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Le Touquet – Paris-Plage, France

Gouleme N.,University Paris Diderot | Ezane M.D.,University Paris Diderot | Wiener-Vacher S.,University Paris Diderot | Wiener-Vacher S.,Vestibular and Oculomotor Evaluation Unit | Bucci M.P.,University Paris Diderot
International Journal of Developmental Neuroscience | Year: 2014

The aim of this study was to explore further the development of postural control in healthy children. The novelty of this study was to resort to both spatial and temporal analysis of the center of pressure (CoP).Forty-six healthy children from 4 to 16 years old (mean age: 9.1. ±. 3 years) and a group of 13 healthy adults (mean age: 25. ±. 3 years) participated to this study. Postural control was tested on both a stable and an unstable platform in three different visual conditions: eyes open fixating a target, under optocinetic stimulation, and eyes closed.Resul*ts showed a significant decrease of both surface area as well as mean velocity of the center of pressure (CoP) during childhood. With the children's increasing age, the spectral power indices decreased significantly and the canceling time increased significantly.Such improvement in postural control could be due to a better use of sensorial inputs and cerebellar integration during development, allowing subjects to achieve more efficient postural control. © 2014.Published by Elsevier Ltd. Source

Lions C.,University Paris Diderot | Bui-Quoc E.,Service dOphtalmologie | Wiener-Vacher S.,Vestibular and Oculomotor Evaluation Unit | Seassau M.,e(ye)BRAIN | Bucci M.P.,University Paris Diderot
PLoS ONE | Year: 2013

Purpose: The objective of our study was to examine horizontal smooth pursuit performance in strabismic children and in children with vergence deficits, and to compare these data with those recorded in a group of control age-matched children. Methods: Binocular eye movements were recorded by video-oculography in ten strabismic children (mean age: 9.8±0.8) and seven children with vergence deficits (mean age: 10.8±0.6). Data were compared to that of age-matched control children (mean age: 9.8±0.8 years). Results: Catch-up saccades amplitude in strabismic children and in children with vergence deficits were significantly higher than in control age-matched children. Moreover, in strabismic children the amplitude of catch-up saccades was significantly higher in rightward than in leftward direction. The number of catch-up saccades was also significantly higher in rightward than in leftward direction. The gain value of pursuits in rightward direction was significantly higher in the right eye than in the left one; for the right eye, the gain value was significantly higher in rightward than in leftward direction. Binocular coordination of pursuit was better in control age-matched children than in children with vergence deficits and than in strabismic children. Conclusions: Binocular coordination of pursuit is abnormal in children with vergence deficits and worse in strabismic children. Binocular vision plays an important role in improving binocular coordination of pursuit. © 2013 Lions et al. Source

Gaertner C.,University Pierre and Marie Curie | Gaertner C.,Vestibular and Oculomotor Evaluation Unit | Bucci M.P.,University Paris Diderot | Ajrezo L.,Vestibular and Oculomotor Evaluation Unit | And 2 more authors.
Vision Research | Year: 2013

Prior studies have pointed toward a link between the saccadic and vergence systems, coordinating binocular saccadic movements. Recent studies have shown that vergence deficits in children induce poor binocular coordination during saccades, but none of them have studied ocular motility in children during a daily task such as reading. The present study tests whether vergence deficits in children perturb binocular coordination of saccades and fixation during reading. Our second objective was to explore whether vergence training could improve the quality of binocular coordination. Twelve patients (from 7.3 to 13.4. years old) complaining from vertigo but without vestibular and neurological pathology underwent orthoptic tests and were selected for our study when they presented vergence deficits. Eye movements were recorded during a reading task with a Mobile EyeBrain® Tracker video-oculography system. Data were compared to twelve age-matched controls with normal orthoptic values. While there was no statistically significant difference in saccade amplitudes between the two groups (p= 0.29), patients showed higher disconjugacy during and after the saccades compared to controls (p< 0.001). After orthoptic training, six patients out of the first 12 examined came back for a second oculomotor test. All showed a significant improvement of their binocular saccade coordination. We suggest that the larger disconjugacy during reading observed in patients before training could be due to poor vergence as initially assessed by orthoptic examination. Such findings support the hypothesis of a tight relationship between the saccadic and vergence systems for controlling the binocular coordination of saccades. The improvement reported after orthoptic training is in line with the hypothesis of an adaptative interaction on a premotor level between the saccadic and vergence system. © 2013 Elsevier Ltd. Source

Ajrezo L.,Vestibular and Oculomotor Evaluation Unit | Ajrezo L.,University Paris Diderot | Wiener-Vacher S.,Vestibular and Oculomotor Evaluation Unit | Wiener-Vacher S.,University Paris Diderot | Bucci M.P.,University Paris Diderot
PLoS ONE | Year: 2013

Introduction: Dual-task performance is known to affect postural stability in children. This study focused on the effect of oculomotor tasks like saccadic eye movements on postural stability, studied in a large population of children by recording simultaneously their eye movements and posture. Materials and Methods: Ninety-five healthy children from 5.8 to 17.6 years old were examined. All children were free of any vestibular, neurological, ophtalmologic and orthoptic abnormalities. Postural control was measured with a force platform TechnoConcept®, and eye movements with video oculography (MobilEBT®). Children performed two oculomotor tasks: fixation of a stable central target and horizontal saccades. We measured the saccade latency and the number of saccades during fixation as well as the surface, length and mean velocity of the center of pressure. Results: During postural measurement, we observed a correlation between the age on the one hand and a decrease in saccade latency as well as an improvement in the quality of fixation on the other. Postural sway decreases with age and is reduced in the dual task (saccades) in comparison with a simple task of fixation. Discussion - Conclusion: These results suggest a maturation of neural circuits controlling posture and eye movements during childhood. This study also shows the presence of an interaction between the oculomotor system and the postural system. Engaging in oculomotor tasks results in a reduction of postural sway. © 2013 Ajrezo et al. Source

Wiener-Vacher S.R.,Vestibular and Oculomotor Evaluation Unit | Obeid R.,Vestibular and Oculomotor Evaluation Unit | Abou-Elew M.,Vestibular and Oculomotor Evaluation Unit
Journal of Pediatrics | Year: 2012

Objective: To examine the findings and impact of postmeningitis vestibular dysfunction on early posturomotor development. Meningitis in children is frequently associated with postural instability, which is often attributed to an undefined neurologic disorder but it could actually be due to vestibular impairment. Study design: In a retrospective cohort study, we compared groups with vestibular loss before versus after independent walking: 37 children (18 girls, 19 boys; median age: 2.3 years) hospitalized for bacterial meningitis and referred for postural instability. A complete vestibular evaluation included 3 tests for function of the 6 semicircular canals (caloric, earth vertical axis rotation, head impulse tests), 2 tests for otolith function assessment (vestibular evoked myogenic potentials, off vertical axis rotation), audiologic evaluation, neurologic examination, and brain and temporal bone imaging. Results: Twenty-nine children (10.5% of the 276 children hospitalized with bacterial meningitis) had vestibular impairment. Vestibular loss was complete bilaterally in 16 of 37 children and partial in 13 of 37, and 8 cases had normal vestibular responses. Neurologically normal children who had meningitis before they walked independently and had complete bilateral vestibular loss walked significantly later and their postural instability lasted longer than children in the other groups. The degree of vestibular impairment correlated with the postural instability duration and with the degree of hearing loss. Conclusions: Bacterial meningitis in young children can impair vestibular function completely, leading to delayed posturomotor development if meningitis occurs before independent walking, even in absence of neurologic impairment. Vestibular evaluations are encouraged for postmeningitis evaluation, particularly in cases with postural instability exceeding 8 days, hearing impairment, and programmed cochlear implant. Copyright © 2012 Mosby Inc. Source

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