picture searching test.
  
  
  METHODS
  According to the diagnostic criteria defined by ICD-10, twenty-eight dyslexic children (mean age (10.12 +/- 1.42) years) were enrolled from the Clinic of Children Behavioral Disorder in the third affiliated hospital of Sun Yat-sen University. And 28 normally reading children (mean age (10.06 +/- 1.29) years), 1:1 matched by age, sex, grade and family condition were chosen from an elementary school in Guangzhou as a control group. Four groups of pictures (cock, accident, canyon, meditate) from Picture Vocabulary Test were chosen as eye movement experiment targets. All the subjects carried out the picture searching task and their eye movement data were recorded by an Eyelink II High-Speed Eye Tracker. The duration time, average fixation duration, average saccade amplitude, fixation counts and saccade counts were compared between the two groups of children.
  
  
  RESULTS
  The dyslexic children had longer total fixation duration and average fixation duration (F = 7.711, P < 0.01; F = 4.520, P < 0.05), more fixation counts and saccade counts (F = 7.498, P < 0.01; F = 11.040, P < 0.01), and a smaller average saccade amplitude (F = 29.743, P < 0.01) compared with controls. But their performance in the picture vocabulary test was the same as those of the control group. The eye movement indexes were affected by the difficulty of the pictures and words, all eye movement indexes, except saccade amplitude, had a significant difference within groups (P < 0.05).
  
  
  CONCLUSIONS
  Chinese dyslexic children have abnormal eye movements in picture searching, applying slow fixations, more fixations and small and frequent saccades. Their abnormal eye movement mode reflects the poor ability and strategy of visual information processing.
authors.affiliation: Faculty of Maternal and Child Health, Preventive Medicine Institute, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Huang
authors.forename: Jin
authors.initials: J
authors.lastname: Jing
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Zou
authors.forename: Meng-Long
authors.initials: ML
authors.lastname: Wang
authors.forename: Xiu-Hong
authors.initials: XH
authors.lastname: Li
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Lin
mesh_terms: D002648:Child; D003071:Cognition; D004410:Dyslexia / Q000503:physiopathology* / Q000523:psychology; D005133:Eye Movements; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D012438:Saccades