Brain images taken a year apart show different recovery trajectories in children after mild-to-traumatic brain injury. In the top row, the color red signifies ongoing decline. In the middle row, the change in color from red to yellow shows cognitive recovery. The bottom row images come from a healthy control.
UCLA scientists have found that a new biological marker may help doctors identify children at risk of poor outcomes after a traumatic brain injury. The discovery will allow researchers to focus on ways to prevent progressive cognitive decline seen in roughly half of children with moderate-to-severe traumatic brain injuries. “It’s really very hopeful. It means there’s something we can do about this,” says Robert Asarnow, PhD, Della Martin Professor of Psychiatry in the UCLA Department of Psychiatry and Biobehavioral Sciences.
The study involved 21 children with moderate-to-severe traumatic brain injuries who were treated in hospital intensive care units in Los Angeles County. Causes of injuries included auto-pedestrian accidents, motor-vehicle accidents and falls from bikes, scooters and skateboards. The children, ages 8 to 18, were evaluated twice — two-to-five months after injury and again at 13-to-19 months post-injury. The results were compared with children of the same age who had not had a brain injury.
Researchers at UCLA and elsewhere have observed that after children sustain a moderate-to-severe traumatic brain injury, they typically follow one of two trajectories — either steady gains toward normal, pre-injury functioning, or progressive, widespread cognitive decline. However, researchers have been unable to predict the outcomes early on. In fact, studies have shown that brain damage visible on a computed tomography scan does not accurately predict a patient’s potential for full recovery. It is only later, often after the child returns to school, that parents start noticing the child is falling behind or has problems with attention, learning or depression.
To detect which individuals might be at risk for ongoing cognitive decline, a team of researchers from different medical specialties used special magnetic resonance images (MRIs) and electroencephalograms to measure the speed of brain signals passing from one hemisphere of the brain to another, a measure of brain function. Previous studies have shown that both children and adults have slow signal transfer times right after a traumatic brain injury.
In the first assessment, the children wore headphones and watched a movie while the MRI scanner assessed the integrity of the brain’s white matter, which connects different brain regions to support cognitive functions. The children also took tests of attention and memory skills. After the first assessment, UCLA researchers found half of the children had brain-signaling speeds within normal range, an indication of healthy white matter. The other half had significantly slower signaling, compared with healthy children, an indication of white matter disorganization or disruption.
At 13-to-19 months after their injuries, the children who had normal signaling at the first assessment still compared favorably with healthy peers. In contrast, the children with slower signaling showed progressive decline in white matter organization and loss of white matter volume. Researchers suspect a prolonged inflammatory process might be causing ongoing damage to the still-maturing brain. Anti-inflammatory agents might alter this course, Dr. Asarnow says, but these agents may have some adverse effects. Researchers noted the study was small, and the results need to be confirmed in larger studies.
“Diverging White Matter Trajectories in Children after Traumatic Brain Injury,” Neurology, March 15, 2017