Sentence intelligibility before and after voice treatment in speakers with idiopathic Parkinson's disease

Michael P. Cannito, Debra M. Suiter, Doriann Beverly, Lesya Chorna, Teresa Wolf, Ronald M. Pfeiffer

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


Objectives/Hypothesis: The purpose of this study was to determine whether sentence intelligibility improves in speakers with idiopathic Parkinson's disease (PD) as a result of Lee Silverman Voice Treatment (LSVT). It was hypothesized that all the speakers would improve following treatment, in association with increased vocal loudness, which was the primary target of the treatment. Study Design: Prospective study of eight Speakers with PD using a single-blinded, randomized pre-post treatment design, with multiple daily assessments before and after treatment was carried out. Resultant data were corrected for regression to the mean. Methods: Randomized digital recordings of sentences produced by speakers with idiopathic PD before and after the treatment were presented to normal-hearing listeners with equalized intensity at conversational loudness in the presence of pink noise. Percentage of words understood was calculated before and after the treatment. Changes in overall vocal intensity were also analyzed. Results: There was a statistically significant group effect from pre-to-post voice treatment; however, there was also significant interaction of treatment with speakers. Six of the speakers with PD improved significantly following voice treatment, one exhibited no change, and one exhibited a decline in sentence intelligibility post-treatment. Conclusions: LSVT yielded significant improvement in sentence intelligibility for most speakers in the study but was not beneficial for two of the speakers despite the fact that they increased their overall vocal loudness.

Original languageEnglish
Pages (from-to)214-219
Number of pages6
JournalJournal of Voice
Issue number2
StatePublished - Mar 2012

Bibliographical note

Funding Information:
Special thanks are given to Dr Corinne Ethington for guidance on the statistical analyses, especially those involving regression to the mean. Funding for this research was provided by a Faculty Research Grant (Michael P. Cannito, Principal Investigator from the University of Memphis).


  • Idiopathic Parkinson's disease
  • Lee Silverman voice treatment
  • Sentence intelligibility

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Speech and Hearing
  • LPN and LVN


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