ACNS Standardized Critical Care EEG Terminology 2021 PDF

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ACNS GUIDELINE American Clinical Neurophysiology Society’s Standardized Critical Care EEG Terminology: 2021 Version Lawrence J. Hirsch,* Michael W.K. Fong,† Markus Leitinger,‡ Suzette M. LaRoche,§ Sandor Beniczky,k Nicholas S. Abend,¶ Jong Woo Lee,# Courtney J. Wusthoff,** Cecil D. Hahn,†† M. Brandon Westover,‡‡ Elizabeth E. Gerard,§§ Susan T. Herman,kk Hiba Arif Haider,§ Gamaleldin Osman,¶¶ Andres Rodriguez-Ruiz,§ Carolina B. Maciel,## Emily J. Gilmore,* Andres Fernandez,*** Eric S. Rosenthal,††† Jan Claassen,‡‡‡ Aatif M. Husain,§§§ Ji Yeoun Yoo,kkk Elson L. So,¶¶¶ Peter W. Kaplan,### Marc R. Nuwer,**** Michel van Putten,†††† Raoul Sutter,‡‡‡‡ Frank W. Drislane,§§§§ Eugen Trinka,‡ and Nicolas Gaspardkkkk Downloaded from https://journals.lww.com/clinicalneurophys by BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3i3D0OdRyi7TvSFl4Cf3VC4/OAVpDDa8KKGKV0Ymy+78= on 01/27/2021 * Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, U.S.A.; †Westmead Comprehensive Epilepsy Unit, Westmead Hospital, University of Sydney, Sydney, Australia; ‡Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria; §Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.; kDepartment of Clinical Neurophysiology, Danish Epilepsy Center, Dianalund and Aarhus University Hospital, Aarhus, Denmark; ¶Departments of Neurology and Pediatrics, The Children’s Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A.; #Brigham and Women’s Hospital, Boston, Massachusetts, U.S.A.; **Division of Child Neurology, Stanford University, Palo Alto, California, U.S.A.; ††Division of Neurology, The Hospital for Sick Children, and Department of Pediatrics, University of Toronto, Toronto, Canada; ‡‡Neurology Department, Massachusetts General Hospital, Massachusetts, U.S.A.; §§ Comprehensive Epilepsy Center, Department of Neurology, Northwestern University, Chicago, Illinois, U.S.A.; kkBarrow Neurological Institute, Phoenix, Arizona, U.S.A.; ¶¶Department of Neurology, Henry Ford Hospital, Detroit, Michigan, U.S.A.; ##Division of Neurocritical Care, Department of Neurology, University of Florida, Gainesville, Florida, U.S.A.; ***Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, U.S.A.; †††Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A.; ‡‡‡Neurocritical Care, Department of Neurology, Columbia University, New York, New York, U.S.A.; §§§Department of Medicine (Neurology), Duke University Medical Center, and Veterans Affairs Medical Center, Durham, North Carolina, U.S.A.; kkkDepartment of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, U.S.A.; ¶¶¶Division of Epilepsy, Mayo Clinic, Rochester, Minnesota, U.S.A.; ###Department of Neurology, Johns Hopkins University School of Medicine, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.; ****Department of Neurology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, U.S.A.; †††† Medisch Spectrum Twente and University of Twente, Enschede, The Netherlands; ‡‡‡‡Medical Intensive Care Units and Department of Neurology, University Hospital Basel, Basel, Switzerland; §§§§Department of Neurology, Harvard Medical School, and Comprehensive Epilepsy Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts, U.S.A.; and kkkkDepartment of Neurology, Université Libre de Bruxelles, H^ opital Erasme, Brussels, Belgium. (J Clin Neurophysiol 2021;38: 1–29) meetings on several continents, subjected to multiple rounds of testing of interrater reliability, underwent many revisions, and was INTRODUCTION then published as an ACNS guideline in 2013.2 Interrater agreement In the early 2000s, a subcommittee of the American Clinical of the 2012 version (published in early 2013) was very good, with Neurophysiology Society (ACNS) set out to “standardize terminol- almost perfect agreement for seizures, main terms 1 and 2, the 1S ogy of periodic and rhythmic EEG patterns in the critically ill to aid modifier, sharpness, absolute amplitude, frequency, and number of in future research involving such patterns.” The initial proposed phases.3 Agreement was substantial for the 1F and 1R modifiers terminology was published in 2005.1 This was presented at many (66% and 67%) but was only moderate for triphasic morphology L. J. Hirsch received consultation fees from Aquestive, Ceribell, Marinus, Medtronic, Neuropace and UCB; received authorship royalties from Wolters Kluwer and Wiley; and received honoraria for speaking from Neuropace and Natus. S. M. LaRoche received royalties from Demos/Springer Publishing. S. Beniczky is consultant for Brain Sentinel & Epihunter and Philips; speaker for Eisai, UCB, GW Pharma, Natus, BIAL; and received research grants from Brain Sentinel, Philips, Eisai, UCB, GW Pharma, Natus, BIAL, Epihunter, Eurostars (EU), Independent Research Fund Denmark, Filadelfia Research Foundation, Juhl Foundation, Hansen Foundation. N. S. Abend received royalties from Demos; grants from PCORI and Epilepsy Foundation; and an institutional grant from UCB Pharma. J. W. Lee received grants from Bioserenity, Teladoc, Epilepsy Foundation; is co-founder of Soterya Inc; is a board member of the American Clinical Neurophysiology Society; does consulting for Biogen; and is site PI for Engage Therapeutics and NIH/NINDS R01-NS062092. C. J. Wustof does consulting for Persyst and PRA Health Care. C. D. Hahn received grants from Takeda Pharmaceuticals, UCB Pharma, Greenwich Biosciences. M. B. Westover is co-founder of Beacon Biosignals. E. E. Gerard received grants from Greenwich Pharmaceuticals, Xenon Pharmaceuticals, Sunovion, and Sage. S. T. Herman received grants from UCB Pharma, Neuropace, Sage. H. A. Haider receives author royalties from UpToDate and Springer; does consulting for Ceribell, and is on advisory board for Eisai. A. Rodriguez-Ruiz is co-owner of Rodzi LLC which has no relationship to this work. E. J. Gilmore received a grant from UCB Pharma. J. Claassen is a shareholder of iCE Neurosystems and received a grant from McDonnell Foundation. A, M. Husain received grants from UCB Pharma, Jazz Pharma, Biogen Idec; and received payment from Marinus Pharma, Eisai Pharma, Neurelis Pharma, Blackthorn Pharma, Demos/Springer and Wolters Kluwer publishers. J. Y. Yoo received grants from NIH NeuroNEXT, Zimmer Biomet, LVIS; and receives author royalties from Elsevier. P. W. Kaplan receives author royalties from Demos and Wiley publishers; does consulting for Ceribell; and is expert witness qEEG. M. R. Nuwer is a shareholder of Corticare. M. van Putten is co-founder of Clinical Science Systems. R. Sutter received grants from Swiss National Foundation (No 320030_169379), and UCB Pharma. F. W. Drislane received a grant from American Academy of Neurology. E. Trinka discloses fees received from UCB, Eisai, Bial, B€ohringer Ingelheim,Medtronic, Everpharma, GSK, Biogen, Takeda, Liva-Nova, Newbridge, Novartis, Sanofi, Sandoz, Sunovion, GW Pharmaceuticals, Marinus, Arvelle; grants from Austrian Science Fund (FWF), Österreichische Nationalbank, European Union, GSK, Biogen, Eisai, Novartis, Red Bull, Bayer, and UCB; other from Neuroconsult Ges.m.b.H., has been a trial investigator for Eisai, UCB, GSK, Pfitzer. The remaining authors have no funding or conflicts of interest to disclose. Many EEG examples are available online as supplemental digital content for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.clinicalneurophys.com). Address correspondence and reprint requests to Lawrence J. Hirsch, MD, Department of Neurology, Comprehensive Epilepsy Center, Yale University School of Medicine, P.O. box 208018, New Haven, CT 06520, U.S.A.; e-mail: [email protected]. Copyright
2020 by the American Clinical Neurophysiology Society ISSN: 0736-0258/20/3801-0001 DOI 10.1097/WNP.0000000000000806 clinicalneurophys.com Journal of Clinical Neurophysiology Volume 38, Number 1, January 2021 1 Copyright © by the American Clinical Neurophysiology Society. Unauthorized reproduction of this article is prohibited.  L. J. Hirsch, et al. Standardized Critical Care EEG Terminology (58%) and fair for evolution (21%, likely at least partly because of the asynchronous” patterns. Electrographic seizures (ESz), electro- short EEG samples provided).3 The authors concluded that interrater graphic status epilepticus (ESE), electroclinical seizures (ECSz), agreement for most terms in the ACNS critical care EEG terminology and electroclinical status epilepticus (ECSE) have now been was high and that these terms were suitable for multicenter research defined, largely based on the “Salzburg criteria.”11,12 Brief on the clinical significance of these critical care EEG patterns. potentially ictal rhythmic discharges (BIRDs) have been added With the help of infrastructure funding from the American based on recent publications13,14, and a consensus definition of the Epilepsy Society and administrative and website support from ictal-interictal continuum (IIC) has been proposed. We also added the ACNS, a database that incorporated the ACNS terminology definitions of identical bursts,15 state changes, cyclic alternating was developed for clinical and research purposes, tested during pattern of encephalopathy (CAPE), and extreme delta brush routine clinical care in multiple centers,4 and made available at (EDB).16 To facilitate daily use, we are also providing the “ACNS no cost on the ACNS website (https://www.acns.org/research/ Standardized Critical Care EEG Terminology 2021: Condensed critical-care-eeg-monitoring-research-consortium-ccemrc/ Version” (see Supplemental Digital Content, http://links.lww.com/ ccemrc-public-database). This greatly enhanced the ability to JCNP/A149) and the “ACNS Standardized Critical Care EEG complete multicenter investigations. Terminology 2021: Reference Chart” (see Supplemental Digital After the establishment of the standardized terminology and Content, http://links.lww.com/JCNP/A150). Finally, for educational free access to a database incorporating these terms, there have been purposes and conceptual clarity, we provided extensive schematic many investigations into the clinical significance of rhythmic and diagrams (Figures 1–42) of most patterns to quickly demonstrate the periodic patterns (RPPs) in critically ill patients. Patterns such as core features and principles. Supplemental figures include EEG lateralized rhythmic delta activity (LRDA) were found to be highly examples from 30 cases and are available as Supplemental Digital associated with acute seizures,5,6 equivalent to the association found Content at http://links.lww.com/JCNP/A134. with lateralized periodic discharges (LPDs) in one study.5 The association of all the main patterns in the nomenclature with seizures was defined in a multicenter cohort of almost 5,000 patients, with seizure rates highest for LPDs, intermediate for LRDA and METHODS generalized periodic discharges (GPDs), and lowest for generalized All the definitions are based on extensive discussions not rhythmic delta activity (GRDA).6 This and other studies have shown only among the authors of this document but also among many that several of the modifiers within the nomenclature do indeed have others, both live and via email and questionnaires. There was clinically relevant meaning. For example, studies have shown that not always complete consensus on some issues; electronic higher frequency (especially.1.5 Hz), higher prevalence, longer voting (with each voter blinded to the opinion of others for the duration, and having a “plus” modifier are all associated with a first round) was used for most of these issues. We considered higher chance of acute seizures.6,7 On the other hand, whether a additional changes from previous versions or from the pattern was spontaneous or “stimulus-induced” did not seem to have literature such as eliminating the 10-second cutoff for defining a significant effect on its association with seizures.6 In other electrographic seizures but because no clear consensus was investigations, the “triphasic morphology” modifier was investigated reached (it was close to a split decision), this was not changed. blindly with multiple expert reviewers, calling into question its relationship with metabolic encephalopathy and its lack of a relationship with seizures.8,9 For patients with refractory status 2021 ACNS CRITICAL CARE EEG TERMINOLOGY epilepticus treated with anesthetic-induced coma, the presence of “highly epileptiform” bursts suggested that an attempted wean off of CONTENTS anesthetics at that time was much more likely to lead to seizure A. EEG BACKGROUND recurrence than if the bursts were not highly epileptiform.10 Even B. SPORADIC EPILEPTIFORM DISCHARGES long-term outcome seemed to be associated with some modifiers, C. RHYTHMIC AND PERIODIC PATTERNS (RPPs) with a higher risk of later epilepsy found if LPDs were more D. ELECTROGRAPHIC AND ELECTROCLINICAL SEI- prevalent, had longer duration, or had a “plus” modifier.7 ZURES [NEW, 2021] E. BRIEF POTENTIALLY ICTAL RHYTHMIC DIS- CHARGES (BIRDs) [NEW, 2021] CHANGES IN THE 2021 VERSION OF F. ICTAL-INTERICTAL CONTINUUM (IIC) [NEW, 2021] THE TERMINOLOGY G. MINIMUM REPORTING REQUIREMENTS Although the previous version of the terminology was easy to H. OTHER TERMS use, reliable, and valuable for both research and clinical care, new terms and concepts have emerged. In this version, we incorporate General Notes recent research findings, add definitions of several new terms, and NOTE: This terminology is intended to be used at all ages, clarify a few definitions of old terms. Most of the old terms remain excluding neonates, although some terms may not be ideal unchanged, but there have been some important clarifications and for infants. For the neonatal version of the terminology, please corrections (such as the calculation of the number of phases) and see https://www.acns.org/UserFiles/file/The_American_Clinical_ multiple additions. All changes have been summarized in Table 1. Neurophysiology_Society_s.12.pdf.18 One new main term 1 was added (Unilateral Independent), and main NOTE: This terminology is intended for use in the term 2 “Lateralized” was updated to include “bilateral critically ill, although it can be applied in other settings as 2 Journal of Clinical Neurophysiology Volume 38, Number 1, January 2021 clinicalneurophys.com Copyright © by the American Clinical Neurophysiology Society. Unauthorized reproduction of this article is prohibited.  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.