New research suggests an increase in cerebrospinal fluid may be present in a high percentage of children with autism.
Children with learning or developmental disorders, such as autism, who receive a diagnosis earlier have a better chance of getting the resources and personalized education to help them succeed.
However, the disorder can present in subjective ways, so an objective measurement could help diagnose children even younger.
Autism spectrum disorder affects about , estimates the Centers for Disease Control and Prevention’s Autism and Developmental Disabilities Monitoring Network.
Earlier this year, researchers at Stanford University published research that concluded that low levels of the hormone vasopressin in a child’s cerebrospinal fluid could help researchers predict a child’s chance of developing autism.
But new research suggests that merely having an elevated level of the protective fluid around the brain could point to clues that might ultimately help diagnose autism earlier in life.
The latest study, published last month in and funded by the National Institutes of Health, was conducted by researchers at the University of California at Davis MIND Institute and the University of North Carolina.
Researchers said they found that an increased amount of extra-axial cerebrospinal fluid was associated with a diagnosis of autism in young children.
Researchers say cerebrospinal fluid was once considered a benign substance that merely protected the brain from shock, such as in the case of a concussion.
But further research suggests the fluid plays a much greater role in the brain, namely acting as a way for the brain to clean out potentially harmful molecules. It does this mostly while we sleep.
However, having too much of the fluid could be a biomarker for autism in young children.
To reach this conclusion, researchers studied 236 children.
Of those, 159 had autism spectrum disorder and 77 didn’t.
The participants were an average of 3 years old.
Each child underwent brain MRIs so researchers could measure their cerebrospinal fluid. The research team also used “sophisticated” algorithms to assess the results.
Researchers say children with autism had about 15 percent more spinal fluid, regardless of their genetic disposition to autism.
“These brain measures distinguished kids with autism from those with typical development with 83 percent accuracy,” the researchers concluded.
Earlier studies by some of the same researchers evaluated children with a higher risk of autism, such as an older sibling with the condition. However, this round of research evaluated both high- and low-risk children and monitored those children for a longer period of time.
Researcher David Amaral is a professor in the UC Davis psychiatry and behavioral science department and the senior author of the paper.
He said in a statement that their first round of research showed that if you conduct an MRI on a child as young as 6 months old, the increased cerebrospinal fluid could predict a subset of autism. Their second set of research confirmed it.
“Now we have validated them a third time in older children with varying degrees of risk,” he said.
The researchers found that extra cerebrospinal fluid was associated with lower nonverbal ability — or the ability to analyze and solve problems without using words.
The study also showed that children with more cerebrospinal fluid had more problems sleeping. Researchers note the importance of this, because the circulation of this fluid, especially during sleep, is important to a healthy brain.
This may help explain why children with autism often have sleep disorders, such as insomnia, and why poor sleep may worsen symptoms associated with autism.
Mark Shen, the first author on the paper and an assistant psychiatry professor at the University of North Carolina, says that during sleep, the brain’s fluid is supposed to be circulating around the brain and cleaning it.
“When someone doesn’t get enough sleep, there is a possibility for buildup of proteins that can affect learning, memory, and general brain function,” he said in a statement.
Dr. David Beversdorf, an autism research expert at University of Missouri Health Care, says he finds the research “quite intriguing.”
He says it’s not simply a marker only for those at familial risk with their specific genetic factors, who had been the focus of previous studies.
“Therefore, the salience of this marker for autism spectrum more broadly is clear after this study,” he told Healthline.
But Beversdorf warns that it’s still not clear how increased cerebrospinal fluid contributes to the causes of autism, because that wasn’t the primary focus of this round of research.
“What it does reveal is a potential biomarker and potentially an early biomarker with predictive potential,” he said. “It is not clear that early imaging will play any role clinically, but this does raise the possibility that it could be utilized at least in a research setting for studies in early clinical neurodevelopment.”
Beversdorf says it’s also not clear whether this new research represents increased cerebrospinal fluid or decreased brain volume, which could leave the appearance of excess fluid surrounding the brain.
“It is also still unknown whether this is specific to autism spectrum disorders among neurodevelopmental conditions,” he said. “However, there are many different causes of autism, and the identification of a biomarker that generally seems to span across these etiologies is potentially quite valuable.”
While more research needs to be done, the latest research out of UC Davis MIND Institute and the University of North Carolina offers one promising way of potentially finding a biomarker that could detect a child’s increased risk of developing autism.
Researchers say extra fluid of the brain may be a sign that a child is at a higher risk of developing autism.
They add it may also help explain why children with autism have problems with verbal skills and sleep patterns.