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Exploradio: Retraining the brain to swallow better
From preemies with nerve damage to Alzheimer's patients, swallowing problems can have serious consequences. But brain training can help
This story is part of a special series.

Reporter / Host
Jeff St. Clair
Some babies have trouble swallowing which can lead to serious complications. But a northeast Ohio researcher is developing tools to retrain a baby's swallowing mechanism.
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It’s one of those things that you don’t pay attention to until something goes wrong. Swallowing is a basic human function that can have serious complications for some people, from preemie babies to elderly adults. 

In this week’s Exploradio, WKSU’s Jeff St.Clair meets a researcher at the Northeast Ohio Medical University who’s studying how to retrain the brain to overcome problems with swallowing.

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Nerve damage makes swallowing difficult for preemies
NEOMED researcher Rebecca German shows me an x-ray video of a baby pig drinking milk from a bottle. It’s not going so well.

“See that? That’s liquid entering the airway," she says, pointing to a tiny smudge moving down the front of the pig's throat.

The milk is going down the wrong pipe because this pig has the same condition as many preemies who have undergone heart surgery. German says that about half of those babies suffer damage to a nerve that plays a role in swallowing that can easily be nicked in tiny patients. 

It's a very curvy nerve. The recurrent laryngeal nerve wraps around the heart's aorta and then travels back up to the voice box, where it senses movement associated with sound production.

“It’s not part of the swallowing pathway," says German, "but yet when you damage the nerve, the recurrent laryngeal nerve, you get swallowing problems.”

That’s because the nerves and muscles that do control swallowing get confused by the lack of input from the voice-box nerve.

German says swallowing is coordinated by a separate set of nerves coming from the brain stem, but their signals get garbled by the damaged recurrent laryngeal nerve.

It presents a problem for babies with a damaged recurrent laryngeal nerve, says German, because "the motor signals to all these other parts that are involved in swallowing are messed up.”

Re-teaching the brain to swallow
But German has a plan to overcome that confusion by "re-teaching the brain how to swallow correctly.”

We head in to her lab to look at a machine she’s developed to help retrain babies how to swallow.

She calls it mater mechanica, the mechanical mother. It controls the amount of milk delivered to baby in a rhythmic way, and re-teaches the brain to coordinate the sensory and the motor pathways involved in swallowing.

German is also working on new nipple designs that stimulate the baby’s tongue in ways that can retrain the sensory and motor pathways between the brain-stem and the muscles involved in swallowing.

She plans to perfect the nipple designs in her lab this summer before testing them on actual newborns.

Swallowing hazards in older adults
But it’s not just babies who suffer from dysphagia, or problem swallowing. Forty percent of older adults in nursing homes have swallowing issues, especially people with Alzheimer's, Parkinson's, or who have had a stroke.

German says it’s one of the major contributors to fatal conditions like pneumonia - when liquids that go down the wrong tube and cause infections.

But like the babies with nerve damage, older adults with swallowing problems can be trained to overcome them.

A uniquely human problem
NEOMED researcher Francois Gould works with German to understand how evolution works in swallowing. He says part of the unique problems humans have compared to other animals is our upright stance.

He says "gravity becomes an enemy for humans in a way that it isn’t for four-legged animals.”

Rebecca German says humans choke more than other animals because "we talk.”

Probably like your mother would, she says we choke because we try to talk with our mouth full. And our brains allow this because we’re human.

“Part of the reason we choke to death," says German, "is because the part of the brain that controls speech overrides the part of the brain that does swallowing.”

Evolution gave priority to speech over the basic process of swallowing, but it didn’t make us smart enough to always separate the two.


The videos below show first problem swallowing and then normal swallowing in baby pigs. A small amount of liquid can be seen dripping down the windpipe of the first subject, mirroring the condition in human babies who have suffered nerve damage. Researchers use animals to learn about medical conditions in humans, and test remedies that can later be used in people with physical problems. 


(Click image for larger view.)

Rebecca German is a professor of anatomy and neurobiology at NEOMED. She's developing devices to help babies who have suffered nerve damage relearn effective swallowing.
Post-doc Francois Gould, team leader Rebbeca German, and researcher Jocelyn Ohlemacher use videofluoroscopic x-rays to study swallowing in baby pigs. The team is developing devices to help human babies overcome problems with swallowing.
Researchers need to wear elaborate lead aprons when using the x-ray fluoroscope to guard against damaging radiation. A zebra stripped ensemble is modeled by WKSU's Jeff St.Clair in Dr. Rebecca German's lab.

Related Links & Resources
Swallowing exercises from the National Foundation of Swallowing Disorders

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