Speech Impairment in a Large Sample of Patients with Parkinson’s Disease

TLDR

The study highlights voice and articulatory deficits in Parkinson’s disease and compares them to motor set instability in gait and handwriting. The study aimed to classify speech impairment severity in 200 Parkinson’s disease patients and detail the type and extent of voice, articulation, and fluency deficits at each level. Two trained raters evaluated voice, fluency, and articulation from two‑minute conversational speech samples in 200 PD patients, classifying impairments into five severity levels. Voice deficits were the most prominent and severe in early stages, while articulatory and fluency deficits appeared later, with articulation becoming most impaired at the profound stage.

Abstract

This study classified speech impairment in 200 patients with Parkinson's disease (PD) into five levels of overall severity and described the corresponding type (voice, articulation, fluency) and extent (rated on a five-point scale) of impairment for each level. From two-minute conversational speech samples, parameters of voice, fluency and articulation were assessed by two trained-raters. Voice was found to be the leading deficit, most frequently affected and impaired to a greater extent than other features in the initial stages. Articulatory and fluency deficits manifested later, articulatory impairment matching voice impairment in frequency and extent at the 'Severe' stage. At the final stage of 'Profound' impairment, articulation was the most frequently impaired feature at the lowest level of performance. This study illustrates the prominence of voice and articulatory speech motor control deficits, and draws parallels with deficits of motor set and motor set instability in skeletal controls of gait and handwriting.