Conversational Vocal Intensity in Parkinson's Disease: Treatment and Environmental Comparisons

Abstract

BackgroundVibrotactile Feedback (VF) using wearable devices is an emerging treatment option for hypophonia in Individuals with Parkinson's disease (IwPD). Studies evaluating the effectiveness of VF in improving conversational vocal intensity in real-life environment in IwPD are limited. ObjectiveTo determine the effect of VF on conversational vocal intensity and compare vocal intensity between a) clinic and real-life environment b) VF and Lee Silverman Voice Treatment (LSVT LOUD®)vs. VF alone in IwPD using a portable voice monitor (VocaLog2). MethodsEight individuals with hypophonia secondary to PD were randomly assigned to two treatment groups- VF and LSVT LOUD® (Group 1) and VF (Group 2). VF was provided using VocaLog2 device. Duration of treatment was 4 weeks for both groups. Vocal intensity was measured in the real-life environment at baseline, during treatment, and at one-month follow-up.Vocal intensity in clinic was obtained at baseline and one-month follow-up. Voice Handicap Index (VHI) questionnaire was administered at baseline and one-month follow-up. ResultsThere was no significant difference in conversational vocal intensity between a) clinic and real-life environment at any point of time b) baseline and follow up for both treatment groups c) the two treatment groups at baseline, during each of the 4 weeks of treatment and at follow up d) VHI baseline and one month follow up scores. ConclusionVF, including when combined with LSVT LOUD®, is limited in improving conversational vocal intensity in real-life in IwPD. The effects of frequency and duration of VF on conversational vocal intensity must be systematically investigated using large scale studies in IwPD.