There are good boys,
and then there are very good boys
like these dogs here. They're searching for a scent
that no human can detect:
the scent of an epileptic seizure.
We've long known that dogs can detect seizures in humans
in some cases 45 minutes before they occur.
That's one reason why organizations like Handi'chiens
in France provide service dogs for people with epilepsy.
And in some cases, this can prove lifesaving.
It might give people time to take medication
that could prevent or reduce the severity of a seizure
or move somewhere safer where an injury
is less likely to occur.
Incredible?
Yes.
But proven?
Not until French researchers teamed up with Medical Mutts,
a US-based organization that trains seizure alert dogs.
That marker, they believed, was a scent
that dogs can detect.
So in 2018, they set up an experiment.
First, they collected dozen of samples of
breath and sweat from people with
different forms of epilepsy.
Some of them were taken during or right after a seizure,
while others were collected after exercise or at rest.
Then they distributed them among seven different
steel containers in this room.
Finally, they let out, or, they let in the dogs.
One by one, Casey, Dodger, Lana, Zoey, and Roo
walked into the room.
They were trained to stop and stand still
if they think they detected the scent of a seizure.
And if they were right, they got a treat,
good dog!
To the researchers' excitement, the canines excelled.
Three of the dogs, Casey, Dodger, and Zoey,
sniffed out the odor associated with seizure with
100% accuracy.
The two other pups, Lana and Roo, who had less
time to train, weren't quite as accurate.
But they still correctly identified two-thirds
of the seizure samples on their first try.
What makes these results even more remarkable
is that the scent samples were from different people
and also produced by different kinds of seizures.
And what exactly is that marker made of?
Here's the thing: We still don't know.
It's likely that seizures trigger a change in the body's
electrical activity, the researchers say.
And those changes can affect the
composition of odor molecules that
we emit through our sweat, breath, and, likely, urine.
Now, whether people emit these odors
before a seizure in time to reduce its worst effects
is still in question,
and it's not something that the researchers tested.
But some experts claim that people emit a specific
group of odor chemicals 15 to 45 minutes prior to seizing,
which dogs can detect.
So what exactly makes canines such smell superstars?
It's their incredible noses.
With as many as 300 million olfactory receptors,
a dog's nose is up to 100 thousand times
stronger than our own.
That means they can detect a few scent molecules
among trillions of them.
Scientists are now trying to build electronic noses
that are just as powerful.
The idea is that they too
could be used to sniff out diseases.
But for now e-noses are nowhere near as good as dogs,
and in some ways, doesn't that seem like a good thing?