Assistance dogs can learn to warn their human companion of an impending panic attack by detecting certain volatile organic compounds in their breath, suggests work conducted at Dalhousie University in Nova Scotia.
Years of work will still be needed to refine this discovery, but if all of this proves to be true, the dog's alert might one day allow humans to defuse a panic attack – at least partially – before it becomes too big.
This may be especially relevant for people with post-traumatic stress disorder (PTSD).
It's nothing new for organizations to train dogs to accompany people with PTSD, recalls Professor Simon Gadbois, who runs a laboratory in Dalhousie that specializes in canine sniffing, but it all remains a bit mysterious.
“People who have these dogs will say that the dogs tend to signal a problem before they realize a panic is coming,” he said. But in science, we don't really know how dogs make these alerts, so it's really interesting.
Professor Gadbois and his team recruited twenty-six people for their study who were also participating in a trauma study; Just over half of them had symptoms consistent with PTSD.
People participated in sessions during which they wore a mask while remaining calm or recalling the trauma they had experienced. Next, masks filled with their own breath were presented to the dogs, eliminating the possibility that the animals were responding to visual cues instead.
Only two of the 25 dogs recruited for the study – Ivy and Callie, both females – demonstrated the ability to distinguish between the two masks, with an accuracy rate reaching 90%.
In the second test, Ivy achieved an accuracy rate of 74% and Callie 81% when provided with individual samples of different stress-related VOCs.
Ivy's performance was associated with the anxiety described by humans, while Callie's performance was associated with the shyness felt by people with two legs. This may mean that dogs have a slightly different idea of what constitutes “stress.”
More specifically, Ivey may have focused on hormones (such as adrenaline) produced by the sympathetic-pituitary-adrenal axis, while Callie may have focused on hormones (such as cortisol) produced by the hypothalamic-pituitary-adrenal axis.
Of the two, it is the medullary sympathoadrenal axis, which is the axis that allows us to react almost immediately if we encounter a bear while hiking in the woods, which is the most relevant in this context, because it is the detection hormones it produces that can allow the dog to alert its human of what is coming .
Professor Gadbois said: “If the dog gives an early alert, it is very likely that it is this system that was activated, which finally detected it, and not the other system that everyone seems to be focusing on. Focus now.”
On the other hand, the hypothalamic-pituitary-adrenal axis is more responsible for chronic stress. The researcher added that when activated, it takes two or three minutes before anything changes in the body, so “it is possible that it is the one that the dogs are targeting, but that bothers me.”
Professor Gadbois and his team recently received the funding needed to continue their work for at least another two years. They will now collaborate with a chemist from Dalhousie to try to more precisely identify the VOCs involved.
“The chemist believes it is possible that dogs are superior to existing technology (for identifying VOCs),” he said. “When we're talking about one part per billion that a dog can detect, that's amazing, but that's the beauty of nature.”
The results of this study were published in the medical journal Frontiers in Allergy.
