A recent study suggests that a decreased sense of smell could mean an early symptom of dementia or Alzheimer’s disease. Elderly people suffering from anosmia, the inability to perceive odor, are more vulnerable to show signs of memory loss within the next three years, scientists say.

US scientists at the Mayo Clinic research centre in Minnesota, tested 1,430 men and women, with an average age of 79 years. Researchers conducted the study, published in the journal JAMA Neurology, using a standardised smell test that asked participants to accurately identify a series of 12 scents – six of foods, such as banana and cinnamon, and other six from non-foods like petrol, soap and roses.

The recent study claims that the deterioration of the sense of smell may be linked to Alzheimer’s disease. Credit: Huffington Post

All participants were healthy, as they didn’t show any signs of dementia at the beginning of the study. After the results, researchers tracked the patient’s progress over the next three and a half years, in order to prove the theory linking sense of smell with dementia.

During that period of time, around 250 participants showed signs of mild cognitive impairment -often, the earliest symptom of dementia. From those 250 patients, 64 of them were diagnosed with dementia and 54 of them with Alzheimer.

Results show that those who had a bad performance at the smell test had a higher risk of suffering from memory issues; and, those with the lowest sense of smell had the higher chances of developing Alzheimer’s. However, researchers didn’t examine the patient’s brains, so there is no hard proof of the link between smell and dementia.

Nevertheless, scientists believe that the relation could be explained by the deterioration on the region of the brain that handles the sense of smell, and its coincidence with degeneration in the region that controls memory abilities.

Experts warn that they are many different reasons behind the loss of the sense of smell that are not necessarily linked with dementia or memory problems. But, they agree that future smell tests combined with other exams could provide an early warning of dementia.

The Brief Smell Identification Test (B-SIT) is easily performed in patients, as it doesn’t require the administration or further knowledge from trained personnel. The test comes with normative data, it is not very expensive and it is non-invasive, according to researchers.

Going down the right path

Although British experts received the findings with enthusiasm, they believe that further research has to be done. Dr. Doug Brown, director of research and development at the Alzheimer’s Society, stated that these study adds evidence that a deteriorating sense of smell could be an early indicator of Alzheimer’s disease.

Dr. Brown believes that this test, combined with others, could be really helpful for researchers that need to identify those people that suffer from the loss of the sense of smell to test potential treatments for dementia at its early stages.

Also, he adds that the fact that most people experience this sensory loss as they age, it shouldn’t concern elderly people about all suffering from dementia or Alzheimer. In fact, according to the Daily Mail, there are more than 60 medical conditions that could affect the ability to smell properly.

“Finding a way to detect Alzheimer’s disease early is vital for future research and to help people manage their condition better. Studies like this are a step in the right direction, but we need significantly more investment to enable a step change in research to help turn discoveries like this into meaningful clinical tools,” Dr. Brown concludes.

Source: Daily Mail UK