Continuous vs Routine EEGs Improve Seizure Detection But Not Outcomes

Compared to routine EEG, continuous EEG increased seizure detection and guided antiseizure treatment, but was not associated with improved outcomes.

Compared to repeated routine electroencephalogram (rEEG), continuous EEG (cEEG) increased the rate of seizure detection and guided antiseizure treatment in critically ill adults with impaired consciousness and no recent seizure; however, it was not associated with improved mortality outcomes, according to study results published in JAMA Neurology.

Study researchers sought to determine if cEEG was associated with less mortality than rEEG. A total of 364 critically ill patients (mean age, 63 years) with no recent seizure or status epilepticus were enrolled in the pragmatic multicenter randomized trial. The study was conducted at 4 tertiary hospitals in Switzerland. All patients had either cerebral conditions, such as brain trauma, cardiac arrest, hemorrhage, or stroke, or were admitted due to noncerebral conditions. An EEG was requested for each patient. Patients were randomly assigned to receive either cEEG for 30 to 48 hours (n= 185) or 2 rEEGs for 20 minutes each (n=183). The primary outcome was mortality at 6 months. Additional outcomes were the detection of interictal and ictal features and changes in antiseizure therapy.

There was no significant difference at 6 months between patients who received cEEG vs rEEG, with respect to mortality (adjusted relative risk [RR], 1.02; 95% CI, 0.83-1.26; P =.85). However, the use of cEEG correlated with improved detection of interictal features (RR, 1.24; 95% CI, 1.06-1.46; P =.009) and seizures (RR, 3.59; 95% CI, 1.68-7.64; P =.001). In addition, patients who received cEEG had more frequent changes to their antiseizure therapy within 60 hours after the start of the EEG intervention (RR, 1.84; 95% CI, 1.12-3.00; P =.01).

Limitations of the study included the relatively small sample size and the exclusion of patients who had seizures immediately before enrollment. Other limitations included the underpowered analysis of additional outcomes and the potential selection bias because of the lack of screening of potential candidates.

Based on these findings, the investigators suggested that “repeated rEEG may represent a reasonable alternative to cEEG, at least in centers with limited resources.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Rossetti AO, Schindler K, Sutter R, et al. Continuous vs routine electroencephalogram in critically ill adults with altered consciousness and no recent seizure: A multicenter randomized clinical trial. JAMA Neurol. Published online July 27, 2020. doi:10.1001/jamaneurol.2020.2264