Human ballistic arm abduction movements

Abstract

In patients with Parkinson9s disease who had never previously been treated with any antiparkinsonism drug, we studied the effects of L-dopa on ballistic arm abduction movement in a step-tracking task. L-Dopatreatment increased the mean velocity of the initial movement towards the target without loss of accuracy and with improved motor performance under open-loop conditions. Performance also improved in motor tasks with expected perturbation. EMG patterns of arm abduction movements showed abnormal features in untreated patients and improved after L-dopa treatment.