The Relationship Between Speech Characteristics and Motor Subtypes of Parkinson's Disease

Purpose: The aim of this study was to examine whether acoustic dysarthria characteristics align with overall motor profile in individuals with Parkinson's disease (PD). Potential speech differences between tremor-dominant and non-tremor-dominant subtypes are theoretically motivated but empirically inconclusive. Method: Twenty-seven individuals with dysarthria from PD provided a contextual speech sample. Participants were grouped into non-tremor-dominant (n = 12) and tremordominant (n = 15) motor subtypes according to the Unified Parkinson Disease Rating Scale. Dependent speech variables included fundamental frequency range, average pause duration, cepstral peak prominence, stuttering dysfluencies, and maze dysfluencies. Results: There were no significant differences between the speech of the tremor-dominant and non-tremor-dominant groups. High within-group variability existed across parameters and motor subtypes. Conclusion: Speech characteristics across the areas of phonation, prosody, and fluency did not differ appreciably between PD motor subtypes.