Implantable devices for epilepsy: a clinical perspective

25% of the world\´s 50 million people with epilepsy have seizures that cannot be controlled by medication or epilepsy surgery. The need for new therapeutic options is clear. Since the 1970\´s clinicians, neuroscientists and engineers have proposed technologies for treating seizures, with the ultimate goal of implanting stimulators or drug infusion devices in brain to abort seizures before clinical onset. Interest in the field has exploded in recent years, due to evidence suggesting that seizures may be predictable. Device designs range from "blind" stimulators, which do not respond to physiological activity, to "intelligent" devices, which are triggered by detecting or predicting seizure onset. To gain acceptance, intracranial implants will need to demonstrate more than marginal efficacy to justify their invasiveness. Unlike their cardiology predecessors, intelligent implantable epilepsy devices will likely process multiple channels of data, be tuned to individual patients and may need to predict events rather than detect them, for maximal effectiveness. Carefully designed clinical trials will be required to perfect and validate the efficacy of implantable devices for epilepsy, before clinical use becomes widespread.