Neurophysiological correlates of gait initiation in individuals with Huntingtons and Parkinsons disease

Background: Huntingtons disease (HD) and Parkinsons disease (PD) are neurodegenerative diseases resulting in motor impairments of gait initiation (GI). However, the neurophysiological underpinnings of GI in HD and PD are not well understood. The aims of this study were to 1) evaluate the feasibility of a wireless EEG system to identify EEG-derived movement-related potentials (MRPs) in individuals with HD and PD during GI, and to 2) determine the tolerance of a high repetition GI protocol. New Method: 3 participants with HD and 3 participants with PD performed 3 blocks of 15 trials of GI. EEG-derived MRPs of readiness potential (RPs) and contingent negative variation (CNV) were identified during GI, using a wireless EEG system synced with kinetic measures of GI. Tolerance of the protocol was determined from changes in COP across GI blocks. Results: There were no differences between HD and PD for CNV and RP amplitudes and latencies, although they were within acceptable ranges of MRP values in HD and PD. There were no differences of COP values between GI blocks. Comparison with old method: A wireless EEG system elicits naturalistic GI biomechanical responses as opposed to previous methods employing tethered systems. In contrast to single-trial EEG studies, this study implemented a larger number of GI trials, which produces greater MRP resolution. Conclusions: This study validated the use of a wireless EEG headset in determining MRP values during GI in HD and PD. Participants within these populations were able to tolerate a high repetition GI protocol. Future work will explore MRPs in larger cross-sectional studies for the development of clinical outcome measures.