FDA Clears the First Smart Watch for Use in Neurology

Wearable device identifies convulsive epileptic seizures and sends alerts to caregivers

The FDA has cleared the Embrace smart watch (Empatica, Inc.) for use by patients with epilepsy. Embrace uses advanced machine learning to monitor for the most dangerous kinds of seizures, known as “grand mal” or “generalized tonic-clonic” seizures, and sends an alert to summon caregivers’ help. It also provides sleep, rest, and physical activity analysis.

In a multisite clinical study, 135 patients diagnosed with epilepsy were admitted to top level IV epilepsy monitoring units for continuous monitoring with video- electroencephalography (EEG) while simultaneously wearing the device. From these patients, 6,530 hours of data were recorded over 272 days, including 40 generalized tonic-clonic seizures. Embrace's algorithm was shown to detect 100% of the seizures. The trial used the gold standard of comparing to seizures clinically labeled by at least two out of three independent epileptologists, who examined the video-EEG data without seeing any data used by Embrace.

The smart watch stands apart from any seizure detection system in that it measures multiple indicators of a seizure. Its unique property is its use of electrodermal activity, a signal used by stress researchers to quantify physiological changes related to sympathetic nervous system activity, also known as the “fight-or-flight” response. Embrace has been approved in Europe as a medical device for seizure monitoring and alert since April 2017.

According to recent estimates by the CDC, 1.2% of the U.S. population suffers from epilepsy, amounting to around 3.4 million patients, including 470,000 children. Approximately 35% of these patients do not respond to medication to control their seizures, while another third are only partially responsive to medication.

Generalized tonic-clonic seizures result in a loss of consciousness and can leave the person in a state of confusion for some time afterward. Traditionally, clinical trials have had to rely upon patients to self-report in a diary when a seizure happens, a process known to be inaccurate. More than 40% of the most dangerous generalized tonic-clonic seizures are not reported, but Embrace's high sensitivity makes seizure reporting easier and more accurate. The bracelet also sends an alert immediately to a caregiver, to bring help at the time of need.

Empatica, Inc., an MIT Media Lab spin-off, initially launched Embrace through a crowdfunding campaign in 2015, focusing heavily on high-quality design. According to Matteo Lai, Co-Founder and CEO of Empatica, “Medical devices face a huge problem: they're usually too bulky and uncomfortable, and people simply don't want to wear them. … We wanted to design the world's first medical device that could win a design award, while being used as a lifesaving product. Patients actually love Embrace and are proud to wear it. We think this has been one of the keys of its success and an interesting lesson for health care. Cutting-edge technology and good design need to go together.”