Untrained Dogs Went Straight for a Stranger's Seizure Sweat in a Small Italian Test

Dogs with no training in medical detection may notice the smell of a seizure, even when it comes from a stranger, according to a new study reported by ScienceAlert. In a University of Milan experiment, 14 of 30 dogs went to the seizure sample first, which ScienceAlert described as 40 percent more often than chance would predict.

The result is early and rests on sweat from a single person, so it points to a research direction more than to a ready-made tool for people with epilepsy.

What did the researchers do?

The team collected sweat from a 6-year-old female volunteer with epilepsy who was not hospitalized. Samples were taken during a seizure and at other times. The dogs, 30 animals of various breeds, both mixed and purebred, did not know the patient or her scent.

Each dog came with its human guardian and had two minutes to explore three scents set out at three stations in a room. One was sweat from during a seizure. One was sweat collected six hours before or after a seizure. The third was a sterilized gauze pad serving as a control. Researchers watched by video, and neither the guardians nor the researcher knew which station held the seizure scent.

What did the dogs do?

More dogs approached the seizure sample first than would be expected by chance. When the researchers added empty food bowls beside each scent to encourage more investigation, the dogs were again more likely to check the seizure scent first.

The dogs did not, however, spend more time sniffing it or return to it more often than to the others. The authors suggested that seizure samples may contain distinctive volatile organic compounds that a dog's nose picks up quickly, so a long investigation would not be needed.

Did the smell bother the dogs?

No, according to the report. Some dogs skipped some stations, but the seizure scent was not avoided any more than the others. The authors wrote that no behavioral signs of distress, fear or anxiety were observed, and that stations left uninvestigated were simply ignored.

Why does it matter?

Seizures are hard to predict and detect, and sometimes even the patient does not know one has happened. Since the 1990s, dogs have been trained to respond to seizures and even to warn patients before one starts, much as dogs can learn to detect the smell of Parkinson's disease, COVID-19 or some types of cancer.

What has been unclear is whether the skill is learned or natural. ScienceAlert notes that many accounts of untrained dogs sensing their owners' seizures come from surveys of guardians or trainers, and that few studies have tested the question. It is also not well established whether dogs rely on sight or smell. The authors said this appears to be the first study designed to characterize how untrained dogs respond to seizure-associated human odor under controlled, socially neutral conditions. A small earlier study of five patients found that dogs can learn to identify seizure-associated odors.

The findings suggest the response may be more of a spontaneous reaction than a trained one. The work was published in the journal Annals of the Italian National Institute of Health.

What are the limits of the study?

All the odor samples came from one patient, so it remains unclear whether the scent dogs picked up is shared across different people. A 2024 review of the evidence said using dogs in epilepsy management shows considerable promise but called for more controlled experiments. The new study helps fill that gap only in part.

What happens next?

The research team is extending the project to include several sweat donors. If the results hold up, ScienceAlert reports, they could indicate that specific volatile organic compounds linked to seizures are detectable by dogs, which could open the door to better screening methods for patients.

Around Prague, based on reporting by ScienceAlert