Odor identification in Alzheimer's disease and depression.
OBJECTIVE
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.
Pentzek
Michael
M
University Medical Center, Department of General Practice, 40225 Düsseldorf, Germany. pentzekm@uni-duesseldorf.de
Grass-Kapanke
Brigitte
B
Ihl
Ralf
R
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology*; D003863:Depression / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009812:Odorants; D012680:Sensitivity and Specificity; D012903:Smell / Q000502:physiology*