Dogs That Smell Disease: A Breakthrough in Early Parkinson’s Detection

A New Frontier in Diagnosing Parkinson’s

In a groundbreaking study, dogs have once again demonstrated their extraordinary abilities—this time by detecting Parkinson’s disease through scent.

Researchers trained two dogs to identify a unique odor signature in people with Parkinson’s using simple skin swabs. The results were astounding: the dogs achieved up to 80% sensitivity and 98% specificity, even when samples came from individuals with other health conditions.

This development offers renewed hope for earlier, non-invasive diagnosis of a disease that often goes undetected until motor symptoms emerge—sometimes decades after biological changes begin. By catching it earlier, treatment could begin sooner, potentially slowing the progression and reducing the impact of symptoms.

Sniffing Out What Science Misses

The research, published in The Journal of Parkinson’s Disease on July 15, was a collaboration between Medical Detection Dogs and the Universities of Bristol and Manchester. The two dogs—Golden Retriever Bumper and Black Labrador Peanut—were trained using over 200 samples. Swabs taken from the skin of individuals with Parkinson’s and those without were presented on a special stand system.

The dogs were rewarded for correctly identifying samples from those with the disease and for accurately ignoring those from healthy participants.

In rigorous double-blind trials, neither the handlers nor observers knew the sample positions—only the computer did. This ensured unbiased results. Samples with no initial decision were re-presented until the dogs had assessed every swab.

The Nose Knows Before the Symptoms Show

There is still no definitive test for Parkinson’s disease, which currently relies on clinical diagnosis after symptoms like tremors, rigidity, and slow movement appear. However, biomarkers—biological indicators of disease—can begin to emerge long before symptoms. According to Claire Guest, CEO and Chief Scientific Officer of Medical Detection Dogs, this study demonstrates that dogs can reliably detect these early indicators.

She emphasized the urgent need for early diagnosis: “There is currently no early test for Parkinson’s, and symptoms may begin up to 20 years before a clinical diagnosis is possible. Early identification is crucial, as treatment could help slow disease progression and reduce the severity of symptoms.”

A Distinct Scent Signature of Parkinson’s

Dr. Nicola Rooney, the study’s lead author from the University of Bristol, praised the dogs’ performance, noting that the accuracy achieved was significantly above chance. “The dogs showed that Parkinson’s has an olfactory signature—an identifiable smell—and that it remains detectable even when other medical conditions are present.”

Her colleague, Professor Perdita Barran from the University of Manchester, reinforced the point, adding that this study contributes to a growing body of evidence supporting the use of skin swabs in Parkinson’s diagnosis. She credited Joy Milne, a woman with an acute sense of smell who first noticed a “Parkinson’s scent” on her husband, as the inspiration for this research and the Nose2Diagnose program.

Toward a Future of Faster, Easier Diagnosis

The implications of this research go far beyond canine abilities. If the specific scent compounds dogs detect can be chemically identified, they may form the basis for new, non-invasive tests for Parkinson’s.

This potential for non-invasive testing offers a reassuring prospect for future Parkinson’s diagnosis. Until then, dogs like Bumper and Peanut remind us that nature still holds secrets that science is only beginning to understand.