{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,5]],"date-time":"2026-11-05T15:03:50Z","timestamp":1793891030134,"version":"4.8.0"},"reference-count":26,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T00:00:00Z","timestamp":1791763200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T00:00:00Z","timestamp":1791763200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/100000065","name":"National Institute of Neurological Disorders and Stroke","doi-asserted-by":"publisher","award":["120038"],"award-info":[{"award-number":["120038"]}],"id":[{"id":"10.13039\/100000065","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000864","name":"Michael J. Fox Foundation for Parkinson's Research","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000864","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["movementdisorders.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Movement Disorders"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Studies reporting \u03b1\u2010synuclein seed amplification assay (aSyn\u2010SAA) results are often cross\u2010sectional.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>In this study, we investigated the intraindividual consistency of aSyn\u2010SAA results (Amprion) over time from participants in the Parkinson's Precision Medicine Initiative (PPMI).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A total of 1238 participants had &gt;1 cerebrospinal fluid (CSF) aSyn\u2010SAA result for analysis (Parkinson's disease [PD]\u2009=\u2009633, prodromal\u2009=\u2009563, healthy control [HC]\u2009=\u200942), collected over a median (minimum, maximum) of 2.0 (0.4, 11.4) years. Emphasis was placed on evaluating consistency in aSyn\u2010SAA\u2010PD participants, aSyn\u2010SAA\u2009+\u2009HC participants, and conversion rates from aSyn\u2010SAA negative to positive results prodromal participants.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Of aSyn\u2010SAA\u2009+\u2009PD participants, 96% (474\/493, 95% confidence interval [CI]:\u200994%\u201398%) remained positive in subsequent samples, and 92% (116\/126, 95% CI:\u200986%\u201396%) of aSyn\u2010SAA\u2010PD participants remained negative. Ninety\u2010nine percent (303\/307, 95% CI:\u200997%\u201399%) of aSyn\u2010SAA\u2009+\u2009prodromal participants remained positive, and 95% (234\/247, 95% CI:\u200991%\u201397%) of aSyn\u2010SAA\u2010prodromal participants remained negative. Eighty\u2010nine percent (16\/18, 95% CI:\u200967%\u201397%) of aSyn\u2010SAA\u2009+\u2009HC participants remained positive, and 87% (20\/23, 95% CI:\u200968%\u201395%) of aSyn\u2010SAA\u2010HC participants remained negative.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>\n                      aSyn\u2010SAA testing is highly consistent over time, even in less expected scenarios. \u00a9 2026 The Author(s).\n                      <jats:italic>Movement Disorders<\/jats:italic>\n                      published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/mds.70509","type":"journal-article","created":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T06:05:38Z","timestamp":1791871538000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Consistency of Serial Cerebrospinal Fluid \u03b1\u2010Synuclein Seed Amplification Assay Results in the Parkinson's Precision Medicine Initiative"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4111-0102","authenticated-orcid":false,"given":"David G.","family":"Coughlin","sequence":"first","affiliation":[{"name":"Department of Neurosciences University of California, San Diego  La Jolla California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-3263-8344","authenticated-orcid":false,"given":"Caroline","family":"Gochanour","sequence":"additional","affiliation":[{"name":"Department of Biostatistics University of Iowa  Iowa City Iowa USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-3923-5117","authenticated-orcid":false,"given":"Jie","family":"Yin","sequence":"additional","affiliation":[{"name":"Department of Biostatistics University of Iowa  Iowa City Iowa USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9454-8389","authenticated-orcid":false,"given":"Luis","family":"Concha\u2010Marambio","sequence":"additional","affiliation":[{"name":"Research and Development Department Amprion  San Diego California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carly","family":"Farris","sequence":"additional","affiliation":[{"name":"Research and Development Department Amprion  San Diego California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yihua","family":"Ma","sequence":"additional","affiliation":[{"name":"Research and Development Department Amprion  San Diego California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2157-7151","authenticated-orcid":false,"given":"David\u2010Erick","family":"Lafontant","sequence":"additional","affiliation":[{"name":"Department of Biostatistics University of Iowa  Iowa City Iowa USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6844-882X","authenticated-orcid":false,"given":"Edwin","family":"Jabbari","sequence":"additional","affiliation":[{"name":"Department of Clinical and Movement Neurosciences UCL Queen Square Institute of Neurology  London United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2347-1644","authenticated-orcid":false,"given":"Tanya","family":"Simuni","sequence":"additional","affiliation":[{"name":"Department of Neurology Northwestern University  Chicago Illinois 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