WASHINGTON (Reuters) - A simple scratch and sniff test may help doctors identify patients with Alzheimer's disease, researchers said on Monday.
They found that patients with early Alzheimer's disease may be unable to smell certain odors, including strawberry, smoke, soap and cloves.
"Early diagnosis of Alzheimer's disease is critical for patients and their families to receive the most beneficial treatment and medications," said Dr. Davangere Devanand, a professor of psychiatry and neurology at New York's Columbia University, who led the study.
"While currently there is no cure for the disease, early diagnosis and treatment can help patients and their families to better plan their lives."
Alzheimer's, which affects an estimated 4.5 million Americans, is an incurable and always fatal brain disease.
It starts out with mild memory loss but progresses to damage the brain severely, causing confusion and eventually leaves the patient unable to care for himself or herself.
There are some drugs that may help slow the progression of the early disease, and researchers are working on vaccines and new drugs to treat Alzheimer's.
While some simple tests such as a challenge to draw a clock face can point to Alzheimer's, in the early stages it is often difficult to tell if a patient has Alzheimer's or some other form of memory loss that may or may not lead to dementia.
For the study Devanand and colleagues studied 150 patients with minimal to mild cognitive impairment. They compared them to 63 healthy elderly people and ran tests on them every 6 months.
The inability to identify 10 specific odors clearly predicted who would go on to develop Alzheimer's, they told a meeting of the American College of Neuropsychopharmacology.
These smells included strawberry, smoke, soap, menthol, clove, pineapple, natural gas, lilac, lemon and leather.
"Narrowing the list of odors can potentially expedite screening and help with early diagnosis," Devanand said in a statement.
This makes sense, he added, because examination of the brains of Alzheimer's patients shows that the nerve pathways involved in smell are affected at a very early stage.
Several groups have tried to link the sense of smell with Alzheimer's and at least one company markets a scratch and sniff test for the disease. But Devanand said it is important to identify the specific odors that may be involved.