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The present longitudinal study investigated the hypothesis that early musical skills (as measured by melodic and rhythmic perception and memory) predict later literacy development via a mediating effect of phonology. We examined 130 French-speaking children, 31 of whom with a familial risk for developmental dyslexia (DD). Their abilities in the three domains were assessed longitudinally with a comprehensive battery of behavioral tests in kindergarten, first grade, and second grade. Using a structural equation modeling approach, we examined potential longitudinal effects from music to literacy via phonology. We then investigated how familial risk for DD may influence these relationships by testing whether atypical music processing is a risk factor for DD. Results showed that children with a familial risk for DD consistently underperformed children without familial risk in music, phonology, and literacy. A small effect of musical ability on literacy via phonology was observed, but may have been induced by differences in stability across domains over time. Furthermore, early musical skills did not add significant predictive power to later literacy difficulties beyond phonological skills and family risk status. These findings are consistent with the idea that certain key auditory skills are shared between music and speech processing, and between DD and congenital amusia. However, they do not support the notion that music perception and memory skills can serve as a reliable early marker of DD, nor as a valuable target for reading remediation. RESEARCH HIGHLIGHTS: Music, phonology, and literacy skills of 130 children, 31 of whom with a familial risk for dyslexia, were examined longitudinally. Children with a familial risk for dyslexia consistently underperformed children without familial risk in musical, phonological, and literacy skills. Structural equation models showed a small effect of musical ability in kindergarten on literacy in second grade, via phonology in first grade. However, early musical skills did not add significant predictive power to later literacy difficulties beyond phonological skills and family risk status., (© 2024 John Wiley & Sons Ltd.)

Reading disabilities have a profound impact on the academic performance and achievement of children. Although oculomotor pattern abnormalities during reading in children with dyslexia are well known, those in individuals with attention deficit and hyperactive disorders (ADHD) - who also frequently exhibit a reading impairment - remain largely undetermined. The objective of the present study was to evaluate the peculiarities of oculomotor pattern abnormalities during a reading task. An eye-tracker was used to record eye movements in four distinct groups of children with neurodevelopmental disorders: children with dyslexia, children with ADHD with and without comorbid dyslexia, and in a group of typically developing children (TD). Ninety-six children participated in the study (24 children per group, IQ- and age-matched groups). The duration of fixation, the total reading time, and the number of forward and backward saccades were similar in children with dyslexia and ADHD + dyslexia, but were significantly different from those observed in children with ADHD and with TD. Our findings suggest a link between dyslexia and oculomotor reading impairments in both children with dyslexia and children with ADHD + dyslexia, indicating that the oculomotor pattern in children with ADHD without comorbid dyslexia is similar to that observed in TD children. We suggest that an objective eye movement recording during a reading task could help clinicians to better evaluate the possible presence of comorbid dyslexia in children with ADHD. Furthermore, children with ADHD with and without comorbid dyslexia could also have working memory deficiencies. Further studies are needed to confirm this finding., (© 2022. The Author(s), under exclusive licence to The International Dyslexia Association.)

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.

Despite evidence for a difference in total brain volume between dyslexic and good readers, no previous neuroimaging study examined differences in allometric scaling (i.e. differences in the relationship between regional and total brain volumes) between dyslexic and good readers. The present study aims to fill this gap by testing differences in allometric scaling and regional brain volume differences in dyslexic and good readers. Object-based morphometry analysis was used to determine grey and white matter volumes of the four lobes, the cerebellum and limbic structures in 130 dyslexic and 106 good readers aged 8-14 years. Data were collected across three countries (France, Poland and Germany). Three methodological approaches were used as follows: principal component analysis (PCA), linear regression and multiple-group confirmatory factor analysis (MGCFA). Difference in total brain volume between good and dyslexic readers was Cohen's d = 0.39. We found no difference in allometric scaling, nor in regional brain volume between dyslexic and good readers. Results of our three methodological approaches (PCA, linear regression and MGCFA) were consistent. This study provides evidence for total brain volume differences between dyslexic and control children, but no evidence for differences in the volumes of the four lobes, the cerebellum or limbic structures, once allometry is taken into account. It also finds no evidence for a difference in allometric relationships between the groups. We highlight the methodological interest of the MGCFA approach to investigate such research issues., (© 2020 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Aim: The aim of the present study was to examine the effects of colored filters on reading performance and eye movement control in children with and without dyslexia., Methods: Eighteen children with dyslexia and 18 children without dyslexia were seated on a chair with their heads stabilized by a forehead and chin support. The children read different texts under the following three filter conditions: no filter, yellow filter, and green filter. The children's eye movements were recorded with a Mobile EyeBrain Tracker. Reading total time, duration of fixation between two successive saccades, pro-saccades amplitude and number of pro- and retro-saccades were obtained., Results: Children with dyslexia read the fastest and had the shortest fixation time in the green filter condition compared with the other conditions. Furthermore, children with dyslexia showed the shortest fixation time in the green filter condition with respect to the other conditions., Conclusions: Taken together, these results suggested that the green filter improved reading performance in children with dyslexia because the filter most likely facilitated cortical activity and decreased visual distortions., (Copyright © 2018. Published by Elsevier Ltd.)

The aim of the present study was to explore the possible change in eye movement performance in a group of dyslexic and non-dyslexic children reading four lines of a text with different font sizes and spaces between the words. Fifteen dyslexic children from 7 to 12 years old and two groups of fifteen non-dyslexic children, respectively reading and chronological age-matched group, participated in this study. Horizontal eye movements from both eyes were recorded by a video-system (EyeBrain T2®) while the children were reading a text. Three different texts were used with different font sizes and spaces between words. Results showed that increasing font size and character spacing significantly reduced duration of the fixation and increased the number and amplitude of prosaccades in all groups of children tested. Interestingly, while reading texts in which the letters were larger and more spaced (Texts 2 and 3), the duration of fixations in dyslexic and in non-dyslexic children groups decreased, becoming similar to those reported in the non-dyslexic children group. We suggest that large letter spacing between words could be employed in schools to help dyslexic children in order to ameliorate their reading performance., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The goal of this study is to explore eye movement recordings during the Developmental Eye Movement (DEM) test in dyslexic and non-dyslexic children. Thirteen children with dyslexia, 13 non-dyslexic chronological age- and IQ-matched children and 13 non-dyslexic reading age- and IQ-matched children were examined. Test C of the DEM test was performed with and without eye movement recordings (eye tracker by SuriCog). The results of the three groups were compared. Children with dyslexia and non-dyslexic children of equivalent reading age have significant longer fixation time and take longer to read Test C of the DEM test than non-dyslexic children of similar chronological age. A significant correlation was also found between the fixation time and the number of words read in one minute with the total time to read Test C of the DEM test. DEM test is a useful test for exploring the oculomotor behavior of dyslexic children during reading. The maturation of cortical structures controlling fixation capability appears to play a crucial role in reading skills., Competing Interests: The authors have declared that no competing interests exist.

The aim of this study was to examine eye movements and postural control performance among dyslexic children while reading a text and performing the Landolt reading task. Fifteen dyslexic and 15 non-dyslexic children were asked to stand upright while performing two experimental visual tasks: text reading and Landolt reading. In the text reading task, children were asked to silently read a text displayed on a monitor, while in the Landolt reading task, the letters in the text were replaced by closed circles and Landolt rings, and children were asked to scan each circle/ring in a reading-like fashion, from left to right, and to count the number of Landolt rings. Eye movements (Mobile T2®, SuriCog) and center of pressure excursions (Framiral®, Grasse, France) were recorded. Visual performance variables were total reading time, mean duration of fixation, number of pro- and retro-saccades, and amplitude of pro-saccades. Postural performance variable was the center of pressure area. The results showed that dyslexic children spent more time reading the text and had a longer duration of fixation than non-dyslexic children. However, no difference was observed between dyslexic and non-dyslexic children in the Landolt reading task. Dyslexic children performed a higher number of pro- and retro-saccades than non-dyslexic children in both text reading and Landolt reading tasks. Dyslexic children had smaller pro-saccade amplitude than non-dyslexic children in the text reading task. Finally, postural performance was poorer in dyslexic children than in non-dyslexic children. Reading difficulties in dyslexic children are related to eye movement strategies required to scan and obtain lexical and semantic meaning. However, postural control performance, which was poor in dyslexic children, is not related to lexical and semantic reading requirements and might not also be related to different eye movement behavior., Competing Interests: The authors have declared that no competing interests exist.

Purpose: The objective of this study was to explore vertical binocular coordination in dyslexic and non-dyslexic children during saccades and post-saccadic fixation period while reading a text., Methods: Binocular eye movements were recorded by an infrared system (Mobile T2 ® , SuriCog) in thirty-six dyslexic children from 7.3 to 13.6 years of age (mean age: 10.4 ± 0.3 years) who were asked to silently read a four-line text during binocular viewing. Data were compared to those of thirty-six age-matched non-dyslexic children., Results: Vertical disconjugacy during post-saccadic fixation was higher in dyslexic children with respect to non-dyslexic children group. Vertical disconjugacy was not age-dependent either for dyslexic children or for non-dyslexic children., Conclusions: The poor binocular vertical coordination observed in dyslexic children while reading could suggest a deficiency in the cerebellum and/or extra-ocular muscles involved in vertical eye alignment. Moreover, the fact that this vertical binocular coordination was not age-dependent could be due to an abnormal eye position and/or to a dysfunction of midbrain structures involved in vertical vergences., (Copyright © 2018. Published by Elsevier B.V.)

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 catchup 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. [ABSTRACT FROM AUTHOR]

Purpose: Preliminary evidence indicated that children with a reading disorder (RD) may have deviance in their ability to perform high demanding cognitive tasks, such as reading, depending on somatosensory inputs. Until now, only anecdotical reports suggested that improving somatosensory inputs may influence their ability to maintain a stable perception of the visual world despite continuous movements of our eyes, head, and body. Here, we investigated whether changes in upright perception, the subjective visual vertical (SVV), were modulated by somatosensory inputs in a group of children with RD. Method: The SVV task was used under two distinct conditions, i.e., with or without somatosensory inputs from the foot. We enrolled a group of 20 children with reading disorders and 20 sex-, age-, IQ- matched children with neurotypical development. Results: Responses to the SVV task were found to be significantly less accurate in children with RD than in children with neurotypical development (p < 0.001). In the latter, SVV response did not depend on somatosensory inputs from the foot. In contrast, in children with RD somatosensory inputs, either improved or worsen their SVV depending on the tilt direction (p < 0.01). Conclusion: Our results suggested that SVV responses in children with RD could be related to an immaturity for heteromodal sensory integration, including somatosensory inputs. [ABSTRACT FROM AUTHOR]

To our knowledge, behavioral studies recording visual fixations abilities in dyslexic children are scarce. The object of this article is to explore further the visual fixation ability in dyslexics compared to chronological age-matched and reading age-matched non-dyslexic children. Fifty-five dyslexic children from 7 to 14 years old, 55 chronological age-matched non-dyslexic children and 55 reading age-matched non-dyslexic children participated to this study. Eye movements from both eyes were recorded horizontally and vertically by a video-oculography system (EyeBrain® T2). The fixation task consisted in fixating a white-filled circle appearing in the center of the screen for 30 s. Results showed that dyslexic children produced a significantly higher number of unwanted saccades than both groups of non-dyslexic children. Moreover, the number of unwanted saccades significantly decreased with age in both groups of non-dyslexic children, but not in dyslexics. Furthermore, dyslexics made more saccades during the last 15 s of fixation period with respect to both groups of non-dyslexic children. Such poor visual fixation capability in dyslexic children could be due to impaired attention abilities, as well as to an immaturity of the cortical areas controlling the fixation system. [ABSTRACT FROM AUTHOR]

Dyslexia is a specific disorder in reading abilities. The aim of this study was to explore whether a short visual attentional training could improve reading capabilities in children with reading disorders by changing their oculomotor characteristics. Two groups (G1 and G2) of 25 children with reading disabilities and who are matched in IQ (intelligence quotient), sex, and age participated in the study. The allocation of a subject to a specific group (G1 = experimental group; G2 = control group) was generated in an unpredictable random sequence. The reading task was recorded twice for G1, i.e., before (T1) and after (T2) 10 min of visual attentional training. Training consisted of oculomotor tasks (saccades and pursuits movements) and searching tasks (three different exercises). For G2, the two reading tasks at T1 and T2 were done at an interval of 10 min instead. We found that at T1, oculomotor performances during reading were statistically similar for both groups of children with reading disabilities (G1 and G2). At T2, the group G1 only improved oculomotor capabilities significantly during reading; in particular, children read faster, and their fixation time was shortest. We conclude that short visual attentional training could improve the cortical mechanisms responsible for attention and reading capabilities. Further studies on a larger number of dyslexic children will be necessary in order to explore the effects of different training types on the visual attentional span given its important role on the orienting and focusing visuospatial attention and on the oculomotor performance in children with dyslexia. [ABSTRACT FROM AUTHOR]

Highlights • Dyslexic children need longer eye fixation in reading a text impairing reading performance. • Reading time and eye fixation are similar for both non- and dyslexic children in the Landolt task. • Dyslexic children postural performance is worse for both visual tasks but more in the Landolt task. • Postural performance in dyslexic children is not related to lexical and semantic requirements. Abstract In this study, we investigated the eye movement and postural control performance in dyslexic children while reading text and performing Landolt reading when sitting and standing. Fifteen dyslexic and 15 non-dyslexic children were asked to sit in a chair while the eye movements were recorded, and were then asked to stand on an unstable platform while eye movements and postural sway were recorded simultaneously at the time of Landolt reading and text reading. Eye movements were recorded binocularly by Mobile EyeBrain Tracker (MobileT2®, SuriCog) and center of pressure excursions were recorded by Multitest Equilibre (by Framiral®). The dependent variables for visual performance in the reading tasks were: total reading time, mean duration of fixation, number of pro- and retro-saccades, and amplitude of pro-saccades. The dependent variable for postural performance was the center of pressure area. The results showed that dyslexic children spent more time reading the text compared to non-dyslexic children (p < 0.02). However, no difference was observed for the Landolt reading task (p > 0.05). Dyslexic children performed longer fixations in the sitting condition as compared to the standing (p < 0.03), namely, higher number of pro- (p < 0.001) and retro- saccades (p < 0.001), and smaller pro-saccades amplitude (p < 0.001). Therefore, when the linguistic and semantic requirements are not involved in the reading task, dyslexic children perform similar to non-dyslexic children even in different task requirements (p > 0.05). Finally, postural performance was poorer in dyslexic children than in non-dyslexic children in both the reading tasks (p < 0.02). However, postural control performance, which was poor in dyslexic children, is not related to lexical and semantic reading requirements. [ABSTRACT FROM AUTHOR]

Highlights • Eye movement's parameters were differently affected by postural conditions. • The quality of fixation was weak in children with neurodevelopmental disorders with respect to typically developmental children. • Postural stability was poor in children with neurodevelopmental disorders with respect to typically developing children. Abstract In everyday life, our activities frequently involve the simultaneous performance of two or more tasks. Sharing attention between two concurrent tasks may result in a decrease in performance specifically among children with neurodevelopmental disorders. The objective of the study was to determine whether the influence of postural conditions (sitting condition, single task; standing condition, dual task) on eye movement performances on three visual tasks with high attentional load (visually-guided saccade task, memory-guided saccade task and fixation task) was different in children with neurodevelopmental disorders (attention deficit and hyperactive disorder, dyslexia, and high functioning autism spectrum disorder) when compared to typically developing children. One hundred and four children (26 per group, sex-age- and IQ-matched groups) were evaluated. We found that for the fixation task only, the three groups of children with neurodevelopmental disorders had poorer eye movements performances in the standing condition compared to the sitting condition while no such difference was found for typically developing children. We suggest that children with neurodevelopmental disorders have fewer attentional resources available for performing correctly oculomotor tasks with high attentional load leading to impairment of these tasks for maintaining a good level of postural stability. [ABSTRACT FROM AUTHOR]

Autism, learning disabilities and attention deficit/hyperactive disorder are often comorbid disorders. In order to try and find some markers that might be transnosographic, we hypothesized that abnormal postural sway profiles may discriminate children with neurodevelopmental disorders (NDDs) from typically developing children. The aim of our study was thus to compare spatial and temporal measures of the Center of Pressure in three distinct groups of children with NDDs (high functioning autism spectrum disorders, learning disabilities (dyslexia) and attention deficit/hyperactive disorders) and in typically developing children. Postural performances were thus evaluated in 92 children (23 per group, sex-, age- and IQ-matched groups) by using the Multitest Equilibre platform (Framiral ® ). Two viewing conditions (eyes open and eyes closed) were tested on a stable and unstable platform. Results reported similar poor postural instability for the three groups of children with NDDs with respect to the typically developing children, and this was observed for both spatial as well as temporal analysis of displacement of the center of pressure. Such postural instability observed in children with NDDs could be due to impairment in using sensorial inputs to eliminate body sway, probably due to poor cerebellar integration. [ABSTRACT FROM AUTHOR]