IMPAIRED PERFORMANCE OF CHILDREN WITH DYSLEXIA ON A RANGE OF CEREBELLAR TASKS

If is now thought that the cerebellum is involved in the acquisition o f ''language dexterity'' in addition to its established role in motor skill acquisition and execution. Mild cerebellar impairment, therefore , provides a possible explanation of a range of problems shown by chil dren with dyslexia. The authors have established suggestive evidence i n support of this hypothesis in tests of balance and of time estimatio n. In a further test of the hypothesis, a battery of clinical tests fo r cerebellar impairment, including tests of muscle tone and of coordin ation, was administered to matched groups of children with dyslexia an d control children aged 10, 14, and 18 years (55 subjects in all). The children with dyslexia showed highly significant impairments on all t he cerebellar tests, and significant impairment compared even with rea ding age controls on II of the 14 tasks. Deficits on the majority of t ests were among the largest found in our research program. The finding s, therefore, provide further intriguing evidence of cerebellar impair ment in dyslexia. We speculate that the well-established phonological deficits in dyslexia may arise initially from inefficient articulatory control attributable to cerebellar impairment.