Loss of smell offers clue to Alzheimer's

Smell test offers clue to Alzheimer's

Telegraph - A patient's inability to identify common smells such as lemon and soap can help doctors to diagnose early Alzheimer's disease in those who have developed mild mental problems, researchers said yesterday.

A five-year study by doctors from the New York State Psychiatric Institute found that patients with "minimal to mild cognitive impairment" who failed the "10 smell test" were much more likely to develop Alzheimer's compared with healthy elderly people.

Prof Devanand told the meeting that other studies of the brains of Alzheimer's patients had shown that the nerve pathways involved in perceiving and recognising odours were among some of the first functions to be affected.

Which tends to point towards a mechanism involving the olfactory bulb as at least involved in causing the disease, perhaps through infection within the sinus to which the olfactory bulb connects; the only part of the brain in direct contact with the external environment.