Abstracts

Summary: Despite the introduction of a large number of new AEDs in recent years, the number of patients with seizures that are refractory to medical therapy has not been significantly reduced. This has prompted renewed interest in studies of therapy with neurostimulation. Neurostimulation for the treatment of epilepsy has the benefits of no drug related side effects and mechanisms of action presumed to be distinct from antiepileptic drugs, although the actual mechanisms of action are not established. Following the approval in 1997 of vagus nerve stimulation for adjunctive treatment of partial seizures, more recent trials have targeted intracranial sites. Two pivotal multicenter trials have recently been completed and submitted to the FDA for review. One trial employs programmed stimulation of the anterior thalamus. The other trial utilizes responsive stimulation where intracranial electrodes placed near the seizure focus are programmed to detect seizure activity early and to deliver a stimulus to hopefully disrupt or terminate the seizure. Both trials have demonstrated significant efficacy during the early double blind periods. Unlike antiepileptic drug trials where dose and side effects are the important and definable criteria, neurostimulation, whether programmed or responsive, involves parameters that are much less easily established. Stimulus frequency, intensity, and proximity to the seizure focus are just some of these considerations. In addition, optimization of the benefits of neurostimulation appears to occur only after a period of time, suggesting that some type of neuromodulation may play a role. This symposium will focus on the principles of neurostimulation, the different types of therapy, the results of the clinical trials, and the questions that remain for the optimal application of these novel therapies.