This study aimed to compare brain activity during GI between PwPD and healthy controls using electroencephalography (EEG), focusing on motor preparation (BP) and post-execution introspection (ERN) phases. We hypothesized that PwPD would show reduced activity in the SMA during BP and in the ACC during ERN compared with healthy controls, potentially contributing to their movement difficulties.
7 PwPD and 16 healthy adults performed a stepping task 20 times while EEG was recorded. Data were analyzed using eLORETA, focusing on two time windows: 3 seconds before toe-off (BP) and 2 seconds after heel contact (ERN). EEG was recorded from 28 scalp sites following the international 10-10 system, with a reference electrode on the right earlobe. Data were collected using Polymate V AP5148 (Miyuki Giken Corporation, Japan). Statistical analyses were conducted using the eLORETA SnPM 26 statistics tool, performing an independent two-sample t-test. The significance level was set at 5%.
Consistent with our preliminary findings, both PwPD and healthy controls showed SMA activity during BP and ACC activity during ERN. However, significant differences in brain activity between the two groups were observed in both phases. During BP, healthy participants exhibited significantly greater activation in the SMA and Brodmann area (BA) 6 compared to PwPD (t = 3.257, p 0.05). Similarly, during ERN, healthy participants demonstrated significantly greater activation in the ACC, BA 32, compared to PwPD (t = 3.398, p 0.05).
Our findings reveal that, although both PwPD and healthy controls engage the SMA during motor preparation and the ACC during post-execution introspection, PwPD exhibited significantly reduced activity in these regions compared to healthy individuals. These alterations may underlie the gait initiation difficulties observed in PD, with reduced SMA activity during BP suggesting impaired motor planning and decreased ACC activity during ERN, indicating deficits in performance monitoring. These insights provide a clearer understanding of the neural mechanisms underlying gait disturbances in PD and highlight the importance of considering both motor preparation and post-execution phases in the impact of the disease on movement control.
By identifying the specific brain regions and processes affected during GI in PwPD, our study suggests potential therapeutic targets for neurorehabilitation. Techniques such as neurofeedback could be employed to enhance SMA activity during motor preparation and ACC activity during post-execution introspection, potentially improving GI in PwPD. Moreover, monitoring BP and ERN with EEG could serve as valuable biomarkers for assessing the effectiveness of interventions and tracking disease progression.
gait initiation
EEG
