Motor impairment in dyslexia: the influence of attention disorders

Developmental dyslexia is a heterogeneous syndrome with a phonological core deficit and frequent association with other developmental disorders. Controversies exist about the influence of motor difficulties frequently encountered in dyslexia. According to different theoretical approaches, these motor impairments would reflect either a frequent co-morbid entity or a cerebellar dysfunction that could constitute the causal factor of reading disabilities. The principal aim of this study was to determine the frequency of motor impairments in a population of children with phonological dyslexia and specify possible links with attention deficit. We analysed retrospectively motor and attention abilities of 58 children with phonological dyslexia. An important sub-group of children with dyslexia (40-57% depending on the severity of motor difficulties) presented a motor impairment affecting co-ordination, balance and manual dexterity suggesting a cerebellar dysfunction. There was a significant association between attention deficit and motor impairments, with a specific impact on balance and co-ordination deficits. The comparison of performance in four groups defined according to the presence versus absence of attention deficit and motor impairment, respectively, were not in favour of a unequivocal causal link between reading disabilities and motor or attention disorders.