The sense of smell is a powerful part of the human experience. It influences taste and even triggers emotions and memories.

If your sense of smell is reduced or you’ve lost it completely that could be an early indicator of brain disease.

The nose knows
While temporary loss of smell is often linked to having a cold, COVID-19 or a respiratory virus, ongoing and progressive smell loss may be one of the most important signals of brain health and an early indicator for Parkinson’s disease.

According to a research study sponsored by The Michael J. Fox Foundation for Parkinson’s Research (MJFF), up to 30 per cent of people experiencing smell loss have shown brain changes associated with Parkinson’s disease – a chronic, neurodegenerative disease that affects an estimated six million people worldwide and over 100,000 Canadians.

What’s more, smell loss can happen years or even decades before traditional Parkinson’s symptoms appear, including tremors or difficulty with balance. However, studies have shown it can be surprisingly difficult to identify smell loss – seven in 10 people living with it didn’t know until they were tested.

A scratch-and-sniff test to the rescue
While scientists are hard at work trying to understand why smell loss occurs with Parkinson’s, they all agree that it could be an important part in understanding the disease, including who’s at risk, who gets it, who doesn’t and why.

There is a simple screening tool to measure the risk for brain disease – a scientist-developed scratch-and-sniff smell test, which is available to all Canadians over 60 living without Parkinson’s. The free test, which can be ordered and delivered right to your door, involves 40 multiple-choice scratch-and-sniff questions. Answers are submitted online and the results have the potential to change the understanding of brain disease.

Smell tests and the evolution of Parkinson’s
Results are analyzed by scientists and may lead to the submitter being asked to join a landmark brain health study, the Parkinson’s Progression Markers Initiative (PPMI) – now in Canada. The global study seeks to enroll 100,000 participants with and without the disease, working with people both in-person and online, to provide insights into Parkinson’s disease, including the link between smell loss and brain health.

Not everyone with smell loss will go on to develop brain disease, but everyone can play a role in helping find better treatments, cures and even ways to prevent brain disease altogether.

Find out more about the smell test at mysmelltest.org/canada