Fine motor skills and interhemispheric transfer in treatment-naive male children with Tourette syndrome.

AIM: This study addressed whether Tourette syndrome is associated with an impairment of fine motor skills or altered interhemispheric transfer. We additionally investigated the association between interhemispheric transfer and size of the corpus callosum.
METHOD: The sample, a subsample of our larger neuroimaging sample, included 27 treatment-naive males with 'pure' Tourette syndrome (age range 10y 2mo-14y 4mo; mean age 11y 10mo, SD 1y 2mo) and 26 matched healthy comparison children (age range 10y 2mo-14y 4mo; mean age 11y 10mo, SD 1y 1mo). A finger tapping task and the Purdue Pegboard were used to assess fine motor skills. Interhemispheric transfer time (ITT) was measured with the Poffenberger paradigm. The neuroanatomical data were derived from our previous neuroimaging study.
RESULTS: ITT was negatively correlated with the size of callosal subregion 3 (r=-0.366, p=0.028), indicating that a shorter ITT was associated with a larger corpus callosum.
INTERPRETATION: Our findings support the assumption that previously reported impairment of motor skills in Tourette syndrome does not directly result from tics but from other factors such as medication or comorbidities. Following the assumption that callosal subregion 3 in Tourette syndrome grows as a consequence of tic performance over years, our preliminary results suggest that this growth might accelerate interhemispheric transfer in Tourette syndrome. © The Authors. Developmental Medicine & Child Neurology