Non-motor symptoms are associated with midline tremor in essential tremor.

OBJECTIVES: Essential tremor (ET) patients presenting tremor in the midline structures may be a distinct subtype of the syndrome. Therefore, we sought to explore the clinical manifestations, especially non-motor symptoms (NMS) of Chinese ET patients with midline tremor (MT). METHODS: In the cross-sectional study, we grouped 290 definite or probable ET patients based on their MT conditions. The NMS in ET patients were evaluated using the NMS scale (NMSS). NMS and other clinical correlates were then compared among subgroups with, and without MT. RESULTS: We revealed that 39.0%, 27.6%, and 6.9% of the patients respectively had neck, voice, and facial tremors. With the accumulation of tremor in midline structures, NMS became more severe and prevalent. Logistic regression analyses revealed that factors such as: female gender (OR = 2.164, 95% CI: 1.307-3.583), having least or highest action arm tremor (OR = 2.512, 95% CI: 1.520-4.151), having higher score of sleep/fatigue domain (OR = 1.692, 95% CI: 1.004-2.850) and mood/apathy (OR = 1.926, 95% CI: 1.143-3.246) domain, to be independently associated with MT manifestation. CONCLUSIONS: Our study demonstrates the heterogeneity of symptoms in ET patients with MT, especially in prominent NMS. In addition, the discrepancy of NMS between patients with, and without MT provides novel insight into the underlying pathophysiology and therapeutic of ET.

A corrugated perfect magnetic conductor surface supporting spoof surface magnon polaritons.

In this paper, we demonstrate that spoof surface magnon polaritons (SSMPs) can propagate along a corrugated perfect magnetic conductor (PMC) surface. From duality theorem, the existence of surface electromagnetic modes on corrugated PMC surfaces are manifest to be transverse electric (TE) mode compared with the transverse magnetic (TM) mode of spoof surface plasmon plaritons (SSPPs) excited on corrugated perfect electric conductor surfaces. Theoretical deduction through modal expansion method and simulation results clearly verify that SSMPs share the same dispersion relationship with the SSPPs. It is worth noting that this metamaterial will have more similar properties and potential applications as the SSPPs in large number of areas.

Association between REM sleep behavior disorder and impulsive-compulsive behaviors in Parkinson's disease: a systematic review and meta-analysis of observational studies.

BACKGROUND: Both REM sleep behavior disorder (RBD) and impulsive-compulsive behaviors (ICBs) are well-recognized non-motor features in patients with Parkinson's disease (PD). Studies have given contradictory results about the potential association between RBD and ICBs. METHODS: PubMed, Embase (via Ovid), and the Cochrane Central Registry of Controlled Trials (CENTRAL) databases were systematically searched till August 20, 2019 to identify studies that explored the possible correlation between RBD and ICBs in patients with PD. Two authors independently screened records, extracted data and evaluated quality of included studies. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by employing a random or fixed-effects model. We performed subgroup and sensitivity analyses, and we assessed potential publication bias. RESULTS: A total of 134 references were screened and 10 studies involving 2781 PD patients were included. Overall, RBD was associated with a more than twofold higher risk of developing ICBs (OR 2.12, 95% CI 1.43-3.14, I2 = 56.7%, P < 0.01). Similar results were obtained in sensitivity analyses and in meta-analyses of subgroups stratified based on multivariable adjustment and methods for diagnosing RBD and ICBs. No significant risk of publication bias was found. CONCLUSION: RBD in PD is confirmed to be a risk factor for ICBs. Clinicians should be aware of this association to help them improve patient management.

Polymorphism in MIR4697 but not VPS13C, GCH1, or SIPA1L2 is associated with risk of Parkinson's disease in a Han Chinese population.

A large meta-analysis recently identified six new loci associated with risk of PD, but subsequent studies have given discrepant results. Here we conducted a case-control study in a Han Chinese population in an attempt to clarify risk associations in Chinese. Among the four single-nucleotide polymorphisms (SNPs) that we examined - VPS13C-rs2414739, MIR4697-rs329648, GCH1-rs11158026, and SIPA1L2- rs10797576 we detected a significant association between rs329648 and risk of developing PD in a recessive model. This association remained significant after adjusting for gender and age (OR 1.87, 95%CI 1.295-2.694, p=8.21×10-4) or Bonferroni correction. The T allele of rs329648 occurred significantly more frequently among patients with PD than among healthy controls (OR 1.22, 95%CI 1.033-1.443, p=0.02), while there was no statistic significant after Bonferroni correction. Subgroup analysis showed a significant association specifically among males in a recessive model (OR 1.943, 95%CI 1.200-3.147, p=0.007). In contrast, genotye and allele frequencies at rs329648 did not differ significantly between female patients with PD and healthy female controls, or between patients with early-onset or late-onset PD. Our results suggest that rs329648 is associated with risk of developing PD in the Han Chinese population. Our findings should be verified in further studies, and they highlight the need for functional studies of MIR4697.