Sensorimotor Integration in Dyslexic Children under Different Sensory Stimulations

Jeff A Beeler,André R Viana,José A Barela,Paulo B De Freitas,Milena Razuk

doi:10.1371/journal.pone.0072719

Jeff A Beeler, André R Viana + Show 3 more

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https://doi.org/10.1371/journal.pone.0072719

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Abstract

Dyslexic children, besides difficulties in mastering literacy, also show poor postural control that might be related to how sensory cues coming from different sensory channels are integrated into proper motor activity. Therefore, the aim of this study was to examine the relationship between sensory information and body sway, with visual and somatosensory information manipulated independent and concurrently, in dyslexic children. Thirty dyslexic and 30 non-dyslexic children were asked to stand as still as possible inside of a moving room either with eyes closed or open and either lightly touching a moveable surface or not for 60 seconds under five experimental conditions: (1) no vision and no touch; (2) moving room; (3) moving bar; (4) moving room and stationary touch; and (5) stationary room and moving bar. Body sway magnitude and the relationship between room/bar movement and body sway were examined. Results showed that dyslexic children swayed more than non-dyslexic children in all sensory condition. Moreover, in those trials with conflicting vision and touch manipulation, dyslexic children swayed less coherent with the stimulus manipulation compared to non-dyslexic children. Finally, dyslexic children showed higher body sway variability and applied higher force while touching the bar compared to non-dyslexic children. Based upon these results, we can suggest that dyslexic children are able to use visual and somatosensory information to control their posture and use the same underlying neural control processes as non-dyslexic children. However, dyslexic children show poorer performance and more variability while relating visual and somatosensory information and motor action even during a task that does not require an active cognitive and motor involvement. Further, in sensory conflict conditions, dyslexic children showed less coherent and more variable body sway. These results suggest that dyslexic children have difficulties in multisensory integration because they may suffer from integrating sensory cues coming from multiple sources.

Highlights

Dyslexia has been characterized by a failure to attain the expected literacy skills for a given age, despite adequate intellectual ability and sufficient educational provision (e.g., [1,2])
Studies have shown that dyslexic children and adults present inconsistent and highly variable motor performance during postural control tasks [1,3,4,5] as well as during gait [3]
We further suggested that motor performance of dyslexic individuals would be affected by their difficulty to transform multiple sensory cues available in relevant information to perform purposeful task in an automatic manner

Summary

Introduction

Dyslexia has been characterized by a failure to attain the expected literacy skills for a given age, despite adequate intellectual ability and sufficient educational provision (e.g., [1,2]). These studies clearly demonstrated that the postural control of dyslexic children was highly impaired by addition of a second task that increases attentional demands [5,6,7] These evidences indicate a much larger scope of symptoms, which question the specificity of this disorder and its relation only to literacy competence. We have recently demonstrated using the moving room paradigm (i.e., paradigm used to observe the effect of dynamic changes in the visual environment on postural sway) that dyslexic children couple sensory information to body oscillation slightly different than their peers in upright stance while visual information was manipulated [10] Based upon these results, we further suggested that motor performance of dyslexic individuals would be affected by their difficulty to transform multiple sensory cues available in relevant information to perform purposeful task in an automatic manner. To use multiple sensory cues to implement proper motor activation required to maintain upright stance [10]

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