New eye-tracking technology could help doctors measure the severity of concussions and traumatic brain injuries (TBIs), which are sometimes difficult to diagnose, researchers say.
A team of scientists used the eye-tracking device on both people with brain injuries and healthy people, to measure whether the eyes moved in sync with each other.
The technology could be used to detect brain injuries in emergency rooms or even on the sidelines at sporting events, according to the study, published today (Jan. 29) in the Journal of Neurotrauma.
Many researchers are trying to find a better way to diagnose brain injuries, said Dr. Uzma Samadani, a neurosurgeon at NYU Langone Medical Center in New York City. "It's a testament to how big the problem is." [ 10 Things You Didn't Know About the Brain ]
Detecting brain injury
Doctors have used electroencephalography, or EEG, to diagnose brain injuries for 40 to 50 years, Samadani told Live Science. In an EEG, electrodes placed on the scalp are used to measure the impulses within the brain, but the technique doesn't have the specificity to pinpoint the injury's location.
Another method entails looking in the blood for biomarkers, such as proteins, that indicate an injury. But recent studies suggest such markers don't make it past the blood-brain barrier, which is the membrane that keeps the blood separate from the brain and spinal fluid, Samadani said.
Then there's neuropsychological testing, which is probably the most widely used technique for measuring brain injury because it's noninvasive. The problem, Samadani said, is that the technique requires a baseline assessment, which measures a person's performance in skills such as memory, recall and concentration, and these can vary greatly from person to person in both children and adults. In addition, athletes or military personnel may deliberately perform worse on their baseline test, to prevent being removed from play or active duty in the event of an injury, she added.
Samadani said the eye-tracking tool she and her colleagues have developed is a more objective way to measure a brain injury. In a healthy person, the eyes should move in coordination. In a brain-injured patient, the eyes often move in different directions, but in a way that is subtle enough that it may not be visible to a doctor evaluating the injured person with only the naked eye.
The device more precisely tracks the location of each eye, and compares their movements.
Diagnosis from the sidelines
In the new experiments, the researchers tested the eye-tracking system on three groups of people: patients who had brain injuries that were visible in a CT scan, patients whose injuries were not visible on a scan, and uninjured people. The researchers tracked the participants' eye movements as they watched music videos, such as Shakira's "Waka Waka," and "Under the Sea" from the movie "The Little Mermaid."
With the eye tracker, the scientists could tell which patients had brain injuries and which patients did not. This technique even worked in the group of patients whose injuries didn't show up on CT scans.
In addition, the severity of the patients' symptoms correlated with the degree to which the test found they lacked eye coordination, Samadani said.
The new device seems promising, said Dr. Michael Lipton, a neuroradiologist at Albert Einstein College of Medicine and Montefiore Medical Center in New York City who was not involved in the research.
The equipment needed to do the test "is something you could have in a backpack and take to the sidelines [of a football game], or take into combat," Lipton told Live Science.
But the study was relatively small, he noted. Traumatic brain injury affects people in many different ways, so larger studies are needed to determine the sensitivity of the eye-tracking test, he said.
Dr. Stephan Mayer, a critical care neurologist at New York City's Mount Sinai Hospital, said the eye-tracking device could be useful for detecting serious concussions, but he added that "the absence of eye-tracking abnormalities doesn't exclude a significant injury that might have cognitive effects down the road."