Changes in vocal loudness following intensive voice treatment (LSVT®) in individuals with Parkinson's disease:: A comparison with untreated patients and normal age-matched controls

This study assessed the impact of the Lee Silverman Voice Treatment (LSVT(R)) on vocal loudness [sound pressure level (SPL)] in a group of dysarthric individuals with idiopathic Parkinson's disease (IPD). Pre- to post-treatment changes in SPL in the treated group were compared with changes in voice SPL during the same time in two control groups: individuals with IPD not treated with the LSVT(R) and in non-disordered individuals. ape-matched to the patients. All subjects produced the same voice and speech tasks-sustaining vowel phonation. reading the "Rainbow Passage," producing a short monologue, and describing a picture. These tasks were recorded at three different occasions: just prior to treatment. just after treatment, and 6 months following treatment. The individuals treated with LSVT(R) increased voice SPL from baseline to post-treatment by an average of 8 dB and from baseline to 6 months follow-up by an average of 6 dB. These changes were statistically significant and perceptibly audible. No significant changes in SPL were observed in the control groups during the time corresponding to the treatment and follow-up. Differences in SPL between the treated and untreated patients at post-treatment and follow-up were statistically significant for all voice and speech tasks. These findings, along with others, provide additional support for the efficacy of the LSVT(R).