Brit Mollenhauer, Chelsea J. Caspell-Garcia, Christopher S. Coffey, Peggy Taylor, Leslie M. Shaw, John Q. Trojanowski, Andy Singleton, Mark Frasier, Kenneth Marek, Douglas Galasko, Kenneth Marek, Danna Jennings, Shirley Lasch, Caroline Tanner, Tanya Simuni, Christopher Coffey, Karl Kieburtz, Renee Wilson, Werner Poewe, Brit Mollenhauer, Tatiana Foroud, Todd Sherer, Sohini Chowdhury, Mark Frasier, Catherine Kopil, Vanessa Arnedo, Alice Rudolph, Cynthia Casaceli, John Seibyl, Susan Mendick, Norbert Schuff, Chelsea Caspell, Liz Uribe, Eric Foster, Katherine Gloer, Jon Yankey, Arthur Toga, Karen Crawford, Paola Casalin, Giulia Malferrari, Brit Mollenhauer, Douglas Galasko, Andrew Singleton, Keith A. Hawkins, David Russell, Stewart Factor, Penelope Hogarth, David Standaert, Robert Hauser, Joseph Jankovic, Matthew Stern, Lana Chahine, James Leverenz, Samuel Frank, Irene Richard, Klaus Seppi, Holly Shill, Hubert Fernandez, Daniela Berg, Isabel Wurster, Douglas Galasko, Zoltan Mari, David Brooks, Nicola Pavese, Paolo Barone, Stuart Isaacson, Alberto Espay, Dominic Rowe, Melanie Brandabur, James Tetrud, Grace Liang, Alex Iranzo, Eduardo Tolosa, Laura Leary, Cheryl Riordan, Linda Rees, Alicia Portillo, Art Lenahan, Karen Williams, Stephanie Guthrie, Ashlee Rawlins, Sherry Harlan, Christine Hunter, Baochan Tran, Abigail Darin, Carly Linder, Marne Baca, Heli Venkov, Cathi-Ann Thomas, Raymond James, Cheryl Deeley, Courtney Bishop, Fabienne Sprenger, Diana Willeke, Sanja Obradov, Jennifer Mule, Nancy Monahan, Katharina Gauss, Deborah Fontaine, Christina Gigliotti, Arita McCoy, Becky Dunlop, Bina Shah, Ainscough Susan, Angela James, Rebecca Silverstein, Kristy Espay, Madelaine Ranola, Kenneth Marek, Investigator, Danna Jennings, Shirley Lasch, Andrew Siderowf, Tanner Caroline, Tanya Simuni, Chris Coffey, Karl Kieburtz, Emily Flagg, Sohini Chowdhury, Werner Poewe, Brit Mollenhauer, Todd Sherer, Mark Frasier, Claire Meunier, Alice Rudolph, Cindy Casaceli, John Seibyl, Investigator, Susan Mendick, Norbert Schuff, Ying Zhang, Arthur Toga, Karen Crawford, Alison Ansbach, Pas-quale De Blasio, Michele Piovella, John Trojanowski, Les Shaw, Andrew Singleton, Keith Hawkins, J PsyDMichael, Jamie Eberling, Deborah Brooks, David Russell, Laura Leary, Stewart Factor, Barbara Sommerfeld, Penelope Hogarth, Emily Pighetti, Karen Williams, David Standaert, Stephanie Guthrie, Robert Hauser, Holly Delgado, Joseph Jankovic, Christine Hunter, Matthew Stern, Baochan Tran, Jim Leverenz, Marne Baca, Sam Frank, Cathi-Ann Thomas, Irene Richard, Cheryl Deeley, Linda Rees, Fabienne Sprenger, Wolfgang Oertel, Elisabeth Lang, Holly Shill, Sanja Obradov, Hubert Fernandez, Adrienna Winters, Daniela Berg, Katharina Gauss, Douglas Galasko, Deborah Fontaine, Zoltan Mari, Melissa Gerstenhaber, David Brooks, Sophie Malloy, Paolo Barone, Katia Longo, Tom Comery, Bernard Ravina, Igor Grachev, Kim Gallagher, Michelle Collins, Katherine L. Widnell, Suzanne Ostrowizki, Paulo Fontoura, F. Hoffmann La-Roche, Tony Ho, Johan Luthman, Marcel van der Brug, Alastair D. Reith, Peggy Taylor

To analyze longitudinal levels of CSF biomarkers in drug-naive patients with Parkinson disease (PD) and healthy controls (HC), examine the extent to which these biomarker changes relate to clinical measures of PD, and identify what may influence them. CSF α-synuclein (α-syn), total and phosphorylated tau (t- and p-tau), and β-amyloid 1-42 (Aβ42) were measured at baseline and 6 and 12 months in 173 patients with PD and 112 matched HC in the international multicenter Parkinson's Progression Marker Initiative. Baseline clinical and demographic variables, PD medications, neuroimaging, and genetic variables were evaluated as potential predictors of CSF biomarker changes. CSF biomarkers were stable over 6 and 12 months, and there was a small but significant increase in CSF Aβ42 in both patients with patients with PD and HC from baseline to 12 months. The t-tau remained stable. The p-tau increased marginally more in patients with PD than in HC. α-syn remained relatively stable in patients with PD and HC. Ratios of p-tau/t-tau increased, while t-tau/Aβ42 decreased over 12 months in patients with PD. CSF biomarker changes did not correlate with changes in Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale motor scores or dopamine imaging. CSF α-syn levels at 12 months were lower in patients with PD treated with dopamine replacement therapy, especially dopamine agonists. These core CSF biomarkers remained stable over 6 and 12 months in patients with early PD and HC. PD medication use may influence CSF α-syn. Novel biomarkers are needed to better profile progressive neurodegeneration in PD.