Time to response and patient visibility during tonic–clonic seizures in the epilepsy monitoring unit

Kristen Malloy, Damon Cardenas, August Blackburn, Luke Whitmire, Jose E. Cavazos

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Objective: There is a high cost associated with recording quality video and electroencephalography (EEG) data in National Association of Epilepsy Center (NAEC) level IV epilepsy monitoring units (EMU). This study considers potential quality measures in EMUs for generalized tonic–clonic (GTC) seizures: types of safety signals, response time, and visibility of patient's limbs for semiology. These quality measures have been summarized across 12 EMUs to estimate response times to GTC seizures and the quality of video data that is captured during admissions. Methods: Video electroencephalographies (vEEGs) from two prospective regulatory studies for the Brain Sentinel device were reviewed. A total of 232 subjects with a history of GTC seizures underwent routine clinical EMU stays. Fifty-four of the study subjects had 96 GTC seizures. The vEEG of events were reviewed for safety signal used, response time, and visibility of patient's limbs. Results: The average response time from members of the hospital team was 22 s from electrographic generalization (minimum − 37 s, maximum 111 s, two no response). For caregivers, average response was 11 s (minimum − 15 s, maximum 33 s, 45 not present/no response). In 73% of events, the patient visibility was limited at seizure onset. In 55% of events with limited limb visibility, the visibility was improved (by removing sheets or improving camera angle) > 30 s after start of the event. The primary safety signals were as follows: an alert from outside the patient room (54%), button press (23%), hospital team present at seizure start (14%), caregiver vocal alert (6%), and no response (2%). Significance: The average response time of caregivers was twice as fast as the hospital team, underscoring the importance of having a person in the room during onset of a GTC seizure. Diagnostic yield could be improved with more timely removal of patient coverings. It was observed that when patients experienced a GTC seizure, 40% were fully or partially obscured for more than 30 s during the event, compromising the ability of epileptologists to evaluate semiology during seizure onset. Automated seizure alarms may help staff get to patients more quickly and improve diagnostic characterization.

Original languageEnglish (US)
Pages (from-to)84-88
Number of pages5
JournalEpilepsy and Behavior
StatePublished - Dec 2018


  • EMU
  • Epilepsy
  • GTC seizure
  • Quality measures
  • Semiology
  • Video-EEG

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology
  • Behavioral Neuroscience


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