Dyslexia and the Integration of Sensory Cues into Motor Action

Abstract

Besides difficulties in mastering literacy, dyslexic children also show poor postural control that might be related to how sensory cues coming from different sensory channels are integrated and trigger proper motor activity. The purpose of this study was to review the body of literature about the functioning of the postural control system in dyslexic children and understand how they use sensory information to produce motor actions. It has been demonstrated that dyslexic children sway more than non-dyslexic ones. Studies have shown that although manipulation of vision and somatosensory information provided by a moving room and a moving touch bar, respectively, induced correspondent body sway in dyslexic children, their postural responses to such manipulations were less coherent as compared to non-dyslexic children. When dyslexic children applied higher force on the moving bar, however, coherence between body sway and sensory manipulations was similar for dyslexic and non-dyslexic children. Finally, in the absence of peripheral visual cues, induced body sway in dyslexic children was temporally delayed regarding visual stimulus. Taken together, these results indicate that poor postural control in dyslexic children is related to impairments in the manner sensory information is acquired and used to produce postural responses. The need of dyslexic children to apply more force on the touch bar to improve coherence between sensory stimulus and body sway, together with the fact that in conditions in which visual cues were less informative, dyslexic children took longer to process sensory stimuli and produce motor responses, suggests that dyslexic children are more dependent on the quality of sensory cues.