A fast and accurate test for diagnosing acute concussions in pediatric patients has proven elusive. For children and adolescents who sustain a concussion, a delayed or absent diagnosis can lead to a premature return to sports or other physical activities, which can complicate recovery.
“Diagnosing concussion typically involves qualitative symptom assessments paired with clinical imaging,” says Dr. Theodore Heyming, medical director of emergency medicine at Children’s Hospital of Orange County (CHOC) and assistant clinical professor of emergency medicine at the University of California, Irvine. “A quick test to identify concussion and the risk of post-concussive symptoms could help screen the numerous children with head injuries presenting to emergency departments [EDs] and determine those who need close follow up.”
The search for such a test led Dr. Heyming and a multidisciplinary group of investigators at CHOC to assess the potential of quantitative pupillometry to diagnose concussions in pediatric patients in the ED within 72 hours after injury. Their findings cast doubt on pupillometry’s utility in this setting but raised some interesting questions.
Gazing into the eyes for diagnostic clues
Studies have suggested that the autonomic nervous system experiences dysregulation after a concussion, according to Dr. Rachel Pearson, director of brain injury medicine in pediatric neurology at CHOC, program director of the UC Irvine Child Neurology Residency Program and assistant clinical professor of pediatrics at UC Irvine. The study team wondered whether using pupillometry to look for signs of this dysregulation could help detect concussion.
“Pupillometry response measurements serve as a window into the functioning of the autonomic nervous system,” Dr. Pearson says. “We have reliable and easy-to-use devices that measure the pupillary response that are already widely used in the intensive care setting. We wanted to see if the same device could be applied to evaluate patients with suspected acute concussion.”
Dr. Heyming and Dr. Pearson were part of a study team featuring members from the CHOC Neuroscience Institute, CHOC Pediatric ED and CHOC Research Institute. The team conducted a prospective, case-control study involving 126 patients ages 5 to 18. Team members used the hand-held NeurOptics PLR-3000 device to conduct pupillometry on concussed patients who presented to the CHOC ED.
“Each patient had their pupillometry light reflexes measured and completed several quantitative analyses, such as a balance test, cognitive assessments and symptom scale, at the initial ED visit, two weeks post-ED visit and three months post-ED visit,” Dr. Heyming says. “Each concussed patient was age- and gender-matched with a non-concussed patient from the general pediatric population who also completed the same measures and pupillometry.”
The eyes don’t have it
The study, published in Pediatric Neurology, found little reason to believe pupillometry is the definitive, rapid concussion diagnostic test for which clinicians and patients have been waiting. Only two pupillary measurements — time to 75% recovery in 5- to 11-year-olds and average dilation velocity in 12- to 18-year-olds, both found in the left pupil — showed statistically significant associations with the odds of a concussion.
“Despite our highest hopes, we found that pupillometry is likely not useful in the diagnosis of concussion in children,” Dr. Heyming says. “It’s our hope that our group or another research team can conduct a much larger study — as ours was only preliminary data with a small cohort — that may demonstrate benefits of using pupillometry in the diagnosis of concussion in children.”
The study raises questions about why statistically significant findings were only found in the left pupil instead of both pupils, and why pupillometry may have a role to play in diagnosing concussions in adults but not children.
“Given that research in adults has shown correlations between pupillary measurements and the presence or absence of concussion, I expected to see a similar correlation in our pediatric patients,” Dr. Pearson says. “The fact that we did not see a similar correlation may reflect a larger spectrum of what’s normal in pediatric patients across varying stages of development as compared to adults. It could also be that the time points we chose were not the right time points, or that we simply need a larger sample to see a difference.”
Looking ahead
For now, clinicians will need to stick with their familiar toolkit for diagnosing concussions in children, Dr. Heyming says. An evaluation by a clinician with expertise in the clinical diagnosis of concussion remains patients’ best bet.
“These findings underscore the importance of making a clinical diagnosis and having clinicians who are trained to do this in various settings, from the sidelines to primary care offices, EDs and specialty clinics,” Dr. Pearson says. “We need to continue the search for rapid and effective tests that can be used to diagnose concussion in the acute timeframe. Furthermore, we need tools that can help us determine early on which patients are at risk for having a prolonged or complicated recovery course.”
Future research may yet show pupillometry has a place in diagnosing concussions in children. In the meantime, the significant need for an effective diagnostic test will keep driving the search.
“Although pupillometry likely isn’t the answer — that is, the quick and easy concussion test we were hoping for — as clinician-scientists, we should continue to think about and investigate novel methods to diagnose concussion in children that are accurate, user-friendly and cost-effective,” Dr. Pearson says. “This is an unmet need with the potential to have a positive impact on our patients’ outcomes.”
CHOC Hospital was named one of the nation’s best children’s hospitals by U.S. News & World Report in its 2023-24 Best Children’s Hospitals rankings and ranked in the neurology/neurosurgery specialty.
