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Background: Parkinson disease (PD) is a common neurodegenerative disorder. Elevations of neurofilament light chain (NfL) concentrations in the cerebrospinal fluid (CSF) and blood are a marker of neuronal/axonal injury and degeneration. However, CSF and blood NfL alterations in patients with PD from existing studies remain inconclusive. To better understand these conflicting data, we will conduct a meta-analysis. Methods: We will comprehensively search PubMed, Embase, and Web of Science databases from each database's inception to 7th June, 2020. This protocol will conform to the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols. We will only include original studies published in English that evaluated differences of NfL concentrations in the CSF or blood between idiopathic PD patients and healthy controls. The Newcastle-Ottawa Scale will be used to evaluate the quality of the included studies. Meta-analyses will be carried out using the STATA software version 13.0. Between-group difference of NfL concentrations in the CSF and blood will be expressed as the weighted standardized mean difference. A random-effects model will be used. Supplementary analyses, such as heterogeneity analysis, sensitivity analysis, publication bias, subgroup analysis, and meta-regression analysis will be performed. Results: The meta-analysis will provide the differences of NfL concentrations in the CSF and blood between patients with PD and healthy controls and will show the magnitudes of their effect sizes. Conclusions: This meta-analysis will provide the evidence of NfL concentrations in the CSF and blood in PD and we hope that our study has an important impact on clinical practice. Registration number: INPLASY202060025

A 4-degree-of-freedom (DOF) parallel mechanism with 3 translations and 1 rotation (3T1R) has wide application potential in the industry. However, most of the existing 3T1R parallel mechanisms have limited rotation capacity of the moving platform, which is usually less than ±90°. In this paper, a new type of 3T1R parallel mechanism is designed by configuration deduction method based on the 3T1R parallel mechanism studied at present. The structure of the parallel mechanism is simple and symmetrical, and the motion pairs are all rotating pairs, which have Selective Compliance Assembly Robot Arm motion and complete rotation capability. Firstly, the branch motion spiral system is established by using the screw theory, and then the constraint spiral of each branch to the motion platform is solved, and the constraint spiral system is analyzed, so as to determine the number of DOFs and properties of the mechanism. Secondly, the position, velocity, and singularity of the mechanism are analyzed, and the workspace of the mechanism is analyzed by the positive position solution. Then, the trajectory planning of operation space is completed, and a mathematical model of portal grasping trajectory is established. Thirdly, the kinematic simulation analysis of the mechanism is carried out. Finally, an equal scale physical model was made by 3D printing technology to verify the rationality of the design and the correctness of the theoretical analysis.

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Background: Neurofilament light chain (NfL), an index of neuroaxonal injury, is a promising diagnostic and prognostic fluid biomarker with high translational value in many neurodegenerative disorders. Blood NfL measurement has been an exciting and active field of research in idiopathic Parkinson disease (PD) and atypical parkinsonisms. However, blood NfL levels in these parkinsonisms from existing literature were inconsistent. No comprehensive meta-analysis has ever been conducted. Methods: Three major biomedical electronic databases PubMed, Embase, and Web of Science were comprehensively searched from inception to July 10, 2020. This protocol will be prepared based on the guidelines recommended by the statement of Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). Original observational studies that measured blood (serum/plasma) NfL concentrations in patients with parkinsonisms (multiple system atrophy [MSA], progressive supranuclear palsy [PSP], corticobasal syndrome [CBS], and dementia with Lewy bodies [DLB]), and healthy controls (HCs) will be included. Quality assessment of the included studies will be performed using the Newcastle Ottawa Scale (NOS). Meta-analyses will be conducted using the STATA software version 13.0. The standardized mean differences as the measure of effect size and 95% confidence intervals were calculated for each comparison of blood NfL levels. Heterogeneity analysis, sensitivity analysis, publication bias, subgroup analysis, and meta-regression analysis will be carried out to test the robustness of the results. Results: The meta-analysis will obtain the effect sizes of blood NfL levels in the following comparisons: PD versus HC, MSA versus HC, PSP versus HC, CBS versus HC, DLB versus HC, MSA versus PD, PSP versus PD, CBS versus PD, and DLB versus PD. Conclusions: The present meta-analysis will provide the quantitative evidence of NfL levels in idiopathic PD and atypical parkinsonisms, hoping to facilitate differential diagnoses in clinical practice. Registration number: INPLASY202070091.

Review question / Objective: The aim of this study is to conduct a meta-analysis to characterize theory of mind and empathy performance in adults with epilepsy. Condition being studied: Epilepsy is one of the most common neurological disorders, which affects over 50 million people worldwide. Cognitive impairment is considered to a common symptom of epilepsy, including memory impairment, language dysfunction, attention deficit, executive dysfunction, and social cognition impairment. Social cognition is defined as the ability to explain and predict the behavior of others based on the beliefs, feelings and intentions of others, and to interact in complex social environments and relationships. Social cognition is a multidimensional construct, mainly involving: theory of mind (ToM), empathy, social perception and social knowledge, and attribution bias. However, there have been inconsistent findings. However, no previous meta-analysis has investigated the difference between cognitive ToM and affective ToM in adult patients with epilepsy, and it is not clear how empathy abilities are affected in adult patients with epilepsy. INPLASY registration number:This protocol was registered with the International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) on 07 December 2021 and was last updated on 07 December 2021 (registration number INPLASY2021120039).

Review question / Objective: The main question to address in the study is to determine whether the concentrations of inflammatory cytokine differ quantitatively between patients diagnosed with multiple system atrophy and control subjects as measured from peripheral blood and cerebrospinal fluid. Condition being studied: Multiple system atrophy (MSA) is a rare, rapidly progressing and fatal neurodegenerative disease. Clinically, MSA is characterized by parkinsonism, cerebellar impairment and autonomic dysfunction. Studies have INPLASY

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