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 tremor-dominant (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.