Deep brain stimulation, a treatment involving the application of electrical currents to specific areas of the brain through implanted electrodes, may be helpful in treating epilepsy(てんかん). In a recent study, 110 people who suffered from regular epileptic seizures and had failed to respond to drug treatment had electrodes implanted in their brains. After 13 months, 41 percent showed a reduction in seizures. Fifty-six percent experienced a reduction after two years. It is estimated that of the 50 million people worldwide with epilepsy, about one third do not respond to antiepileptic drugs.