Original Research

Continuous EEG Findings in Autoimmune Encephalitis

Moise, Anna-Marieta^*,†; Karakis, Ioannis^*; Herlopian, Aline^‡; Dhakar, Monica^*; Hirsch, Lawrence J.^‡; Cotsonis, George^*; LaRoche, Suzette^†; Cabrera Kang, Christian M.^§; Westover, Brandon^‖; Rodriguez, Andres^*

Author Information

^*Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.;

^†Mission Neurosciences Program, Epilepsy Department, Mission Health, Asheville, North Carolina, U.S.A.;

^‡Department of Neurology and Yale Comprehensive Epilepsy Center, Yale University, New Haven, Connecticut, U.S.A.;

^§Neurology Division, Laureate Medical Group, Atlanta, Georgia, U.S.A.;

^‖MGH Epilepsy Service and Division of Clinical Neurophysiology, Massachusetts General Hospital, Boston, Massachusetts, U.S.A.

Address correspondence and reprint requests to Anna-Marieta Moise, MD, 890 Hendersonville Rd Suite 200, Asheville, NC 28803, U.S.A.; e-mail: [email protected]

The authors have no conflicts of interest to disclose.

Supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Number UL1TR000454. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Presented at the American Epilepsy Society Meeting, Washington, DC, December, 2017.

Supplemental digital content is available 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).

Journal of Clinical Neurophysiology 38(2):p 124-129, March 2021. | DOI: 10.1097/WNP.0000000000000654

Abstract

Purpose:

Autoimmune encephalitis (AE) is a cause of new-onset seizures, including new-onset refractory status epilepticus, yet there have been few studies assessing the EEG signature of AE.

Methods:

Multicenter retrospective review of patients diagnosed with AE who underwent continuous EEG monitoring.

Results:

We identified 64 patients (male, 39%; white, 49%; median age, 44 years); of whom, 43 (67%) were antibody-proven AE patients. Of the patients with confirmed antibody AE, the following were identified: N-methyl-D-aspartate receptor (n = 17, 27%), voltage-gated potassium channel (n = 16, 25%), glutamic acid decarboxylase (n = 6, 9%), and other (n = 4, 6%). The remaining patients were classified as probable antibody-negative AE (n = 11, 17%), definite limbic encephalitis (antibody-negative) (n = 2, 3%), and Hashimoto encephalopathy (n = 8, 13%). Fifty-three percent exhibited electrographic seizures. New-onset refractory status epilepticus was identified in 19% of patients. Sixty-three percent had periodic or rhythmic patterns; of which, 38% had plus modifiers. Generalized rhythmic delta activity was identified in 33% of patients. Generalized rhythmic delta activity and generalized rhythmic delta activity plus fast activity were more common in anti-N-methyl-D-aspartate AE (P = 0.0001 and 0.0003, respectively). No other periodic or rhythmic patterns exhibited AE subtype association. Forty-two percent had good outcome on discharge. Periodic or rhythmic patterns, seizures, and new-onset refractory status epilepticus conferred an increased risk of poor outcome (OR, 6.4; P = 0.0012; OR, 3; P = 0.0372; OR, 12.3; P = 0.02, respectively).

Conclusion:

Our study confirms a signature EEG pattern in anti-N-methyl-D-aspartate AE, termed extreme delta brush, identified as generalized rhythmic delta activity plus fast activity in our study. We found no other pattern association with other AE subtypes. We also found a high incidence of seizures among patients with AE. Finally, periodic or rhythmic patterns, seizures, and new-onset refractory status epilepticus conferred an increased risk of poor outcome regardless of AE subtype.

Article Keywords

Keywords
Continuous EEG, Autoimmune encephalitis, Electrographic findings in autoimmune encephalitis, Encephalitis, Anti-NMDA-receptor encephalitis, Limbic encephalitis, Hashimoto encephalopathy, NORSE

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