Olfactory Dysfunction Discriminates Alzheimer's Dementia From Major Depression

This study tested the hypothesis that olfactory dysfunction could discriminate between groups of patients with Alzheimer's disease and major depression. Forty patients meeting DSM-IV criteria for Alzheimer's disease and for major depression (20 per group) underwent assessment with the Pocket Smell Test (PST), a three-item screening measure of cranial nerve I function. A PST score of < or = 1 (1 or 0 correct) discriminated between the groups with a hit rate of 90% (sensitivity = 80%, specificity = 100%). Olfactory assessment may be a useful adjunctive screening measure in differentiating Alzheimer's disease from depression in elderly patients.