Literature Monitor

How Long Should Ambulatory EEGs Be Recorded?

Epilepsy Res; 2019 Jan; Kuo et al.


Although ambulatory EEGs (aEEGs) can help distinguish epileptic attacks from non-epileptic attacks, they have their limitations. A recent retrospective review of EEG procedure notes from the Stanford Comprehensive Epilepsy Center has found that they rarely yield useful information beyond 24 hours duration.

  • Stanford researchers analyzed 358 adult aEEG readings from 2010 to 2017 and found epileptiform discharges or epileptic seizures in 101 of the readings (28%).
  • The analysis compared detection rates for 20-30 hours, 30-50 hours, and 50-76 hours and found little difference.
  • Epilepsy seizures were observed in 11%, 7%, and 10% respectively for the 3 duration periods.
  • An analysis of the epileptiform abnormalities revealed no significant differences in detection rates for the 3 duration periods.
  • Among aEEGs that were ordered to characterize suspected events, however, 72 hours was the best option because it generated a higher rate of capture.

Kuo J, Lee-Messer C, Le S. Optimal recording duration of ambulatory EEG (aEEG). Epilepsy Res. 2018;149:9-12.

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