Effects of loud speech on tongue kinematics in dysarthric speakers with Parkinson’s disease

Abstract

PURPOSE: Previous perceptual and acoustic studies have reported positive effects of increased loudness on articulatory system in individuals with Parkinson’s disease (PD), but little is known about the physiological basis of loud speech in these individuals. The aim of the present investigation was to evaluate the effect of increased loudness on tongue kinematics in dysarthric speakers with PD. METHODS: Electromagnetic articulography was used to record tongue tip movement during habitual and loud sentence production in two participants with PD. The sentence used was loaded with alveolar consonants to examine tongue tip movement. An age and gender-matched healthy individual served as a control for each speaker with PD. RESULTS: Results showed that Participant One had greater tongue kinematic parameters during habitual and loud sentence production when compared to the control; and within-subject comparisons showed that P1 increased distance and maximum velocity of tongue movement from habitual to loud speech. Participant Two had greater tongue kinematic parameters during habitual and loud sentence production when compared to the control; and within-subject comparisons showed that P2 reduced maximum acceleration from habitual to loud speech. CONCLUSION: These individual differences in tongue kinematics may be predictive of the efficacy of loudness-based treatments for articulatory and consequent perceptual improvements. The positive effects of transient loudness manipulations on articulatory kinematics may indicate that more permanent articulatory reorganisation is possible with intensive loudness-based treatments like LSVT.