Pet dogs of various breeds can be trained to detect scents linked to Parkinson’s disease with nearly 90 per cent accuracy. With further research, this may be a relatively conclusive and inexpensive way of diagnosing the condition that enables earlier access to treatments.
People with Parkinson’s disease have hundreds of unique chemicals in their sebum, the oily substance that hydrates the skin. With the condition having no set test, it has been suggested that these chemicals could be used to aid diagnosis.
Dogs, , have previously been found to detect scents relating to , and . The breeds typically used include Labrador retrievers and different shepherd dogs, with animals being considered for such roles tending to be raised in expensive training centres.
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Seeking a new approach, Lisa Holt and Samuel Johnston at the charity PADs for Parkinson’s in Washington state recruited 23 pet dogs of 16 breeds. These included breeds that have previously been used to detect different medical conditions, as well as those that generally aren’t raised for this purpose, such as Pomeranians and English mastiffs.
Forty-three people who had been diagnosed with Parkinson’s disease and 31 volunteers with no known medical conditions provided sebum samples, either via T-shirts worn overnight or swabs of their upper backs.
Each dog was put through a training programme lasting at least eight months. They were trained to communicate when they identified a Parkinson’s sample by sitting, barking, tapping a paw or bobbing their nose. To incentivise them, each sniffing sample provided by a participant with Parkinson’s disease was paired with a reward, such as food or a toy.
Once their training was complete, the dogs were exposed to sebum samples they hadn’t previously encountered. Their owners weren’t aware if the samples were from someone with or without Parkinson’s.
Overall, the dogs identified the samples from someone with Parkinson’s disease with 86 per cent accuracy, on average, and didn’t respond to the healthy volunteers’ samples 89 per cent of the time.
Testing of the training programme is continuing at the Alfort National Veterinary School in France, says Holt. “Once that training was done, it would then be possible to test whether dogs could identify Parkinson’s at a much earlier stage, when the full suite of symptoms are not yet present,” she says. The researchers hope that odorants relating to Parkinson’s disease could one day be packaged into a training aid for dogs.
“Many dog studies for disease detection are proof of principle, with just two dogs, for example,” says at the University of Bristol, UK. “This study shows training can be successful with a variety of home-housed dogs.”
But despite testing several breeds, the dataset isn’t large enough to conclude which ones detect Parkinson’s best, she says.
bioRxiv
