A study of motor performance and motor learning in episodic ataxia

Episodic ataxias are rare disorders in which periodic episodes of ataxia are separated by normal or near normal motor behaviour. They probably arise from dysfunctional membrane ion channels in the cerebellum. A patient with episodic ataxia EA-2 performed three motor tasks, before, during and after an ataxic episode. In all three tasks there were significant performance deficits during the ataxic episode. Two of the tasks also assessed motor adaptation (prism adaptation) or motor learning (ideogram drawing). In neither task was there significant disruption of motor adaptation or learning. These results suggest that the cerebellum may have separate roles in learning and in performance of visually guided movements, and that the dysfunction in this patient affected only his motor performance.