Ballistic Movements are less impaired in Parkinson's Disease than Controlled Movements

Parkinson's disease (PD) is a slowly progressing neurodegenerative disorder that leads to characteristic motor symptoms such as tremor, rigidity and bradykinesia [1]. It has been shown that the basal ganglia play an important role in timing of movement [2]. However, the movements of PD patients under certain conditions are less impaired than one would expect. Improved movements can be triggered by external timing cues [3], by sensory cues, like, for example, auditory cues [4] or visual cues [5; 6]. It has been hypothesized that by timing movements externally the basal ganglia function for timing of movements is…