A collaboration between teams of Dutch scientists has developed a monitoring and alert device designed to warn epilepsy sufferers of night time seizures. Currently, there are no accurate technologies in existence to wake people up before a seizure kicks in, which can sometimes even lead to deaths.

The new NightWatch device is an upper arm strap-on that measures the heart rate and movement of the sleeping person, directly from the body. It is not terribly intrusive and can probably be made thinner and lighter than the current prototype.

The researchers compared their technology to a bed sensor that is currently a standard in the field. The existing sensor detects jerky movements while the patient is in bed, and it failed to warn of severe seizures once every four nights, while the NightWatch missed only once every 25 nights on average.

Currently, the NightWatch measures the heart rate and motion, triggering its alarms based on whether any of the two readings cross certain thresholds. The next step will be to combine the two numbers into a unified metric and to unite this technology with others, such as video, to improve the system’s accuracy.

Here’s a video that shows off the NightWatch and how it was tested: