Patients in the study had electrodes implanted in their brains
Deep brain stimulation is a promising therapy for epilepsy, US researchers from Stanford University have said.
In a clinical trial, 110 people had electrodes implanted in their brains and their seizures were monitored.
Forty-one per cent of patients showed a reduction in seizures after 13 months while 56% experienced a reduction after two years.
The patients all suffered from regular epileptic seizures and had failed to respond to drug treatment.
Deep brain stimulation (DBS) is a surgical treatment involving the implantation of a medical device called a brain pacemaker, which sends electrical impulses to specific parts of the brain.
In the group of patients who received brain stimulation, researchers noted a 41% reduction in seizures compared to a 14.5% decline in seizures in a control group. This group did not receive stimulation.
Epilepsy is a common neurological disorder which is characterised by recurrent seizures. These seizures can cause temporary loss of consciousness, convulsions, confusion or disturbances in sensations.
According to the World Health Organization, epilepsy affects 50 million people worldwide.
Previous studies indicate that one third of those with epilepsy do not respond to anti-epileptic drugs.
Dr Robert Fisher, director of the Epilepsy Centre at Stanford University and lead author of the study, said electrical deep brain stimulation does reduce seizure frequency in patients.
But he cautioned: "DBS therapy is invasive and serious complications can occur. Additional clinical knowledge would help to determine the best candidates for DBS therapy."
Simon Wigglesworth, deputy chief executive at UK charity Epilepsy Action, said: "We have been hopeful for some time that deep brain stimulation may be a treatment option for some people with epilepsy.
"This study is exciting news and could be an important development in the treatment of epilepsy in the 30% of people whose seizures don't respond to traditional drug therapies."
The research is published online in the journal Epilepsia.