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 0.0125 by Bonferroni correction. Results: For both pre- and post-ST, the patient's OD (p = 0.002) and maximum phonation time (p = 0.002) significantly improved, except for Speech Dysfunction scores of the Scale for Assessment and Rating of Ataxia (p = 0.705) and the VHI-10 (p = 0.018). The Assessment of Motor Speech for Dysarthria Articulation, OD, and inspiratory pressure were identified as independent variables of VHI-10 (adjusted R[subscript 2] = 0.820) 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.