ABSTRACT
<p><b>OBJECTIVE</b>To compare the eye-movement patterns of Chinese children with developmental dyslexia (DD children) with those of non-dyslexic children as they perform the Stroop Color and Word Test (SCWT), and to explore the relationship between their eye-movement patterns and interference effect.</p><p><b>METHODS</b>An EyeLink II was used to record the eye-movement parameters of 32 DD children and 37 non-dyslexic children as they performed the SCWT. The independent samples t-test and repeated measures were used to analyze behavioral and eye-movement parameters.</p><p><b>RESULTS</b>Compared to the control group, Chinese DD children presented lower accuracy (F = 8.488), slower response time (F = 25.306), and larger interference effect (t = 2.29); Chinese DD children also exhibited lower frequency of fixations (F = 6.069), greater numbers of saccades (F = 7.914) and fixations (F = 5.272), and shorter mean saccade distance (F = 4.03). All behavioral and eye-movement parameters differed significantly among the three tasks in the SCWT. There was significant interaction between groups and tasks in accuracy (F = 5.844), and marginally significant interaction in response time (F = 3.040). Chinese DD children tended to have lower accuracy and longer response time than the control group in the 'color-word naming' task.</p><p><b>CONCLUSION</b>Compared to non-dyslexic children, Chinese DD children are subject to a stronger interference effect. When performing the SCWT, Chinese DD children exhibit abnormal eye-movement patterns, namely shorter mean saccade distance, lower frequency of fixations, and more fixations and saccades. These abnormal eye movements may be relatively stable oculomotor patterns of DD children performing visual processing, and not influenced by impaired interference effect.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To explore the abilities of verbal and visual-spatial memory in Chinese children with developmental dyslexia.</p><p><b>METHODS</b>Thirty-two children with developmental dyslexia (aged 8-12 years) and thirty-nine age- and gender-matched normal children were involved in the study. Their verbal short-term and verbal working memories were measured using the digit ordering and the digit span tests, respectively. Their visual-spatial short-term and visual-spatial working memories were examined using the forward and backward block-tapping tests, respectively.</p><p><b>RESULTS</b>The DD children scored lower in the digit ordering and the digit span tests than the control children (P<0.05). The scores for the forward and backward block-tapping tests did not vary between the two groups (P>0.05).</p><p><b>CONCLUSIONS</b>The children with DD have the deficits in both verbal short-term memory and verbal working memory.</p>
Subject(s)
Child , Female , Humans , Male , Dyslexia , Psychology , Memory, Short-Term , Spatial MemoryABSTRACT
To evaluate the visual performance of the patients with traumatic corneal astigmatism, after the treatment of topography guided off-flap epipolis laser in situ keratomileusi (off-flap Epi-LASlK). ●METHODS: This prospective clinical study was comprised of 21 eyes of 21 patients with irregular corneal astigmatism caused by trauma, they were treated by off-flap Epi - LASlK from July 2012 to December 2013. The data included uncorrected visual acuity ( UCVA), best spectacle - corrected visual acuity ( BSCVA ), contrast sensitivity 1, 6mo before and after surgery; the healing area percentage of corneal epithelia, the healing time of corneal epithelia and pain score at 3d after surgery. ●RESULTS: Postoperative 1mo both UCVA and BSCVA were improved significantly than that before surgery (t =15. 703, 4. 351, P0. 05 ). Postoperative 6mo except the 3c/ d spatial frequency, the remaining 3 spatial frequency contrast sensitivity compared with those before operation were significantly improved ( P ●CONCLUSlON: Topography-guided off-flap Epi-LASlK is safe and effective in treating the patients with traumatic corneal irregular astigmatism. The operation can improve both the contrast sensitivity and the visual performance.
ABSTRACT
<p><b>BACKGROUND</b>Developmental dyslexia (DD) is a disorder in which children with normal intelligence and sensory abilities show learning deficits in reading. Abnormal eye movements have been found in DD. However, eye-movement abnormalities during visual search among Chinese children with DD remain unknown. We aimed to identify the eyemovement characteristics and search efficiency of Chinese children with DD during visual search for targets of different conceptual categories, under same-category conditions.</p><p><b>METHODS</b>We compared 32 Chinese dyslexic children and 39 non-dyslexic children in visual search tasks, which were assessed using EyeLink II High-Speed Eye Tracker (SR Research Ltd., Canada). Letters, single Chinese characters, digits, Chinese phrases, figures and facial expressions were used as stimuli. Targets were similar to distractors in meaning, phonology and/or shape.</p><p><b>RESULTS</b>A main effect of task on visual search scores and all eye-movement parameters were found. Search scores, average saccade amplitude and saccade distance were significantly smaller in the DD group than in the controls. An interaction between group and task was found for pupil diameter.</p><p><b>CONCLUSIONS</b>Unlike normal readers, children with DD had a reduction in the visual attention span and search accuracy. Besides, children with DD could not increase their mental workload with increase in task difficulty. The conceptual category of the stimulus materials significantly impacts search speed, accuracy and eye-movement parameters.</p>
Subject(s)
Adolescent , Child , Female , Humans , Male , Asian People , Dyslexia , Eye Movements , PhysiologyABSTRACT
<p><b>BACKGROUND</b>Currently, whether or not there is visuospatial impairments in Chinese dyslexic children is still a matter of discussion. The relatively recent application of an eye-tracking paradigm may offer an opportunity to address this issue. In China, in comparison with reading studies, there have not been nearly as many eye movement studies dealing with nonreading tasks such as picture identification and whether Chinese children with dyslexia have a picture processing deficit is not clear. The purposes of the present study were to determine whether or not there is visuospatial impairments in Chinese dyslexic children. Moreover, we attempted to discuss whether or not the abnormal eye movement pattern that dyslexic subjects show during reading of text appropriate for their age is a consequence of their linguistic difficulties.</p><p><b>METHODS</b>An eye-link II High-Speed Eye Tracker was used to track the series of eye-movement of 19 Chinese dyslexic children and 19 Chinese normal children. All of the subjects were presented with three pictures for this eye-tracking task and 6 relative eye-movement parameters, first fixation duration, average fixation duration, average saccade amplitude, mean saccade distance, fixation frequency and saccade frequency were recorded for analysis.</p><p><b>RESULTS</b>Analyzing the relative parameter among three pictures, except for the fixation frequency and the saccade frequency, other eye-movement parameters were significantly different among the three pictures (P<0.05). Among the three pictures, the first fixation duration was longer, and the average fixation duration, the average saccade amplitude and the mean saccade distance were shorter from picture 2 to picture 3. Comparing all eye-movement parameter between the two groups, the scores of average saccade amplitude (P=0.017) and the mean saccade distance (P=0.02) were less in the dyslexia group than in the normal group (P<0.05), other parameters were the same in the two different groups (P>0.05).</p><p><b>CONCLUSIONS</b>The characteristics of the pictures can significantly influence the visuospatial cognitive processing capability of the Chinese children. There is a detectable disability for the Chinese dyslexic children in the visuospatial cognitive processing: their saccade amplitude and mean saccade distance are shorter, which may be interpreted as specific for their reading disability.</p>
Subject(s)
Child , Female , Humans , Male , Case-Control Studies , Dyslexia , Psychology , Eye Movements , SaccadesABSTRACT
<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSIONS</b>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.</p>