Repetitive transcranial magnetic stimulation (rTMS) fails to improve cognition in patients with parkinson's disease: a Meta-analysis of randomized controlled trials.

BACKGROUND: Cognitive decline is one of the greatest concerns for patients with Parkinson's disease (PD) and their care partners. Repetitive transcranial magnetic stimulation (rTMS) is a nonpharmacological treatment option used to improve cognitive function in PD, but its efficacy is unclear. We performed a meta-analysis to determine whether rTMS improves cognition in PD patients. METHODS: Eligibility criteria (PICOS) were as follows: (1) 'P': The patients participating were diagnosed with idiopathic PD; (2) 'I': Intervention using rTMS; (3) 'C': Sham stimulation as control; (4) 'O': The outcome of the study included cognitive evaluations; (5) 'S': The study adopted randomized controlled design. The standardized mean difference (SMD) of change of score was applied to measure efficacy, and we used Version 2 of the Cochrane tool to assess risk of bias. RESULTS: Twelve studies met the inclusion criteria. Compared with sham-controlled group, the pooled result showed a non-significant short-term effect of rTMS on global cognition (SMD: -0.15, 95% CI: -0.59 to 0.29, I2 = 36.7%), executive function (SMD: 0.03, 95% CI: -0.21 to 0.26, I2 = 0.0%), and attention and working memory (SMD: 0.05, 95% CI: -0.25 to 0.35, I2 = 0.0%). Long-term outcomes were either shown to be statistically nonsignificant. CONCLUSIONS: Based on a limited number of studies, rTMS fails to improve cognition in PD. We call for additional high-quality randomized controlled trials with adequate sample sizes to determine the efficacy of rTMS.

Alterations in intrinsic functional networks in Parkinson's disease patients with depression: A resting-state functional magnetic resonance imaging study.

AIMS: The aim of this research was to investigate the alterations in functional brain networks and to assess the relationship between depressive impairment and topological network changes in Parkinson's disease (PD) patients with depression (DPD). METHODS: Twenty-two DPD patients, 23 PD patients without depression (NDPD), and 25 matched healthy controls (HCs) were enrolled. All participants were examined by resting-state functional magnetic resonance imaging scans. Graph theoretical analysis and network-based statistic methods were used to analyze brain network topological properties and abnormal subnetworks, respectively. RESULTS: The DPD group showed significantly decreased local efficiency compared with the HC group (P = .008, FDR corrected). In nodal metrics analyses, the degree of the right inferior occipital gyrus (P = .0001, FDR corrected) was positively correlated with the Hamilton Depression Rating Scale scores in the DPD group. Meanwhile, the temporal visual cortex, including the bilateral middle temporal gyri and right inferior temporal gyrus in the HC and NDPD groups and the left posterior cingulate gyrus in the NDPD group, was defined as hub region, but not in the DPD group. Compared with the HC group, the DPD group had extensive weakening of connections between the temporal-occipital visual cortex and the prefrontal-limbic network. CONCLUSIONS: These results suggest that PD depression is associated with disruptions in the topological organization of functional brain networks, mainly involved the temporal-occipital visual cortex and the posterior cingulate gyrus and may advance our current understanding of the pathophysiological mechanisms underlying DPD.

RIT2 polymorphism is associated with Parkinson's disease in a Han Chinese population.

Recently, a meta-analysis including 5 large genome-wide association studies has identified rs12456492 variant of RIT2 gene as a novel risk locus for Parkinson's disease (PD) in Caucasian populations. However, the association between RIT2 polymorphism and PD risk has not been positively replicated in Asian population yet. We detected the genotypes of rs12456492 in 524 PD patients and 521 control subjects from a Han Chinese population. The allele and genotype distribution of rs12456492 variant were significantly different between PD patients and controls (allele p = 0.001, genotype p = 0.002). Logistic regression analysis showed that the G-carrying genotype (AG + GG) individuals exhibited a nearly 1.4-fold increased risk for PD compared with the AA genotype carriers (OR = 1.390; 95% confidence interval = 1.079-1.791; p = 0.011). Our data support that the carriage of G allele of rs12456492 variant of RIT2 gene significantly increases the risk for PD in Han Chinese population, suggesting a potential role of RIT2 in the etiology of PD.

Triggering receptor expressed on myeloid cells 2 variants are rare in Parkinson's disease in a Han Chinese cohort.

Recent studies have reported that a rare nonsynonymous variant rs75932628-T in the TREM2 gene is associated with increased risk of Alzheimer's disease and Parkinson's disease (PD) in European-descended populations. However, the association between rare TREM2 mutations and PD risk remains unknown in Chinese population. We directly sequenced exon2 of TREM2 in a cohort of 476 PD patients and 432 healthy controls from a Han Chinese population. Rs75932628-T (p.R47H) was found in 0.2% of PD cases (1/476) but in none of the controls (0/432, p = 1.000), with a minor allele frequency of 0.06% among the 908 subjects. Our findings suggest that variants in exon2 of TREM2 are extremely rare, and it is not a genetic risk factor for PD in the southern Han Chinese population.