Freezing of gait and the effects of vibrotactile cueing in Parkinson’s disease, a study protocol of a cross-sectional multimodal brain imaging approach in virtual walking scenarios

BackgroundFreezing of gait (FOG) is one of the most debilitating motor symptoms in Parkinson’s disease (PD), affecting a substantial proportion of people with PD. Numerous hypothetical mechanisms exist, attempting to explain FOG. Current evidence originated from stationary measures in lying positions, limiting the understanding of neurophysiological changes elicited by FOG episodes during regular locomotion. Neurophysiological aspects of FOG, especially in response to vibrotactile cueing, have been explored only by a few studies. To address this gap, the current study aims to investigate FOG episodes in people with PD and the impact of vibrotactile cueing while walking through virtual environments on a self-paced treadmill.MethodsThirty people with Parkinson’s Disease and FOG will be recruited. They will undergo screening and familiarization before performing different walking tests in virtual reality using the Gait Real-time Analysis Interactive Lab (GRAIL). Participants will perform two experimental blocks, each consisting of four walking trials of approximately 10 min. A break of 10 to 30 min will be provided between blocks. Walking with or without vibrotactile cueing will be performed in alternation. During walking, electrocortical (EEG), hemodynamic (fNIRS), kinematic data (3D motion capture), and kinetic data (force plates) will be recorded. Data will be analyzed to investigate spatiotemporal and frequency characteristics of electrocortical and hemodynamic brain activity related to FOG and the impact of vibrotactile cueing on neural signatures and gait improvements in FOG.DiscussionCombining neurophysiological measurements of EEG and fNIRS paired with kinematics and kinetics will provide insights into the cortical and behavioral changes associated with FOG and vibrotactile cueing, to derive results that can be used for the design of intervention strategies for treating PD.Study protocol registrationhttps://drks.de/search/de/trial/DRKS00034584, identifier DRKS00034584.