Measuring whether a heart is working correctly is a relatively straightforward task, because the heart has a straightforward purpose: reliably pumping blood.
The brain has many more functions, which makes it notoriously difficult to assess the brain’s physical performance in the hospital emergency room, on the sidelines of an athletic event or during long-duration space travel. But a new system developed by a Hennepin County Medical Center neurosurgeon may be on the cusp of assessing brain function in real time in all of those locations.
“We have really good ways of assessing heart function. ... but with the brain, it is super difficult, ” said HCMC attending neurosurgeon Dr. Uzma Samadani. “We need better tools to assess physiologic brain function. That’s what this is.”
Samadani was discussing the EyeBox, a relatively simple device that pairs proprietary software with an infrared scanner, a computer monitor and standard opthamological equipment that consumers might expect to see when getting their vision checked.
The technology, which is patented and licensed to a New York company co-founded by Samadani called Oculogica, is based on the premise that a large share of the brain’s functions are thought to impact eye movement. So tracking small discrepancies in eye movements can reveal a lot about what is going on inside the skull.
The device is not yet cleared for sale in the U.S. Oculogica has published several papers on its results, and this week the company published its latest in the Journal of Neurosurgery that said the EyeBox system was able to detect “elevated intracranial pressure” in an observational study of 23 hospital patients who watched four-minute videos while getting their eyes scanned.
Having too much pressure inside the skull can be caused by many things, including congenital or acquired hydrocephalus, which affects about 7 million Americans. Elevated head pressure can also be caused by tumors and strokes, as well as swelling that follows a concussive blow to the head.
Using a version of the device to look for concussions during contact sports could be a promising application, Samadani said. A concussed brain is more sensitive to damage from a second blow, but players may not want to be pulled from a game — famed NFL quarterback Peyton Manning admitted in 2011 that he intentionally manipulated preseason “baseline” neurological testing to avoid being listed as injured if he got hit in the head.
EyeBox test results can’t be faked.
Clinical testing of the device was funded by the National Space Biomedical Research Institute, which is interested in measuring intracranial pressure in astronauts.
In 2015, an aerospace journal article reported that six astronauts exposed to prolonged microgravity in space ended up developing eye dysfunctions potentially related to increased cranial pressure.
So far the device is subject to more than a dozen patents, including one that is assigned to HCMC, which gives the public safety net hospital a financial interest in Oculogica. (The patients in the recent study were treated at a hospital in New York.)
The machine is now in clinical testing at the Mayo Clinic and a dozen other hospitals around the country. It’s not clear when the FDA will be able to pass judgment on an application to sell the device in the U.S., or what path the device might take to market.
The device works by having a patient place their chin on a support in a metal frame and then watching a 4-minute music video that slowly moves around a computer screen. An infrared scanner takes 500 readings per second of each pupil’s position. A computer algorithm analyzes the data to see if the eyes are moving in sync horizontally and vertically.
When the eyes do not move in sync, a problem may be evident. The study documented correlations between intracranial pressure and eye function in 55 tests, with the strongest correlations showing up between out-of-sync horizontal eye movements and increased head pressure.
“The eyes are an excellent indicator of neural dysfunction, because there are so many things that affect eye movement,” Samadani said.