Dogs diagnosing Parkinson’s… what’s the story?

You may have heard in the news this week that dogs are being trained to identify Parkinson’s using their sense of smell alone and that this unusual research could lead to better, earlier diagnosis. It may sound barking (ahem) but it’s part of a global drive to develop tests that can diagnose and monitor the condition.

A trial is under way to determine whether dogs can be used detect Parkinson’s disease, possibly several years before symptoms start to show.

Research charity Medical Detection Dogs and Manchester University, funded by Parkinson’s UK and the Michael J Fox Foundation, are collaborating on a study that will use dogs to test skin swabs for Parkinson’s using their extraordinary sense of smell.

Chief executive of Medical Detection Dogs, Claire Guest commented:

“The full potential of dogs to detect human disease is just beginning to be understood. If all diseases have an odour, which we have reason to believe they do, we can use dogs to identify them.
“Dogs have 300 million smell receptors in their noses compared to our mere five million. They are first-rate bio sensors and their ability to help us make important scientific advances should not be dismissed on account of their waggy tails and fluffy coats.”

The researchers are hoping to use the dogs to hone in on the chemical indicator of Parkinson’s found on the skin of people living with the condition.

Two Labradors and a cocker spaniel will next week start work on swabs from 700 people to spot a smell that appears years before people start experiencing mobility problems.

The team will also be using mass spectrometers to split up samples into its component molecules, and they will also run each past the dogs to identify which key chemical indicator is involved in Parkinson’s.

Where did the idea come from?

You may already have heard the amazing story of Joy Milne, the lady who kickstarted this area of research. Joy has an unusually sensitive sense of smell, and noticed a change in her husband Les’ scent several years before he was diagnosed with Parkinson’s.

Initially Joy did not realise the change in smell and Parkinson’s were connected. It was only when she and Les attended their local Parkinson’s UK group that she realised that other people with Parkinson’s seemed to carry the same scent and she started to wonder.

As a result, we launched a study at the University of Manchester in 2015 which is studying the chemicals present on the surface of the skin. The research aims to identify differences between people with Parkinson’s and those without that could be harnessed to develop new tests that could both diagnose and potentially monitor the condition.

Why is early diagnosis important?

Currently we cannot diagnose Parkinson’s with 100% accuracy. Diagnosis is based around the major movement symptoms — slowness, stiffness and shaking — and we know that by the time these appear up to 50% of the precious dopamine producing brain cells have already been lost or damaged.

Many people tell us that it took them months or even years to get their Parkinson’s diagnosis and that that period of uncertainty was incredibly stressful and worrying. Having a simple test that can diagnose Parkinson’s would greatly improve this experience for people and make sure they get access to treatments, therapies and services at the earliest stage to help them manage their condition.

We also believe that early diagnosis will be a crucial in future, when we have treatments that can slow, stop or reverse the condition. The sooner these new treatments can be used, the greater the chance they will have to save and preserve dying brain cells.

But how does any of this help people who already have Parkinson’s?

If you’ve already been diagnosed, all this may sound interesting but not particularly helpful. However, we believe that having tests that can diagnose Parkinson’s will accelerate the development of new and better treatments for people living with the condition today.

Developing a diagnostic test would likely take advantage of a measurable change in the body, such as changes in the chemical on our skin that cause this subtle smell. The same changes could also allow researchers to measure the progress of the condition, which is something we cannot do at the moment. This inability to objectively measure whether Parkinson’s is getting better or worse (or how quickly) is a major barrier in clinical trials that are testing new treatments that aim to slow, stop or reverse the condition.

These biological fingerprints are also known as biomarkers and they are widely used in medicine. People with diabetes measure their blood glucose levels to help them monitor their condition and decide when they need to take medication. While in HIV, we can now measure the amount of HIV virus in the blood which helps to monitor how HIV treatment is working.

Having similar ways to biologically identify and measure Parkinson’s is one of the missing tools we desperately need to develop better treatments and one day a cure.

Will dogs be diagnosing Parkinson’s in future?

We’ve been asked this a lot in the last week! This research is still in it’s early stages and we hope that it will lead to important new tests that can detect and monitor Parkinson’s — whether these tests involve dogs directly or something more portable is yet to be determined. So watch this space!