Long-term effects of Lee Silverman Voice Treatment on daily voice use in Parkinson's disease as measured with a portable voice accumulator.

This study examines the effects of an intensive voice treatment focusing on increasing voice intensity, LSVT LOUD® Lee Silverman Voice Treatment, on voice use in daily life in a participant with Parkinson's disease, using a portable voice accumulator, the VoxLog. A secondary aim was to compare voice use between the participant and a matched healthy control. Participants were an individual with Parkinson's disease and his healthy monozygotic twin. Voice use was registered with the VoxLog during 9 weeks for the individual with Parkinson's disease and 2 weeks for the control. This included baseline registrations for both participants, 4 weeks during LSVT LOUD for the individual with Parkinson's disease and 1 week after treatment for both participants. For the participant with Parkinson's disease, follow-up registrations at 3, 6, and 12 months post-treatment were made. The individual with Parkinson's disease increased voice intensity during registrations in daily life with 4.1 dB post-treatment and 1.4 dB at 1-year follow-up compared to before treatment. When monitored during laboratory recordings an increase of 5.6 dB was seen post-treatment and 3.8 dB at 1-year follow-up. Changes in voice intensity were interpreted as a treatment effect as no significant correlations between changes in voice intensity and background noise were found for the individual with Parkinson's disease. The increase in voice intensity in a laboratory setting was comparable to findings previously reported following LSVT LOUD. The increase registered using ambulatory monitoring in daily life was lower but still reflecting a clinically relevant change.