There is a growing body of evidence that concussion can impair eye movement. During the past seven years, clinician-scientists at Children’s Hospital of Philadelphia’s (CHOP) Center for Injury Research and Prevention (CIRP) have evaluated the utility of a visio-vestibular exam to detect deficits in concussed pediatric and adolescent patients, and the use of automated eye tracking technology to objectively measure these deficits.
In four separate recently published studies, researchers found that having either an automated eye tracking assessment, or a visio-vestibular examination, in the days following a head injury can help establish the diagnosis of concussion. These studies also show that patients with subtle initial symptoms can be diagnosed based on these examination methods. An earlier diagnosis can help families, doctors and teachers develop appropriate school accommodations during the recovery period.
“Many concussed youths have vision deficits, but if you aren’t looking for them, you won’t find them. If you don’t find them, you can’t treat them,” says Christina L Master, MD, FAAP, CAQSM, co-lead of CIRP’s concussion research program and a pediatric primary care sports medicine specialist at CHOP. “Having reliable practical clinical tools that can detect vision deficits soon after a concussion injury is critical to improving concussion care for kids.”
Visio-vestibular exams predict prolonged recovery and are feasible in acute care settings
A visio-vestibular exam (VVE) assesses the systems responsible for integrating balance, vision and movement. It measures how eyes track a moving object, jump quickly between visual targets, and whether they can view an object at near distance without double vision.
Taken in the context of a preceding injury, abnormal test results can assist in the diagnosis of concussion, as well as potentially aid in predicting children who will suffer from prolonged symptoms.
In one study published in Clinical Journal of Sports Medicine, researchers looked retrospectively at 432 randomly selected children ages 5 to 18 years who were seen in a specialty concussion program, and found that 88 percent presented with a visio-vestibular deficit on initial clinical examination. A patient’s inability to track and focus on an object, double vision, and a loss of balance predicted prolonged concussion recovery.
Researchers wanted to see if primary and acute care healthcare providers could implement the VVE because they usually see patients with concussion first, and can initiate an appropriate recovery plan sooner.
To do this, they analyzed patient charts of 400 children ages 6 to 18 who presented to the emergency department over a 12-month period in 2016 and 2017 with head injury, and were considered to potentially have a concussion by the provider caring for them. Researchers found that 64 percent of the patients were assessed using the VVE. Of those ultimately diagnosed with concussion, 73 percent were assessed with a VVE, and 9 percent of patients diagnosed with a concussion had one or fewer symptoms but abnormal exam findings, demonstrating that the exam can assist in more accurately identifying concussed patients.
“This study showed us that, with training and clinical support tools, pediatricians, emergency medicine clinicians and advanced practice practitioners are able to conduct the VVE in a high-volume acute care setting,” says Daniel Corwin, MD, MSCE, lead author and pediatric emergency medicine physician at CHOP. “We can potentially avoid a premature return to risky activity and secondary injury if patients are appropriately diagnosed right after the injury.”
Automated eye tracking assessment is an objective biomarker for concussion in youth
In two additional studies, the CIRP research team collaborated with clinician-scientists at other institutions to evaluate a promising technology, called an automated eye tracking assessment, as an objective method for identifying concussions in young patients. Collaborators came from Children’s Hospital of Colorado, Boston Children’s Hospital, and University of Minnesota.
The automated eye tracking assessment is a rapid, objective, non-invasive aid in the diagnosis of concussion, and it does not require an individual patient’s pre-injury baseline as a comparison to identify a concussion. Additionally, this eye-tracking methodology reflects natural, automatic, physiologic brain activity, and thus can be an objective alternative to traditional subjective, symptom-based assessments.
During the assessment, a clinician records a patient’s binocular eye movements with an eye tracker. The patient’s head is stabilized on a chin strap to minimize head movement while they watch a 220-second video move continuously in the monitor. Software then analyzes the ability of the eyes to move together.
“Based on our findings, the automated eye-tracking assessment could ultimately advance clinical practice such that healthcare providers and athletic trainers could systematically, objectively and quickly identify a child or youth with a concussion by assessing eye movements,” says Master. “However, we still see this as one tool in a clinician’s diagnostic toolbox. There still isn’t one definitive test for concussion.”