Effect of Propofol on Interictal Epileptiform Activity

Abstract

In Response: As Meyer et al. (1) indicate, our study (2) was not designed to determine whether anesthesia increases or decreases detection of interictal epileptiform discharges because our patients only had magnetoencephalography (MEG) recordings performed during anesthesia. Rather we wanted to determine whether anesthesia changed the proportion of MEG studies with successful detection of interictal epileptiform discharges when compared with MEG studies performed on nonsedated patients. As we indicated in the discussion, the best way to determine the effects of anesthesia would be to do two studies on the same patient, one study with anesthesia and one without. As the patient population we studied under anesthesia was chosen solely because they were unable to lie still, we compared these patients recorded under anesthesia to a larger population of nonsedated patients with epilepsy of all ages as well as a subgroup of children with epilepsy and found that the results in each group were similar. We found successful detection of interictal epileptiform activity in 71% of the patients who received general anesthesia compared to 80% success where no anesthesia was used. We concur that future studies of anesthesia effects on MEG or electroencephalogram recordings should document brain activity patterns relative to induction, maintenance, or withdrawal of the anesthetic agent(s). It is well known that the abrupt withdrawal of anticonvulsant drugs increases seizures and spiking rates. This is the basis of the methohexital suppression test, which occasionally is used as a diagnostic test in the evaluation of patients for epilepsy surgery. We would also like to thank Meyer et al. for drawing our attention to a typographic error in the dosing of propofol in our article. On page 1494, the dose of propofol should read 50–150 μg · kg−1 · min−1. We apologize for not noticing this earlier. Guruswamy Balakrishnan, MD Department of Anesthesiology Henry Ford Medical Group Detroit, Michigan Kavita M. Grover, MD Karen Mason, BS T Department of Neurology Henry Ford Medical Group Detroit, Michigan Brien Smith, MD Gregory L. Barkley, MD Susan M. Bowyer, PhD Department of Neurology Henry Ford Medical Group Detroit, Michigan Department of Neurology Wayne State University Detroit, Michigan [email protected] Norman Tepley, PhD Department of Neurology Henry Ford Medical Group Detroit, Michigan Department of Physics Oakland University Rochester, Michigan