Resting-state functional connectivity in patients with minimally disabled Parkinson’s disease: A case-control study

Abstract

OBJECTIVE: To assess the resting-state functional connectivity within the default mode network (DMN) and the whole brain in minimally disabled Parkinson’s disease (MiPD) patients and compare it with age- and gender-matched healthy controls (HCs). METHODS: Twenty-seven MiPD patients (Hoehn and Yahr score, H–Y = 1–3) and 21 HCs underwent resting-state functional magnetic resonance imaging. The data collected included demographic profiles of both groups along with duration of illness, age of PD onset, and the H–Y score in PD patients. The Fazekas scores were calculated in all PD patients and HCs. The region of interest (ROI) functional connectivity method was used to assess resting-state functional connectivity within DMN and whole brain using the CONN toolbox. A total of 132 ROIs were selected in the whole brain using the Harvard Atlas. RESULTS: The mean age, gender, and median Fazekas scores in both groups were comparable. Mean (±SD) age of PD onset in patients was 52.92 ± 8.32 years. The median (range) H–Y score was 2 (1–3). Regions of increased functional connectivity were observed in the whole-brain analysis in the MiPD group. Four ROI pairs showed increased functional connectivity in the MiPD group compared to HCs (p < 0.001), prominently involving the frontoparietal, cerebellar, and basal ganglia region. Functional connectivity within DMN was comparable between the two groups. CONCLUSION: Compared to age- and gender-matched healthy controls, MiPD patients showed increased functional connectivity in selected regions, in particular, those involving the precuneus, thalamus, pallidum, and vermis, which may be related to initial compensation in PD.

Keywords

• default mode network
• functional magnetic resonance imaging
• parkinson’s disease
• precuneus
• resting-state functional connectivity