Abnormal Functional Brain Network in Parkinson's Disease and the Effect of Acute Deep Brain Stimulation

Zhibao Li; Chong Liu; Qiao Wang; Kun Liang; Chunlei Han; Hui Qiao; Jianguo Zhang; Fangang Meng

doi:10.3389/fneur.2021.715455

Abnormal Functional Brain Network in Parkinson's Disease and the Effect of Acute Deep Brain Stimulation

Front Neurol. 2021 Oct 14:12:715455. doi: 10.3389/fneur.2021.715455. eCollection 2021.

Authors

Zhibao Li¹, Chong Liu¹, Qiao Wang¹, Kun Liang¹, Chunlei Han^{2

3}, Hui Qiao⁴, Jianguo Zhang^{1

2

3}, Fangang Meng^{1

2

3

5}

Affiliations

¹ Department of Functional Neurosurgery, Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.
² Department of Functional Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
³ Beijing Key Laboratory of Neurostimulation, Beijing, China.
⁴ Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.
⁵ Chinese Institute for Brain Research, Beijing (CIBR), Beijing, China.

Abstract

Objective: The objective of this study was to use functional connectivity and graphic indicators to investigate the abnormal brain network topological characteristics caused by Parkinson's disease (PD) and the effect of acute deep brain stimulation (DBS) on those characteristics in patients with PD. Methods: We recorded high-density EEG (256 channels) data from 21 healthy controls (HC) and 20 patients with PD who were in the DBS-OFF state and DBS-ON state during the resting state with eyes closed. A high-density EEG source connectivity method was used to identify functional brain networks. Power spectral density (PSD) analysis was compared between the groups. Functional connectivity was calculated for 68 brain regions in the theta (4-8 Hz), alpha (8-13 Hz), beta1 (13-20 Hz), and beta2 (20-30 Hz) frequency bands. Network estimates were measured at both the global (network topology) and local (inter-regional connection) levels. Results: Compared with HC, PSD was significantly increased in the theta (p = 0.003) frequency band and was decreased in the beta1 (p = 0.009) and beta2 (p = 0.04) frequency bands in patients with PD. However, there were no differences in any frequency bands between patients with PD with DBS-OFF and DBS-ON. The clustering coefficient and local efficiency of patients with PD showed a significant decrease in the alpha, beta1, and beta2 frequency bands (p < 0.001). In addition, edgewise statistics showed a significant difference between the HC and patients with PD in all analyzed frequency bands (p < 0.005). However, there were no significant differences between the DBS-OFF state and DBS-ON state in the brain network, except for the functional connectivity in the beta2 frequency band (p < 0.05). Conclusion: Compared with HC, patients with PD showed the following characteristics: slowed EEG background activity, decreased clustering coefficient and local efficiency of the brain network, as well as both increased and decreased functional connectivity between different brain areas. Acute DBS induces a local response of the brain network in patients with PD, mainly showing decreased functional connectivity in a few brain regions in the beta2 frequency band.

Keywords: Parkinson's disease; brain network; deep brain stimulation; functional connectivity; graph theory; high-density EEG.