ACNS Standardized Critical Care EEG Terminology (2012)

Overview

Standardized terminology of periodic and rhythmic EEG patterns in the critically ill has been proposed by the ACNS and is reproduced in outline form below. This terminology is designed for research purposes, not for clinical use. Terms were chosen to avoid clinical connotations and to ensure adequate inter-rater reliability.

The full text of the article: American Clinical Neurophysiology Society’s Standardized Critical Care EEG Terminology: 2012 version can be found at the ACNS website, here: http://www.acns.org/pdf/guidelines/Guideline-14.pdf

Rhythmic or periodic patterns

All terms consist of main term # 1 followed by #2, with modifiers added as appropriate.

Main Term 1

Generalized (G)

Lateralized (L)

Bilateral Independent (BI)

Multifocal (Mf)

Main Term 2

Periodic Discharges (PD)

Rhythmic Delta Activity (RDA)

Spike or Sharp and Wave (SW)

Modifiers

Prevalence

Duration

Frequency

Number of phases

Sharpness

Amplitude

Polarity

Stimulus-Inducing (SI)

Evolving OR Fluctuating

Plus (+)

Minor Modifiers

Quasi-

Sudden OR gradual onset

Triphasic morphology

A-P or P-A lag

Sporadic epileptiform

Abundant

Frequent

Occasional

Rare

Background EEG

Symmetry

Posterior Dominant Rhythm

Predominant frequency

Anterior-Posterior Gradient

Variability

Reactivity

Voltage

Stage II sleep transients

Continuity

Continuous

Nearly continuous

Discontinuous

Burst attenuation / suppression

Suppression

ACNS 2012 terminology