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Parkinson’s Disease
Volume 2011, Article ID 897494, 9 pages
http://dx.doi.org/10.4061/2011/897494
Research Article

Effect of LSVT on Lexical Tone in Speakers with Parkinson's Disease

Division of Speech and Hearing Sciences, The University of Hong Kong, Pokfulam, Hong Kong

Received 15 March 2011; Revised 28 June 2011; Accepted 30 June 2011

Academic Editor: B. E. Murdoch

Copyright © 2011 Tara L. Whitehill et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Lee Silverman Voice Treatment (LSVT) has well-documented treatment efficacy for individuals with hypokinetic dysarthria associated with Parkinson's disease (PD). Positive changes have been noted after treatment not only for vocal loudness but also for many other speech dimensions, including intonation (monotonicity). There have been few studies investigating the effect of LSVT on lexical tone which, like intonation, is controlled by variations in fundamental frequency. This study involved 12 Cantonese speakers with idiopathic PD who were enrolled in a standard LVST treatment protocol. Speech data were collected 3-4 days before treatment and 1 day after treatment. A wide variety of perceptual and acoustic variables were analyzed. The results showed significant improvements in loudness and intonation after treatment, but no significant changes in lexical tone. These results have theoretical implications for the relationship between tone and intonation and for models of the physiological control of fundamental frequency.