Differential diagnosis of vergence and saccade disorders in dyslexia

Abstract Previous studies suggest vergence and saccade abnormalities in dyslexic adolescents. However, these studies are mainly clinically based and do not provide objective measurements of eye movements, but rather subjectively evaluate vergence using haplosopic conditions in which the two eyes are...

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Autores principales: Lindsey M. Ward, Zoï Kapoula
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Publicado: Nature Portfolio 2020
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spelling oai:doaj.org-article:a72f85a65d334871befb7df8b8f121ef2021-12-02T12:42:18ZDifferential diagnosis of vergence and saccade disorders in dyslexia10.1038/s41598-020-79089-12045-2322https://doaj.org/article/a72f85a65d334871befb7df8b8f121ef2020-12-01T00:00:00Zhttps://doi.org/10.1038/s41598-020-79089-1https://doaj.org/toc/2045-2322Abstract Previous studies suggest vergence and saccade abnormalities in dyslexic adolescents. However, these studies are mainly clinically based and do not provide objective measurements of eye movements, but rather subjectively evaluate vergence using haplosopic conditions in which the two eyes are dissociated (via polarizers, prisms, or intermittent spectacles). Other studies have identified deficits with binocular coordination during reading in dyslexics. Yet, there are few studies that provide objective measurements of eye movements in the dyslexic population to help provide more information regarding if these deficits could be due to an intrinsic motor problem or if they are the consequence of poor reading. 47 dyslexic adolescents (18 female, 29 male; mean age 15.5) and 44 non-dyslexic adolescents (22 female, 22 male; mean age 14.8) wore a head-based eye tracker (PupilCore, Pupil Labs, Berlin) which recorded wide angle saccade and vergence eye movements at 200 Hz. Tests were run using the REMOBI device, which produced a saccade or vergence audiovisual target. Analysis of eye movements was performed with lab-developed software, AIDEAL. The results showed statistically significant abnormalities in vergence and saccades. In vergence, dyslexics displayed a reduced amplitude of the visually driven portion of convergence and a longer duration in the initial phase of divergence. In saccades, dyslexic adolescents demonstrated slower saccades in both directions. They also had an increased disconjugate drift in the first 80 or 160 ms following saccades to the right, suggesting poor binocular coordination. For both vergence and saccades, the peak velocity and time to peak velocity was higher and earlier, respectively, in non-dyslexics compared to dyslexics; yet the average velocity of both movements was lower in dyslexics. Thus, these results indicate peculiar velocity profiles in dyslexics, particularly a slow deceleration phase in both vergence and saccades. The study provides an objective method to diagnose vergence and saccade abnormalities while viewing targets in the real three-dimensional space in a dyslexic population. Vergence abnormalities are demonstrated to be a problem in dyslexics, occurring independently from reading. We hypothesize these disconjugate drifts following saccades are the result of slow vergence capacity. Rehabilitation programs, such as those using REMOBI, should aim to target these deficits in vergence velocity, as this has been shown to improve binocular control.Lindsey M. WardZoï KapoulaNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 10, Iss 1, Pp 1-15 (2020)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Lindsey M. Ward
Zoï Kapoula
Differential diagnosis of vergence and saccade disorders in dyslexia
description Abstract Previous studies suggest vergence and saccade abnormalities in dyslexic adolescents. However, these studies are mainly clinically based and do not provide objective measurements of eye movements, but rather subjectively evaluate vergence using haplosopic conditions in which the two eyes are dissociated (via polarizers, prisms, or intermittent spectacles). Other studies have identified deficits with binocular coordination during reading in dyslexics. Yet, there are few studies that provide objective measurements of eye movements in the dyslexic population to help provide more information regarding if these deficits could be due to an intrinsic motor problem or if they are the consequence of poor reading. 47 dyslexic adolescents (18 female, 29 male; mean age 15.5) and 44 non-dyslexic adolescents (22 female, 22 male; mean age 14.8) wore a head-based eye tracker (PupilCore, Pupil Labs, Berlin) which recorded wide angle saccade and vergence eye movements at 200 Hz. Tests were run using the REMOBI device, which produced a saccade or vergence audiovisual target. Analysis of eye movements was performed with lab-developed software, AIDEAL. The results showed statistically significant abnormalities in vergence and saccades. In vergence, dyslexics displayed a reduced amplitude of the visually driven portion of convergence and a longer duration in the initial phase of divergence. In saccades, dyslexic adolescents demonstrated slower saccades in both directions. They also had an increased disconjugate drift in the first 80 or 160 ms following saccades to the right, suggesting poor binocular coordination. For both vergence and saccades, the peak velocity and time to peak velocity was higher and earlier, respectively, in non-dyslexics compared to dyslexics; yet the average velocity of both movements was lower in dyslexics. Thus, these results indicate peculiar velocity profiles in dyslexics, particularly a slow deceleration phase in both vergence and saccades. The study provides an objective method to diagnose vergence and saccade abnormalities while viewing targets in the real three-dimensional space in a dyslexic population. Vergence abnormalities are demonstrated to be a problem in dyslexics, occurring independently from reading. We hypothesize these disconjugate drifts following saccades are the result of slow vergence capacity. Rehabilitation programs, such as those using REMOBI, should aim to target these deficits in vergence velocity, as this has been shown to improve binocular control.
format article
author Lindsey M. Ward
Zoï Kapoula
author_facet Lindsey M. Ward
Zoï Kapoula
author_sort Lindsey M. Ward
title Differential diagnosis of vergence and saccade disorders in dyslexia
title_short Differential diagnosis of vergence and saccade disorders in dyslexia
title_full Differential diagnosis of vergence and saccade disorders in dyslexia
title_fullStr Differential diagnosis of vergence and saccade disorders in dyslexia
title_full_unstemmed Differential diagnosis of vergence and saccade disorders in dyslexia
title_sort differential diagnosis of vergence and saccade disorders in dyslexia
publisher Nature Portfolio
publishDate 2020
url https://doaj.org/article/a72f85a65d334871befb7df8b8f121ef
work_keys_str_mv AT lindseymward differentialdiagnosisofvergenceandsaccadedisordersindyslexia
AT zoikapoula differentialdiagnosisofvergenceandsaccadedisordersindyslexia
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