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Vernet M, Bellocchi S, Danna J, Massendari D, Jover M, Chaix Y, Ducrot S. The determinants of saccade targeting strategy in neurodevelopmental disorders: The influence of suboptimal reading experience. Vision Res 2023; 204:108162. [PMID: 36565661 DOI: 10.1016/j.visres.2022.108162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022]
Abstract
Whether eye-movements deficits are causal in reading disorders (RD) or rather a consequence of linguistic processing difficulty experienced by disabled readers has been extensively debated.Since RD are frequently comorbid with the Neurofibromatosis type1 (NF1), children with NF1 were used as a comparison group for children with dyslexia in this study.Eye movements were recorded while 21 dyslexic, 20 NF1, and 20 typically developing children performed an oculomotor lateralized bisection task. In this experiment, we manipulated the type of stimulus - discrete (words and strings of hashes) versus continuous (solid lines) - and the visual field where the stimulus was displayed (left vs right). The results showed that (1) only proficient readers (TD and NF1 without RD) showed fully developed oculomotor mechanisms for efficient reading, with a clear preferred viewing location located to the left of the word's centre in both visual fields, and fine-tuned saccade targeting guided by the between-character space information and (2) NF1 poor readers mirrored the dyslexic eye movement behaviour, with less accuracy and more variability in saccadic programming, no sensitivity to the discreteness of the stimuli, particularly in the left visual field. We concluded that disruption to oculomotor behaviour reflectsthe fact that many of the processes involved in reading are not yet automatized for children with RD, independently of NF1. This suggests that the differences in saccade targeting strategy between children with and without RD would be secondary consequences of their reduced reading experience.
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Affiliation(s)
- Marie Vernet
- ToNIC, Toulouse NeuroImaging Center, University of Toulouse, Inserm, UPS, France; Aix Marseille Univ, CNRS, LPL, Aix-en-Provence, France; CLLE, Université de Toulouse, CNRS, Toulouse, France.
| | - Stéphanie Bellocchi
- Univ. Paul Valéry Montpellier 3, EPSYLON UR 4556, F34000, Montpellier, France
| | - Jérémy Danna
- CLLE, Université de Toulouse, CNRS, Toulouse, France
| | | | | | - Yves Chaix
- ToNIC, Toulouse NeuroImaging Center, University of Toulouse, Inserm, UPS, France; Children's Hospital, Toulouse-Purpan University Hospital, Toulouse, France
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Caldani S, Baghdadi M, Peyre H, Khoury E, Delorme R, Bucci MP. Poor visuo-spatial orientation and path memorization in children with dyslexia. Nord J Psychiatry 2022; 76:195-201. [PMID: 34278919 DOI: 10.1080/08039488.2021.1943705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE Given the importance of spatial representation and navigation in the natural environment and the presence of sensory motor integration impairment in dyslexic children the aim of this study was to explore the capability in spatial orientation task in dyslexic children. MATERIALS AND METHODS We included forty children: 26 dyslexic children (mean age: 10.1 ± 0.3 years old) and 14 typically developing (TD) children (mean age: 10.1 ± 0.4 years old). Children have to walk on an unguided isosceles rectangle triangle of 3 meters that was marked on the ground of a room, during two visual conditions: eyes open and eyes closed. Their paths were recorded using the HTC Vive system (Base + Trackers) with a refresh rate of 90 Hz with accuracy < 0.05 mm. RESULTS Results underlined that both groups of children reported poor performance during eyes closed condition. Moreover, dyslexic children, reported poor spatial orientation capabilities in the most difficult conditions, that is during reproduction of hypotenuse and angle of 45 deg. CONCLUSIONS We suggested that visual information is important during walking; the poor body orientation observed in dyslexic children could be due to a deficient integration of the sensorial inputs (visual, vestibular and proprioceptive). Further studies testing vestibular/cerebellar rehabilitation could be useful for these kinds of children.HighlightsChildren with dyslexia showed poor spatial orientation capabilities compared to typically developing children, particularly when visual inputs are not available and in the most difficult conditions (like rotation of the body).Poor motor abilities reported by children with dyslexia could be due to cerebrocerebellar pathways impairments.
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Affiliation(s)
- Simona Caldani
- UMR 7114 MoDyCo, CNRS, Paris Nanterre University, Nanterre, France.,Pediatric Balance Evaluation Center (EFEE), ENT Department, AP-HP, Robert Debré Hospital, Paris, France.,Paris University, Paris, France
| | - Moetez Baghdadi
- UMR 7114 MoDyCo, CNRS, Paris Nanterre University, Nanterre, France
| | - Hugo Peyre
- Paris University, Paris, France.,Child and Adolescent Psychiatry Department, AP-HP, Robert Debré Hospital, Paris, France
| | - Elie Khoury
- Child and Adolescent Psychiatry Department, AP-HP, Robert Debré Hospital, Paris, France
| | - Richard Delorme
- Paris University, Paris, France.,Child and Adolescent Psychiatry Department, AP-HP, Robert Debré Hospital, Paris, France.,Human Genetics & Cognitive Function, Institut Pasteur, Paris, France
| | - Maria Pia Bucci
- UMR 7114 MoDyCo, CNRS, Paris Nanterre University, Nanterre, France.,Pediatric Balance Evaluation Center (EFEE), ENT Department, AP-HP, Robert Debré Hospital, Paris, France.,Paris University, Paris, France
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Franzen L, Stark Z, Johnson AP. Individuals with dyslexia use a different visual sampling strategy to read text. Sci Rep 2021; 11:6449. [PMID: 33742007 PMCID: PMC7979812 DOI: 10.1038/s41598-021-84945-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 02/18/2021] [Indexed: 11/09/2022] Open
Abstract
Individuals with dyslexia present with reading-related deficits including inaccurate and/or less fluent word recognition and poor decoding abilities. Slow reading speed and worse text comprehension can occur as secondary consequences of these deficits. Reports of visual symptoms such as atypical eye movements during reading gave rise to a search for these deficits' underlying mechanisms. This study sought to replicate established behavioral deficits in reading and cognitive processing speed while investigating their underlying mechanisms in more detail by developing a comprehensive profile of eye movements specific to reading in adult dyslexia. Using a validated standardized reading assessment, our findings confirm a reading speed deficit among adults with dyslexia. We observed different eye movements in readers with dyslexia across numerous eye movement metrics including the duration of a stop (i.e., fixation), the length of jumps (i.e., saccades), and the number of times a reader's eyes expressed a jump atypical for reading. We conclude that individuals with dyslexia visually sample written information in a laborious and more effortful manner that is fundamentally different from those without dyslexia. Our findings suggest a mix of aberrant cognitive linguistic and oculomotor processes being present in adults with dyslexia.
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Affiliation(s)
- Léon Franzen
- Department of Psychology, Concordia University, Montréal, Canada.
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK.
| | - Zoey Stark
- Department of Psychology, Concordia University, Montréal, Canada
| | - Aaron P Johnson
- Department of Psychology, Concordia University, Montréal, Canada
- CRIR/Lethbridge-Layton-Mackay Centre de Réadaptation du CIUSSS du Centre-Ouest-de-l'Île-de-Montréal, Montréal, Canada
- Réseau de Recherche en Santé de La Vision, Montréal, Canada
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Ono Y, Niida T, Shinomiya Y, Suzuki K, Hara N, Azegami Y, Sato T, Mimori C, Shimoizumi H. Eye-tracker-based Evaluation of Saccadic Deficits in Young Children with Developmental Disorders. ADVANCED BIOMEDICAL ENGINEERING 2021. [DOI: 10.14326/abe.10.70] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Yumie Ono
- Department of Electronics and Bioinformatics, School of Science and Technology, Meiji University
- Department of Psychiatry, Yale School of Medicine
| | - Takahiro Niida
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare
| | - Yuma Shinomiya
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare
| | - Kenji Suzuki
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare
| | - Naoto Hara
- Department of Orthoptics and Visual Sciences, School of Health Sciences, International University of Health and Welfare
| | - Yasuhiko Azegami
- Department of Speech and Hearing Sciences, School of Health Sciences, International University of Health and Welfare
| | - Taeko Sato
- Department of Speech and Hearing Sciences, School of Health Sciences, International University of Health and Welfare
| | - Chigusa Mimori
- Department of Speech and Hearing Sciences, School of Health Sciences, International University of Health and Welfare
| | - Hideo Shimoizumi
- Rehabilitation Center, International University of Health and Welfare
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Jafarlou F, Ahadi M, Jarollahi F. Eye movement patterns in Iranian dyslexic children compared to non-dyslexic children. Auris Nasus Larynx 2020; 48:594-600. [PMID: 33261980 DOI: 10.1016/j.anl.2020.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/09/2020] [Accepted: 11/18/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Dyslexia is the most common learning disorder that affects 5-10% of school aged children. Eye movement abnormalities and visual processing deficits have been reported in some of dyslexic children. Objective of this study is to compare the eye-movement patterns of Iranian dyslexic children with those of non-dyslexic children as they perform the oculomotor tests and to explore the relationship between their eye-movement patterns and their reading ability. METHODS Binocular eye movements were recorded by oculomotor subtype of videonystagmography (VNG) testing on 30 dyslexic children and 20 non-dyslexic age-matched children (aged 8-12) in both genders. Dyslexic children were diagnosed with DSM-V scale by experts in reading disorder centers. Gain of the pursuit and optokinetic tests and the latency, accuracy and velocity of the saccade test were measured in both groups of dyslexic and non-dyslexic children. The independent samples t-test, Chi-square test and linear regression test in SPSS v. 21 were used to analyze behavioral and eye-movement parameters. RESULTS Compared to the non-dyslexic group, dyslexic children presented lower gain in pursuit and optokinetic tests, and increased latency with decreased accuracy in saccade test. All behavioral and eye-movement parameters without saccade velocity differed significantly among two groups. CONCLUSION The atypical eye movement patterns observed in dyslexic children suggests a deficiency in the visual information processing and an immaturity of brain structures responsible for oculomotor skills.
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Affiliation(s)
- Fatemeh Jafarlou
- Department of Audiology, School of Rehabilitation Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Mohsen Ahadi
- Department of Audiology, Rehabilitation Research Center, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran.
| | - Farnoush Jarollahi
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran.
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Caldani S, Gerard CL, Peyre H, Bucci MP. Pursuit eye movements in dyslexic children: evidence for an immaturity of brain oculomotor structures? J Eye Mov Res 2020; 13. [PMID: 33828780 PMCID: PMC7881873 DOI: 10.16910/jemr.13.1.5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Background: Dyslexia is a disorder found in 5-10% of school-aged children. Several studies reported visual deficits and oculomotor abnormalities in dyslexic children. The objective of our study was to examine horizontal pursuit performance in dyslexic children, despite its poor involvement in reading. Methods: Eye movements were recorded by video-oculography in 92 children (46 dyslexic children, mean age: 9.77 ± 0.26 and 46 non dyslexic, IQ- and age-matched children). Both the number of catch-up saccades occurring during pursuit task and the gain of pursuit were measured. Results: Catch-up saccades were significantly more frequent in the dyslexic group than in the non-dyslexic group of children. Pursuit performance (in terms of the number of catch-up saccades and gain) significantly improved with increasing age in the non-dyslexic children group only. Conclusions: The atypical pursuit patterns observed in dyslexic children suggest a deficiency in the visual attentional processing and an immaturity of brain structures responsible for pursuit triggering. This finding needs to be validated by neuroimaging studies on dyslexia population.
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Abstract
Developmental dyslexia, a severe deficit in literacy learning, is a neurodevelopmental learning disorder. Yet, it is not clear whether existing neurobiological accounts of dyslexia capture potential predispositions of the deficit or consequences of reduced reading experience. Here, we longitudinally followed 32 children from preliterate to school age using functional and structural magnetic resonance imaging techniques. Based on standardised and age-normed reading and spelling tests administered at school age, children were classified as 16 dyslexic participants and 16 controls. This longitudinal design allowed us to disentangle possible neurobiological predispositions for developing dyslexia from effects of individual differences in literacy experience. In our sample, the disorder can be predicted already before literacy learning from auditory cortex gyrification and aberrant downstream connectivity within the speech processing system. These results provide evidence for the notion that dyslexia may originate from an atypical maturation of the speech network that precedes literacy instruction.
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