Robert Asarnow is identifying new predictors of traumatic brain injury recovery in kids

Robert Asarnow, PhD, a professor of psychiatry and psychology at the University of California, Los Angeles, has spent nearly four decades researching traumatic brain injury (TBI) in children, from risk factors to psychiatric consequences. His work has informed clinicians and parents on what to expect after a child suffers a blow to the head and how best to respond. 

In his work, Asarnow asks three questions: What are the varying levels of severity in traumatic brain injury, in terms of cognitive function? What is the time course for recovery? And what factors influence the trajectory of recovery from a brain injury? 

“Answering that question gives us the opportunity to develop interventions that could improve the quality of care that patients receive,” Asarnow says. 

Asarnow’s five-decade-long career has been wide ranging. Early on, at the University of Waterloo and McMaster University in Canada, he conducted foundational research on the heritability of cognitive impairments in schizophrenia—work that he continues today, alongside his research on traumatic brain injury. 

Since then, Asarnow has led some of the largest studies on traumatic brain injury in children, including a landmark longitudinal study comparing the cognitive and psychological function of children before and after concussion and a controlled trial on a cognitive retraining intervention. Today, Asarnow and his colleagues in a study funded by National Institute of Neurological Disorders and Stroke (NINDS) are working to identify environmental factors and biomarkers that predict which adolescents with concussion are at risk for persistent concussive—work that could help clinicians concentrate care on the patients who need it most.

Traumatic brain injuries, which result from an outside force like a fall or blow to the head, are one of the leading causes of death and disabilityopens in new window in children. “They’re very common events in kids,” Asarnow says. “It’s a big problem.”— children get these injuries from sports and falls, gun wounds and abuse, according to the National Institutes of Health (PDF, 265KB)opens in new window. A traumatic brain injury can range from a mild concussion to a catastrophic brain bleedopens in new window. 

Traumatic brain injuries also affect children very differently from adults, Asarnow says. That’s because a child’s brain is still developing. “The job of a child is to learn and acquire a variety of new skills, including cognitive skills,” Asarnow says. In 2011, Asarnow and his colleague Talin Babikian conducted a meta-analysis of academic and language outcomesopens in new window in children following traumatic brain injury. While children with concussions (also known as mild traumatic brain injuries) bounced back, “kids with severe traumatic brain injuries fell progressively behind,” Asarnow says. “What the traumatic brain injury has done is really disrupt the brain systems critical for acquiring new cognitive skills.”

Prognoses for traumatic brain injuries can vary widely. In the case of concussions, some children recover within days; for others it can take months. For moderate and severe injuries, some children improve with active rehabilitation, while others continue to deteriorate.

The problem is, our measures of injury severity—and likely long-term outcomes—are imperfect, Asarnow says. The primary measure of acute traumatic brain injury severity is the Glasgow Coma Scaleopens in new window, which measures level of consciousness upon admission to the emergency department. “These are messy measures,” Asarnow says. The amount of time that passes before a child with a traumatic brain injury even arrives at the emergency department can vary enormously, and level of consciousness can wax and wane in those early days. On top of that, the scale does a poor job of predicting the pace of long-term cognitive recovery. “It was never intended to measure the whole gamut of TBI severity,” Asarnow says.

Asarnow and his UCLA colleagues, including pediatric neurologist Chris Giza and neuropsychologist Talin Babikian have been working to develop new methods of predicting the pace of recovery in patients with traumatic brain injuries, in order to provide proactive care to those most at risk of prolonged symptoms.

In a 2018 longitudinal studyopens in new window led by then post-doc Emily Dennis, Asarnow and his colleagues examined  brain imaging in 29 children at two time points following a traumatic brain injury: between two to five months, and 15 to 18 months. Meanwhile, the researchers measured the transfer of visual information between the hemispheres. Normally, the visual information from one eye first goes to the visual cortex on the opposite side of the brain, before transferring to the other hemisphere. About half of the children with traumatic brain injury showed a very slow transfer of information between the two hemispheres two to five months post-TBI—and brain imaging showed that these children were experiencing degeneration in their condition over time. Brain scans showed a progressive loss of white matter, tissue important for the transfer of information. The children with normal transfer of visual information at 2-5 months post TBI were able to recover white matter volume and organization. “This was a big deal for us because it identified a group of kids who were at most risk, and it really couldn't have been predicted by their initial Glasgow Coma Scale,” Asarnow says. “Here was a new biological measure that predicted outcomes.” 

In the case of concussion, predicting outcomes becomes even more complicated by the fact that most people don’t immediately seek help—instead, they wait until it’s clear that their symptoms aren’t resolving, usually two to three weeks after the initial injury. “It’s a difficult problem to identify prognostic factors in concussion because you’re always studying it retrospectively,” Asarnow says. With the help of a grant from the National Institute of Neurological Diseases and Stroke, Asarnow and colleagues at six academic medical centers in the Care for Kids network are working to identify biomarkers that predict persistence of symptoms in concussion. One project is using brain imaging, while another is identifying blood biomarkers, such as inflammatory proteins. Asarnow himself is leading a project that looks at the function of the autonomic nervous system, which regulates involuntary functions like blood pressure. 

Using this data, the researchers have developed a model that appears to outperform the clinical predictors currently in use. In a second phase of the study, they’re testing their model in an independent population of kids to see if it accurately predicts their long-term recovery.

These biological predictors could be important breakthroughs for clinical care, Asarnow says. That’s because there aren’t enough resources to provide long-term follow-up to every child who shows up at the emergency department or primary care with a traumatic brain injury. “What this research starts to say is, if you can identify the people who are really at risk for long-term adverse outcomes, you can track them and be able to help them get the support they need,” Asarnow says.