Performance of Aβ1-40, Aβ1-42, total tau, and phosphorylated tau as predictors of dementia in a cohort of patients with mild cognitive impairment

Lucilla Parnetti, Davide Chiasserini, Paolo Eusebi, David Giannandrea, Gianni Bellomo, Claudia De Carlo, Chiara Padiglioni, Sara Mastrocola, Viviana Lisetti, Paolo Calabresi

Research output: Contribution to journalArticlepeer-review


Mild cognitive impairment (MCI) is a common condition in the elderly which may remain stable along time (MCI-MCI) or evolve into Alzheimer's disease (MCI-AD) or other dementias. Cerebrospinal fluid (CSF) classical biomarkers, i.e., amyloid-β 1-42 (Aβ1-42), total tau (t-tau), and phosphorylated tau (p-tau) reflect the neuropathological changes taking place in AD brains, thus disclosing the disease in its prodromal phase. With the aim to evaluate the power of each biomarker and/or their combination in predicting AD progression, we have measured CSF Aβ1-40, Aβ 1-42, t-tau, and p-tau in patients with AD, MCI-MCI, MCI-AD, and other neurological diseases without dementia (OND) followed up for four years. Aβ1-42 levels were significantly lower in AD and MCI-AD than in MCI-MCI. T-tau and p-tau levels were significantly increased in AD and MCI-AD versus OND and MCI-MCI. The Aβ1-42/Aβ1-40 ratio showed a significant decrease in AD and MCI-AD as compared to MCI-MCI. Both Aβ1-42/t-tau and Aβ1-42/p-tau ratios showed significantly decreased values in AD and MCI-AD with respect to OND and MCI-MCI. Aβ1-42/p-tau ratio was the best parameter for discriminating MCI-AD from MCI-MCI (sensitivity 81%, specificity 95%), being also correlated with the annual change rate in the Mini Mental State Examination annual change rate score (MMSE-ACR, rS = -0.71, p <0.0001). Survival analysis showed that 81% of MCI with a low Aβ1-42/p-tau ratio (1-42 and p-tau (sensitivity 75%, 95%CI: 70-80%; specificity 96%, 95%CI: 94-98%). We can conclude that Aβ1-42 and p-tau reliably predict conversion to AD in MCI patients.

Original languageEnglish
Pages (from-to)229-238
Number of pages10
JournalJournal of Alzheimer's Disease
Issue number1
Publication statusPublished - 2012


  • Alzheimer's disease
  • amyloid-β 1-40
  • amyloid-β 1-42
  • biomarker
  • cerebrospinal fluid
  • dementia
  • mild cognitive impairment
  • phosphorylated tau
  • total tau

ASJC Scopus subject areas

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


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