Dogs can detect smell linked to epileptic seizures, study suggests
Dogs can detect a smell associated with epileptic seizures, new research suggests.
A small study, published in the Scientific Reports journal, found trained dogs were able to distinguish between an odour emitted during a human seizure and one taken following exercise.
The findings suggest epileptic seizures have a specific odour profile, and could pave the way for a new method of anticipating fits before they occur.
Advance warning would help sufferers make sure they are in a safe environment beforehand.
Dogs have already been shown to sniff out breast cancer, lung cancer and diabetes with some success.
Some people with epilepsy already rely on the animals to alert others to seizures.
In this study, researchers from the University of Rennes in France presented three female and two male trained dogs with seven cans on nine occasions.
Only one of them contained breath or body odour taken from an unknown patient with epilepsy during a seizure.
Two of the dogs identified the can containing the seizure odour 67% of the time, while the remaining three dogs identified the right one every time.
“This study, in which trained dogs were confronted with bodily odours from epileptic patients sampled during and outside seizures, shows that these dogs were clearly able to discriminate the seizure odours from odours of the same patient outside seizures and for all patients tested,” the authors wrote.
“From the first trial on, they responded to the ‘right’ odour and explored it longer than any of the other odours.
“This clearly demonstrates for the first time that there is indeed a seizure-specific odour across individuals and types of seizures.”
They added: “The results are extremely clear and constitute a first step towards identifying a seizure-specific odour.”
Lead author Amelie Catala said it is hoped the findings will open new lines of research, and lead to studies involving more dogs and patients.
“For now, the origin of the odour associated with epilepsy is still unknown,” she said.
“Further research is needed but it is possible that the change in electrical activity triggers the releasing of some neurohormones, that in the end triggers the scent, or that it is linked to stress-related molecules and pathways.”