It may be possible to train dogs to warn patients before the onset of epileptic seizures, according to a new study published in the journal Scientific Reports. The study’s authors found that dogs can reliably identify an odor emitted from patients having a seizure.
The study follows up on individual reports of dogs detecting seizures in their owners, as the first research to thoroughly examine the phenomenon. Some anecdotal evidence suggests dogs can detect a seizure as much as five hours in advance.
Being warned ahead of a seizure could help patients take medication in advance, get help from others, avoid injury, and improve their independence and quality of life, according to The Guardian.
According to a spokeswoman for Epilepsy Action, many patients already use dogs to plan ahead for seizures:
“At the moment there are anecdotes that some people report dogs alert them before a seizure, but we don’t have any strong evidence in the scientific literature. So this research is interesting and could be a next step in understanding how dogs can further support people living with uncontrolled epilepsy.”
The study’s first author, Amélie Catala of the University of Rennes in France, told The Guardian:
“At the moment there are anecdotes that some people report dogs alert them before a seizure, but we don’t have any strong evidence in the scientific literature.”
It’s also been unclear whether dogs in these cases were responding to visual signs, behavioral changes, or smells.
A telltale scent emitted before a seizure could also lead to the development of devices that can detect the odor and warn patients, according to Gizmodo.
Dogs in the study were first trained to detect body odor and breath samples taken from patients while having a seizure. They were given seven containers, one of which contained an odor from a patient having a seizure. Others contained samples from other patients with other forms of epilepsy, as well as control odors taken from the same patients while not having a seizure, and others taken after exercise.
The dogs identified the seizure samples with 67 to 100 percent accuracy, and correctly responded to non-seizure samples with accuracy ranging from 95 to 100 percent. Three out of five of the dogs scored perfectly on all nine of the tests. This outcome suggests that there is an odor emitted in the event of seizures, common among different types of seizures, which dogs can detect despite a patient’s other body odor.
“From the first trial on, they responded to the ‘right’ odor and explored it longer than any of the other odors. This clearly demonstrates for the first time that there is indeed a seizure-specific odor across individuals and types of seizures,” the authors wrote.
In future studies, the researchers hope to investigate whether the scent comes ahead of a seizure rather than during, which would allow dogs to alert patients ahead of time.
Other studies have also shown that dogs can smell certain cancers, as well as low blood sugar in diabetics, and the scent of malaria in a patient’s socks.