The canine nose has capacities exceeding modern medical equipment, with trained sniffer dogs able to detect diabetes, certain cancers, and Parkinson's disease. Now scientists have found that dogs also have the potential to detect epileptic seizures before they occur, potentially allowing sufferers to get to safety before a seizure takes hold. Somewhat surprisingly, the dogs in an initial trial picked “seizure scents” more reliably than their counterparts have diagnosed diseases.
Dogs can detect some diseases before other methods because their noses recognize even tiny numbers of molecules tumors or damaged organs release into the breath or blood.
Epileptics, however, don't have to be told they have the condition, instead needing warning when it will strike, creating a unique challenge. Nevertheless, inspired by the capacity of some dogs to recognize the signs of oncoming migraines, and anecdotal accounts of dogs that can alert their owners before seizures, University of Rennes PhD student Amélie Catala decided to investigate.
In Scientific Reports Catala describes collecting the breath and sweat of patients during seizures, during exercise, and at other times, and letting five dogs from the Medical Mutts facility in Indianapolis smell the products. The dogs were taught to associate the seizure odor with a reward. Once trained the dogs were put in a room with seven cans of scent, one collected during a seizure and the others during exercise or at random times. All came from a patient different from those whose scent was used to train the dogs.
Three of the canine investigators were 100 percent successful over nine trials, always recognizing the seizure can. The other two dogs made mistakes, sometimes missing the smells collected during the seizure and getting excited about scent from other times, but still did much better than chance.
The experiment in action. Jennifer Cattet
It remains to be seen whether dogs are equally capable with live people. Real life diabetes detection, for example, has not matched laboratory trials. Moreover, we don't know how long prior to a seizure smells would provide a warning. Nevertheless, Catala is encouraged dogs could distinguish the smell of a seizure even from a person whose odor they had never been exposed to before.
Electronic devices have been developed to recognize the same molecules dogs use to spot cancer and some other diseases, but so far they're poor substitutes, requiring concentrations approximately 100,000 times as high as the best bloodhound. The gap will presumably narrow, but for the moment it seems if we're going to sniff out disease, we will have to continue to rely on our best friends. And let's face it, would you rather your doctor prescribed a soulless machine to warn you before a seizure, or an animal you can cuddle?