One of the great but nebulous promises of wearable health trackers is that, by monitoring something 24-7 that previously was only ever monitored intermittently, it will help us discover new things about our bodies and health. MIT Professor and Empatica Chief Scientist Rosalind Picard can do one better -- a wearable device she designed helped her to make an accidental discovery that could change the way seizure disorders are managed.

Empatica's Embrace wearable, which was recently successfully funded on Indiegogo, is the latest in a line of wearable electrodermal activity sensors Picard has been developing for a number of years at the MIT Media Lab. But originally, the devices were designed to help people with autism better communicate their emotions, and to help understand what the stressors were for non-verbal children with autism.

"Once you build something that can leave the lab, people want to borrow it," Picard told the crowd at the Partners Connected Health Symposium in Boston. "So this was a sweatband that had embedded in it these electrodermal activity sensors early on, and it was the end of the semester. One of the undergrads who worked in my lab said ‘Professor Picard, can I please borrow one of your sensors? My little brother has autism, he can’t speak, and I want to see what’s stressing him out over vacation.'"

Picard gave the student two sensors, since they had been breaking because of a wiring problem and she wanted the student to have a backup. But the student's brother ended up wearing both, one on each wrist. That's important to the story, because during that vacation, the readings showed a very unusual spike, wherein one wrist was off the charts and the other registered nothing. After confirming that the devices weren't broken, Picard called the student and learned that at the time of the spike, the brother had suffered a grand mal seizure.

"We had stressed people out in every way we could imagine at MIT, including one of our papers winning best of the decade for Boston driver stress," she said. "We’ve popped balloons in people’s ears, given them qualifying exams, and nobody’s stress was as high as this."

Picard called a friend-of-a-friend who specialized in seizures, and he happened to mention that occasionally, seizures were preceded by the patient's arm hair standing on end -- but only on one arm.

Over time, and with a lot more research, Picard's team discovered that not only could the unusual autonomic response reliably predict seizures, but it was related to brain activity in ways that they still don't fully understand. There's a small peak during sleep that seems to coincide with memory consolidation, and activating particular sections of the right and left brain can produce corresponding signals on the right and left side of the body.

"Our initial idea that this was just an indicator of general emotional arousal [was wrong. This] carries a lot more information than we originally thought," she said. "It’s not just sweat, it’s not just general arousal, but there are different signals going to different regions of the body. And now our challenge is just to understand those and map that out with real life technology that can tell us what’s going on in everyday experiences."

If there's a moral to Picard's story, it's that the data we collect in the age of connected health isn't just good for creating a more granular understanding of symptoms or conditions. It can actually lead to discoveries we'd never considered before, in a seemingly unrelated area of health.