Reading Errors in Young Adults with Vermis or Cerebellar Hemispheric Lesions pp. 337-349
Authors: (Rita Moretti, Paola Torre, Rodolfo M. Antonello, Department of Internal Medicine and Clinical Neurology, UCO of Clinical Neurology , Cognitive Disturbances Section, University of Trieste, Trieste, Italy)
Abstract: Some evidence associates dyslexia, both developmental and acquired, with binocular instability, reduced amplitude of accomodation and reduced contrast sensitivity for both low spatial frequencies and uniform field flicker. If vision plays a dominant role in the guidance of movements, cerebellar lesions produce profound deficits in visuomotor control, considering that visual information is integrated in lobule VIc and VII of the caudal vermis important for the control of both smooth pursuit and target-directed saccades. Considering these perspectives, we studied 5 young patients with selective vermian/paravermian lesions, , and 5 young adults with selective hemispheric cerebellar lesion, who before did never complain reading troubles, in order to detect eventual difficulties or abnormalities in reading process. We have compared the results to those obtained by a group of normal volunteers. We suggest that only vermian patients (and not those with hemispheric lesions) respond imperfectly to normal controlling influences exerted by the vermis region on the SC and the pontine nuclei; therefore, this may cause inappropriate eye positioning sufficient to decrease the ability of reading. In particular, we hypothesize that vermian lesions produce a defective control of saccadic movements, fundamental for the execution of the reading task.