NightWatch makes detection of nocturnal epileptic seizures possible



The growing call of parents of children and adults with epilepsy for a sensitive seizure detection device was the reason that professional experts of an university and two epilepsy centers came together to discuss the possibilities. Consortium TeleEpilepsy was born.
The aim of the consortium was to develop a system to detects nocturnal  life threatening epileptic seizures. The system should be easy to use and acceptable for the person with epilepsy. The goal was a system with a high sensitivity for severe seizures that required immediate care and with only a few false alarms.

Such a system will support the parents and caregivers (nurses in residential homes for people with an  intellectual disability and epilepsy) in caring/nursing the child or pupil during seizures. The parents can sleep and the nurses can work more relaxed because they will be alarmed in case of a seizure. Giving care as soon as possible prevents worsening (status epilepticus) and increases the (feeling of) security.  An unobserved seizure can, especially in younger persons, result in SUDEP (sudden unexpected death in epilepsy).

People with intellectual disability and epilepsy often have refractory type of epilepsy. This group of people show to have a high seizure frequency in spite of  a combination of different medicines. A second group with a refractory type of epilepsy are children with special syndromes. These two groups especially, show to have more often life-threatening epileptic seizures, but these type of seizures can occur in every person with epilepsy.

A device, the NightWatch, consisting two sensors was developed. One sensor to measure the movements of the user.: the accelerometer, a second sensor to measure the heart rate.

The first phase of the testing the device in development, was performed in the first group of 28 participants. They were living in residential homes special for people with intellectual disability and epilepsy. The NightWatch was combined with video and audio monitoring to check if the alarm was correct or false. During the first weeks of testing on the participants the algorithm, which  calculated and alarmed for a critical situation: a seizure, was optimized after the first results. In the following three months no change was made. After the period of testing the nurses were asked about their experiences with the device, by filling out a questionnaire. The results of these questionnaires and after checking the video of every alarm and measuring the missed seizures by checking whole night, all results were analyzed. After discussing these findings the algorithm was optimized especially for use in children in who a more variable heart rate was expected.

In this second phase of the study, in 24 children living with their parents, the testing period started with adjustments of the algorithm, followed by a period of three months with fixed algorithm. This phase is recently stopped, data are not analyzed yet.

The results of the first phase are positive. A high sensitivity was measured for tonic clonic seizures (associated with high SUDEP risk).  Median sensitivity per participant amounted 86% (CI95% : 77% – 93%), false negative alarm rate was 0.03 per night (CI95% : 0.01 – 0.05) and positive predictive value 49% (CI95% : 33%– 64%).

The consortium TeleEpilepsy, with members from both epilepsy centers and the university clinic, which are all professional experts (neurologists and nurses) and members with a more research background (engineer, statistician and epidemiologist) or are experiential experts (parents and assembly of patients and their family) are  still working together with the manufacture to develop and improve the system.