Brain
Implant Relieves Depression
Four of six severely depressed patients who
underwent deep brain stimulation, which involves surgically implanting
electrodes in a targeted area of the brain thought to be involved in
depression, experienced a "striking and sustained" let-up in their
depression, investigators report in the medical journal Neuron.
The six patients had been suffering with
depression for between 1.5 to 10 years, despite treatment with antidepressant
medications, psychotherapy and electroconvulsive therapy, according to the
team.
When the electrodes were "turned on"
patients reported effects such as sudden calmness, heightened awareness and
increased interest. They also exhibited increased motor speed and higher rates
of spontaneous speech.
After 2 months of continuous electrical
stimulation, five of the six patients exhibited decreases in their Hamilton
Depression scores of at least 50 percent. At 6 months, four continued to have
an antidepressant response.
Other improvements included increased energy, interest, and psychomotor speed, decreased apathy and improved ability to initiate and complete tasks.
Living a Nightmare
Debbie (not her real name) is
typical of the patients in the study. Her third bout of depression had lasted
eight years when she decided to have the experimental surgery a year and a half
ago.
Her dark moods left her suicidal
and unable to function. While antidepressant drugs work for most people with
depression, they did nothing to lift Debbie's depression. She says the only
thing electroconvulsive "shock" therapy did was wipe out a big part
of her memory.
"I was to the point where I
wasn't really planning on living this nightmare too much longer," the
47-year-old Canadian says. "I had been hospitalized repeatedly because I
was a danger to myself. I would have tried anything."
Deep brain stimulation targeted an
area of Debbie's brain known as the subgenual cingulate region, or Cg25. In
earlier research, Helen Mayberg, MD, showed that Cg25 is overactive in people
with treatment-resistant depression.
In collaboration with Andres Lozano,
MD, who is a leading expert on deep-brain stimulation, Mayberg and colleagues
theorized that sustained electrical jolts could normalize the targeted region
and make the entire brain behave more normally.
How It's
Done
Two holes, the size of nickels,
were drilled into the skulls of the patients who remained awake. The area of
the surgery was numbed with anesthetic. Using magnetic imaging to guide them,
surgeons then implanted two thin wires with electrode contacts near the Cg25
area of the patients' brains. The loose end of the wires were then threaded
under the skin and attached to the pacemaker device, which was implanted in the
chest.
All six of the patients reported
improvement soon after the surgery. Two of the six became depressed again
within six months.
The four other patients had few
depression symptoms six months after surgery, and all still have the implants.
Imaging studies revealed brain changes consistent with a return to normal Cg25
activity. These changes have also been seen in depressed patients who respond
well to drug treatment.
Mayberg says the findings could
represent the first step in a paradigm shift in the thinking about depression.
Drug treatments target chemical imbalances within the brain. But the early
research indicates that for some patients successful treatment will require
"rewiring" parts of the brain's circuitry.
"This study tells us that this
strategy has real potential … that our first target [within the brain] looks
like it was a good selection," she says. "It may be that there are
other areas of the brain that are better, but that remains to be
determined."
Return to
One of the big advantages of the
brain pacemaker is that the electrical impulses can be adjusted in patients who
don't respond as hoped. Debbie says it took about a year of tweaking, but she
now feels "perfectly normal" for the first time in almost a decade.
Unable to do much more than stare
out her bedroom window for hours at a time before the surgery, she is now
planning to open her own business.
"Unlike the drugs that have
failed me, I feel like if, God forbid, this stops working they can make
adjustments to get me back on the right track," she says.
All agree that more study is needed
to confirm the findings, and that, as with Parkinson's disease, only the
sickest patients who don't respond to other treatments would be candidates for
the procedure.
"Even brain surgery that is
relatively benign, as this is, is a serious procedure," Mayberg says.
"You don't operate on
someone's brain if there are other reasonable treatment options. But this is
also a serious disease that leaves people morbidly sick for long periods of
time. When you see these people living normal lives the way other people do, it
is both sobering and humbling," she explains.
SOURCES: Mayberg, H. Neuron,
March 3, 2005; vol 45: pp 1-10. Helen S. Mayberg, MD,
formerly, The Rotman Research Institute at Baycrest Center for Geriatric Care, Toronto Western
Hospital; currently, Emory University School of Medicine, Atlanta. Andres M. Loranzo, MD, surgeon,
