BACKGROUND AND OBJECTIVES: EEG reactivity (EEG-R) is currently classified as present, absent, or stimulus-induced rhythmic, periodic, or ictal discharges, per the American Clinical Neurophysiology Society's 2021 Critical Care EEG Terminology. However, our previous study suggested that there may be other forms of EEG-R that warrant distinction, potentially associated with different comorbidities and outcomes. We, therefore, aimed to define "typical" vs "atypical" EEG-R, referring to increased power of arrhythmic alpha/beta frequencies vs delta frequencies after stimulation, respectively, and to identify their associated comorbidities and outcomes. METHODS: This was a retrospective single-center study, examining adult patients admitted between 2015 and 2022, who underwent continuous EEG (cEEG) as standard-of-care work-up for their illnesses. Univariate testing and logistic regression were performed. The primary patient outcome at hospital discharge was categorized by the modified Rankin Scale (0-2: good; 3-6: poor). The primary independent variable was the presence of typical vs atypical EEG-R. Additional covariates included age, presence of critical illness, and acute intracranial and nonintracranial pathologies. RESULTS: < 0.0001). DISCUSSION: Granular, frequency-based assessments of EEG-R, such as the differentiation between typical vs atypical EEG-R, may provide further insight into the potential outcomes of patients with altered states of consciousness. Limitations of this study include the single-center retrospective nature.
Hwang et al. (Mon,) studied this question.