[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-450297-105":59,"doc-detail-450297-en":134},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":127,"head_meta":129,"extra_data":131,"updated_unix":133},105,"en","quantification-of-cerebrospinal-fluid-alpha-synuclein-seeds-by-endpoint-dilution-seed-amplification-assay-in-parkinsons-disease","Quantification of cerebrospinal fl uid α-synuclein seeds by endpoint dilution seed amplification assay in Parkinson’s disease","","Quantitative pathology-specific biomarkers are needed for Parkinson’s disease (PD). The study estimated the α-syn seeding dose producing 50% positive endpoint dilution seed amplification assay (SAA) reactions (SD50) using serially diluted samples from 260 PD participants, including 54 with longitudinal follow-up. Higher SD50 associated with older age, longer disease duration, worse motor and cognitive scores, REM sleep behavior disorder, and visual hallucinations. Baseline SD50 predicted motor wearing-off and severe cognitive impairment; SD50 remained stable over time. Endpoint dilution SAA quantification may serve as a surrogate marker of Lewy body pathological burden to support prognostication and patient stratification.",{"@graph":69,"@context":126},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/quantification-of-cerebrospinal-fluid-alpha-synuclein-seeds-by-endpoint-dilution-seed-amplification-assay-in-parkinsons-disease/450297/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/quantification-of-cerebrospinal-fluid-alpha-synuclein-seeds-by-endpoint-dilution-seed-amplification-assay-in-parkinsons-disease/450297.png","ImageObject",300,407,{"name":92,"@type":93},"Genevieve","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-07","2026-09-30",true,{"@type":102,"interactionType":103,"userInteractionCount":29},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118,122],{"name":109,"@type":110,"acceptedAnswer":111},"How is SD50 defined in this study?","Question",{"text":112,"@type":113},"SD50 is the estimated α-syn seeding dose that yields positive endpoint dilution seed amplification assay (SAA) reactions in 50% of replicate wells, based on serial dilutions.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"Which factors were associated with higher SD50 values?",{"text":117,"@type":113},"Higher SD50 values significantly correlated with older age, longer disease duration, worse motor and cognitive scores, REM sleep behavior disorder, and visual hallucinations.",{"name":119,"@type":110,"acceptedAnswer":120},"Does baseline SD50 predict future clinical outcomes?",{"text":121,"@type":113},"Yes. Baseline SD50 predicted the development of motor wearing-off and severe cognitive impairment.",{"name":123,"@type":110,"acceptedAnswer":124},"How stable were SD50 values over time in participants with longitudinal samples?",{"text":125,"@type":113},"In participants with longitudinal samples, SD50 values remained substantially stable over time, indicating consistency of the quantitative measure.","https://schema.org",{"og:url":83,"og:type":128,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":130,"canonical":83},"index,follow",{"doc_id":132,"site_id":62},450297,1790834801,{"code":4,"msg":5,"data":135},{"doc_id":132,"user_id":136,"nickname":92,"user_avatar":137,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":138,"file_id":139,"file_url":140,"file_type":141,"file_size":142,"view_count":29,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":52,"language":143,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":144,"faqs":145,"seo_title":146,"seo_description":67,"update_tm":147,"read_time":148},1374391974585,"https://ap-avatar.wpscdn.com/davatar_276721f389ce27ea32af1340a28f341c","npj | parkinson’s disease Article  \n\n| Published in partnership with the Parkinson ’s Foundation |  | |\n| --- | --- | --- |\n| [https://doi.org/10.1038/s41531-025-01221-7](https://doi.org/10.1038/s41531-025-01221-7) |  |  |\n| Quantification of cerebrospinal fl uid α -synuclein seeds by endpoint dilution seedamplification assay in Parkinson’s disease\u003Cbr> Check for updates |  |  |\n| Kathrin Brockmann1,2,6, Alice Ticca3,4,6, Stefanie Lerche1,2, Andrea Mastrangelo3,4, Angela Mammana3, Isabel Wurster1,2,5, Erica Vittoriosi4, Benjamin Roeben1,2, Ann-Kathrin Hauser1,2, Christian Deuschle1,2, Simone Baiardi3,4, Claudia Schulte1,2, Thomas Gasser1,2 & Piero Parchi3,4  |  |  |\n| Quantitative pathology-specific biomarkers are needed for patients with Parkinson ’s disease (PD). We estimated the α-syn seeding dose giving 50% of positive seed amplification assay (SAA) reactions (SD50) in serially diluted samples from 260 PD participants, of whom 54 had longitudinal samples. We then evaluated the associations between SD50 values and demographic and clinical parameters, including motor and cognitive scales, REM sleep behaviour disorder (RBD), and hyposmia. Higher SD50 values were significantly associated with older age, longer disease duration, worse motor and cognitive scores, and presence of RBD and visual hallucinations. Baseline SD50 values predicted the development of motor wearing-off and severe cognitive impairment. In participants with longitudinal samples, SD50 values remained substantially stable over time. Quantification of α-syn through endpoint dilution SAA may serve asa potential surrogate marker of LB pathological burden, which may support prognostication and patient stratification. |  |  |\n| The clinicopathological heterogeneity in Lewy body disorders (LBD), including Parkinson’s disease (PD) and Dementia with Lewy bodies (DLB), underscores the need for pathology-specific biomarkers to facilitate accurate diagnosis and predict disease trajectories. Recently, the development of ultrasensitive seed amplification assays (SAA), capable of detecting minute amounts of misfolded alpha-synuclein (α-syn) in cerebrospinal fluid (CSF) and other tissues, has drastically improved the identification ofpatients with LBD in vivo, even at preclinical or prodromal stages1–5. This has led to the proposal of new biologically based research criteria for this prevalent disorder6,7. While the current assays’ qualitative dichotomous seeding response (positive vs. negative seeding) is valuable for stratifying and enriching cohorts for α-syn pathology in general, more quantitative parameters reflecting the Lewy body (LB) pathology load would be essential. These could be particularly helpful in predicting dynamics of disease progression, trajectories until reaching disease milestones and might serve as exploratory outcome measures in clinical trials targeting α-syn. Recent evidence from the analysis of brain homogenates suggests that SAA kinetic parameters, which describe the dynamics of α-syn aggregation and amplification, could provide quantitative data that indirectly reveals the | concentration of α-syn seeds present in biological samples and, possibly, the LB pathology burden8. Initial attempts to translate these findings using biofluids have identified the number of positive outcomes in multiple replicatesand the time to threshold(TTT)or lag phase(i.e. the time required for the fluorescent signal to reach the positivity threshold) as the most promising kinetic variables for α-syn seeds quantification in CSF samples, with some studies reporting associations of these parameters, at both baseline and longitudinally, with parameters of clinical progression9–11. However, evidence also indicates that pre-analytical and analytical factors, such as matrix composition and batch-to-batch variations in the critical assay reagents, may affect these parameters, reducing their discrimination power12, 13.\u003Cbr>New perspectives on SAA implementation are currently emerging, primarily dr","cbCaidDN3okntYeu","https://ap.wps.com/l/cbCaidDN3okntYeu","pdf",983789,"English","# Background\n# Study approach and SD50 estimation\n# Associations with clinical and demographic parameters\n# Prognostic value and longitudinal stability\n# Implications for biomarkers and patient stratification","[{\"question\":\"How is SD50 defined in this study?\",\"answer\":\"SD50 is the estimated α-syn seeding dose that yields positive endpoint dilution seed amplification assay (SAA) reactions in 50% of replicate wells, based on serial dilutions.\"},{\"question\":\"Which factors were associated with higher SD50 values?\",\"answer\":\"Higher SD50 values significantly correlated with older age, longer disease duration, worse motor and cognitive scores, REM sleep behavior disorder, and visual hallucinations.\"},{\"question\":\"Does baseline SD50 predict future clinical outcomes?\",\"answer\":\"Yes. Baseline SD50 predicted the development of motor wearing-off and severe cognitive impairment.\"},{\"question\":\"How stable were SD50 values over time in participants with longitudinal samples?\",\"answer\":\"In participants with longitudinal samples, SD50 values remained substantially stable over time, indicating consistency of the quantitative measure.\"}]","Quantification of cerebrospinal fl uid α-synuclein seeds by endpoint dilution seed amplification assay in Parkinson’s disease | PDF",1790732803,25]