A study coauthored by Melissa Hunfalvay, PhD, cofounder and chief science author of RightEye, Bethesda, Md, has shown that tracking vertical smooth pursuit (VSP) in a patient’s eyes can help doctors accurately and quantifiably differentiate those with moderate and severe traumatic brain injury (TBI).1
“People who suffer moderate to severe concussions end up finding it difficult to visually follow things that move up and down,” says Hunfalvay. “In studying this, we’ve found a correlation between VSP impairment and concussion severity which can easily be tracked using RightEye’s Brain Health EyeQ.”
Red and blue lines illustrate the path of vertical eye movements of a person without brain injury (left) and of a person with a concussion (right).
“We have an epidemic of head injuries with increasing death and disability throughout the world,” says Frederick R. Carrick, PhD, a professor of neurology at the University of Central Florida. “Our team has been searching for a test that can identify when a person suffers a concussion and tell us how bad the injury is. Eye-tracking data from RightEye provides an objective measure of brain function that can assist doctors in the diagnosis of moderate to severe brain injuries.”
The study is the first to use eye tracking to compare VSP in healthy subjects to patients with different levels of clinically diagnosed TBI. Variance and smooth pursuit percentage (SP%) were the two metrics used to quantify eye movements associated with smooth pursuit.
Melissa Hunfalvay, PhD, RightEye.
For the study, 92 subjects were recruited from eye health clinics in the United States. Participants included 23 who were clinically verified with TBI at one of the following severity levels: no-TBI, mTBI, moderate TBI, or severe TBI. Participants were clinically verified by a board-certified neurologist or neurooptometrist, according to the medical diagnosis guidelines. The participants with TBI had sustained their head injuries within 30 days prior to the testing.
Analysis of variance metrics revealed significant differences between the TBI groups and the control group. Results indicated that VSP can be used to distinguish between severe and moderate TBI and control groups, but not mild TBI and control groups.
Analysis of SP% metrics also yielded a significant difference between groups, along with a main effect. Similar to variance, SP% was able to distinguish severe and moderate groups from control groups but not the mTBI group.
According to RightEye, eye tracking has potential to fill a void in the world of TBI testing. As the only method of objectively and accurately measuring visual behavior, eye tracking can be used to confirm or deny the presence of TBIs in a unique way. Such objectivity and accuracy address many of the issues with conventional TBI tests, including subjectivity and inaccurate reporting.
By itself, says RightEye, VSP offers great insight into a patient’s condition. But the company notes that VSP is just one of the metrics that can be measured using eye tracking. Combined with other metrics, VSP has potential to offer a quick and easy-to-administer TBI detection system.
For more information, visit RightEye.
Reference
1. Hunfalvay M, Roberts CM, Murray NP, et al. Vertical smooth pursuit as a diagnostic marker of traumatic brain injury. Concussion. 2020;5(1):CNC69; doi: 10.2217/cnc-2019-0013.
Featured image: A young athlete takes the RightEye test. Photo courtesy RightEye.
