F-wave and motor-evoked potentials during motor imagery and observation in apraxia of Parkinson disease.

INTRODUCTION

The amplitudes of F-waves and motor-evoked potentials (MEPs) increase during imagination or active motor performance. The aim of this study was to investigate F-wave and MEP facilitation during assessment of apraxia.

METHODS

Eight Parkinson disease (PD) patients with apraxia, 11 patients without apraxia, and 8 healthy volunteers were enrolled. F-waves and MEPs were recorded during 4 states (resting, imagination, observation, and active movement).

RESULTS

The mean amplitude of the F-waves increased significantly during imagination and active movement as compared with at rest in healthy individuals (P = 0.028) and in the nonapraxia group (P = 0.005). PD patients with apraxia did not have similar facilitation. The mean amplitude of the MEPs also showed a similar loss of facilitation in PD with apraxia.

CONCLUSIONS

Loss of facilitation during the preparation for movement is closely related to the "gold standard" clinical praxis battery. This study provides additional support and a potential electrophysiological assessment method for apraxia in PD.