Alteration of Functional Brain Networks During Lower Limb Movement in Parkinson's Disease Patients With Freezing of Gait

Abnormal brain structures have been observed in Parkinson's disease (PD) patients with freezing of gait (FoG), but the neural mechanisms behind FoG are still not well understood. This study analyzed EEG data from 13 PD patients with FoG and 13 healthy controls (HCs) during a pedaling task. Eight key brain regions were selected to measure power density and connectivity across different frequency bands and time windows. Using graph theory, the study examined neural changes between FoG patients and HCs, focusing on metrics: clustering coefficient, degree, nodal efficiency, and global efficiency. FoG patients had decreased δ and θ activity in the precentral-L and frontal-mid-L regions and increased β activity in the precentral-R and postcentral regions during motor initiation (0–400 ms postcue). FoG patients also exhibited decreased connectivity in the bilateral frontal-mid, supplementary motor area (SMA), postcentral, and precentral regions in the δ and θ bands during motor initiation. During motor execution (0–1 s postcue), fewer significant connections were observed in the α band in these regions. Furthermore, FoG patients also had a decreased clustering coefficient in δ, θ, and α bands during motor initiation and in the θ band during motor execution in regions such as SMA-L, frontal-mid-R, and postcentral-R. The nodal efficiency increased in the regions of precentral-R and postcentral-R (δ band), postcentral-L (θ band) for motor initiation, and precentral-L (θ band) for motor execution. FoG in PD is characterized by the changes of brain functional network, including the decrease of δ and θ activities and the increase of β activity in some brain regions during gait initiation and the abnormal network reorganization. These findings may help to understand the neural mechanisms of FoG in PD and could guide future brain stimulation studies.