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. 2023 Jan 1;40(1):2-8.
doi: 10.1097/WNP.0000000000000972. Epub 2022 Sep 30.

From Alpha to Zeta: A Systematic Review of Zeta Waves

Brin E Freund  1 , Tara Brigham  2 , Saif Salman  1 , Peter W Kaplan  3 , William O Tatum 4th  1
Affiliations

From Alpha to Zeta: A Systematic Review of Zeta Waves

Brin E Freund et al. J Clin Neurophysiol. .

Abstract

Purpose: Electroencephalogram is used for prognostication and diagnosis in critically ill patients and is vital in developing clinical management algorithms. Unique waveforms on EEG may distinguish neurological disorders and define a potential for seizures. To better characterize zeta waves, we sought to define their electroclinical spectrum.

Methods: We performed a systematic review using MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Review [through Ovid], Scopus, Science Citation Index Expanded and Emerging Sources Citation Index [through the Web of Science], and Epistemonikos. Grey literature resources were searched.

Results: Five hundred thirty-seven articles were identified. After excluding duplicates and reviewing titles, abstracts, and bodies and bibliographies of articles, four studies reported 64 cases describing data from patients with zeta waves, with a prevalence of 3 to 4%. Various and often incomplete clinical, neuroimaging, and EEG data were available. 57 patients (89.1%) had a focal cerebral lesion concordant with the location of zeta waves on EEG. 26 patients (40.6%) had clinical seizures, all but one being focal onset. Thirteen patients (20%) had epileptiform activity on EEG. Typically, zeta waves were located in the frontal head regions, often with generalized, frontal, predominant, rhythmic delta activity and associated with focal EEG suppression.

Conclusions: Zeta waves frequently represent an underlying focal structural lesion. Their presence suggests a heightened risk for seizures. The small number of retrospective cases series in the literature reporting zeta waves might be an underrepresentation. We suggest a need for prospective studies of cEEG in critically ill patients to determine their clinical significance.

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Conflict of interest statement

The authors have no funding or conflicts of interest to disclose.

References

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    1. Tatum WO, Thottempudi N, Gupta V, et al. De novo temporal intermittent rhythmic delta activity after laser interstitial thermal therapy for mesial temporal lobe epilepsy predicts poor seizure outcome. Clin Neurophysiol 2019;130:122–127.

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