Proceedings of The Physiological Society

University College London December 2005 (2006) Proc Physiol Soc 1, C21

Oral Communications

A cerebellar deficit in dyslexics? Evidence from peg-moving

Stein, John; Stoodley, Catherine J;

1. University Laboratory of Physiology, Oxford OX1 3DP, United Kingdom.

Developmental dyslexia is diagnosed when literacy skills are not commensurate with a persons general cognitive ability and education. While the most common difficulty found in dyslexia is poor phonological processing, many dyslexics are remarkably clumsy; they have poor balance and atrocious handwriting, suggesting that they may also have motor deficits. These have been ascribed to cerebellar abnormalities. To establish whether the motor difficulties described in dyslexic children persist into adulthood, we tested 18 dyslexic adults and 22 control good readers matched for age and general IQ on Annetts peg-moving task. The dyslexic participants performed significantly more slowly than control adults on the peg-moving task with their dominant hands (p = 0.004). Furthermore, the response times of both dyslexics and controls carrying out orthographic and phonological reading tasks (that did not involve hand movements) correlated with their dominant hand peg-moving ability (orthographic r = 0.45, p = 0.005; phonological r = 0.38, p = 0.025). These results suggest that the motor speed deficit in dyslexia may not be simply a sign of developmental delay, but their cerebellar deficit may persist into adulthood. Furthermore, motor speed may be related to the speed at which literacy information is processed. These results add to the mounting evidence that cerebellar abnormalities are involved in dyslexia.

Where applicable, experiments conform with Society ethical requirements