Effects of Intensive Voice Treatment (the Lee Silverman Voice Treatment [LSVT]) on Vowel Articulation in Dysarthric Individuals With Idiopathic Parkinson Disease: Acoustic and Perceptual Findings

TLDR

The study evaluated whether intensive voice treatment (LSVT) improves vowel articulation in dysarthric Parkinson’s disease patients. Researchers compared 14 PD patients receiving LSVT, 15 PD patients not receiving LSVT, and 14 healthy controls on vocal sound pressure level, formant frequencies of vowels /i/, /u/, /a/, vowel triangle area, and perceptual ratings derived from words embedded in phrases and assessed by trained raters. LSVT led to significant improvements in vocal sound pressure level, F2 of /u/, the F2i/F2u ratio, and perceptual vowel ratings, supporting its broad therapeutic benefit for orofacial functions in PD.

Abstract

Purpose To evaluate the effects of intensive voice treatment targeting vocal loudness (the Lee Silverman Voice Treatment [LSVT]) on vowel articulation in dysarthric individuals with idiopathic Parkinson’s disease (PD). Method A group of individuals with PD receiving LSVT ( n = 14) was compared to a group of individuals with PD not receiving LSVT ( n = 15) and a group of age-matched healthy individuals ( n = 14) on the variables vocal sound pressure level (VocSPL); various measures of the first (F1) and second (F2) formants of the vowels /i/, /u/, and /a/; vowel triangle area; and perceptual vowel ratings. The vowels were extracted from the words key, stew, and Bobby embedded in phrases. Perceptual vowel rating was performed by trained raters using a visual analog scale. Results Only VocSPL, F2 of the vowel /u/ (F2u), and the ratio F2i/F2u significantly differed between patients and healthy individuals pretreatment. These variables, along with perceptual vowel ratings, significantly changed (improved) in the group receiving LSVT only. Conclusion These results, along with previous findings, add further support to the generalized therapeutic impact of intensive voice treatment on orofacial functions (speech, swallowing, facial expression) and respiratory and laryngeal functions in individuals with PD.