Eye-movement Patterns of Chinese Children with Developmental Dyslexia during the Stroop Test / 生物医学与环境科学（英文）

<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>

Eye-movement study during visual search in Chinese children with developmental dyslexia / 中华医学杂志(英文版)

<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>

Regional cerebral blood flow in children with autism spectrum disorders: a quantitative ⁹⁹mTc-ECD brain SPECT study with statistical parametric mapping evaluation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Autism spectrum disorders (ASD), which include autism, asperger syndrome (AS) and pervasive developmental disorder-not otherwise specified (PDD-NOS), are devastating neurodevelopmental disorders of childhood resulting in deficits in social interaction, repetitive patterns of behaviors, and restricted interests and activities. Single photon emission computed tomography (SPECT) is a common technique used to measure regional cerebral blood flow (rCBF). Several studies have measured rCBF in children with ASD using SPECT, however, findings are discordant. In addition, the majority of subjects used in these studies were autistic. In this study, we aimed to investigate changes in rCBF in children with ASD using SPECT.</p><p><b>METHODS</b>A Technetium-99m-ethyl cysteinate dimmer (⁹⁹m)Tc-ECD) brain SPECT study was performed on an ASD group consisting of 23 children (3 girls and 20 boys; mean age (7.2 ± 3.0) years) who were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria and an age-matched control group with 8 children (1 girl and 7 boys, mean age (5.5 ± 2.4) years). Image data were evaluated with Statistical Parametric Mapping, 5th version (SPM5). A Student's t test for unpaired data was used to compare rCBF and asymmetry in the autism and corresponding control group. The covariance analysis, taking age as covariance, was performed between the ASD and control group.</p><p><b>RESULTS</b>There was a significant reduction in rCBF in the bilateral frontal lobe (frontal poles, arcula frontal gyrus) and the bilateral basal ganglia in the autism group, and a reduction in the bilateral frontal, temporal, parietal, legumina nucleus and cerebellum in the AS group compared to the control. In addition, asymmetry of hemispheric hypoperfusion in the ASD group was observed. Inner-group comparison analysis revealed that rCBF decreased significantly in the bilateral frontal lobe (42.7%), basal nucleus (24.9%) and temporal lobe (22.8%) in the autism group, and in the bilateral cerebellum (22.8%), basal nucleus (19.3%) and right thalamencephalon (16.6%) in the AS group (P < 0.05).</p><p><b>CONCLUSIONS</b>The decrease in rCBF in ASD is a global event, which involves the bilateral frontal, temporal, limbic system and basal ganglias. Asymmetry of hemispheric hypoperfusion was more obvious in the AS group than the autism group, which indicates a different neurobiological mechanism from that of autism.</p>

Picture perception in Chinese dyslexic children: an eye-movement study / 中华医学杂志(英文版)

<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>

Neuropsychological characteristics of selective attention in children with nonverbal learning disabilities / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the neuropsychological characteristics of selective attention such as attention control, working memory and attention persistence of frontal lobe in children with nonverbal learning disabilities (NLD).</p><p><b>METHODS</b>With Auditory Detection Test (ADT), Wisconsin Card Sorting Test (WCST) and C-WISC, 14 children with NLD and 23 controls were tested and the results of sub-tests of C-WISC were analyzed with factor analysis. ADT was mainly applied to test the ability of auditory discernment and the function of dominance lateralization in the cerebra; WCST was employed to test the function of working memory which was based on the frontal lobe, and, C-WISC, to test the intelligent structure and characteristics.</p><p><b>RESULTS</b>Compared with control group, the correct response rate of ADT in NLD group was much lower (P < 0.01), and the number of incorrect response was much larger (P < 0.01). Children with NLD had deficits of auditory selective attention. Moreover, the number of categories achieved (CA) and perseverative error (PE) of WCST were much lower (P < 0.05), which indicated that children with NLD had the disorders of selective attention and performance function. Factor analysis showed that perceptual organization (PO) related to visual space and freedom from distractibility (FD) related to attention persistence in NLD group were obviously lower than those in control group (P < 0.01, P < 0.05). These findings further supported the above-mentioned results.</p><p><b>CONCLUSIONS</b>Children with NLD had attention control disorder and working memory disorder mainly in frontal lobe; we suppose that the disorder in right frontal lobe was distinctive.</p>

Neuropsychological characteristics of selective attention in children with nonverbal learning disabilities / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Children with nonverbal learning disabilities (NLD) usually manifest defective attention function. This study sought to investigate the neuropsychological characteristics of selective attention, such as attention control, working memory, and attention persistence of the frontal lobe in children with NLD.</p><p><b>METHODS</b>Using the auditory detection test (ADT), Wisconsin card sorting test (WCST), and C-WISC, 27 children with NLD and 33 normal children in the control group were tested, and the results of C-WISC subtests were analyzed with factor analysis.</p><p><b>RESULTS</b>Compared with the control group, the correct response rate in the auditory detection test in the NLD group was much lower (P < 0.01), and the number of incorrect responses was much higher (P < 0.01); NLD children also scored lower in WCST categories achieved (CA) and perseverative errors (PE) (P < 0.05). Factor analysis showed that perceptual organization (PO) related to visual space and freedom from distractibility (FD) relating to attention persistence in the NLD group were obviously lower than in the control group (P < 0.01).</p><p><b>CONCLUSIONS</b>Children with NLD have attention control disorder and working memory disorder mainly in the frontal lobe. We believe that the disorder is particularly prominent in the right frontal lobe.</p>