Researchers say a biomarker may be able to identify which children will have more trouble recovering from a serious brain injury.

The Centers for Disease Control and Prevention (CDC) report that traumatic brain injury (TBI) is the number one cause of disability and death among children and adolescents in the United States.

This particularly true for children under 4 years of age and teens between 15 and 19.

Research has shown that TBIs are particularly traumatic for children, as they impact the child’s brain development and can cause serious cognitive impairment over time.

Negative effects include a decline in reasoning and trouble processing information.

Some of these adverse effects are not obvious right away. They may come up later when the children advance in age and are faced with different cognitive challenges.

New research – published in Neurology, the journal of the American Academy of Neurology (AAN) – suggests that a new biomarker may help anticipate which children will have more trouble recovering from a TBI and consequently require more aggressive treatment.

Emily L. Dennis, Ph.D., of the University of Southern California (USC) and one of the authors of the new study, explains the motivation behind the research:

“Traumatic brain injury is a leading cause of disability in children, but it is very difficult to predict long-term outcome and which kids might need more aggressive treatment,” she said. “While the severity of the injury certainly plays a role in this, there is still a lot of uncertainty – you frequently have two patients with similar injuries who have different recoveries.”

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The study looked at 21 children aged between 8 and 18 who had been admitted to a pediatric intensive care unit in a Los Angeles County hospital as a result of a moderate to severe TBI.

Reasons for the brain injury included traffic accidents as well as falls from skateboards or bikes.

The study also used a control group of 20 children who did not experience TBI.

Researchers examined the patients’ brain by using a special type of imaging device called a diffusion-weighted MRI. They scanned the patients’ brain two to five months after the injury and then again 12 months later.

The scientists also administered reasoning and memory tests.

Additionally, they examined the patients’ brain using an electroencephalogram as they were completing a pattern-matching task that focused on the time it takes for their brain to transfer information from one hemisphere to another.

The team focused on this aspect of brain activity because previous studies had shown that both children and adults who had TBI exhibit slower transfer times immediately after the injury.

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The researchers found that a few months after the injury, half of the children with TBI had slow transfer time while half had a normal transfer time – that is, within the same range as the healthy control group.

In the slow-transfer half of the TBI group, the scans revealed disruptions in the white matter that connects the two hemispheres of the brain, called the corpus callosum.

These disruptions worsened between the first scan and the second one, which took place a year later.

By contrast, the half of the TBI group that had normal transfer time did not reveal any differences from the control group in their brain scans.

In other words, as Dennis explains: “The TBI slow-transfer time group showed progressive decline during this period, while the other group showed signs of recovery.”

Finally, the reasoning and memory tests also revealed poorer scores in the TBI slow-transfer group, compared with the normal-transfer TBI group and the control group.

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Although the study sample was small and the findings need to be confirmed by larger studies, the current results point to the disruption in the white matter as a reliable biomarker for predicting the children who will have more trouble recovering from a TBI.

“The finding in this study that there is degeneration of white matter in about half of the children with moderate to severe TBI during the first 16 months after an injury should stimulate attempts to understand why this is happening so that treatments may be developed to lessen this progressive decline in white matter,” said Dennis.

Dr. Bradley L. Schlaggar, Ph.D., of the Washington University School of Medicine in St. Louis, MO, and a member of the AAN, also commented on the significance of the study in an accompanying editorial:

“This study is an important step forward to identifying a functional biomarker that may predict the trajectory of TBI recovery,” he said.“Success in confirming these results would be transformative for the field. We need tools that will allow us to make individual predictions so we can make the best decisions about treatment and how to educate and counsel our patients and their families.”