Abstracts

Rationale: Benign epileptiform variants (BEVs) are non-pathological EEG findings of healthy persons. Examples include phantom spike-waves (PSWs), small sharp spikes, wicket waves, 14 and 6 Hz positive spikes, rhythmic mid-temporal theta of drowsiness and subclinical rhythmic electrographic discharge of adults. While the benign character of BEVs has been well characterized in the healthy population, it has been scarcely considered whether BEVs may hold a different significance in the critical care setting. Methods: Two case reports and a literature search. Results: Patient 1 presented with status epilepticus as three generalized tonic-clonic seizures, severe electrolyte derangements, metabolic acidosis (pH 6.87), and bizarre behavior. EEG demonstrated near-continuous generalized PSW complexes (figure 1A). NCSE was diagnosed after Phenytoin therapy normalized the EEG and completely resolved abnormal behavior. Patient 2 presented with fluctuating level of consciousness, acute psychosis, and multiple small ischemic strokes due to septic emboli secondary to MRSA-infective aortic endocarditis. EEG demonstrated frequent bilateral parietal-sagittal PSW (figure 1B).PubMed searches for “benign epileptiform variant” and “phantom spike wave” returned 17 and 15 results respectively; however, searching for “benign epileptiform variant critical care” and “phantom spike wave critical care” returns 0 results. No filters were applied, ensuring a broad scope. Analogous searches for the other known BEVs had similar outcomes. The only “critical care”-containing search to return a result was “subclinical rhythmic electrographic discharge of adults critical care,” which returned a single study assessing the degree of agreement between human interpretation versus computer algorithm interpretation of cEEG data in the ICU. The outcomes of this search were replicated in the EMBASE and Scopus databases; no literature was obtained on BEVs in the critical care setting. Conclusions: Though BEVs are well recognized in healthy patients, these cases indicate that BEVs such as PSWs in the critically ill population may not actually be benign. BEV-like waveforms may hold a different significance in the critical care setting than in the healthy general population, and our literature review demonstrates that this research question has not yet been well- studied. This is an opportunity for future research into the significance of BEVs in the disparate settings of healthy general and ICU patient populations. A united approach to EEG is desired and vital, especially as EEG recording continues to increase in the critically ill population and more EEG readers from different training backgrounds (e.g. centers emphasizing critical care EEG versus epilepsy surgery versus routine outpatient EEG) are confronted with patterns of unknown significance in the ICU, which may very well include BEV-like potentials. Funding: None