While more research needs to be done, excess cerebrospinal fluid may help to explain why children with autism experience problems with verbal skills and sleep disturbances.
According to a recent study, children with autism ages 2 to 4 have around 15% more fluid build-up between their skull and brain, as opposed to their typical peers. Based on the researchers’ findings, the excess fluid may indicate an early warning sign for autism, thereby possibly helping to improve both treatment and quality of life.
A possible biological marker for autism
In the new study, researchers at the UC Davis MIND Institute and the University of North Carolina at Chapel Hill monitored a total of 236 children - 159 children with autism and 77 children with typical development. Out of the 159 children with autism, 27 had a sibling with autism. As a result, they were regarded to be at high-risk for the disorder even before their diagnosis. The average age of both the high-risk and low-risk children was 3.
The researcher team performed brain MRIs to measure cerebrospinal fluid, which is the fluid found in the brain and spinal cord, in the children during sleep. They also used top of the line algorithms, as well as two parent questionnaires on the children’s sleep patterns to evaluate the results and develop predictive biomarkers. Based on their discoveries, high levels of cerebrospinal fluid were seen among the children who were 3 years old – those with autism and with typical development. Additionally, it was observed that the children with autism had heightened levels of cerebrospinal fluid, as opposed to the typically developing children. “We knew from our previous studies that it was present at six months, and this study in a different group of children showed CSF was abnormally increased at age three. It appears to be present in high-risk kids with autism, as well as kids with autism from the general community” said Mark Shen, lead author of the study and assistant professor of psychiatry at UNC Chapel Hill.
The study also revealed that the children with autism with heightened levels of cerebrospinal fluid experienced more severe sleep disturbances. This was a noteworthy discovery, seeing as how proper fluid circulation, especially during sleep, is vital to brain health. “Sleep is when this brain 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” said Shen. Controversy, he and his fellow colleagues did not find excess fluid to be associated with sleep problems among the typically developing children.
Although very little is known about how cerebrospinal fluid is linked to autism, what is known is that it gets rid of inflammatory proteins in the brain. While a buildup of the fluid in typically developing children may well be harmless, it may indicate a problem with the process in children with autism. “The result is that there could be a buildup of neuro-inflammation that isn’t being washed way” said Shen.
Shen and his fellow colleagues plan to continue monitoring the children with autism in their study in order to determine if their elevated levels of cerebrospinal fluid will remain the same as they get older.
Forecasting autism in infants
The latest study, published in the journal The Lancet Psychiatry, is the 3rd study in 5 years to suggest that excess cerebrospinal fluid is associated with a diagnosis of autism among young children.
The first study, published back in 2013 in the journal Brain, found the infants who go on to develop autism have excess cerebrospinal fluid. The build-up continues from 6 months until 2 years of age, and may indicate early detection of autism. “This could be very helpful to families to make the decision about whether they want to invest the time and financial resources to get their child into intensive behavioral therapy,” said David Amaral, lead author of the study and professor in the UC Davis Department of Psychiatry and Behavioral Sciences.
Amaral and his fellow colleagues looked at infant siblings of children with autism, who were considered to be at a higher risk for the disorder, as opposed to that of the general population. They monitored the sleep patterns of 33 high-risk infants and 22 low-risk infants using MRI scans. Out of the 55 infants, a heightened amount of brain fluid– by 20% - was observed among the high-risk children from the MRI scans. The build-up was observed up until the 2-year mark and throughout the months, its persistence was evident.
The second study, published in 2017 in the journal Biological Psychiatry, was conducted by the same research team and confirmed the initial findings of the 2013 study.
In the 2017 study, 221 infant siblings of children with autism and 122 children with no family history of autism or related conditions were monitored using MRI scans. Based on the gathered results and a machine-learning algorithm to predict which infants would go on to be diagnosed with autism, the system predicted the disorder with 69% accuracy.
According to Amaral and his fellow colleagues, cerebrospinal fluid circulation problems could trigger a build-up of the fluid, and consequently, excess harmful molecules that alter normal development of the brain.
A major step forward
While more research needs to be done, excess cerebrospinal fluid may help to explain why children with autism experience problems with verbal skills and sleep disturbances. And, as a result, early detection of risk for autism could lead to more effective treatment options down the road. “Getting younger children into intensive behavioral therapy would be very helpful. And, if there is a biological treatment, it would be great to get them on it at six months, rather than three or four years when kids are often diagnosed” said Amaral.
Seeing as how there are very few early biomarkers associated with risk for autism, the discoveries prove valuable for early detection. In due time, cerebrospinal fluid could become a therapeutic target. “It could help signal risk using regular MRIs that you find in any hospital because it is easily seen with the naked eye on a standard MRI,” said Shen.