Feedforward motor control in developmental dyslexia and developmental coordination disorder: Does comorbidity matter?

Publication date: May 2018
Source:Research in Developmental Disabilities, Volume 76
Author(s): Fabien Cignetti, Marianne Vaugoyeau, Aurelie Fontan, Marianne Jover, Marie-Odile Livet, Catherine Hugonenq, Frédérique Audic, Brigitte Chabrol, Christine Assaiante
Background and aimFeedforward and online controls are two facets of predictive motor control from internal models, which is suspected to be impaired in learning disorders. We examined whether the feedforward component is affected in children (8–12 years) with developmental dyslexia (DD) and/or with developmental coordination disorder (DCD) compared to typically developing (TD) children.MethodsChildren underwent a bimanual unloading paradigm during which a load supported to one arm, the postural arm, was either unexpectedly unloaded by a computer or voluntary unloaded by the subject with the other arm.ResultsAll children showed a better stabilization (lower flexion) of the postural arm and an earlier inhibition of the arm flexors during voluntary unloading, indicating anticipation of unloading. Between-group comparisons of kinematics and electromyographic activity of the postural arm revealed that the difference during voluntary unloading was between DD-DCD children and the other groups, with the former showing a delayed inhibition of the flexor muscles.ConclusionDeficit of the feedforward component of motor control may particularly apply to comorbid subtypes, here the DD-DCD subtype. The development of a comprehensive framework for motor performance deficits in children with learning disorders will be achieved only by dissociating key components of motor prediction and focusing on subtypes and comorbidities.



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