Speech and oral motor learning in individuals with cerebellar atrophy

The purpose of this study was to determine whether cerebellar pathology interferes with motor learning for either speech or novel tasks. Practice effects were contrasted between persons with cerebellar cortical atrophy (CCA) and control participants on previously learned real speech, nonsense speech, and novel nonspeech oral-movement tasks. Studies of limb motor learning suggested that control participants would evidence reduced variability, increased speed of movement, and reduced movement amplitude with practice as compared with the CCA group. No significant differences were found between the real- and nonsense-speech tasks. For both speech tasks, although neither group reduced their movement variability with practice, both groups significantly reduced jaw closing displacement and velocity with practice. For the novel nonspeech oral-movement task, no change with practice was observed in either group in terms of variability, amplitude, or peak velocity. No effects of cerebellar pathology were seen in either the speech- or oral-movement tasks. These results demonstrated that with practice of speech tasks, a previously learned motor skill, movement speed and displacement decreased in both groups. Therefore, the effects of practice differed between previously learned speech tasks and the novel oral-movement task regardless of cerebellar pathology.