Speech Characteristics Across Motor Subtypes of Parkinson's Disease

What is already known on the subject The existing literature is limited by varied and unclear methodological approaches to speech analysis and subtype classification, small sample sizes and a need for further comparison with a control group. Furthermore, no studies were found that assess speech in the mixed subtype. What this paper adds to the existing knowledge In diadochokinesis and monologue, the nontremor-dominant subtype showed shorter production time and, consequently, a smaller number of syllables when compared to the control group. The mixed subtype did not differ from the control group, performing similarly in all tasks. Significant differences were between the mixed subtypes and nontremor-dominant regarding the average duration of the syllables in the monologue task. What are the potential or actual clinical implications of this work? This study has a limitation: assessments were performed during the ON phase of medication, which may have masked some speech changes, especially in the dominant tremor subtype. These findings represent a pattern observed across subtypes at a single time point in a cross-sectional study. As such, they may not reflect changes or developments that may occur over time or in different contexts. Therefore, as part of future perspectives, it is not yet known whether these results persist over a long period. We encourage researchers to conduct longitudinal studies with this population to better identify speech changes.