Music therapy and music and rhythm in general can support standard physiotherapy for people suffering from Parkinson’s disease to improve the motion performance and quality, sometimes even helping to overcome motion blocks. With the availability of cheap motion-tracking devices, exergames have become an interesting option to complement traditional physiotherapy. However, the role of music and rhythm in the context of games for this special audience is still largely unexplored. Based on a prototype exergame we developed, a user study was conducted to compare the effects of different auditory clues and their absence in exergames for this target group. The results show significant performance differences with music versus without music, but surprisingly no differences were found between music synchronized with the interaction and unsynchronized background music.