Precipitous increase in sympathetic activity is consistent with airway obstruction
MarkStewart, Professor, Dean, SUNY Downstate Medical Center
Published September 07, 2017
I read with great interest the Clinical/Scientific Note by Picard et al, which described activity detected in a SUDEP case by the Embrace smartwatch (Empatica [Milan, Italy]). [1] The authors noted "an unusual fast rising... postictal electrodermal response (EDR)" after the convulsive activity detected by the watch's accelerometers. Help arrived at 15 minutes post detection and resuscitation efforts were unsuccessful.
Although the patient was found prone with their face in the pillow, this case is likely an example of obstructive apnea, possibly due to laryngospasm. [2,3] The electrodermal response indicative of intense sympathetic activity corresponds in time to the massive increases in both sympathetic and parasympathetic activity established for airway obstruction. [4] Also, as we pointed out, with respect to the MORTEMUS data, [3,5] effort to inspire can be confused with actual breaths when evaluated with motion sensors. Further, the timing is consistent with the time course reported for the MORTEMUS patients.
The EDR is exactly as one expects in the case of sudden onset airway obstruction and is not likely indicative of cerebral dysfunction. Unfortunately, without reestablishing the airway early, death is inevitable. [5]</p>
1. Picard RW, Migliorini M, Caborni C, et al. Wrist sensor reveals sympathetic hyperactivity and hypoventilation before probable SUDEP. Neurology 2017;89:633-635.
2. Nakase K, Kollmar R, Lazar J, et al. Laryngospasm, central and obstructive apnea during seizures: Defining pathophysiology for sudden death in a rat model. Epilepsy Res 2016;128:126-139.
3. Stewart M, Kollmar R, Nakase K, et al. Obstructive apnea due to laryngospasm links ictal to postictal events in SUDEP cases and offers practical biomarkers for review of past cases and prevention of new ones. Epilepsia 2017;58:e87-e90.
4. Hotta H, Koizumi K, Stewart M. Cardiac sympathetic nerve activity during kainic acid-induced limbic cortical seizures in rats. Epilepsia 2009;50:923-927.
5. Ryvlin P, Nashef L, Lhatoo SD, et al. Incidence and mechanisms of cardiorespiratory arrests in epilepsy monitoring units (MORTEMUS): a retrospective study. Lancet Neurol 2013;12:966-977.
I read with great interest the Clinical/Scientific Note by Picard et al, which described activity detected in a SUDEP case by the Embrace smartwatch (Empatica [Milan, Italy]). [1] The authors noted "an unusual fast rising... postictal electrodermal response (EDR)" after the convulsive activity detected by the watch's accelerometers. Help arrived at 15 minutes post detection and resuscitation efforts were unsuccessful.
Although the patient was found prone with their face in the pillow, this case is likely an example of obstructive apnea, possibly due to laryngospasm. [2,3] The electrodermal response indicative of intense sympathetic activity corresponds in time to the massive increases in both sympathetic and parasympathetic activity established for airway obstruction. [4] Also, as we pointed out, with respect to the MORTEMUS data, [3,5] effort to inspire can be confused with actual breaths when evaluated with motion sensors. Further, the timing is consistent with the time course reported for the MORTEMUS patients.
The EDR is exactly as one expects in the case of sudden onset airway obstruction and is not likely indicative of cerebral dysfunction. Unfortunately, without reestablishing the airway early, death is inevitable. [5]</p>
1. Picard RW, Migliorini M, Caborni C, et al. Wrist sensor reveals sympathetic hyperactivity and hypoventilation before probable SUDEP. Neurology 2017;89:633-635.
2. Nakase K, Kollmar R, Lazar J, et al. Laryngospasm, central and obstructive apnea during seizures: Defining pathophysiology for sudden death in a rat model. Epilepsy Res 2016;128:126-139.
3. Stewart M, Kollmar R, Nakase K, et al. Obstructive apnea due to laryngospasm links ictal to postictal events in SUDEP cases and offers practical biomarkers for review of past cases and prevention of new ones. Epilepsia 2017;58:e87-e90.
4. Hotta H, Koizumi K, Stewart M. Cardiac sympathetic nerve activity during kainic acid-induced limbic cortical seizures in rats. Epilepsia 2009;50:923-927.
5. Ryvlin P, Nashef L, Lhatoo SD, et al. Incidence and mechanisms of cardiorespiratory arrests in epilepsy monitoring units (MORTEMUS): a retrospective study. Lancet Neurol 2013;12:966-977.
For disclosures, please contact the editorial office at journal@neurology.org.