Bimanual coordination in Huntington's disease and Parkinson's disease

Abstract

Special populations that suffer from Parkinson's disease (PD) and Huntington's disease (HD) display poorer performance in movement and bimanual coordination tasks. Both PD and HD are basal ganglia disorders with neuropathology distinct from one another. The production of internally guided movements is disrupted in PD and HD, therefore utilization of the external pathway may be able to stabilize movements for these groups. The current study examines the effect of auditory cueing for these two populations in timing performance. A total of 10 PD patients, 10 healthy controls (matched for age and gender) and 2 HD patients were examined on a repetitive bimanual finger tapping task. PD patients and healthy controls were asked to perform finger tapping at two different frequencies (1.0 Hz, 2.0 Hz) and two movement types (in-phase, anti-phase). Additionally half of the trials were performed with an external cue (metronome beat), while the other half were not (cue was turned off after 10 metronome heats). Results showed that PD patients were able to effectively use the cue to facilitate bimanual coordination as it was shown that absolute mean timing errors were decreased during the cue trials. PD patients were able to perform both movement types although the more complex mirror asymmetrical anti-phase trials were more difficult to perform. HD patients were not able to achieve the designated fast and slow frequencies that PD and healthy controls performed. The HD patients' movement was highly variable due to tremors and involuntary tics experienced by the patients. Through the examination of raw trajectories and polar plots of phase differences it was concluded that the external cue did not seem to stabilize bimanual coordination for the HD patients.