Assessment of a quasi-piezoelectric mattress monitor as a detection system for generalized convulsions

The risk of sudden unexpected death in epilepsy (SUDEP) is highest with nocturnal, unattended generalized convulsions, and basic resuscitation may be able to prevent SUDEP. This study investigates an under-mattress device (ElectroMechanical Film - Emfit®) which is triggered by rhythmic motor activity of a specifiable duration, frequency, and intensity using a quasi-piezoelectric material sensitive to changes in mattress pressure. The device was tested during inpatient video-EEG monitoring. Eighteen GTCSs were recorded, 10 out of wakefulness and 8 out of sleep. Sixteen of the 18 seizures (89%) resulted in Emfit® activation with both false negative alarms occurring during wakefulness. On average, the device was activated within 9 s of onset of bilateral clonic motor movements (range: -37 to +39 s) and occurred, on average, 45 s before seizure end (range: 19 to 76 s). Only 21 false alarms were encountered, all occurring during wakefulness (PPV: 43%). The data suggest that the Emfit® detection device has a high predictive value for generalized convulsions, offers caregivers a reliable and early warning to assist the patient during convulsions, and may be a novel way to prevent SUDEP.