In a recent video posted on Facebook, 1-year-old Jaxon Buell coos and mumbles, "I love you," to his parents.
A typical social media share, except that Jaxon was born with microhydranencephaly, a condition so rare it usually only gets a couple of lines in medical textbooks, experts say. He wasn't predicted to live more than a few days, much less come close to saying "I love you." (The post has over 333,801 views so far.)
But Jaxon's case isn't only generating social media support; Jaxon and the other patients with rare brain disorders give doctors a rare window into how our brains work, experts say.
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"We believe the medical world will also benefit from Jaxon's story, from his rare neurological condition, and from his diagnosis, because we are certainly seeing firsthand how much there is still to learn about the human brain," Jaxon's dad, Brandon Buell, wrote on Facebook.
"Children with these sorts of problems can help us rethink the role of the brain stem and the cortex in consciousness," said Dr. Marc Patterson, Professor of Neurology, Pediatrics and Medical Genetics at the Mayo Clinic in Rochester, Minnesota.
Indeed, Dr. Ganeshwaran H. Mochida, Assistant Professor of pediatrics at Harvard Medical School and a staff physician and principal investigator at the Division of Genetics and Genomics at Boston Children's Hospital, says he's often amazed when he looks at a brain scan and then sees kids who are outperforming his expectations.
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"Learning from each child is extremely important and hopefully as we understand more about the molecular and genetic basis of brain development and function, we will be able to also care better for these children and present accurate information to the families," he said, adding that he hasn't personally seen Jaxon.
Microhydranencephaly is a combination of two conditions, microcephaly, or small skull, and hydranencephaly, in which the skull is filled with spinal fluid instead of the cerebral hemispheres. Jaxon's ability to talk, then, may shed some light on the role of the brain stem versus the cerebral cortex.
Since Jaxon's small skull is filled with spinal fluid, he relies on his brain stem, which is responsible for basic functions such as sleep/wake cycles, breathing, and circulation, to function. The cerebral cortex is generally thought to be responsible for content. How, then, does Jaxon say, "Mommy" and "Daddy"?
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It could be that more happens in the brain stem than was thought, or that the brain is better able to adapt than previously believed.
Especially in children, the brain can be surprisingly "plastic," or flexible.
"Even in a young child, if a part of the brain is damaged, sometimes the other parts can take over better than in the case of older children or adults," Mochida said.
Either way, says Patterson, who has seen a half dozen or so similar cases in his career, it's important to keep these rare cases in mind when doctors encounter patients with severe traumatic brain damage.
"It emphasizes the fact that we need to be cautious in categorizing patients as minimally conscious versus in a vegetative state," he said. "There's an assumption that if there's no cortex there's no consciousness, but that's not necessarily true."
He points to a survey given to about 100 families who had experience with hydroencephaly. Most parents said they thought their children were aware of their surroundings. It raises key questions, Patterson said: "What is consciousness, and what neural structures do you need to support consciousness?"
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There are far more questions than answers, but Jaxon's parents hope that their son may be able to help answer a few.
"We plan to work with the top infant neurological teams in the country, if not the world, for all of these benefits, and we keep our focus as broad as we possibly can so that Jaxon's story does not end with Jaxon, but so that he will truly leave behind a legacy because of who he is, what he goes through, and for the fight that he wakes up and keeps fighting every day," Brandon Buell wrote.