ACNS 2012 Terminology

background EEG > continuity

  • 1. Continuous: no periods of attenuation or suppression
  • 2. Nearly Continuous: continuous, but with occasional (<10% of the record) periods of attenuation or suppression. Describe typical duration of attenuation/suppression as above.
    • a. Nearly continuous with attenuation: periods of lower voltage are >10µV but <50% of the background voltage.
    • b. Nearly continuous with suppression: periods of lower voltage are <10 µV;
    • c. If suppressions/attenuations are stimulus-induced, code as “nearly continuous with SI-attenuation” or “…with SI-suppression”;
  • 3. Discontinuous: 10-49% of the record consisting of attenuation or suppression, as defined above.
  • 4. Burst-attenuation/Burst-suppression: more than 50% of the record consisting of attenuation or suppression, as defined above, with bursts alternating with attenuation or suppression; specify the following:
    • a. Typical duration of bursts and interburst intervals;
    • b. Sharpest component of a typical burst using the sharpness categories defined above under modifiers;
    • c. Presence or absence of Highly Epileptiform Bursts: Present if multiple epileptiform discharges (traditional definition) are seen within the majority (>50%) of bursts and occur at an average of 1/s or faster; record typical frequency (using categories above) and location (G, L, BI or Mf). Also present if a rhythmic, potentially ictal-appearing pattern occurs at 1/s or faster within the majority (>50%) of bursts; record frequency and location as well.
  • 5. Suppression: entirety of the record consisting of suppression (<10 µV, as defined above).

    NOTE: Bursts must average more than 0.5 seconds; if shorter, they should be considered single discharges (as defined above under main term 2). Bursts within burst-suppression or burst-attenuation can last up to 30 seconds.