Seattle Children’s researchers have published the results of a 10-year, multi-site study tracking the cognitive development of children with single-suture craniosynostosis from infancy to school age. The results could help families and clinicians better predict which children with this condition are at greater risk of having learning deficits so that they might intervene early in the child’s life.
The study, published today by the American Academy of Pediatrics and titled “Intellectual and Academic Functioning of School-Age Children with Single-Suture Craniosynostosis,” reported children with single-suture craniosynostosis, on average, were more likely than children without the disorder to have learning deficits once they started school. However, despite this trend, a little over half of the children with single-suture craniosynostosis showed no discernible learning problems.
Living with the unknown
The research is significant for parents like Cindy and Todd Bush. Twelve years ago, Cindy and Todd learned their 3-month-old daughter, Olivia, had craniosynostosis, a condition in which one or more of the special joints in a baby’s skull (sutures) grow together (fuse) earlier than normal. When these joints come together too early, a baby’s skull cannot grow properly. Craniosynostosis occurs in approximately one in 1700-2500 live births. Corrective surgery to restore the suture is preferentially performed in the first year of life.
“Our whole world changed at that point,” Cindy said. “We had expected our daughter to live a normal, healthy life, and all of the sudden we were faced with a diagnosis we knew nothing about.”
The family was referred to Seattle Children’s Craniofacial Center, an international leader in treating craniosynostosis that has the largest multidisciplinary team in the country, with more than 50 providers from 19 medical specialties. While the Bush family was comforted by the Center’s highly specialized team, they were unsure of how Olivia’s condition might affect her brain development.
“Our minds started wandering down some frightening roads,” Todd said. “So much was unknown at that time that we were left wondering what her future would hold.”
Investigating the issue
The Bush family was not alone. Neurodevelopmental impairment has long been suspected among children with single-suture craniosynostosis and is a focus of treatment and research at Seattle Children’s Craniofacial Center. The prematurely fused suture is believed to constrain or alter brain structures and increase intracranial pressure.
Dr. Matthew Speltz, a clinical psychologist in Seattle Children’s Craniofacial Center and a principal investigator at Seattle Children’s Research Institute’s Center for Child Health, Behavior and Development, had studied infants and preschoolers with single-suture craniosynostosis and discovered they consistently scored lower, on average, than same-aged children without this condition. He wanted to determine if these delays persisted into the school-age years and manifested as learning disabilities.
“There have been clinical impressions and hypotheses about the cognitive status of children who’ve had single-suture craniosynostosis, but kids with this disorder had never been studied longitudinally in order to see how they develop over time and how they compare to unaffected children over the same time period,” Speltz said. “Understanding the cognitive development of these children is important so we know which children are at greater risk of developing learning disabilities and how we can intervene early in their lives to make a difference.”
In 2002, Speltz initiated the first large-cohort study to track the development of children with single-suture craniosynostosis and unaffected controls from infancy to school age. The Bush family was eager to sign up for the study.
“We wanted to learn as much as we could about Olivia’s condition and how it might affect her growing up,” Cindy said. “And we wanted future families of children with craniosynostosis to have more information available to them than we had when Olivia was diagnosed.”
Over 10 years, Speltz compared the developmental status of 182 school age children with single-suture craniosynostosis and 182 unaffected children using standardized tests of intelligence, reading, spelling and math.
The children with craniosynostosis averaged lower scores than the control group on all measures. The largest observed differences were in full-scale IQ and math computation. The smallest differences were observed in reading and spelling. Still, most children with craniosynostosis performed well academically and 58% had no discernible learning problem.
“Although developmental delays observed among infants with single-suture craniosynostosis were partially evident in elementary school, our results provide more good news than bad for parents,” Speltz said. “On average, the children with single-suture craniosynostosis experienced mild cognitive and academic deficits, and most of them were doing pretty well in early elementary school.”
Researchers also discovered developmental delays varied significantly based on the subtype of craniosynostosis. Children with metopic, unicoronal or lambdoid synostosis were much more likely to have a learning problem than children with the most common form of single-suture craniosynostosis – sagittal synostosis. In related research, Speltz and colleagues also found that boys with single-suture craniosynostosis tended to score lower on academic and IQ tests than girls with this condition.
“This information helps us determine which children are at greatest risk of falling behind,” Speltz said. “This will enable us to better target children with single-suture craniosynostosis for early screening and intervention programs that prevent or minimize cognitive and academic difficulties later in life.”
Over the years, Olivia’s cognitive function almost always measured above average. Today, she is one of the best performing students in her sixth grade class.
“It’s amazing to see her now,” Todd said. “She loves school and we are so proud of her. We didn’t know what to expect 12 years ago, but today she is a happy, healthy child. We hope other families will find this research comforting.”
Other Seattle Children’s collaborators on this study include Dr. Michael Cunningham, medical director of Seattle Children’s Craniofacial Center and investigator in Seattle Children’s Research Institute’s Center for Developmental Biology and Regenerative Medicine, and Dr. Brent Collett, clinical psychologist in Seattle Children’s Craniofacial Center and investigator in Seattle Children’s Research Institute’s Center for Child Health, Behavior and Development.
Parents of children with craniosynostosis may contact the Seattle Children’s Craniofacial Center by calling 206-987-2208.