ATHENS, Ohio -- An Ohio University researcher is developing a new way to measure reading and listening comprehension in brain injury victims by tracking their eye movements, a technique that could improve the accuracy of traditional testing methods.
People with neurological damage who develop problems with speech, language, hearing or movement often are considered mentally impaired. But by studying their eye movements, researchers hope to see sparks of understanding that traditional comprehension tests aren't designed to spot, says Brooke Hallowell, assistant professor of hearing and speech sciences and lead author of the research.
"We often underestimate what people with neurological problems are taking in," says Hallowell, whose work was published recently in the journal Brain and Language. "I've seen so many cases where people don't talk to patients because they think they can't understand. Family members might not interact with someone because they don't think this person is comprehending anything. But what if they can?"
When patients with neurological problems are tested for comprehension, they are asked to respond to questions using speech and movement. But some patients, either through a stroke or brain injury, have lost their ability to respond to the clinician giving the test.
"Many of these patients then are considered to be limited in their comprehension when they actually do understand. They just can't physically or verbally do what's asked," Hallowell says.
Eye movement is a good indicator for comprehension, Hallowell says, because eye function rarely is affected by neurological damage. "Eye movement problems are very rare compared to other faculties that can diminish," she says. "It's one of the last systems to go."
In her study, Hallowell experimented with eye movement tests on a control group of 10 adults with no neurological disorders. The participants were given the most widely used standardized test of reading comprehension for patients with aphasia, a neurological disorder that often follows a stroke, inhibiting speaking and comprehension of words.
The test measures comprehension by asking patients to select words, either by pointing or speaking, that correspond to a certain picture. For example, a booklet might show a school bus with three corresponding words -- sub, bun and bus.
In the eye movement portion of the study, the subjects weren't given any instructions and simply were told to look at the images from the standardized test on a computer screen. As the same image of the school bus and the three words appeared on the screen, a video-based system tracked reflections from a near-infrared light shining on their eyes. Their comprehension level was determined by the amount of time they spent looking from the image of the bus to the word "bus."
"If they are comprehending it, they will look from the word 'bus' to the actual bus, and they'll spend more time doing that than looking at the other words," Hallowell says. "We look for these kinds of predictable patterns."
Hallowell found that the results from the traditional test matched the results from the eye movement test, which suggests the eye movement assessment is effective. Using this information, she now is developing new tests for patients with neurological disorders.
"You have to be much more careful with visual stimuli when it comes to people with neurological disorders," she says. "You have to make sure the objects on the screen are far apart from one another. Also, you need to give these subjects more time to look at the stimuli."
Her work on developing new tests is being funded through a five-year $466,970 grant from the National Institutes of Health. Part of that will support the development of eye movement tests for hearing comprehension. Hallowell's research was co-authored by Richard Katz of the Carl T. Hayden Veterans Administration Medical Center in Phoenix, Ariz. Hallowell holds an appointment in the College of Health and Human Services
Attention reporters and editors: A photo of Brooke Hallowell demonstrating her eye movement tests may be downloaded from the Web at http://www.ohio.edu/news/pix/EYE.JPG. To receive the image as a JPG attachment by e-mail or to obtain the journal article on which this story is based, contact Melissa Rake at 740-593-1891 or Kim Walker at 740-593-1043. The cutline is below.
Cutline information: Ohio University Assistant Professor Brooke Hallowell and her colleague Norman Garber demonstrate a new test to measure comprehension levels of patients with neurological damage. A video-based system tracks reflections from a near-infrared light shining on the patient's eyes. Photo credit: Rick Fatica.
Journal
Brain and Language