Abstracts

Dexmedetomidine, a selective [alpha][sub]2[/sub]-agonist, exerts anesthetic and analgesic effects without suppressing respiratory function. It has been reported to lower the seizure threshold in animals but this effect has not been noted in humans. To determine its potential utility for epilepsy surgery, we studied this agent[apos]s effect on epileptiform activity in patients with refractory epilepsy. An anesthesiologist administered dexmedetomidine intravenously over the course of one hour to five patients undergoing inpatient video/EEG monitoring. EEG was recorded for at least 15 minutes prior to the infusion and for at least one hour after the infusion was stopped. EEG was reviewed by a board certified clinical neurophysiologist. Epileptiform discharges and bursts of epileptiform discharges were counted for 15 one-minute epochs prior to the infusion and after the infusion. Comparison of spiking rates before and after the infusion was performed for each patient using two-tailed student t tests. The spiking rate was not significantly changed in two patients. The spiking rate was at least modestly increased in three patients. Two patients with increased spiking also had an increase in the frequency of bursts of spikes and subclinical, electrographic seizures. One of the patients that did not have an increase in spiking had a typical, clinical seizure 30 minutes after the infusion ceased. Localization of all epileptiform discharges during the infusion was identical to the pre-infusion localization. Dexmedetomidine does not suppress epileptiform activity. It seems to modestly enhance epileptiform activity in some patients. These findings suggest that it may be a useful anesthetic agent during seizure surgery.