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Updated: Jul 14, 2026

A Free-breathing fMRI Method to Study Human Olfactory Function
Published on: July 30, 2017
Odor identification in Alzheimer's disease and depression
Michael Pentzek1, Brigitte Grass-Kapanke, Ralf Ihl
1University Medical Center, Department of General Practice, 40225 Düsseldorf, Germany. pentzekm@uni-duesseldorf.de
Background And Aims:
In Alzheimer's disease (AD) olfactory deficits are common and depression is a difficult differential diagnosis. We therefore investigated the usefulness of an odor identification test to differentiate both conditions.
Methods:
Twenty patients with probable Alzheimer's disease (AD), twenty elderly patients with a depressive disorder, and thirty healthy elderly subjects performed a German odor identification test.
Results:
AD patients had significantly lower odor identification scores, compared with both depressive patients and control subjects (F=121.96, df=2, 67, p<0.001). With a cut-off score of 10/11, the sensitivity of the identification test to differentiate AD patients from depressive patients was 100%, and specificity was 95%.
Conclusions:
The odor identification test used in this study is able to reveal olfactory deficits in AD. It also seems to be a useful instrument to differentiate AD from depression.
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