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Affair With Triphasic Waves—Their Striking Presence, Mysterious Significance, and Cryptic Origins

What are They?

Kaplan, Peter W.*; Sutter, Raoul†,‡

Journal of Clinical Neurophysiology: October 2015 - Volume 32 - Issue 5 - p 401–405
doi: 10.1097/WNP.0000000000000151
Special Article

Summary: Triphasic waves, which have been recorded in the EEG of encephalopathy for more than 50 years, remain clearly identifiable but historically purportedly of uncertain significance. Initially described with liver failure and high serum ammonias, they came to be reported in an ever-expanding list of metabolic, toxic, and structural conditions. Often a dynamic finding (in which the occurrence of triphasic waves might increase or decrease with stimulation or arousal of the patient during EEG), there has been increasing insight into their correlation with multiple concurrent conditions, including subcortical white-matter disease, infections and metabolic disturbances, and their prognostic significance. There are sparse data, but there is active controversy into their confusion for, or occurrence in, nonconvulsive status epilepticus. This review and commentary discuss our current understanding of triphasic waves and the newer areas of contention surrounding this mysterious EEG morphology.

*Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.;

Clinic for Intensive Care Medicine, University Hospital Base, Basel, Switzerland; and

Department of Neurology, Division of Clinical Neurophysiology, University Hospital Basel, Basel, Switzerland.

Address correspondence and reprint requests to Peter W. Kaplan, MBBS, FRCP, Department of Neurology, Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, MD 21224, U.S.A.; e-mail:

© 2015 by the American Clinical Neurophysiology Society