High Soluble Amyloid-β42Predicts Normal Cognition in Amyloid-Positive Individuals with Alzheimer's Disease-Causing Mutations

Andrea Sturchio, Alok K. Dwivedi, Tarja Malm, Matthew J.A. Wood, Roberto Cilia, Jennifer S. Sharma, Emily J. Hill, Lon S. Schneider, Neill R. Graff-Radford, Hiroshi Mori, Georg Nübling, Samir El Andaloussi, Per Svenningsson, Kariem Ezzat, Alberto J. Espay

Research output: Contribution to journalArticlepeer-review


Background: In amyloid-positive individuals at risk for Alzheimer's disease (AD), high soluble 42-amino acid amyloid-β (Aβ42) levels are associated with normal cognition. It is unknown if this relationship applies longitudinally in a genetic cohort. Objective: To test the hypothesis that high Aβ42 preserves normal cognition in amyloid-positive individuals with Alzheimer's disease (AD)-causing mutations (APP, PSEN1, or PSEN2) to a greater extent than lower levels of brain amyloid, cerebrospinal fluid (CSF) phosphorylated tau (p-tau), or total tau (t-tau). Methods: Cognitive progression was defined as any increase in Clinical Dementia Rating (CDR=0, normal cognition; 0.5, very mild dementia; 1, mild dementia) over 3 years. Amyloid-positivity was defined as a standard uptake value ratio (SUVR) ≥1.42 by Pittsburgh compound-B positron emission tomography (PiB-PET). We used modified Poisson regression models to estimate relative risk (RR), adjusted for age at onset, sex, education, APOE4 status, and duration of follow-up. The results were confirmed with multiple sensitivity analyses, including Cox regression. Results: Of 232 mutation carriers, 108 were PiB-PET-positive at baseline, with 43 (39.8%) meeting criteria for progression after 3.3±2.0 years. Soluble Aβ42 levels were higher among CDR non-progressors than CDR progressors. Higher Aβ42 predicted a lower risk of progression (adjusted RR, 0.36; 95% confidence interval [CI], 0.19-0.67; p=0.002) better than lower SUVR (RR, 0.81; 95% CI, 0.68-0.96; p=0.018). CSF Aβ42 levels predicting lower risk of progression increased with higher SUVR levels. Conclusion: High CSF Aβ42 levels predict normal cognition in amyloid-positive individuals with AD-causing genetic mutations.

Original languageEnglish (US)
Pages (from-to)333-348
Number of pages16
JournalJournal of Alzheimer's Disease
Issue number1
StatePublished - 2022


  • Alzheimer's disease
  • amyloid-β
  • atrophy
  • cognition

ASJC Scopus subject areas

  • Geriatrics and Gerontology
  • Psychiatry and Mental health
  • Clinical Psychology
  • General Neuroscience


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