Dog Senses Stranger’s Seizure 40 Minutes Before It Occurs—How Is This Possible?

It doesn’t take much for our dogs to impress us. Even just watching them dig out a well-hidden toy from under the couch or sit and extend their paw for a treat can make most of us clap and say “good boy.” If you’re looking to be really impressed, though, there are many dogs out there who are capable of truly incredible work supporting the people who need it most.

One remarkable pup was just hanging out at an adoption event, hoping to find a new home when she made headlines for sensing a stranger’s oncoming epileptic seizure 40 minutes in advance. Sienna, a four-year-old Labradoodle / Pit mix, actually has no special training at all. She was greeting attendees to the event when she suddenly broke away and approached a man who had just arrived.

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The shelter wrote on Facebook that Sienna “sat quietly at his feet, refused to budge, and softly placed her paw on his leg.” Just moments later, according to the shelter, the man’s wife approached and said that he was either about to have a seizure or had already had one. As the shelter wrote: “Sienna wasn’t trained to do this. She simply felt it.”

By knowing in advance that they are going to have a seizure, someone with epilepsy can get to a safe place and avoid injury. While this kind of ability to sense an oncoming seizure isn’t unique to Sienna, her gift for sensing seizures and alerting the sufferer without any training is. While we don’t know if a future as a medical assistance dog is in her future, we were happy to learn that she has found a forever home.

Some pups just have an innate sense for this.

Dr. Emma Scales-Theobald, PhD, is a canine behaviorist and Pooch and Mutt’s canine behavior expert. Dr. Scales-Theobald says that, typically, “this is something dogs are trained to do, but some seem to alert people instinctively.”

The training is lengthy and complex, and some dogs pick it up faster than others. While it’s thought that most dogs have the heightened sense of smell and ability to read our subtle behaviors and sense an oncoming seizure, we don’t know if this is true of all dogs. Training is given to encourage the dogs to notice these signs as significant.

“Although some pet dogs have been seen to perform this instinctively, most dogs lack the temperament to perform this consistently and become a reliable service dog,” Dr. Scales-Theobald says.

Dr. Berkcan Yanar is a veterinarian and a reviewer at comparison and tips site PawsRank. He says that, in general, a seizure-alert dog is able to pick up on slight health variations and signal their handler. They are trained to alert the handler, who is then able to prepare by, for example, sitting or reclining in a safe position or calling someone to assist. They can even fetch medication, trigger a medical alert device, and guide their handler to a safe location.

“Not only do these canines provide physical assistance, they also provide emotional support, allowing their owners to live independently to a larger degree and with less fear of an imminent seizure,” Dr. Yanar says.

According to Dr. Yanar, the amount of warning a dog is able to give depends on the dog, the person, and the seizure itself. “From experience and case studies, most seizure alert dogs that have been trained give one to five minutes’ warning, already a lifesaving margin,” he says. “However, some gifted dogs have been able to give up to 20 to 40 minutes’ notice, as in Sienna’s case.”

Dr. Scales-Theobald says that some research suggests that dogs are capable of detecting an epileptic seizure as early as 68.2 minutes before they occur. However, it’s worth being aware that this does not happen frequently and is not guaranteed. When it does happen, it gives the person valuable time to stop activities that can put them into danger, move to a safe area, or give emergency medication in hopes to reduce the intensity of the seizure.

Even still, Sienna’s story is pretty impressive.

What is pretty unique about Sienna’s case is the fact that she was aware of a seizure in someone she had never met.

“Most seizure-alert dogs react to the direct odor and behavioral signals of their handler, but other dogs are very sensitive and will pick up on anything showing physiological change preceding a seizure,” Dr. Yanar says. “In the case of Sienna, it is likely that the man’s scent profile, breathing rate, or positioning changed in a way that was unmistakable to her senses, even though she wasn’t trained to do specifically so. This heightened sensitivity is one of the reasons that dogs are used for medical detection work, such as detecting cancer, low blood sugar, or even stress-related changes.” 

Dr. Scales-Theobald agrees, adding that dogs do have the ability to sense a seizure from anyone. “However, it’s very rare to hear of dogs alerting strangers to them. It is more common for untrained pets to alert their owners instead of strangers, potentially due to the strong bond between the dog and their owner,” she says. “Typically, these alert behaviors from untrained pet dogs are described by owners as intense staring, anxious barking, pacing, whimpering, protective, or licking. It’s possible that these behaviors might be dismissed or interrupted with a stranger.”

We don’t yet understand completely how alert dogs can detect an oncoming seizure. However, Dr. Yanar says, the most widely accepted theory is that they catch a scent of some sort related to body chemical changes before a seizure.

“In the pre-ictal period (prior to a seizure), the body releases volatile organic compounds (VOCs) via perspiration, skin, and breathing,” he says. “With 300 million scent receptors, dogs possess 10 times more receptors than a human’s five million can deliver, so they have the ability to discern the differences long, long before any person perceives even a hint of a difference. They are also attuned to subtle signals, such as muscle spasms, micro-contractions of facial expression, changes in posture, or tone of speech.”

While Sienna’s story is really incredible, it tells us what we all know to be true: dogs are sensitive, special, and make amazing companions for all kinds of people. We are glad that she has found the right forever home for her unique skills and temperament.