Speech characteristics across motor subtypes of Parkinson's disease

Abstract

Background: Speech differences may occur between motor subtypes of Parkinson’s disease (PD), but the literature remainslimited.Aims: Examine speech characteristics in individuals with PD across the tremor-dominant, nontremor-dominant and mixedsubtypes comparing to healthy controls.Methods and Procedures: A total of 115 individuals with PD were included in the study, classified as tremor-dominant (n = 61),nontremor-dominant (n = 39) and mixed (n = 15) subtypes according to the Movement Disorder Society – Unified Parkinson’sDisease Rating Scale. The control group (CG) consisted of 15 individuals. Speech samples were collected through sustained vowel/a/, diadochokinesis (/pataka/), and monologue and were analysed using both auditory perceptual and acoustic analyses.Outcomes and Results: In the diadochokinesis and monologue task, the nontremor-dominant subtype showed shorterproduction time and, consequently, produced fewer syllables than the CG. The mixed subtype, on the other hand, did not differfrom the CG and performed similarly across all tasks. However, the average duration of the syllables in the monologue tasksignificantly differed between the mixed and nontremor-dominant subtypes.Conclusions and Implications: There are speech variations among PD motor subtypes. The nontremor-dominant subtypeexhibited poorer speech performance, while the mixed subtype’s speech patterns were more similar to those of the CG.