Keagan always loved taking the school bus. He asked his father one day whether he could walk to the bus stop on his own. His parents would normally accompany him to the corner because of his seizures.
Moments after Keagan took off on his own, the phone rang: It was the school's transportation department. Keagan had seized and collapsed before getting on the bus.
"I had no clues what was going on," Chris Dysart said. "I tried to wake my son up, and he's not responding, I mean, not responding in the least bit. At that point, I was like, 'We've got to do something.'"
For years, little could be done to stop the laughing seizures, short of an invasive craniotomy. Fraught with danger, the brain is separated, carved open and the lesion, deep in the brain's center, cut out. The risks are every parent's nightmare: a possible loss of sight, uncontrollable urination, stroke and even death if the kidneys shut down.
"And that's what led us to want to explore new technologies to be able to get to these deep centers in the brain, without having to do traditional surgery," said Dr. Angus Wilfong, the medical director at the Comprehensive Epilepsy Program at Texas Children's Hospital in Houston.
Now there is hope. For the first time, in an experimental pilot program at Texas Children's Hospital, doctors are using real time MRI-guided lasers to destroy lesions that cause laughing seizures in epilepsy patients like Mateo and Keagan.
"So the new techniques, this MRI-guided laser ablation have increased our accuracy and our safety and our worry factor," said neurosurgeon Dr. Daniel Curry, who, along with Wilfong, is behind this potential breakthrough.
It's a journey to the center of the brain. With MRI imaging guiding their every move, doctors drill a small hole the size of a pencil into the child's skull inserting a laser probe and then guide it to the lesion. The lesion is destroyed in a matter of seconds and a lifetime of misery and suffering averted.
This Friday, "20/20's" cameras take you inside this amazing new surgery. "It's curing epilepsy at the speed of light. So, it really is a new world," Wilfong of Texas Children's Hospital said.
Keagan and Mateo underwent the surgery -- Keagan last year at age 8 and Mateo earlier this year at age 7. Today, both boys are seizure free, filled with real laughter, the kind parents don't want to stop.
"Robin and I were in the kitchen and then we hear this laughter," Chris Dysart remembered shortly after Keagan had the laser ablation surgery. "And Robin and I just kind of tensed up and froze. And we walk around into the living room, and he was laughing, like really laughing, at the TV show, and at appropriate times.
"And I think Robin and I just sat there in tears for about five, 10 minutes, because this was the first time we'd heard him laugh. And he wasn't having a seizure."
For more information: