New epilepsy warning device detects severe nighttime seizures

A new epilepsy monitoring device detects 85 percent of all severe night-time seizures, which the designers say is a big technological improvement.

Researchers in the Netherlands tested the bracelet, known as Nightwatch, in 28 intellectually disabled epilepsy patients over an average of 65 nights per patient. Their findings were published this week in the journal Neurology.

People with an intellectual disability and severe therapy-resistant epilepsy possibly have a 20 percent lifetime risk of dying from epilepsy, the researchers said. A major cause of mortality in epilepsy patients is sudden unexpected death.

"A substantial amount of the people with treatment-resistant epilepsy have seizures at night," researcher leader Dr. Johan Arends said in a Eindhoven University of Technology video. "Because the seizures can have serious consequences, both professional and voluntary carers want to be able to observe them as early as possible.

"Nightwatch was developed because we are unable to observe many night-time seizures and the current systems cannot do that effectively yet. That is why we've developed this small device to make it simple and reliable."

Researchers developed a bracelet that recognizes two essential characteristics of severe attacks: an abnormally fast heartbeat and rhythmic jolting movements. The bracelet sends a wireless alert to caregivers or nurses.

Tested were 34 participants over a total of 1,826 nights, during which there were 809 major seizures. Six of them did not complete the study.

The bracelet was restricted to sounding an alarm during a severe seizure. To check if there were any false alarms or attacks that Nightwatch might have missed, the patients also were filmed.

Besides a success rate of 85 percent of severe attacks, it detected 96 percent of the most severe ones, called tonic-clonic seizures.

The current device for detecting seizures -- a bed sensor that reacts to vibrations due to rhythmic jerks -- only detects 21 percent of serious attacks.

With the new system, patients did not experience much discomfort from the bracelet and it was rated positively by care staff.

Arends said in a Eindhoven University of Technology press release he expects the device to be widely used among adults in institutions and at home. He said believes it may reduce the number of cases of suddden death due to epilipsy by two-thirds, although he noted it depends on how quickly and adequately care providers or informal caregivers respond to the alerts.

The NightWatch has been available to healthcare institutions since early this year. In addition, the bracelet has limited availability for home use.

The bracelet generates separate alarms based on the two sensors but the Tele-epilepsy Consortium is investigating how the two can act together for even better alerts. The consortium is also working on improving alarm systems on sound and video.

Eindhoven University of Technology and Kempenhaeghe, an epilepsy treatment center, have been developing the system for about 20 years with other collaborators. LivAssured was been established to market the Nightwatch.