Wrist sensor reveals sympathetic hyperactivity and hypoventilation before probable SUDEP

July 12, 2017


Rosalind W. Picard, ScD, Matteo Migliorini, PhD, Chiara Caborni, MSc, Francesco Onorati, PhD, Giulia Regalia, PhD, Daniel Friedman, MD, Orrin Devinsky, MD Neurology; published ahead of print July 12, 2017, doi:10.1212/WNL.0000000000004208: 1526-632X


We report a probable sudden unexpected death in epilepsy (SUDEP) in a 20-year old man wearing a smartwatch that recorded wrist motion via 3-axis accelerometer (ACC) and electrodermal activity (EDA). EDA reflects sympathetic activity without parasympathetic antagonism. The smartwatch (Empatica’s Embrace, with CE Medical clearance from the European Union for seizure detection) issued an alert, received by the caregiver at 08:50, indicating a probable convulsive seizure. An adult trained in CPR arrived at 09:05, found him pulseless, prone, face in his pillow with mucus in his mouth, and commenced CPR for 15 minutes without recovery. 

This case obtained continuous EDA 24/7, finding an unusually large (66.7S) EDR preceding death [...]

These data reveal a critical window of postictal autonomic dysregulation, probably relevant to SUDEP pathophysiology, that is detectable with a wristband sensor.  While medical support, even within two minutes of a seizure, does not always prevent SUDEP, evidence supports that SUDEP is less likely to occur when somebody can rapidly stimulate or reposition.  [...] 

Patients and families should be informed about SUDEP risk and strategies to reduce risk (e.g., medication adherence, sleep hygiene). They should be told that SUDEP can happen in the minutes following a seizure, and if somebody is there to immediately stimulate, reposition, or provide first aid, the patient may have a better chance of survival. For high-risk patients, seizure detection and alert monitors may bring help. As this case illustrates, their utility in preventing SUDEP is predicated on a helper arriving quickly and providing appropriate aid. 

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