Untrained dogs predict if an epileptic seizure is imminent

PET dogs with no training can smell when their owner is about to have an epileptic fit, new research has found.

The nose of a dog is ultra-sensitive to faint and distant aromas, and has been used by humans for centuries for a range of purposes. In recent years, their olfactory prowess has been repurposed to sniff out drugs, cancer, Covid-19, Japanese knotweed and many other things.

Scientists from Queen’s University Belfast wanted to see if they could also detect epilepsy, the brain condition that causes seizures and for which there is no reliable early warning system.

Some epileptics have previously claimed their dog knows when they are about to have a seizure, saying their pet became more attentive.

However, this research, published in the journal MDPI Animals, is the first to test the theory scientifically.

Dr Neil Powell, who started his PHD in 2015 at 71 after a career as a dog handler working with fire services, mountain rescue and bomb detection squads, believed that dogs were able to smell chemicals made by the brain during an epileptic seizure which were then exhaled by a person.

He recruited 19 pet dogs and their non-epileptic owners. All the animals had no previous experience with epilepsy. He also obtained sweat samples from three people with epilepsy from before, during and after a seizure, as well as control samples.

The owners sat down with their pet in the room and the researchers pumped in the sweat scent via a thin hose placed under the owner’s thighs.

“Our findings suggest that seizures are associated with an odour and that dogs detect this odour and demonstrate a marked increase in affiliative behaviour directed at their owners,” the authors wrote in their paper.

“A characteristic response of all 19 dogs to seizure odour presentation was an intense stare.”

Dr Powell added: “Our findings clearly showed that all dogs reacted to the seizure-associated odour, whether this was through making eye contact with their owner, touching them, crying or barking.

“There is a unique volatile smell linked to epileptic seizures, detectable by dogs who can, in turn, warn their owner a seizure is likely to occur.

“Our research was based on pet dogs with no prior training. If we can train dogs, this has the potential to make a big difference to owners who experience unpredictable seizures and should go a long way in improving not only their safety but also their quality of life.”