Distinct changes in global brain synchronization in different motor subtypes of Parkinson's disease

Abstract

This study investigated alterations in degree centrality (DC) in different motor subtypes of Parkinson's disease (PD) and analyzed its clinical significance during disease occurrence. A total of 146 subjects were recruited in the study, including 90 patients with PD [51 and 39 with tremor dominant (TD) and akinetic-rigid dominant (ARD) disease, respectively] and 56 healthy controls (HCs). The resting-state functional magnetic resonance imaging data of all the subjects were obtained by 3.0 T magnetic resonance scans. The DC values, an indicator of whole brain synchronization, were calculated and compared among the TD, ARD, and HC groups. Disparities in DC values among the three groups were evaluated by analysis of variance and post hoc two-sample t-tests. Correlation between brain regions with DC differences and clinical variables were performed using partial correlation analysis after controlling for age, gender, and disease duration. Compared to the HCs, both TD and ARD groups demonstrated increased DC values bilaterally in the cerebellum; DC values were decreased in the left putamen and paracentral lobule in the TD group and in the left anterior cingulate gyrus and right supplementary motor area in the ARD group. Compared to the ARD group, the TD group showed decreased DC values in bilateral cerebellar hemispheres and increased DC values in the left anterior cingulate gyrus and right supplementary motor area. The DC of the whole brain showed inconsistencies and shared neural bases among patients with the two subtypes of PD. The differences between brain regions with abnormal DC values may be closely related to different clinical presentations of the two motor subtypes. Our findings provide new insights into the clinical heterogeneity of PD with respect to different motor subtypes.

Keywords: Parkinson’s disease; brain network; degree centrality; global brain synchronization; resting-state functional MRI.

Figure 1

Comparison of degree centrality (DC) among TD, ARD, and HC groups. Significant differences were showed in the following brain regions: bilateral cerebellar hemispheres (Cerebellum_9_R/L), left putamen, left anterior cingulate gyrus, right supplementary motor area, and the left para-central lobule (p < 0.05).

Figure 2

(A) TD vs. HCs; DC values had decreased in the Putamen_L and Paracentral_Lobule_L and increased in the Cerebellum_9_R/L. (B) ARD vs. HCs; DC values had decreased in the Cingulum_Ant_L and Supp_Motor_Area_R, and increased in the Cerebellum_9_R/L. (C) TD vs. ARD groups; DC values had decreased in the Cerebellum_9_R/L, and increased in the Cingulum_Ant_L and Supp_Motor_Area_R.