Scientists found a little-known symptom Alzheimer’s disease that might help supply earlier diagnosis in patients.
It is believed that initial damage to the brain from dementia occurs around 20 years before any symptoms appear, but there are no tests to confirm whether or not this is true. However, scientists at McGill University in Quebec believe they have found a connection between the loss of smell and Alzheimer’s disease.
The researchers tested their theory on 300 participants who were at risk of developing Alzheimer’s disease due to having a parent who suffered from it. Each of them had to take a multiple choice scent test. All of them were asked to identify strong scents like bubblegum, petrol and lemon. Out of the group, 100 volunteered to have regular lumbar punctures to measure proteins related to the disease in their spinal fluid, according to the Independent. Those who found it the most difficult to identify odours were the ones who had the most biological indications of Alzheimer’s disease.
“This is the first time that anyone has been able to show clearly that the loss of the ability to identify smells is correlated with biological markers indicating the advance of the disease,” said Marie-Elyse Lafaille-Magnan, first author of the study, in a statement. “For more than 30 years, scientists have been exploring the connection between memory loss and the difficulty that patients may have in identifying different odors. This makes sense because it’s known that the olfactory bulb (involved with the sense of smell) and the entorhinal cortex (involved with memory and naming of odors) are among the first brain structures first to be affected by the disease.”
There are no available treatments for Alzheimer’s disease, but experts believe this smell test might be used to track the disease before other symptoms appear and prevent the magnitude of the symptoms. “If we can delay the onset of symptoms by just five years, we should be able to reduce the prevalence and severity of these symptoms by more than 50 percent,” said Dr. John Breitner, the director of the Centre for Studies on Prevention of Alzheimer’s Disease at McGill University.