Functional Connectivity in Parkinson’s Disease Patients with Mild Cognitive Impairment

Figures & data

Table 1 Demographic and Neuropsychological Data for HCs, PD with Normal Cognition and PD with MCI

	PD with MCI (n = 20)	PD with Normal Cognition (n = 13)	HC (n = 13)	P (KW)
Age (years)	72.6±6.1	70.4±6.4	70.2±7.1	0.233
Gender (M/F)	12/8	7/6	4/9	0.247
Education (years)	11.7±3.3	12.2±3.9	12.1±3.5	0.688
MMSE	26.9±3.1***	28.5±1.5	28.8±1.4	<0.001
AVLT-20min DR	2.9±1.2***	6.9±1.1	7.7±1.5	<0.001
CFT-20min DR	13.3±4.9***	17.5±4.5	19.2±4.9	<0.001
CDT	8.0±2.1*	9.2±1.4	8.9±1.0	0.037
DSST	33.8±7.8***	41.2±8.8	40.3±10.7	<0.001
TMT-A (second)	75.8±14.5*	63.6±19.8	66.2±20.1	0.019
VFT	17.1±4.1***	19.9±4.4	21.1±5.2	<0.001
TMT-B (second)	210.9±70.1***	197.1±72.1	187.3±74.1	<0.001

Notes: Data was represented as mean±SD. Kruskal Wallis tests followed by Dunn-Bonferroni post hoc were performed as the neuropsychological data were not normally distributed (P < 0.05 for Kolmogorov–Smirnov test). The χ² tests were performed for gender. *Indicates a statistical difference compared with HC. *Indicate P < 0.05 and ***Indicate P < 0.001.

Abbreviations: MMSE, Mini-Mental State examination; AVLT-20, Auditory Verbal Learning Test-20-minute delayed recall; CFT20, Rey-Osterrieth Complex Figure Test-20-minute delayed recall; CDT, Clock Drawing Test; DSST, Digital Symbol Substitution Test; TMT-A, Trail Making Test-A; VFT, Verbal Fluency Test; TMT-B, Trail Making Test-B.

Figure 1 Whole-brain voxelwise pattern of the default mode network in each group. The DMN pattern for each group was obtained by using PCC (MNI coordinate: −2, −45, 34, radius = 6 mm) seed-based functional activity analysis. The random-effects one-sample t-test was performed and threshold was set at a corrected P < 0.01, determined by Monte Carlo simulation.

Table 2 Descriptions of Disease-Related Differences in DMN Revealed by One-Way ANOVA

Brain Region	Peak MNI Coordiates x, y, z (mm)	Peak F value	Cluster Size (mm^3)
Bilateral Precuneus	−9, −63, 51	12.4	6615

Notes: All the regions survived the Monte Carlo Stimulations, and the thresholds were set as voxel-wise P < 0.01, cluster sizes larger than 6156 mm³.

Figure 2 One-way ANOVA of DMN functional connectivity. Thresholds were set at a corrected P < 0.01, determined by Monte Carlo simulation.

Figure 3 Group-level differences of the disease-related differences in DMN. Compared to PD patients with normal cognition and PD patients with MCI, the HCs showed significantly increased FC within BPcu. Further, there was also significant difference regarding the FC within BPcu between the two PD groups. ***Indicate P < 0.001.

Figure 4 Behavior significances of the regions with disease-related differences in DMN. For PD patients with MCI, the higher FC within BPcu were related to better performances of TMTA, DSST and CFT-20 min DR. For PD patients with normal cognition, the FC within BPcu were associated with scores of MMSE.