Effect of Lee Silverman Voice Treatment® BIG on the major motor symptoms in patients with moderate Parkinson’s disease: an observational study

Background and aims. This study investigated the effect of Lee Silverman Voice Treatment® BIG (LSVT® BIG) on four major motor symptoms (tremor, rigidity, bradykinesia, and postural instability/gait disorder) in patients with Parkinson's disease classified as Hoehn and Yahr (HY) stages II-III. Methods. This retrospective, observational, single-center study included 17 patients with Parkinson's disease classified as HY stages II-III. To examine the effect of the LSVT® BIG, the total scores of the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III and each score of the major motor symptoms (tremor, rigidity, bradykinesia, and postural instability/ gait disorder) extracted from the MDS-UPDRS Part III were assessed pre- and post-LSVT® BIG. The Wilcoxon signed-rank test was used for statistical analysis. Results. The total scores of MDS-UPDRS Part III, bradykinesia, and postural instability/gait disorder improved when comparing pre- and post-LSVT® BIG (median [interquartile range]: 24 [16-36] to 18 [13-22], 8 [6-11] to 6 [5-8], and 5 [3-8] to 3 [1-5], respectively). The tremor and rigidity scores showed a trend toward improvement but did not achieve statistical significance (median [interquartile range]: 4 [0-6] to 3 [0-5], and 4 [2-10] to 4 [2-6], respectively). Conclusions. These results suggest that LSVT® BIG for patients with Parkinson's disease classified as HY stages II-III is effective for improving bradykinesia and postural instability/gait disorder. The findings have important clinical implications for preliminarily estimating the effect of LSVT® BIG on each major motor symptom.