Quantitative EEG During Critical Illness Correlates with Patterns of Long-Term Cognitive Impairment.

OBJECTIVE: Many intensive care unit (ICU) survivors suffer disabling long-term cognitive impairment (LTCI) after critical illness. We compared EEG characteristics during critical illness with patients' 1-year neuropsychological outcomes. METHODS: We performed a post hoc analysis of patients in the BRAIN-ICU study who had undergone EEG for clinical purposes during admission (n = 10). All survivors underwent formal cognitive assessments at 12-month follow-up. We evaluated EEGs by conventional visual inspection and computed 10 quantitative features. We explored associations between EEG and patterns of LTCI using Wilcoxon rank-sum tests and Spearman's rank correlations. RESULTS: Of 521 Vanderbilt patients enrolled in the parent study, 24 had EEG recordings during admission. Ten survivors had EEG tracings available and completed follow-up cognitive testing. All but one inpatient EEG showed generalized background slowing. All patients demonstrated cognitive impairment in at least one domain at follow-up. The most common deficits occurred in delayed memory (DM-median index 62) and visuospatial/constructional (VC-median index 69) domains. Relative alpha power correlated with VC score (ρ = 0.78, P = .008). Peak interhemispheric coherence correlated negatively with DM (ρ = -0.81, P = .018). CONCLUSIONS: Quantitative EEG features during critical illness correlated with domain-specific cognitive performance in our small cohort of ICU survivors. Further study in larger prospective cohorts is required to determine whether these relationships hold. SIGNIFICANCE: EEG may serve as a prognostic biomarker predicting patterns of long-term cognitive impairment.

Effect of sleep patterns on levetiracetam induced mood changes.

A common side effect of levetiracetam is the onset of neuropsychiatric symptoms such as mood changes including depression, anxiety, agitation, and sometimes psychosis. We performed a retrospective analysis to examine the effect of sleep pattern and chronotype on individual susceptibility to levetiracetam-induced mood changes. We reviewed records of 110 adults with epilepsy presenting to our clinic during a 3-month period, and categorized them into those currently on levetiracetam, and those no longer taking it because of mood-related adverse effects. Patients were administered Morningness-Eveningness Questionnaire (MEQ), Beck's Depression Inventory-II, and Neurological Disorders Depression Inventory in Epilepsy. Using various statistical methods, we analyzed the comparison of these 3 different scales amongst one another and between those subjects who tolerated levetiracetam and those who did not. Of 110 patients, 74 (67%) tolerated levetiracetam and 36 (33%) did not tolerate it because of mood changes with chronotype being a significant determining factor. Of those who tolerated the drug, 62% were intermediate chronotypes and 20.3% and 17.6% were morning and evening chronotypes, respectively. For those intolerant, 86.1% were morning chronotypes, 13.9% were intermediate chronotypes, and none were evening chronotypes (p<0.001). Thirty-two percent of morning chronotypes, 100% of evening chronotypes, and 90.2% of intermediate chronotypes were tolerant of levetiracetam (p<0.001). Chronotype significantly affected toleration of levetiracetam. Chronotype, but not depression, was a significant factor in determining tolerability of mood-altering side effects of levetiracetam, via statistically significant trend for an increasing ability to tolerate levetiracetam as chronotype would shift from morning to intermediate to evening. Additional research may help establish if this is related to possible underreporting of poor mood with evening chronotypes, and morning chronotypes having more stringent sleep schedules, genetic factors, or other reasons.