Could dogs sniff out Parkinson’s disease?

Researchers claim that dogs can be trained to detect the specific scent of people with Parkinson’s disease, with an accuracy rate of over 80%. Photo: AFP

Dogs are well-known for their sense of smell, which can enable them, with training, to identify people with a wide range of diseases, including cancer, malaria and Covid-19. A new study reveals more about canines’ extraordinary ability to detect human pathologies.

This research, published on pre-publication site bioRxiv, focuses on Parkinson’s disease, a neurodegenerative pathology characterised by the progressive demise of brain cells essential to the proper functioning of the entire body.

The study’s authors, Lisa Holt and Samuel Johnston, claim that dogs can be trained to detect the specific scent of people with this disease, with an accuracy rate of over 80%. And that’s regardless of the dog’s breed.

Indeed, dogs have a super-powerful sense of smell. It is estimated to be 10,000 to 100,000 times more powerful than that of humans. Their sense of smell enables them to detect more odours than us, and at much lower concentrations.

Recent scientific studies suggest that people with Parkinson’s disease have volatile organic compounds in their sebum that smell different from those of healthy people. As such, Holt and Johnston wanted to see if dogs could “smell” Parkinson’s disease. To do this, they conducted an experiment involving 23 dogs of 16 different breeds, including Labrador Retrievers, Hungarian Vizslas, English Mastiffs and Pomeranians.

The dogs were asked to sniff sebum samples taken from 43 people with Parkinson’s disease and 31 volunteers with no health problems.

To ensure that the experiment ran smoothly, the selected dogs underwent eight months of training. Procedures included sitting, barking, pawing and muzzle wagging when they identified an olfactory marker of Parkinson’s disease.

During the experiment, the dogs were rewarded with a toy or treat each time they correctly identified a sebum sample.

On average, the dogs were able to recognise people with Parkinson’s disease in 86% of cases. On the other hand, they failed to react to “healthy” sebum samples in 89% of cases.

“This study demonstrates that companion dogs can detect a Parkinson’s-associated target odour, which likely exists as one or more volatile organic compound(s),” explain the researchers in their paper.

While the conclusions of this research are promising, they must be taken with caution, given the small number of dogs involved. Nevertheless, there is every reason to believe that dogs could be valuable allies in the detection of Parkinson’s disease. – AFP Relaxnews