Effect of rapid EEG on anti-seizure medication usage

To study how early diagnoses from rapid EEG (rEEG) during the initial evaluation of patients with suspected non-convulsive seizures correlates with changes in anti-seizure medication (ASM) use.

We performed a retrospective chart review of 100 consecutive adult patients at an academic medical center who underwent rEEG monitoring for suspected non-convulsive seizures. We collected information on the timing of ASM administration and categorized EEG diagnoses as seizures (SZ), highly epileptiform patterns (HEP), or normal or slow activity (NL/SL). We used a χ² test to determine whether the use of ASMs was significantly different between SZ/HEP and NL/SL cases.

Of 100 patients, SZ were found in 5%, HEP in 14%, and no epileptiform/ictal activity in 81%. Forty-six percent of patients had received ASM(s) before rEEG. While 84% of HEP/SZ cases were started or continued on ASMs, only 51% of NL/SL cases were started or continued on ASMs after rEEG (χ² [1, n=100] = 7.09, p=0.008). Thirty-seven patients had received sedation (i.e., propofol or dexmedetomidine) prior to rEEG. In 15 patients (13/30 NL/SL, 2/7 HEP/SZ), sedation was discontinued following rEEG.

Our study demonstrates that seizures were rapidly ruled out with rEEG in 81% of patients while 19% of patients were rapidly identified as having seizures or being at higher risk for seizures. The rapid evaluation of patients correlated with a significant reduction in ASM treatment in NL/SL cases compared to HEP/SZ cases. Thus, early access to EEG information may lead to more informed and targeted management of patients suspected to have nonconvulsive seizures.