Visual Perception and Reading: New Clues to Patterns of Dysfunction Across Multiple Visual Channels in Developmental Dyslexia
| Autor: | José Rebola, Miguel Castelo-Branco, Ana João Rodrigues, Marieke van Asselen, Marcelino Pereira, Maria J. Ribeiro, Helena Jorge |
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| Rok vydání: | 2017 |
| Předmět: |
Male
medicine.medical_specialty Visual perception genetic structures media_common.quotation_subject Audiology behavioral disciplines and activities Biological theories of dyslexia 050105 experimental psychology Contrast Sensitivity Dyslexia 03 medical and health sciences Fluency 0302 clinical medicine Reading (process) medicine Psychophysics Contrast (vision) Humans 0501 psychology and cognitive sciences Visual Pathways Vision test Visual threshold Child media_common Vision Tests 05 social sciences medicine.disease Reading Case-Control Studies Sensory Thresholds Visual Perception Female Psychology psychological phenomena and processes 030217 neurology & neurosurgery Photic Stimulation Follow-Up Studies |
| Zdroj: | Investigative ophthalmologyvisual science. 58(1) |
| ISSN: | 1552-5783 |
| Popis: | Purpose The specificity of visual channel impairment in dyslexia has been the subject of much controversy. The purpose of this study was to determine if a differential pattern of impairment can be verified between visual channels in children with developmental dyslexia, and in particular, if the pattern of deficits is more conspicuous in tasks where the magnocellular-dorsal system recruitment prevails. Additionally, we also aimed at investigating the association between visual perception thresholds and reading. Methods In the present case-control study, we compared perception thresholds of 33 children diagnosed with developmental dyslexia and 34 controls in a speed discrimination task, an achromatic contrast sensitivity task, and a chromatic contrast sensitivity task. Moreover, we addressed the correlation between the different perception thresholds and reading performance, as assessed by means of a standardized reading test (accuracy and fluency). Group comparisons were performed by the Mann-Whitney U test, and Spearman's rho was used as a measure of correlation. Results Results showed that, when compared to controls, children with dyslexia were more impaired in the speed discrimination task, followed by the achromatic contrast sensitivity task, with no impairment in the chromatic contrast sensitivity task. These results are also consistent with the magnocellular theory since the impairment profile of children with dyslexia in the visual threshold tasks reflected the amount of magnocellular-dorsal stream involvement. Moreover, both speed and achromatic thresholds were significantly correlated with reading performance, in terms of accuracy and fluency. Notably, chromatic contrast sensitivity thresholds did not correlate with any of the reading measures. Conclusions Our evidence stands in favor of a differential visual channel deficit in children with developmental dyslexia and contributes to the debate on the pathophysiology of reading impairments. |
| Databáze: | OpenAIRE |
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