Multidimensional voice assessment after Lee Silverman Voice Therapy (LSVT®) in Parkinson’s disease

ObjectiveTo investigate the effectiveness of Lee Silvermann Voice Treatment (LSVT®) in improving prosody in patients with Parkinson's disease over medium-term follow-up. Methods15 patients with Parkinson's disease were assessed before LSVT®, within one week, and 3 and 6 months after treatment. Subjective and objective evaluation included: Voice Handicap Index - 10 (VHI-10), perceptual assessment by GRBAS scale and item 18 of the Unified Parkinson's Disease Rating Scale III (UPDRS III), maximum phonation time (MPT /s/) and acoustic analysis by means the Voice Range Profile (VRP) and the "Intonation Stimulability Protocol" of the Motor Speech Profile (MSP). ResultsA significant increase of the mean values of Imax and rF0 was observed until 6 months post-therapy (p < 0.001), whereas Running Speech Standard Deviation (rSTD) (p = 0.004), Amplitude Variability (rVAm) (p = 0.02) and Frequency Variability (rvF0) (p = 0-01) improved significantly after 3 months, but returned to pre-therapy levels after 6 months. The score of item 18 of the UPDRS III increased significantly early post-therapy (p = 0.03), but did not maintain the improvement at 3 and 6 months. Median values of Grade (G), Asthenia (A) and mean values VHI-10 score significantly decreased at each post-therapy control (p < 0.05). ConclusionsIn addition to the subjective and perceptual beneficial effect of LSVT®, we found a long-lasting increase of loudness and fundamental frequency. There was also improvement of acoustic parameters related to prosody, although it was temporary.