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Pacemaker-like device used to treat eating disorder
by Bill Catlin, Minnesota Public Radio
March 9, 2005

Chris North says she hasn't had an episode of bingeing and vomiting since shortly after receiving a device that stimulates a key nerve in her neck. (Photo courtesy of Chris North)

University of Minnesota researchers are reporting initial success treating severe cases of an eating disorder with an approach generally associated with treating heart problems. The study is using a pacemaker-like device to treat bulimia. Bulimia typically involves binge eating followed by self-induced vomiting or other methods to prevent weight gain. One woman says the device has lifted an enormous burden from her life.

St. Paul, Minn. — Chris North, a professor of communication in North Dakota, battled bulimia for about half her 39 years. She's been through three different treatment programs, taken anti-depressants, and had years of therapy. Nothing brought her eating disorder under control for any sustained period of time.

"I was probably throwing up anywhere from $500 to $800 worth of food a month," says North.

She says the bingeing and purging was a coping mechanism, a way to deal with stress. But it ruled her life, even when money was tight.

"I would go to the plasma center, and I would donate plasma. I would get my $20 check. I would go straight to the grocery store, cash that $20 check at the grocery store to get food to go home and binge," says North. "And I felt every bit as out of control as a coke addict or a heroin addict looking for their next fix."

In a typical binge, North says she might eat a large package of Twizzlers candy, a box of macaroni and cheese, and a dozen doughnuts. She says the powerful urge to binge could hijack her grocery shopping, and leave her with nothing but a bunch of binge food.

"Whenever I would walk past the doughnuts it's like, 'Oh man, I need some of that!'" North describes a "constant mental dialog and battle. Sometimes I could get out of the grocery store at that moment without them. I'd usually go back," she says.

Researchers at the University of Minnesota contend that what starts as a mostly psychological problem can become an almost purely physiological problem in severe cases like North's. The theory is that repeated bingeing and vomiting destabilizes the vagus nerve, a key neural pathway from the stomach to the brain.

U of M psychiatry professor Patricia Faris says activity in the damaged nerve cycles up and down. She says surging activity in the vagus nerve corresponds to the urge to binge and vomit. Faris says North and five other women have received an implanted device that delivers electrical pulses to the vagus nerve in the neck.

"The analogy here would be to a cardiac pacemaker, where the electrical activity of the heart would be irregular. And by applying very regular bursts of stimulation to the heart, you can normalize the electrical activity," says Faris. "We're using the vagal nerve stimulator as a pacemaker, to normalize or stabilize activity in the vagus nerve."

So far, Faris says the patients report bingeing and purging have either stopped altogether, or declined by 85 to 90 percent.

The treatment is one example of the expanding use of pacemaker-like devices to treat neurological problems, including epilepsy, depression, chronic pain and Parkinson's disease.

Mid-conversation, Chris North's device cycles on. The electrical pulsing causes a rapid tremolo in her voice, as if someone were tapping her on the back.

That pulsing brings some hoarseness, but also liberation.

Chris North says she hasn't had an episode of bingeing and vomiting since soon after receiving the device in July 2004. Before that, she averaged about two a day.

North remembers the first time she left the grocery store with nothing more than the things on her list. She called a friend.

"I was just giggling, and I said, 'I can't believe it. I just walked into the grocery store and all I bought was this and this, and I just walked out," says North. "I walked by the doughnuts, and they didn't even look appealing. I didn't even want to buy any. It just wasn't even anything. I just looked at them!'"

North says she has gained a little weight since receiving the device. But it hasn't triggered the extreme binge-and-purge behavior it would have in the past. She says that's a testimony to the treatment's effectiveness.