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Aims: The study aimed to investigate alterations in the inherent connectivity pattern of global functional networks in Parkinson's disease (PD) patients with fatigue. Methods: Eighteen PD patients with fatigue (PD‐F), 20 PD patients without fatigue (PD‐NF), and 23 healthy controls (HCs) were recruited and analyzed by the voxel‐wise degree centrality (DC) and the seed‐based functional connectivity (FC) analysis. Meanwhile, the surface‐based morphometry (SBM) analysis was also commanded to explore the structural alternations among groups. Results: PD‐F patients displayed reduced DC values in the left postcentral gyrus relative to PD‐NF and HCs groups, while increased DC values in the bilateral precuneus compared to HCs. Simultaneously, altered DC value in the left postcentral gyrus negatively corresponded to the mean fatigue severity scale (FSS) in PD‐F patients. Additionally, the receiver operating characteristic (ROC) curves uncovered that the reduced DC value of the left postcentral gyrus could discriminate PD‐F from PD‐NF and HCs groups. Our FC analysis further revealed that altered FC was located predominantly in the sensorimotor network in the PD‐F group. Moreover, we discovered no statistically significant differences between the three groups concerning cortical thickness. Conclusion: Our findings indicated that the altered functional connectivity in the sensorimotor network centering on the left postcentral gyrus and the bilateral precuneus might be the potential pathogenesis of PD with fatigue. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to clarify the dynamic neural activity of levodopa‐induced dyskinesia (LID) in Parkinson's disease (PD). Methods: Using dynamic functional network connectivity (dFNC) analysis, we evaluated 41 PD patients with LID (LID group) and 34 PD patients without LID (No‐LID group). Group spatial independent component analysis and sliding‐window approach were employed. Moreover, we applied a k‐means clustering algorithm on windowed functional connectivity (FC) matrices to identify reoccurring FC patterns (i.e., states). Results: The optimal number of states was determined to be five, the so‐called State 1, 2, 3, 4, and 5. In ON phase, compared with No‐LID group, LID group occurred more frequently and dwelled longer in strongly connected State 1, characterized by strong positive connections between visual network (VIS) and sensorimotor network (SMN). When switching from OFF to ON phase, LID group occurred less frequently in State 3 and State 4. Meanwhile, LID group dwelled longer in State 2 and shorter in State 3. No‐LID group occurred more frequently in State 5 and less frequently in State 3. Additionally, correlation analysis demonstrated that dyskinesia's severity was associated with frequency of occurrence and dwell time in State 2, dominated by inferior frontal cortex in cognitive executive network (CEN). Conclusion: Using dFNC analysis, we found that dyskinesia may be related to the dysfunctional inhibition of CEN on motor loops and excessive excitation of VIS and SMN, which provided evidence of the changes in brain dynamics associated with the occurrence of dyskinesia. [ABSTRACT FROM AUTHOR]

Object: Excessive daytime sleepiness (EDS) is common in Parkinson disease (PD), but the neural basis of EDS in PD is unclear. We aim to analyze the neural activity changes in PD-related EDS. Methods: In the present study, 38 PD patients and 19 healthy controls underwent clinical assessments and resting state functional magnetic resonance imaging (MRI) at 3T. Patients were further classified into PD patients with EDS (n = 17) and PD patients without EDS (n = 21), according to the Epworth Sleepiness Scale (ESS) cutoff score with greater than 10 or less than 3. We evaluated all patients using PD-related motor and non-motor clinical scales. An analysis of covariance and post hoc two-sample t -tests were performed to examine between-groups differences of the amplitude of low-frequency fluctuations (ALFF) and functional connectivity (FC). Results: We found that, all PD-EDS subjects in our study were male. Compared with the control subjects, PD patients with EDS had decreased ALFF in the Pons and increased ALFF in the Frontal_Mid_Orb_L (p < 0.01, corrected). Moreover, PD patients with EDS showed decreased ALFF in the left posterior cingulate cortex (PCC) relative to PD without EDS, which was negatively correlated with the ESS score (p < 0.001). After that, the FC analysis with the left PCC region of interest showed reduced FC of the right PCC and right precuneus in PD with EDS compared with PD without EDS (p < 0.01, corrected). Conclusion: We hypothesized the wake-promoting pathways and the default mode network dysfunction underlying the EDS in male PD patients. [ABSTRACT FROM AUTHOR]

Freezing of gait (FOG) is an intractable and paroxysmal gait disorder that seriously affects the quality of life of Parkinson's disease (PD) patients. Emerging studies have reported abnormal brain activity of distributed networks in FOG patients, whereas ignoring the intrinsic dynamic fluctuations of functional connectivity. The purpose of this study was to examine the dynamic functional network connectivity (dFNC) of PD-FOG. In total, 52 PD patients with FOG (PD-FOG), 73 without FOG (PD-NFOG) and 38 healthy controls (HCs) received resting state functional magnetic resonance imaging (rs-fMRI). Sliding window method, k-means clustering and graph theory analysis were employed to retrieve dynamic characteristics of PD-FOG. Partial correlation analysis was conducted to verify whether the dFNC was related to freezing gait severity. Seven brain networks were identified and configured into seven states. Compared to PD-NFOG, significant spatial pattern was identified for state 2 in freezers, showing increased functional coupling between default mode network (DMN) and basal ganglia network (BG), as a concrete manifestation of increased precuneus-caudate coupling. The mean dwell time and fractional window of state 2 had a positive correlation with FOG severity. Furthermore, PD-FOG group exhibited lower variance in nodal efficiency of independent components (IC) 7 (left precuneus). Our study suggested that aberrant coupling of precuneus-caudate and disrupted variability of precuneus efficiency might be associated to the neural mechanisms of FOG. • altered coupling of DMN-BG. • decreased variance in Ne of precuneus. • visuospatial overload. [ABSTRACT FROM AUTHOR]

• DFC in state IV differed between PD-pRBD and PD-npRBD. • FC among DMN, VIS and BG had abnormalities in pRBD. • Temporal metrics altered in RBD. Rapid eye movement (REM) sleep behavior disorder (RBD) is one of the common nonmotor symptoms of Parkinson's disease (PD), characterized by frequently occurring REM sleep without muscle atonia. Our aim was to explore dynamic network connection changes in PD patients with RBD. On the basis of RBD screening questionnaire (RBDSQ), 126 PD patients were classified into those with probable RBD symptoms (PD-pRBD) and without probable RBD (PD-npRBD). We applied independent component analysis, sliding window approach and k-means clustering methods to clarify dynamic functional connectivity alterations. In contrast to PD-npRBD, PD-pRBD patients were liable to engage in a brain pattern mainly marked by weaker positive couplings between visual network (VIS) and default mode network (DMN), DMN and basal ganglia network (BG), and within DMN (State IV). In addition, we discovered that both PD patients with or without pRBD had shorter dwell time and fewer occurrences in State III, characterized by positive correlations between VIS and DMN, BG and DMN, and positive within-network coupling of sensorimotor network (SMN), relative to healthy controls. Our study suggested that the weaker positive couplings between VIS and DMN, DMN and BG, and within DMN in State IV could be involved in the pathogenesis of PD patients with probable RBD on an overall level. [ABSTRACT FROM AUTHOR]