Vertical disconjugacy during reading in dyslexic and non-dyslexic children

Nathalie Goulème (1, 2) , Cynthia Lions (1, 2) , Christophe-Loic Gerard (3) , Hugo Peyre (1, 3) , Hung Thai-Van (2) , Maria Pia Bucci (1)

1 NeuroDiderot (UMR_S_1141 / U1141) - Maladies neurodéveloppementales et neurovasculaires
2 CRNL - Centre de recherche en neurosciences de Lyon - Lyon Neuroscience Research Center
3 Service psychiatrique de l'enfant et de l'adolescent [CHU Hôpital Robert Debré]

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 adeficiency 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.

Domaines: Neurosciences; Organes des sens; Pédiatrie

Nathalie Goulème, Cynthia Lions, Christophe-Loic Gerard, Hugo Peyre, Hung Thai-Van, et al.. Vertical disconjugacy during reading in dyslexic and non-dyslexic children. Neuroscience Letters, 2018, 671, pp.82-87. ⟨10.1016/j.neulet.2018.02.016⟩. ⟨hal-03151289⟩