A technique called cortical brain stimulation improved symptoms and, in some cases, launched a full remission for people with major depression who had suffered for decades and who had failed multiple other treatments, researchers report.
"On average, these individuals had had depression for 27 years and had failed about 10 medication trials," said Dr Emad Eskandar, lead author of a study presented this week at the annual meeting of the American Association of Neurological Surgeons (AANS), in San Diego.
"Their current depressive episode had lasted an average of six years or longer. These were very, very sick people who were out of options."
Cortical stimulation, which involves placing electrodes near the surface of the brain (i.e. outside the lining of the brain but not actually in the brain), is potentially much less invasive than other therapies currently available.
Brain stimulation tools promising
Placement of the electrodes, which emit tiny, adjustable, electrical pulses that block dysfunctional activity in the brain, is done with minimally invasive surgery. Brain stimulation tools may be emerging as the next wave of treatments for depression and other brain-related disorders, experts say.
In April, other researchers reported that deep brain stimulation - where electrodes are inserted into specific brain areas - cut symptoms of otherwise intractable depression by 50% for about half of those treated. The technique has also been successful in treating some cases of obsessive-compulsive disorder.
"Deep brain stimulation has been known to us. The first treatment for Parkinson's was done in 1987, and now it's gaining acceptance and more widespread use in psychiatry," said Dr Vladan Novakovic, a psychiatrist with Maimonides Medical Centre in New York City.
"This is an emerging area of therapeutic neuromodulation. The brain is an electrical organ. There is a role for both chemical and electrical interventions in the treatment of brain-based disorders."
How the trial was done
About one-fifth of people suffering from depression get no relief from psychotherapy and/or medication. About 70% of these "non-responders" can, however, benefit from electroconvulsive therapy. But many of these will later relapse, and there's still the group of individuals who fail all treatments.
For this trial, a dozen patients with refractory depression were randomly assigned to receive eight weeks of cortical stimulation of the left dorsolateral prefrontal cortex (DLPFC) area of the brain, which appears to play a role in depression, or to get "sham" stimulation. Those receiving the sham treatment were then switched over to active therapy.
Stimulation was delivered via an investigational epidural cortical stimulation system, developed by Northstar Neuroscience, which funded the study. One of the authors is a consultant to the company.
On average, participants experienced an improvement of about 25 -30% on different measures of both depression and quality of life. Three people went into complete remission.
"That may not sound like a lot, but to get any response at all in an otherwise extremely refractory group is extremely promising. This is a potentially less invasive therapy," said Eskandar, who is an attending neurosurgeon at Massachusetts General Hospital and associate professor of neurosurgery at Harvard Medical School, both in Boston.
Larger trial planned
"We also learned that improving the electrode position and giving more current got better effects, so, in the future, we have a pretty good idea of how to improve on this."
The group is now organising a larger trial to study the potential of the method.
A second study also being presented at AANS found that a type of deep brain stimulation known as globus pallidus internus (GPi) deep brain stimulation was effective in relieving symptoms of primary dystonia in children.
People with this movement disorder suffer from disabling involuntary muscle contractions, explained researchers led by Dr Jan Mehrkens of Ludwig-Maximilians University in Munich, Germany.
According to the authors, GPi deep brain stimulation has been shown to be effective in adults, but there is little research in children, even though the condition often begins at a young age.
Brain stimulation 'safe' on brain
For this study, researchers implanted electrodes in five patients aged 16 or younger who had not responded to other treatments for primary dystonia.
"Significant" improvements were seen for over a year, with all children being able to go back to school, said the authors, two of whom had received speaker's fees from medical device maker Medtronic.
"The advantage of deep brain stimulation over the earlier surgeries is you don't have to destroy any part of the brain. You're essentially turning off the overly active part of the brain and letting the healthy parts of the brain take over," said Dr Alain de Lotbiniere, medical director of the Northern Westchester Hospital Cancer Treatment and Wellness Centre, and a practising neurosurgeon who has performed several deep brain stimulation procedures.
"It's a very exciting area because, up to now, everyone's heard of deep brain stimulation for Parkinson's and for essential tremor, but these are additional areas that border neurology and psychiatry where we're just beginning to understand what happens in terms of the brain chemistry and the brain electricity," he continued.
"We're just at the beginning of understanding this. There's a lot of hope there for patients who otherwise may have felt that there was nothing they could do." – (HealthDay News, May 2009)
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