Formant steadiness: Treatment-related changes in speakers with hypokinetic dysarthria

Dorian Beverly, Michael P. Cannito, Debra M. Suiter, Lesya Chorna, Teresa Wolf, Jeremy Watkins, Ronald Pfeiffer

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


This study was designed to investigate the effects of intensive voice treatment (Lee Silverman Voice Treatment®) on formant steadiness in 10 speakers with hypokinetic dysarthria associated with idiopathic Parkinson's disease and parkinsonian syndromes. Digital acoustic analysis was used to measure the variability of formant frequencies around their means across sustained vowel phonation. This technique was previously used to demonstrate reduced formant steadiness in speakers with movement disorders including Parkinson's disease. One hundred eighty productions of "ah" were examined yielding coefficients of variation for the formant frequencies of each vowel production. Statistical analysis demonstrated a significant main effect of treatment (p <.05) wherein variability associated with the first and second formants (F1, F2) decreased following treatment. The results of this study suggest that increasing vocal effort/intensity also improves formant steadiness.

Original languageEnglish
Pages (from-to)199-205
Number of pages7
JournalJournal of Medical Speech-Language Pathology
Issue number4
StatePublished - Dec 2008

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Rehabilitation
  • Speech and Hearing


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