"If you can get in there while these kids' brains are still plastic, you can still create [connections]," said Mary Kay Ballasiotes, of Evans, Ga., whose daughter Michelle had a stroke in utero during Ballasiotes' second trimester. "That's what's frustrating, when these babies are being diagnosed at 18 months or two years, you've lost all this time creating these new connections."
Michelle, 11, began occupational therapy at 6 months and continues to work with a therapist. She has not had another stroke since her birth but she does have cerebral palsy and wears an ankle brace to steady her leg muscles.
"Sometimes I wish I didn't have [the disorder] to see what it felt like not to have it, but I will never know any different," Michelle said. "Learning and remembering things is still hard for me and I run slow... I'm probably as good as I can get."
Many parents attribute their children's stroke diagnoses to their own observations which they must then urge doctors to pursue.
"Many times it is more difficult to identify strokes in children because they may not be cognitively developed enough to effectively communicate symptoms related to a stroke," said Dr. Edward Smith, a neurosurgeon at the Children's Hospital in Boston. "This may lead to a missed opportunity to diagnose a stroke."
But parents of children who have had strokes find the community of survivors and their families is larger than they expected, underscoring the UCSF study's findings that pediatric stroke occurs more frequently than expected.
Ballasiotes said she is part of a support group she founded for pediatric stroke survivors of over 80 families in the Chicago area.
Matt McDermott said he learned that several families in his Gardner, Mass., neighborhood had experience with pediatric stroke after he discovered that his daughter Kayelyn, now age 3, had had a stroke in utero.
"I couldn't name anyone with family members that this had happened to," said McDermott, whose daughter was diagnosed at six months. "Since Kayelyn was diagnosed, I know of three or four families in the area where we live who had the same thing happen to their children."
Dr. Lori Jordan, assistant professor of neurology and pediatrics at Johns Hopkins Children's Center, said that while "strokes in kids are rare, they are as common as brain tumors, which get a lot more [attention]... understanding the frequency and causes of stroke in kids should help target research that will prevent strokes and improve outcome."
Brendon, now four, receives regular physical therapy to strengthen and coordinate the muscles on his affected right side, but Spear still worries that his asymmetrical body might weaken to the point where he might need a hip or knee replacement when he is in his twenties.
Still, Spear said he has developed into a high functioning, talkative boy and his risk of having another stroke continues to decrease over time. The same is true of other children.
"They get frustrated but they don't let things stop them," Spear said. "They figure out a way to get what they want."
ABC News' Lauren Cox, Courtney Hutchison and Lara Salahi, and Med Page Today's Todd Neale contributed to this report.