The Therapeutic Potential of Focal Cooling for Neocortical Epilepsy

The therapy of the focal cortical epilepsies remains unsatisfactory. Close to a third of patients fail to gain adequate control with antiepileptic drugs and a portion of those who do, experience unacceptable side effects. Morever, the favorable response rate after surgical resection, approximately 60%, is not nearly as high as the response rate of complex partial seizures caused by mesial temporal sclerosis. The suppressive effect of cooling on neuronal activity has been recognized for over a century. Therefore, we have begun to explore the possible application of cooling as a therapy for focal cortical seizures. In initial brain slice experiments, we found that cooling to 20 degrees C could rapidly terminate paroxysmal activity. Then we developed an in vivo model of focal seizures using a local injection of the convulsant 4-aminopyridine and found that cooling the injected area to less than 24 degrees C with a thermoelectric Peltier device aborted seizures within a few seconds. Other laboratories have independently confirmed our initial observations. More recent experiments from our laboratory have shown that cooling, per se, is not associated with significant cortical damage, even at surface temperatures as low as 5 degrees C. Advances in the fabrication of extremely thin thermoelectric devices, less than a few hundred microns thick, has raised the possibility of incorporating an implantable cooling unit into a closed loop seizure detection and treatment system.