The Motor Dysfunction Seen in Isolated REM Sleep Behavior Disorder.

BACKGROUND: Isolated Rapid Eye Movement (REM) sleep Behavior Disorder (iRBD) requires quantitative tools to detect incipient Parkinson's disease (PD). METHODS: A motor battery was designed and compared with the Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS-III) in people with iRBD and controls. This included two keyboard-based tests (BRadykinesia Akinesia INcoordination tap test and Distal Finger Tapping) and two dual tasking tests (walking and finger tapping). RESULTS: We included 33 iRBD patients and 29 controls. The iRBD group performed both keyboard-based tapping tests more slowly (P < 0.001, P = 0.020) and less rhythmically (P < 0.001, P = 0.006) than controls. Unlike controls, the iRBD group increased their walking duration (P < 0.001) and had a smaller amplitude (P = 0.001) and slower (P = 0.007) finger tapping with dual task. The combination of the most salient motor markers showed 90.3% sensitivity for 89.3% specificity (area under the ROC curve [AUC], 0.94), which was higher than the MDS-UPDRS-III (minus action tremor) (69.7% sensitivity, 72.4% specificity; AUC, 0.81) for detecting motor dysfunction. CONCLUSION: Speed, rhythm, and dual task motor deterioration might be accurate indicators of incipient PD in iRBD. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Phenotypic effect of GBA1 variants in individuals with and without Parkinson's disease: The RAPSODI study.

BACKGROUND: Variants in the GBA1 gene cause the lysosomal storage disorder Gaucher disease (GD). They are also risk factors for Parkinson's disease (PD), and modify the expression of the PD phenotype. The penetrance of GBA1 variants in PD is incomplete, and the ability to determine who among GBA1 variant carriers are at higher risk of developing PD, would represent an advantage for prognostic and trial design purposes. OBJECTIVES: To compare the motor and non-motor phenotype of GBA1 carriers and non-carriers. METHODS: We present the cross-sectional results of the baseline assessment from the RAPSODI study, an online assessment tool for PD patients and GBA1 variant carriers. The assessment includes clinically validated questionnaires, a tap-test, the University of Pennsyllvania Smell Identification Test and cognitive tests. Additional, homogeneous data from the PREDICT-PD cohort were included. RESULTS: A total of 379 participants completed all parts of the RAPSODI assessment (89 GBA1-negative controls, 169 GBA1-negative PD, 47 GBA1-positive PD, 47 non-affected GBA1 carriers, 27 GD). Eighty-six participants were recruited through PREDICT-PD (43 non-affected GBA1 carriers and 43 GBA1-negative controls). GBA1-positive PD patients showed worse performance in visual cognitive tasks and olfaction compared to GBA1-negative PD patients. No differences were detected between non-affected GBA1 carriers carriers and GBA1-negative controls. No phenotypic differences were observed between any of the non-PD groups. CONCLUSIONS: Our results support previous evidence that GBA1-positive PD has a specific phenotype with more severe non-motor symptoms. However, we did not reproduce previous findings of more frequent prodromal PD signs in non-affected GBA1 carriers.

The Views of Patients with Isolated Rapid Eye Movement Sleep Behavior Disorder on Risk Disclosure.

BACKGROUND: Isolated rapid eye movement sleep behavior disorder (iRBD) is associated with an increased risk of Parkinson's disease and other synucleinopathies. There is no consensus about disclosure of this risk to patients with iRBD. OBJECTIVE: The objective of our study was to assess the experiences of risk disclosure in a group of patients with iRBD and their views on what, when, and how this should be done. METHODS: A survey was administered to patients with iRBD to explore their experiences and views on risk disclosure. RESULTS: Thirty-one patients with iRBD (28 males; mean age, 70 [SD 8.7] years; mean disease duration, 8.7 [SD 6.4] years) were included. A third reported they had not been informed about the link between iRBD and other conditions by clinicians at diagnosis, but 90% would have liked to have received prognostic information, and 60% indicated that this should happen at the point that iRBD was diagnosed. Most participants wanted this information to come from the clinician diagnosing and treating iRBD (90.3%). Almost three-quarters (72.2%) had searched for this information online. CONCLUSIONS: Patients with iRBD mostly wished to have received information regarding the potential implications of iRBD when the diagnosis was made. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Alcohol and Parkinson's Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: A substantial body of research has examined the relationship between alcohol consumption and risk of Parkinson's disease (PD). OBJECTIVE: To provide an updated systematic review and meta-analysis of observational studies examining the relationship between alcohol consumption and risk of PD. METHODS: Eligible studies comparing PD risk in ever vs. never alcohol drinkers were sourced from six databases. Outcomes were pooled using standard meta-analysis techniques. Separate female and male estimates were generated from studies reporting sex-specific data. Additionally, cohort studies stratifying participants by quantity of alcohol intake were integrated in a dose-response analysis. RESULTS: 52 studies were included, totaling 63,707 PD patients and 9,817,924 controls. Our meta-analysis supported a statistically significant overrepresentation of never drinkers among PD subjects; odds ratio (OR) for ever drinking alcohol 0.84 (95% confidence interval (CI) 0.76 - 0.92). A subgroup analysis revealed similar effect estimates in females and males. A further synthesis of seven cohort studies suggested a negative, dose-dependent association between alcohol and risk of PD. CONCLUSION: In the absence of a known neuroprotective pathway, there may be reason to doubt a true biological effect. The role of survivor bias, selection and recall bias, misclassification, and residual confounding requires consideration. Alternatively, observations might be attributable to reverse causation if those predestined for PD alter their alcohol habits during the preclinical phase. Major limitations of our study include high between-study heterogeneity (I2 = 93.2%) and lack of adjustment for key confounders, namely smoking status.

Type 2 Diabetes as a Determinant of Parkinson's Disease Risk and Progression.

BACKGROUND: Type 2 diabetes (T2DM) and Parkinson's disease (PD) are prevalent diseases that affect an aging population. Previous systematic reviews and meta-analyses have explored the relationship between diabetes and the risk of PD, but the results have been conflicting. OBJECTIVE: The objective was to investigate T2DM as a determinant of PD through a meta-analysis of observational and genetic summary data. METHODS: A systematic review and meta-analysis of observational studies was undertaken by searching 6 databases. We selected the highest-quality studies investigating the association of T2DM with PD risk and progression. We then used Mendelian randomization (MR) to investigate the causal effects of genetic liability toward T2DM on PD risk and progression, using summary data derived from genome-wide association studies. RESULTS: In the observational part of the study, pooled effect estimates showed that T2DM was associated with an increased risk of PD (odds ratio [OR] 1.21, 95% confidence interval [CI] 1.07-1.36), and there was some evidence that T2DM was associated with faster progression of motor symptoms (standardized mean difference [SMD] 0.55, 95% CI 0.39-0.72) and cognitive decline (SMD -0.92, 95% CI -1.50 to -0.34). Using MR, we found supportive evidence for a causal effect of diabetes on PD risk (inverse-variance weighted method [IVW] OR 1.08, 95% CI 1.02-1.14; P = 0.010) and some evidence of an effect on motor progression (IVW OR 1.10, 95% CI 1.01-1.20; P = 0.032) but not on cognitive progression. CONCLUSIONS: Using meta-analyses of traditional observational studies and genetic data, we observed convincing evidence for an effect of T2DM on PD risk and new evidence to support a role in PD progression. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.