Title: Loss of Smell as a Prognostic Biomarker in DLB and AD: Clinical and Neuroanatomical Signatures

Keywords: Alzheimer's disease, dementia with Lewy bodies, magnetic resonance imaging, olfaction, voxel-based morphometry, cognitive decline, biomarker.

Summary: This poster, presented at the Alzheimer's Association International Conference (AAIC) 2026 in London, investigates multidimensional olfactory deficits as prognostic biomarkers for cognitive decline in Dementia with Lewy Bodies (DLB) and Alzheimer's disease (AD). Assessing 72 participants (37 DLB, 17 AD, 18 Cognitively Unimpaired) using clinical olfactory assessments and whole-brain Voxel-Based Morphometry (VBM), the study reveals distinct modality-specific profiles:

• Baseline odor identification strongly predicts the annualized rate of cognitive decline across both DLB and AD cohorts.

• DLB patients exhibit a specific, significant reduction in subjective odor familiarity compared to controls.

• In DLB, multidimensional odor deficits associate with central neurodegenerative networks: decreased hedonicity correlates with the right parietal operculum, altered familiarity with fronto-striatal degradation (caudate nucleus), and detection with bilateral cerebellar pathways.

These findings demonstrate that multidimensional smell testing offers a sensitive, low-cost first-line strategy to improve early differential diagnosis and better target neuroimaging examinations in memory clinics.

Authors: Maria Fiori, Cécile Pernossi, Laura David, Olivier Bousiges, Léa Sanna, Candice Muller, Alix Ravier, Catherine Demuynck, Frédéric Blanc, Luc Marlier.

Affiliations: ICube Laboratory, University of Strasbourg & CNRS; Laboratory of Biochemistry and Molecular Biology, Hautepierre Hospital; CM2R, University Hospitals of Strasbourg.