Can Wearables Track Epileptic Seizures? MIT Says Yes

How wearables can track epileptic seizures and prevent sudden death.

Posted Jun 11, 2018

Rosalind Picard is Professor of Media Arts and Sciences at the Massachusetts Institute of Technology and co-founder of the startups Affectiva and Empatica.  At the Third Annual Brain Health and Performance Summit presented by The Ohio State University Wexner Medical Center’s Neuroscience Research Institute and The Stanley D. and Joan H. Ross Center for Brain Health and Performance, Dr. Picard spoke about how wearable tracking devices developed in her lab led to a life-saving product for people with epilepsy.

When Picard, the founder and director of the Affective Computing Research Group at the MIT Media Lab, lent out two wrist wearables they had developed in the lab to one of her students, she had no idea it would lead to a life-saving discovery.

The student wanted to use the devices, which measure changes in electricity on the skin, to help track emotional responses in his brother, who suffers from autism. From her lab, Picard noticed an astounding jump in the boy’s electrical activity over the course of a few minutes. She later learned that the spikes had occurred while the wearer was having a seizure. Picard realized that skin conductance, which results from electrical signals that the brain sends to the skin, dramatically increased during the episode—but that the spike only occurred on one side of the wearer’s body.

“In our first controlled study, 100 percent of the grand mal seizures had a significantly high skin conductance response,” Picard explained. “Since then, with lots more studies, we have learned it is not always 100% of the time. But, the conductance is generally larger when there is more post-seizure brain suppression."

That has major implications for epilepsy patients. Crucially, Picard and her team showed that combining the skin conductance with motion, both sensed from the wrist, could give a seizure detector that was more sensitive and specific than “shake detectors” that were on the market.  

“The biggest skin conductance we’ve ever seen was a result of Sudden Unexpected Death in Epilepsy (SUDEP),” Picard noted. Distressingly, little is known about SUDEP, a fatal condition in which the brain essentially fails to reboot itself after a seizure — “The seizure ends and after some time the person stops breathing and the brain shuts off,” Picard explained. Scientists have yet to figure out how or why this happens. And its toll is enormous. Picard’s conservative estimates suggest that SUDEP is second only to stroke in terms of the total number of years in life expectancy lost by its victims. And, there is evidence that the actual rate is worse, with most studies putting SUDEP at #1. Globally, there is a SUDEP-related death every seven to nine minutes, according to Picard.

Wearables have shown that with a typical seizure, skin-level electricity subsides as the brain returns to its pre-seizure state. “The flattening usually resolves itself and the brain waves go back to normal,” said Picard. “The duration of the cortical flattening before the brain fixes itself is related to the size of the sweat response on the wrist."

After lending her student those two wearables months earlier, Picard and her team were inspired to conduct further research and tests. From this research, Picard co-founded Empatica, which means “Empathetic” in Italian, which commercialized this for consumer use.

Empatica’s initial product, the “Embrace” wristband, became the first smart watch approved by the FDA for use in neurology. The Embrace uses AI and machine learning to continually track and detect convulsive seizures, and alerts the patient’s caregiver/s when a seizure episode is occurring so they can respond earlier and help prevent incidents of SUDEP.

Wearables that record electrical currents, on the skin can do more than just indicate that a seizure is happening. There is some evidence that Empatica’s device could eventually be used to detect the onset of some types of seizures, although research in this area is still ongoing. Data suggests that the device may also be able to prevent a seizure from progressing in severity through earlier detection, minimizing the response time from a seizure’s onset.

Picard explained that wearables measuring skin conductance could have a range of other uses. Electrodermal activity patterns are part of AI methods that her team at MIT has built to help forecast a person’s stress, mood, and health. If someone is experiencing stress, they might be more likely to have depressive feelings the next day—and the increase in stress would lead to changes in skin conductance that a wearable would be able to detect. Data from wearables can be downloaded “into machine learning systems to be able to accurately predict the emotional ‘weather’ the next day,” Picard said.

Empatica also manufactures another device, the E4 wristband, which is used by numerous researchers around the world in studies of stress, sleep, migraines, depression, and many other conditions.

Picard explained that wearables remind researchers of just how little scientists really know about the brain, while also providing pivotal clues for future life-saving research. “Don’t leave these mysteries on the side,” Picard said, looking back on the at-first puzzling results of her first accidental experiment with tracking seizures using wearables. “Go after them. You may help people.”