Difficulty identifying common smells such as lemon, cinnamon and coffee may be the first sign of Alzheimer’s
disease, according to a study that could lead “sniff tests” to determine a person’s risk for the disorder.
Such tests could be important if scientists find ways to slow or stop Alzheimer’s and the severe memory loss associated with it. For now, there’s no cure for the millions across the world with the disease.
Scientists have long known that microscopic lesions, considered the hallmarks of Alzheimer’s, first appear in a brain region important to the sense of smell.
In the study, appearing in Archives of General Psychiatry, 600 people between the ages of 54 and 100 were asked to identify a dozen familiar smells, such as onion, cinnamon, lemon, etc.
A quarter of the people correctly identified all the odours or missed only one. Half of them knew at least nine. The lowest-scoring quarter of the people correctly identified eight or fewer of the odours.
The subjects took 21 cognitive tests annually over the next five years. About one-third of the people developed at least mild trouble with memory and thinking.
The people who made at least four errors on the odour test were 50 per cent more likely to develop problems than people who made no more than one error. Difficulty identifying odours was also associated with a higher risk of Alzheimer’s.
But, lead author Robert Wilson of US-based Rush University Medical Centre said a diminishing sense of smell isn’t cause for panic.
“Not all low scorers went on to have cognitive problems,” Wilson said.
disease, according to a study that could lead “sniff tests” to determine a person’s risk for the disorder.
Such tests could be important if scientists find ways to slow or stop Alzheimer’s and the severe memory loss associated with it. For now, there’s no cure for the millions across the world with the disease.
Scientists have long known that microscopic lesions, considered the hallmarks of Alzheimer’s, first appear in a brain region important to the sense of smell.
In the study, appearing in Archives of General Psychiatry, 600 people between the ages of 54 and 100 were asked to identify a dozen familiar smells, such as onion, cinnamon, lemon, etc.
A quarter of the people correctly identified all the odours or missed only one. Half of them knew at least nine. The lowest-scoring quarter of the people correctly identified eight or fewer of the odours.
The subjects took 21 cognitive tests annually over the next five years. About one-third of the people developed at least mild trouble with memory and thinking.
The people who made at least four errors on the odour test were 50 per cent more likely to develop problems than people who made no more than one error. Difficulty identifying odours was also associated with a higher risk of Alzheimer’s.
But, lead author Robert Wilson of US-based Rush University Medical Centre said a diminishing sense of smell isn’t cause for panic.
“Not all low scorers went on to have cognitive problems,” Wilson said.