Do you smell that? Good!
The sense of smell, or lack of it, can be an indicator of the future onset of dementia.
In a study of 3,000 adults, researchers at the University of Chicago Medical Center found that those who could not identify four out of five common odours were twice as likely to develop dementia within five years.
The study, “Olfactory Dysfunction Predicts Subsequent Dementia in Older US Adults”, was published in September 2017 in the Journal of the American Geriatrics Society. The scents used, in increasing difficulty of recognition, were peppermint, fish, orange, rose and leather. The study found that 78.1% of those studied had a normal sense of smell, and could identify four out of the five scents. 18.7% could identify only three of the scents, and 3.2% could only identify one or two of the scents.
After five years, almost all of those who could only identify one or less scents were diagnosed with dementia.
According to the study, the sense of smell may signal a key mechanism that also underlies human cognition. The olfactory system has stem cells which regenerate, and “a decrease in the brain’s ability to smell may signal a decrease in the brain’s ability to rebuild key components that are declining with age, leading to the pathological changes of many different dementias.”
Because the smell test is so easy to administer, it is believed that the test could lead to an earlier determination of the possible onset of dementia.