Relation of odor identification with Alzheimer's disease markers in cerebrospinal fluid and cognition

Babette L.R. Reijs, Inez H.G.B. Ramakers, Lyzel Elias-Sonnenschein, Charlotte E. Teunissen, Marleen Koel-Simmelink, Magda Tsolaki, Lars Olof Wahlund, Gunhild Waldemar, Lucrezia Hausner, Peter Johannsen, Hugo Vanderstichele, Frans Verhey, D. P. Devanand, Pieter Jelle Visser*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background: Impaired olfactory function is an early characteristic of Alzheimer's disease (AD), but it remains unclear if odor identification also relates to early markers of AD in cerebrospinal fluid (CSF). Objective: To investigate the association between odor identification and amyloid-β 1-42 (Aβ42) and total tau (t-Tau) concentrations in CSF. In addition, to examine the relation between odor identification and cognitive function at baseline and at follow-up, and whether these associations are moderated by CSF Aβ42 and t-Tau and apolipoprotein E (APOE) genotype. Methods: We included 160 individuals (40 with normal cognition, 45 with mild cognitive impairment (MCI), 42 with ADtype dementia, and 26 individuals with non-AD dementia) from the EDAR study. Individuals were recruited from six memory clinics across Europe. Odor identification was tested with the brief University of Pennsylvania Smell Identification Test. CSF A-42 and t-Tau were assessed with INNO-BIA AlzBio3 Luminex assay. Neuropsychological assessment included tests for verbal memory, verbal fluency, attention, executive function, and visuoconstruction. Follow-up was performed within 3 years after baseline. Results: Lower odor identification scores correlated with increased CSF t-Tau concentrations and with lower scores on all cognitive measures at baseline independent of diagnostic group. Lower odor identification scores predicted decline on the MMSE in the total group, and decline on wordlist learning and delayed recall in APOE β4 carriers and in individuals with abnormal Aβ42. Conclusion: Odor identification impairment may be an indicator of neuronal injury rather than amyloid pathology.

Original languageEnglish
Pages (from-to)1025-1034
Number of pages10
JournalJournal of Alzheimer's Disease
Volume60
Issue number3
DOIs
Publication statusPublished - 2017

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