Use of Transcranial Magnetic Stimulation to Probe Neuroplasticity and Predict Gait Performance After Treadmill Training in Parkinson's Disease

Background: Reduced step length is a hallmark of gait disturbance in people with Parkinson's disease (PD). Although treadmill training is effective for improving step length, the associated neural mechanisms have not been fully investigated. Moreover, exploring the baseline neurophysiological predictors for step length improvement after training could facilitate personalized gait rehabilitation for PD.

Objective: The aim of this study was to investigate the neuroplastic changes in corticomotor excitability after treadmill training and to explore whether baseline neurophysiological measures could predict step length improvement in PD.

Methods: Data from 61 participants with idiopathic PD who completed 12 treadmill training sessions were included. Gait performances and corticomotor excitability measured by transcranial magnetic stimulation (TMS) were obtained at baseline, postintervention, and 1-month follow-up. TMS outcomes included motor-evoked potentials, cortical silent period (CSP), intracortical facilitation (ICF), and short-interval intracortical inhibition (SICI). General estimating equation analysis and principal-component analyses were used to determine the neuroplastic changes induced by training, and multiple linear regression analysis was performed to explore the baseline TMS predictors for step length improvement at 1-month follow-up.

Results: After treadmill training, SICI and CSP significantly increased and shared an emerging relationship. Regression analysis showed that female sex and greater baseline ICF and SICI were significant predictors of step length improvement at the follow-up.

Conclusions: This study advanced the understanding of neuroplastic changes induced by treadmill training in PD and showed that preserved SICI and ICF were predictors for lasting step length improvement after training. Future studies could investigate other influential factors for treadmill training in PD. © 2024 International Parkinson and Movement Disorder Society.