WASHINGTON (AP) -- The former shipbuilder had such severe
depression, unrelieved by any of today's therapies, that he had
trouble even leaving the house. Then doctors implanted a
pacemaker-like device to stimulate a part of his brain thought
important for mood -- and that very day the man laughed.
"It was remarkable," recalled Dr. Mark George of the Medical
University of South Carolina, who performed the experimental
implant. "I said, 'Are you being forced to laugh or do you feel
good inside?' He said both."
Stimulating a nerve that runs from the neck into one of the
brain's most mysterious regions appears promising enough at
relieving once-untreatable depression that the government has
granted permission for a study at 15 U.S. hospitals.
The treatment, called vagus nerve stimulation, involves sending
tiny electric shocks into the vagus nerve in the neck which then
relays the messages deep into the brain.
About half of the 30 depressed patients treated in a pilot study
-- people who had failed every other treatment -- "got a very good
response," George said in an interview.
The results are not definitive, he cautioned. But he added,
"Stimulating there really is a wonderful portal into the base of
Indeed, scientists think stimulating this nerve could have even
more far-reaching effects, such as enhancing memory or treating
obesity by curbing appetite.
That's because the vagus nerve is what Dr. Mitchell Roslin of
Brooklyn's Maimonedes Medical Center calls "one of the information
superhighways" between the brain and other organs. It relays
messages, such as signals to regulate heartbeat, and sends messages
back to the brain, such as when the stomach is full.
The nerve also reaches deep into regions of the brain thought to
regulate mood and emotion, said Dr. John Rush of the University of
Texas Southwestern Medical Center, who heads the depression study.
If the implant truly signals the depressed brain circuits to act
more normally, it could prove important for some of the estimated 1
million Americans with depression uneased by conventional therapy.
The stimulator is essentially a brain pacemaker. A generator the
size of a pocket watch is implanted into the chest with wires
snaking up the neck that zap the nerve every few minutes.
Two years ago, the Food and Drug Administration approved the
implant to treat severe epilepsy.
Soon after the implants began selling, doctors began reporting
epilepsy patients who felt happier even if the implant failed to
reduce their seizures.
"There's certainly an overlap between emotions and the site
where people have intractable seizures," said Dr. Cynthia Harden
of Cornell University, author of one of those early studies.
So manufacturer Cyberonics Inc. funded a pilot study of patients
with untreatable depression not complicated by epilepsy. Full
results won't be unveiled until December, but George said about
half the patients responded well -- prompting the FDA last week to
approve a new study to prove it.
The vagus nerve might also:
Because the nerve signals the brain when someone's stomach is
full, Roslin implanted Cyberonics stimulators in dogs to see they
suppressed appetite. For a week, the dogs continued to gulp
whatever food was in sight. But gradually their appetite dropped,
until eventually they left half their food uneaten each day and
lost one-third of their weight. Then Roslin switched off the
stimulators, and within five days the dogs' appetite and weight
Roslin hopes to begin an implant study in obese New Yorkers
early next year to see if they get the same effect.
--Help stroke or head-injury victims' memory recover.
In a study last year, epilepsy patients scored 36 percent better
at recalling words read just before their vagus nerve was
stimulated. The theory: Emotional hormones seem to stimulate the
vagus nerve to store memories, so maybe the implant could mimic
that effect in injured patients.
These potential treatments require much more research to
determine how to best stimulate the vagus nerve, said George. His
depressed shipbuilder, for instance, was initially overstimulated
into a hyper state associated with manic-depression. Later patients
were better controlled.
But because the implant is so unique -- and can immediately be
switched off if someone suffers a side effect -- scientists are