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Background and Purpose: Recently, some emerging cerebrospinal fluid (CSF) markers have been proposed as diagnostic tools for Alzheimer disease (AD) that can have an effect on disease progression. We analyze the accuracy of these CSF markers for diagnosis of AD in reference to brain amyloid positron emission tomography (PET). We also investigated whether they help in differentiating AD from other dementias and examined their influence in tracing the progression to dementia., Methods: Amyloid-β (Aβ) 1-42, total tau (t-tau), phosphorylated tau, Aβ 40 , Aβ 38 , beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1), neurogranin (ng), phosphorylated neurofilament heavy-chain, and α-synuclein (α-syn) CSF levels were analyzed in 319 subjects, among whom 57 also underwent an amyloid PET scan. We also analyzed longitudinal clinical data from 239 subjects., Results: Emerging CSF markers, especially ng/BACE-1 ratio (area under the curve = 0.77) and their combinations with core AD CSF markers (all AUCs >0.85), showed high accuracy to discriminate amyloid PET positivity. Subjects with AD had higher CSF BACE-1, ng, and α-syn levels than those with non-AD dementia. CSF t-tau/α-syn ratio was higher in subjects with dementia with Lewy bodies than in those with frontotemporal dementia. Most emerging/core AD ratios predicted a faster conversion from mild cognitive impairment (MCI) stage to AD and appeared to be helpful when core AD CSF markers were discordant. In addition, the rate of cognitive decline was associated with all CSF core AD markers, several emerging/core AD two-marker ratios, and CSF ng levels., Conclusions: These results suggest that emerging biomarkers in conjunction with core AD markers improve diagnosis of AD, are associated with the conversion from MCI into AD, and predict a faster progression of dementia., (© 2020 European Academy of Neurology.)

Background and Purpose: Epidemiologic studies of incidence and prevalence in Parkinson's Disease (PD) show highly variable results. Despite the large number of studies performed worldwide during the last decades, little is known about its prevalence in South America and no incidence studies have been performed. The goal of this study is to assess the incidence and prevalence of PD in a health maintenance organization from Buenos Aires City, the capital city of Argentina., Methods: The population were all members of the 'Plan de Salud, Hospital Italiano de Buenos Aires', a large prepaid health medical organization in Buenos Aires. From 1 January 2003 to 31 December 2008 patients diagnosed with PD according to Brain Bank of London diagnostic criteria were identified retrospectively. Incidence density was calculated with 95% confidence interval., Results: Hundred and forty thousand people were followed for a total of 754,082 person-years. A total of 239 incident cases of PD were identified. Crude incidence density was 31.2/100,000 person-years. Prevalence was 394/100,000 in the population older than 40 years. Male to female ratio was 1.31., Conclusions: This is the first study in South America that estimates the incidence of PD. Our results are consistent with other studies from other regions using similar methodologies., (© 2012 The Author(s). European Journal of Neurology © 2012 EFNS.)