ACNS Standardized Critical Care EEG Terminology 2021 PDF

Standardized Critical Care EEG Terminology L. J. Hirsch, et al. TABLE 1. ACNS Standardized Critical Care EEG Terminology: Major and Minor Changes Between the 2012 and 2021 Versions Major changes EEG bac...

Standardized Critical Care EEG Terminology L. J. Hirsch, et al. TABLE 1. ACNS Standardized Critical Care EEG Terminology: Major and Minor Changes Between the 2012 and 2021 Versions Major changes EEG background  “Variability” and “Stage II sleep transients (K-complexes and spindles)” now combined under “State changes”.  Cyclic Alternating Pattern of Encephalopathy (CAPE) (new term: Section A7, page 7)  Identical bursts (new term: Section A4d, page 6) Rhythmic and Periodic Patterns (RPPs: PDs, RDA and SW)  Unilateral Independent (UI) (new Main Term 1 option: Section C1d, page 10)  Lateralized (bilateral asynchronous) (Main Term 1: Section C1b, page 9)  Patterns that consistently begin in one hemisphere and propagate to the other hemisphere can now be included as a lateralized (bilateral asynchronous) pattern.  Frequency  For PDs and SW, typical frequencies.2.5 Hz can only be applied to RPPs ,10 s duration (“very brief” by definition); if PDs or SW have a typical frequency.2.5 Hz and are $ 10 s these would qualify as electrographic seizures (criterion A) and should be referred to as such rather than as PDs or SW.  No RPP in this terminology can have a typical frequency of.4 Hz; if a pattern is. 4 Hz and $ 0.5 s, it would always meet criteria for either BIRDs (if ,10 s) or an electrographic seizure (if $ 10 s) (see definitions below). If ,0.5 s, this would not qualify as any RPP, but might qualify as a polyspike.  Evolution  Evolution of an RPP is now limited to patterns that are #4 Hz AND ,10 s duration. Any.4-Hz RPP with evolution lasting ,10 s would qualify as a definite BIRD (see Section E, page 24). Any RPP with evolution lasting $ 10 s meets criterion B of an electrographic seizure and should be coded as such.  Extreme Delta Brush (EDB) (new term: Section C3i, page 19)  Stimulus-Terminated (new modifier) Electrographic and Electroclinical Seizure Activity  Electrographic seizure (ESz) (new term: Section D1, page 22)  Electrographic status epilepticus (ESE) (new term: Section D2, page 23)  Electroclinical seizure (ECSz) (new term: Section D3, page 24)  Electroclinical status epilepticus (ECSE) (new term: Section D4, page 24)  Possible electroclinical status epilepticus (new term: Section D4b, page 24) Brief Potentially Ictal Rhythmic Discharges (BIRDs) (new term: Section E, page 24) Ictal-Interictal Continuum (IIC) (new term: Section F, page 25) Minor changes EEG background  Predominant background frequency  Beta (.13 Hz) has now been added (rather than only “alpha or faster”)  Continuity  Nearly continuous changed from #10% to 1–9% attenuation/suppression  Burst suppression changed from.50% attenuation/suppression to 50–99%  Suppression/attenuation changed from entirety to.99% of the record  Burst attenuation/suppression  Can now also be described by applying the location descriptions of Main term 1  Highly Epileptiform Bursts  Previously: present if multiple epileptiform discharges are seen within the majority (.50%) of bursts and occur at an average of 1/s or faster OR if a rhythmic, potentially ictal-appearing pattern occurs at 1/s or faster within the majority (.50%) of bursts.  Updated to: present if 2 or more epileptiform discharges (spikes or sharp waves) are seen within the majority (.50%) of bursts and occur at an average of 1 Hz or faster within a single burst (frequency is calculated as the inverse of the typical interpeak latency of consecutive epileptiform discharges within a single burst) OR if a rhythmic, potentially ictal-appearing pattern occurs at 1/s or faster within the majority (.50%) of bursts.  Voltage  High (most or all activity $ 150 mV) has now been added as a category Rhythmic and periodic patterns  Duration:  Intermediate duration changed from 1–4.9 mins to 1–9.9 mins (to match the definition of focal status epilepticus with impaired consciousness by the International League Against Epilepsy).17  Long duration accordingly changed from 5–59 mins to 10–59 mins  Absolute voltage (amplitude)  Medium, changed from 50–199 mV to 50–149 mV  High accordingly changed from $ 200 mV to $ 150 mV  Polarity changed from major modifier to minor modifier well. It is mostly compatible with the 2017 multinational NOTE: Although any finding on EEG can be focal, regional, revised glossary of terms most commonly used by clinical or hemispheric, such as an asymmetry or slowing, and this is a electroencephalographers.19 very important distinction in some circumstances such as clinicalneurophys.com Journal of Clinical Neurophysiology Volume 38, Number 1, January 2021 3 Copyright © by the American Clinical Neurophysiology Society. Unauthorized reproduction of this article is prohibited.