Short-Term Effect of Intensive Speech Therapy on Dysarthria in Patients With Sporadic Spinocerebellar Degeneration

Purpose The aim of this study was to investigate a structured approach for effective speech therapy (ST) for dysarthria and speech-related quality of life in patients with sporadic spinocerebellar degeneration (SCD), including cerebellar-type multiple-system atrophy and cerebellar cortical atrophy. Method Twenty-two patients with SCD (cerebellar-type multiple system atrophy, 15 patients; cerebellar cortical atrophy, seven patients) who underwent intensive ST were examined. Dysarthria was evaluated using the Scale for Assessment and Rating of Ataxia Speech Dysfunction, Assessment of Motor Speech for Dysarthria Articulation, oral diadochokinesis (OD), and Voice Handicap Index-10 (VHI-10). Respiratory muscle strength (inspiratory and expiratory pressure) and respiratory–phonatory coordination (maximum phonation time) were measured. Cognitive function was evaluated using the Montréal Cognitive Assessment and the word fluency test. Mood was evaluated using the Hospital Anxiety and Depression Scale. The relationships between dysarthria scales (particularly, VHI-10) and clinical data were analyzed using stepwise regression. The differences in outcomes after intensive ST were analyzed using the Wilcoxon signed-rank test. The alpha level ( p ) for statistical significance was set at .0125 by Bonferroni correction. Results For both pre- and post-ST, the patient's OD ( p = .002) and maximum phonation time ( p = .002) significantly improved, except for Speech Dysfunction scores of the Scale for Assessment and Rating of Ataxia ( p = .705) and the VHI-10 ( p = .018). The Assessment of Motor Speech for Dysarthria Articulation, OD, and inspiratory pressure were identified as independent variables of VHI-10 (adjusted R 2 = .820) for speech-related quality of life; no correlations among the Montréal Cognitive Assessment, word fluency test, and Hospital Anxiety and Depression Scale scores were observed. Conclusion OD and VHI-10 showed improvements due to changes in speech function and respiratory–phonatory coordination, justifying intensive ST treatment for dysarthria in patients with SCD.

Modulation of error-sensitivity during a prism adaptation task in people with cerebellar degeneration

Cerebellar damage can profoundly impair human motor adaptation. For example, if reaching movements are perturbed abruptly, cerebellar damage impairs the ability to learn from the perturbation-induced errors. Interestingly, if the perturbation is imposed gradually over many trials, people with cerebellar damage may exhibit improved adaptation. However, this result is controversial, since the differential effects of gradual vs. abrupt protocols have not been observed in all studies. To examine this question, we recruited patients with pure cerebellar ataxia due to cerebellar cortical atrophy ( n = 13) and asked them to reach to a target while viewing the scene through wedge prisms. The prisms were computer controlled, making it possible to impose the full perturbation abruptly in one trial, or build up the perturbation gradually over many trials. To control visual feedback, we employed shutter glasses that removed visual feedback during the reach, allowing us to measure trial-by-trial learning from error (termed error-sensitivity), and trial-by-trial decay of motor memory (termed forgetting). We found that the patients benefited significantly from the gradual protocol, improving their performance with respect to the abrupt protocol by exhibiting smaller errors during the exposure block, and producing larger aftereffects during the postexposure block. Trial-by-trial analysis suggested that this improvement was due to increased error-sensitivity in the gradual protocol. Therefore, cerebellar patients exhibited an improved ability to learn from error if they experienced those errors gradually. This improvement coincided with increased error-sensitivity and was present in both groups of subjects, suggesting that control of error-sensitivity may be spared despite cerebellar damage.

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.