Limb-kinetic apraxia in Parkinson disease.

To learn if limb-kinetic apraxia (LKA) is associated with Parkinson disease (PD), participants with PD (on medications) and control subjects performed finger tapping (FT), measuring movement speed, and performed coin rotation (CR), measuring precise coordinated but independent finger movements and speed. There were no group differences in FT, a measure of bradykinesia-rigidity, but CR rotation was impaired in PD. Thus, LKA, not related to bradykinesia-rigidity, is associated with PD.