1000 Section - Gait-synchronized transcranial alternating current stimulation improves gait patterns in patients with Parkinson’s disease

Objectives : Parkinson’s disease (PD) is characterized by gait disturbances such as small step length and bradykinetic walking. Although deep brain stimulation can improve gait, its invasiveness and limited applicability underscore the need for non-invasive approaches. Transcranial alternating current stimulation (tACS) has recently emerged as a promising method to modulate neural activity and enhance motor performance. However, its effects on detailed gait kinematics remain insufficiently explored. This study aimed to clarify the mechanism of gait improvement by gait-synchronized cerebellar tACS in patients with PD.

Design: Ten patients with PD (mean age 72.5 ± 12.7 years; 7 men, 3 women) participated. Each received gait rehabilitation combined with tACS: 4 minutes × 4 bouts per session, 1–2 sessions per week, for 10 sessions in total. The anodal electrode was placed over the cerebellum on the more affected side, and the cathodal electrode over the contralateral neck. Individual stimulation frequency was determined by the most frequent gait cycle measured before intervention. Three-dimensional motion analysis was performed pre- and post-intervention. Walking speed, cadence, stride length, range of motion (ROM), mean angular velocity (MAV) of lower limb joints, and trailing limb angle (TLA) were analyzed. Wilcoxon signed-rank tests were used for statistical evaluation.

Results: Walking speed significantly increased from 0.74 ± 0.20 to 0.86 ± 0.27 m/s (p = 0.03), and cadence from 109.3 ± 4.9 to 118.1 ± 3.9 steps/min (p = 0.02). MAV of the hip and knee on the affected side significantly improved (hip: 24.8 ± 8.2 to 28.1 ± 8.7°/s, p = 0.04; knee: 129.6 ± 27.8 to 140.9 ± 22.3°/s, p = 0.02). Other parameters showed no significant changes.

Conclusion: Gait-synchronized cerebellar tACS improved walking speed and cadence in PD, likely through increased joint angular velocity. These findings suggest that tACS can directly modulate neural circuits underlying gait pattern generation in PD.