Association of Periodic and Rhythmic Electroencephalographic Patterns With Seizures in Critically Ill Patients

Abstract

for the Critical Care EEG Monitoring Research Consortium IMPORTANCE Periodic and rhythmic electroencephalographic patterns have been associated with risk of seizures in critically ill patients. However, specific features that confer higher seizure risk remain unclear.OBJECTIVE To analyze the association of distinct characteristics of periodic and rhythmic patterns with seizures. DESIGN, SETTING, AND PARTICIPANTSWe reviewed electroencephalographic recordings from 4772 critically ill adults in 3 academic medical centers from February 2013 to September 2015 and performed a multivariate analysis to determine features associated with seizures. INTERVENTIONS Continuous electroencephalography.MAIN OUTCOMES AND MEASURES Association of periodic and rhythmic patterns and specific characteristics, such as pattern frequency (hertz), Plus modifier, prevalence, and stimulation-induced patterns, and the risk for seizures. RESULTSOf the 4772 patients included in our study, 2868 were men and 1904 were women. Lateralized periodic discharges (LPDs) had the highest association with seizures regardless of frequency and the association was greater when the Plus modifier was present (58%; odds ratio [OR], 2.00, P < .001). Generalized periodic discharges (GPDs) and lateralized rhythmic delta activity (LRDA) were associated with seizures in a frequency-dependent manner (1.

Effect of epileptiform abnormality burden on neurologic outcome and antiepileptic drug management after subarachnoid hemorrhage

“…In conclusion, going beyond previous studies that show a higher burden of high frequency periodic discharges and lateralized rhythmic delta activity are associated with seizures, we find that these patients are also more likely to have worse outcomes (Ruiz et al ., 2017). Yet we find no evidence of a clear benefit of broad unstandardized AED treatment.…”

Time‐dependent risk of seizures in critically ill patients on continuous electroencephalogram

“…The EEG factors used to define the “EEG risk state” were selected a priori based on large cohort studies showing an association of these factors with seizures. 1,20,21,26 Their association was confirmed in the study dataset using chi-square or Fisher exact test and time-dependent survival analysis to ensure time dependency did not affect the results. The EEG factors were combined into a single factor to simplify the prediction model and increase the effect size.…”

“…Different EEG patterns portend a variable risk of seizures, which is largest for BIRDs and LPDs and smallest for sporadic epileptiform discharges. 1,20,21,26 Further studies, necessarily of larger size, should attempt to refine this initial model by stratifying the EEG risk state to provide more precise prediction for each category of EEG pattern. Accounting for other features of abnormal EEG patterns may be important as well, such as prevalence (eg, occasional vs frequent vs abundant) or frequency.…”

“…Accounting for other features of abnormal EEG patterns may be important as well, such as prevalence (eg, occasional vs frequent vs abundant) or frequency. 26 Coma was defined as a lack of purposeful response to noxious stimulation. This differs from previous studies that have defined coma on the basis of the clinical scores, mainly the Glasgow Coma Scale (GCS).…”

Population of the ictal-interictal zone: The significance of periodic and rhythmic activity

“…However, the largest series of patients on cEEG monitoring found no increased association of seizures in patients with stimulus-induced compared to spontaneous patterns (Rodriguez Ruiz et al, 2016). When present, focal seizure onset locations often have no relation to the location of focal SIRPIDs (Hirsch et al, 2004).…”