Electroencephalographic patterns on continuous video-EEG as predictors of functional outcome in intensive care unit patients

Abstract

Background: Continuous video-electroencephalography (VEEG) has become a fundamental tool in the evaluation of critically ill patients admitted to the intensive care unit (ICU), particularly those with impaired level of consciousness, suspected nonconvulsive seizures, or electrographic status epilepticus. In this context, the identification of patterns such as status epilepticus, interictal epileptiform activity, and findings consistent with diffuse encephalopathy contributes to diagnostic clarification and characterization of cerebral dysfunction severity. These findings reflect distinct pathophysiological mechanisms and varying degrees of neurological impairment and may be associated with significant differences in prognosis and functional recovery, constituting a key element in the management of critically ill patients. Objective: To analyze video-electroencephalographic (VEEG) findings in adult ICU patients and their association with in-hospital functional outcomes. Methods: This was a retrospective observational study including adult patients admitted to the ICU of a tertiary care hospital who were evaluated by the neurology team and underwent VEEG. Data were obtained from institutional records. Demographic characteristics, final electroencephalographic diagnosis, and clinical outcomes were analyzed, including the modified Rankin Scale and in-hospital mortality. VEEG findings were classified into four mutually exclusive categories (status epilepticus, interictal epileptiform activity, encephalopathy, and non-epileptic events/normal examination), and a hierarchical classification criterion was applied when appropriate. Functional outcome was dichotomized as favorable or unfavorable. Associations were assessed using tests for categorical variables in R software. Results: A total of 158 individuals were included in the study. The mean age was 55.8 years; 75 patients (47.4%) were female and 63 (39.9%) were male, while sex data were unavailable for 20 participants (12.7%). VEEG categories were distributed as follows: encephalopathy (62%), interictal epileptiform activity (19%), status epilepticus (4.4%), non-epileptic findings (3.2%), and other/indeterminate (11.4%). Most cases classified as interictal (80.8%), encephalopathy (80.4%), and status epilepticus (57.1%) were associated with unfavorable outcomes. In contrast, a minority of cases in the non-epileptic VEEG category (20%) were associated with unfavorable outcomes. Statistical analysis demonstrated a significant association between VEEG category and functional outcome (p = 0.00893; p < 0.05). Conclusion: VEEG patterns were significantly associated with in-hospital functional outcomes in critically ill patients. Encephalopathy, interictal epileptiform activity, and status epilepticus were predictors of unfavorable prognosis, whereas non-epileptic findings were associated with better outcomes. These findings highlight the prognostic value of VEEG monitoring in the critical care setting.