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Introduction: Studies estimate that >80% of patients with idiopathic REM sleep behavior disorder (iRBD) eventually develop parkinsonism or dementia. However, a small group remains disease-free for long periods, raising the question of whether they truly have prodromal disease., Methods: We selected subjects with iRBD who were diagnosed at least 10 years previously, and were still disease free (longstanding iRBD) (n = 11). We compared them to 'early converters' (n = 27) defined as those who phenoconverted to parkinsonism or dementia within 4 years after diagnosis, and to age- and sex-matched healthy controls (n = 68). We compared the frequency and progression of numerous markers of prodromal synucleinopathy between groups, and assessed likelihood of meeting prodromal Parkinson's disease criteria., Results: After at least 10 years follow-up, almost all longstanding iRBD subjects showed multiple features of neurodegeneration, and 9/11 met criteria for prodromal PD. Evolution of markers was slower than early-converters, with an annual increase in prodromal PD probability of 3.9 ± 3.2% in longstanding iRBD compared to 12.4 ± 7.8% for early-convertors (p-value = 0.002). However, subjects with longstanding iRBD at their last visit had similar prodromal measures as the baseline evaluation of the early-convertors, with similarly-abnormal UPDRS scores, quantitative motor tests, cognition and autonomic symptoms and signs., Conclusion: Although phenoconversion rates can differ dramatically between patients, almost all individuals with iRBD in our cohort appear to have underlying neurodegeneration., (Copyright © 2018. Published by Elsevier Ltd.)

Background: Recently, the International Parkinson and Movement Disorder Society introduced the prodromal criteria for PD. Objectives Our study aimed to examine diagnostic accuracy of the criteria as well as the independence of prodromal markers to predict conversion to PD or dementia with Lewy bodies., Methods: This prospective cohort study was performed on 121 individuals with rapid eye movement sleep behavior disorder who were followed annually for 1 to 12 years. Using data from a comprehensive panel of prodromal markers, likelihood ratio and post-test probability of the criteria were calculated at baseline and during each follow-up visit., Results: Forty-eight (39.7%) individuals with rapid eye movement sleep behavior disorder converted to PD/dementia with Lewy bodies. The prodromal criteria had 81.3% sensitivity and 67.9% specificity for conversion to PD/dementia with Lewy bodies at 4-year follow-up. One year before conversion, sensitivity was 100%. The criteria predicted dementia with Lewy bodies with even higher accuracy than PD without dementia at onset. Those who met the threshold of prodromal criteria at baseline had significantly more rapid conversion into a neurodegenerative state (4.8 vs. 9.1 years; P < 0.001). Pair-wise combinations of different prodromal markers showed that markers were independent of one another., Conclusion: The prodromal criteria are a promising tool for predicting incidence of PD/dementia with Lewy bodies and conversion time in a rapid eye movement sleep behavior disorder cohort, with high sensitivity and high specificity with long follow-up. Prodromal markers influence the overall likelihood ratio independently, allowing them to be reliably multiplied. Defining additional markers with high likelihood ratio, further studies with longitudinal assessment and testing thresholds in different target populations will improve the criteria. © 2017 International Parkinson and Movement Disorder Society., (© 2017 International Parkinson and Movement Disorder Society.)

Objective: To assess whether risk factors for Parkinson disease and dementia with Lewy bodies increase rate of defined neurodegenerative disease in idiopathic rapid eye movement (REM) sleep behavior disorder (RBD)., Methods: Twelve centers administered a detailed questionnaire assessing risk factors for neurodegenerative synucleinopathy to patients with idiopathic RBD. Variables included demographics, lifestyle factors, pesticide exposures, occupation, comorbid conditions, medication use, family history, and autonomic/motor symptoms. After 4 years of follow-up, patients were assessed for dementia or parkinsonism. Disease risk was assessed with Kaplan-Meier analysis, and epidemiologic variables were compared between convertors and those still idiopathic using logistic regression., Results: Of 305 patients, follow-up information was available for 279, of whom 93 (33.3%) developed defined neurodegenerative disease. Disease risk was 25% at 3 years and 41% after 5 years. Patients who converted were older (difference = 4.5 years, p < 0.001), with similar sex distribution. Neither caffeine, smoking, nor alcohol exposure predicted conversion. Although occupation was similar between groups, those who converted had a lower likelihood of pesticide exposure (occupational insecticide = 2.3% vs 9.0%). Convertors were more likely to report family history of dementia (odds ratio [OR] = 2.09), without significant differences in Parkinson disease or sleep disorders. Medication exposures and medical history were similar between groups. Autonomic and motor symptoms were more common among those who converted. Risk factors for primary dementia and parkinsonism were generally similar, except for a notably higher clonazepam use in dementia convertors (OR = 2.6)., Interpretation: Patients with idiopathic RBD are at very high risk of neurodegenerative synucleinopathy. Risk factor profiles between convertors and nonconvertors have both important commonalities and differences., (© 2015 American Neurological Association.)

Parkinson's disease has a long prodromal stage with various subclinical motor and non-motor manifestations; however, their evolution in the years before Parkinson's disease is diagnosed is unclear. We traced the evolution of early motor and non-motor manifestations of synucleinopathy from the stage of idiopathic rapid eye movement (REM) sleep behaviour disorder until defined neurodegenerative disease. During 2004-16, we recruited and then annually followed 154 polysomnography-proven patients with idiopathic REM sleep behaviour disorder, of whom 55 phenoconverted to defined parkinsonism or dementia. Longitudinal data on multiple prodromal features, including the Unified Parkinson's Disease Rating Scale parts I-III, quantitative motor tests, olfaction, colour vision, cognition, and autonomic functions were gathered annually (average = five follow-up visits, range: 2-12 years). The same measures were also assessed in 102 age- and sex-matched healthy control subjects. By looking backward from the time of dementia or parkinsonism diagnosis, we examined trajectories of each prodromal feature using mixed effect models. Based on analysis, olfactory loss was first to develop, with predicted onset >20 years before phenoconversion. This was followed by impaired colour vision, constipation, and erectile dysfunction, starting 10-16 years prior to phenoconversion. At 7-9 years before phenoconversion, slight urinary dysfunction and subtle cognitive decline could be detected. Among motor symptoms altered handwriting, turning in bed, walking, salivation, speech, and facial expression began to be disrupted starting 7-11 years prior to parkinsonism diagnosis, but remained mild until soon before phenoconversion. Motor examination abnormalities began 5-7 years before phenoconversion, with the alternate tap test having the longest interval (8 years before phenoconversion). Among cardinal motor phenotypes, bradykinesia appeared first, ∼5-6 years prior to phenoconversion, followed by rigidity (Year -3) and tremor (Year -2). With direct prospective evaluation of an idiopathic REM sleep behaviour disorder cohort during phenoconversion, we documented an evolution of prodromal manifestations similar to that predicted by pathological staging models, with predicted prodromal intervals as long as 20 years. [ABSTRACT FROM AUTHOR]