Doctors have long known that smell is one of the first senses to fail as Alzheimer's begins its slow and incurable progression. Tracking the process whereby a person loses their ability to smell could play a pivotal role in early detection and treatment of Alzheimer's. And now researchers at Columbia have developed a tool that will aid early detection.
The system that governs our sense of smell is centered in the same area of the brain that is first attacked, then damaged, during the original stages of Alzheimer's. But for researchers such as Davangere Devanand, professor of psychiatry and neurology at Columbia University Medical Center, the perplexing issue was, exactly which smells people lose the ability to recognize. Could memory loss be detected soon enough to allow for early treatment, and once isolated, what might findings about smell loss suggest for developing detection and treatment methods for Alzheimer's?
There are 4.5 million Americans suffering from Alzheimer's, with an estimated annual medical tab of $100 billion in related treatment and health care costs. This fact was not lost on Devanand, who clearly saw the value in examining the link between diminished smell and Alzheimer's.
To discover possible connections, Deavand and his team assembled a test group of 150 people, from 43 to 85 years old, and with varied degrees of memory loss. To establish a baseline, this group was initially tested then re-tested every six months in order to measure overall ability to identify 10 separate smells: lemon, leather, clove, lilac, menthol, pineapple, natural gas, soap, strawberry and lavender. The results were compared to a control group of 63 healthy volunteer with no memory impairment. Volunteers were given scented cards and asked to identify a series of smells. The results, gathered over nine years, indicated that volunteers who preformed poorly at identifying the smells over time went on to develop Alzheimer's. None of the non-afflicted subjects developed the disease.
Devanand says, "Early diagnosis of Alzheimer's disease is critical for patients and their families to receive the most beneficial treatment and medications." He added that tests such as these may very soon go a long way toward helping detect Alzheimer's far sooner than is currently possible. He recently presented his findings at a meeting of the American College of Neuropsychopharmacology.
The trial conducted by Devanand and his team also lays important groundwork for future advances. For now, the medical community has another valuable early indicator of the progression of the disease. But in future, medical investigators will be able to build on the work of Devanand and his researchers to perhaps find a cure for Alzheimer's.