Smell test identifies AD risk

Just when the medical community is becoming excited about PET for Alzheimer's disease, along comes a new nemesis, the scratch-and-sniff test. Apparently, in Alzheimer's, the nose knows.

Autopsy results have indicated that the nerve pathways involved in smell are affected at an early stage in the brains of Alzheimer's pa-tients. Researchers at Columbia University have pinpointed 10 specific odors that patients with early Alzheimer's cannot identify: clove, leather, lemon, lilac, menthol, natural gas, pineapple, smoke, soap, and strawberry. The inability to identify these specific odors predicted who would go on to develop AD, according to Dr. Davangere Devanand and colleagues, who presented the findings at the American Col-lege of Neuropsychopharmacology meeting in December.

Devanand had ear-lier found a global relationship between loss of smell and Alzheimer's. But knowing the specific odors involved can help physicians make a definitive diagnosis and start therapy earlier, he said.