Manuel Peterka, Thorsten Odorfer, Michael Schwab, Jens Volkmann, Daniel Zeller

• Background There is growing evidence for proprioceptive dysfunction in patients with Parkinson's disease (PD). The Lee Silvermann Voice Treatment-BIG therapy (LSVT-BIG), a special training program aiming at an increase of movement amplitudes in persons with PD (PwPD), has shown to be effective on motor symptoms. LSVT-BIG is conceptionally based on improving bradykinesia, in particular the decrement of repetitive movements, by proprioceptive recalibration. Objective To assess proprioceptive impairment in PwPD as compared to matchedBackground There is growing evidence for proprioceptive dysfunction in patients with Parkinson's disease (PD). The Lee Silvermann Voice Treatment-BIG therapy (LSVT-BIG), a special training program aiming at an increase of movement amplitudes in persons with PD (PwPD), has shown to be effective on motor symptoms. LSVT-BIG is conceptionally based on improving bradykinesia, in particular the decrement of repetitive movements, by proprioceptive recalibration. Objective To assess proprioceptive impairment in PwPD as compared to matched controls and to probe potential recalibration effects of the LSVT-BIG therapy on proprioception. Methods Proprioceptive performance and fine motor skills were assessed in 30 PwPD and 15 matched controls. Measurements with significant impairment in PwPD were chosen as outcome parameters for a standardized 4 weeks amplitude-based training intervention (LSVT-BIG) in 11 PwPD. Proprioceptive performance served as primary outcome measure. Secondary outcome measures included the motor part of the MDS-UPDRS, the nine-hole-peg test, and a questionnaire on quality of life. Post-interventional assessments were conducted at weeks 4 and 8. Results Compared to the control group, PwPD showed significantly larger pointing errors. After 4 weeks of LSVT-BIG therapy and even more so after an additional 4 weeks of continued training, proprioceptive performance improved significantly. In addition, quality of life improved as indicated by a questionnaire. Conclusion LSVT-BIG training may achieve a recalibration of proprioceptive processing in PwPD. Our data indicates a probable physiological mechanism of a symptom-specific, amplitude-based behavioral intervention in PwPD.…