ARTICLE IN BRIEF
A visual training regimen, which seemed to bolster the performance of a college baseball team, may have application for survivors of stroke and traumatic brain injury, experts say.
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A computer-based visual training regimen that helped college baseball players improve their performance might also help people with cortically based visual disturbances, according to the researchers who conducted the study, published in the February issue of Current Biology.
“I've been working to get access to stroke and traumatic brain injury [TBI] patients so I can validate this idea,” said lead author Aaron R. Seitz, PhD, a professor of psychology at the University of California (UC), Riverside. “There are some vision training programs, such as NovaVision, that try to fill in cortical scotomas in stroke patients, and I want to see if our program can produce similar benefits. Our program is designed to help improve not just vision, but [also] attention, which is an issue with TBI, so it seems likely that it should help patients see and develop better focus.”
THE STUDY METHOD
The Current Biology study involved 19 players on the UC Riverside baseball team, who participated in 30 sessions of visual training over two months, each lasting about 25 minutes.
The players did two main types of exercises. Static exercises involved spotting Gabor patches — targets of varying spatial frequency and orientation — on the computer screen and clicking on the targets as fast as possible. The dynamic exercises involved spotting targets one at a time as they appeared at different points on the screen. Both types of exercises introduced distractors that became increasingly similar to the targets, and the exercises increased in difficulty as the players improved.
After completing the training, the visual acuity of the players improved an average of 31 percent — from a pre-training mean of 20/13 to a post-training mean of 20/10, with seven players achieving visual acuity of 20/7.5.
“To get a reading of 20.7.5 the players had to stand 40 feet from the eye chart instead of 20 before attempting to read the 20/15 line,” Dr. Seitz said. “These players had spectacular vision to begin with. I'm kind of amazed that people who started off with such good vision could improve so much.”
A control group of 18 pitchers with similar visual acuity who did not undergo the visual training showed only marginal improvement.
Also, the team reduced their strikeouts by 4.4 percent — the only significant year-to-year reduction in strikeouts in the Big West League over the last five years. A sabermetric analysis — the method of analyzing baseball statistics used in the movie “Moneyball” — estimated that the UC-Riverside team won four to five more games than expected based on typical year-over-year improvements found in other Big West teams.
Dr. Seitz and his colleagues compared the improvement among the UC Riverside players to every other team in the league going back five years. In that time, those teams engaged in various strength-building and dietary interventions. Some also used cameras that record a batter's swing and generate suggestions on how to improve.
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A version of the eye training program is available for download as an app called UltimEyes. “It's a slightly improved version of the research program we used,” Dr. Seitz said.
Dr. Seitz and his colleagues set out to create an integrated approach to visual training by combining results from other studies that attempted to increase the strength of eye muscles and increase brain processing of visual signals.
“Basically we put them all together in the same program and tried to figure out how to get the largest effects possible,” Dr. Seitz said. “Now we're conducting studies where we take them out one at a time and try to measure how each one contributes.”
The training presumably relies on brain plasticity, but where in the brain the most significant changes occur remains ambiguous. “The entire visual system undergoes some degree of plasticity when you learn to perform any task better, but typically there is less plasticity in the early visual areas than in the later visual areas,” Dr. Seitz said. “I think some of the effects are due to improved attention, and other effects are due to early visual neurons, maybe in the visual cortex.”
DOES IT WORK FOR NEUROLOGY?
Visual training has been used for decades to improve various visual disorders, but the exercises tend to be arduous, with patients slow to improve. For example, Krystel R. Huxlin, PhD, a professor of ophthalmology at the Flaum Eye Institute of the University of Rochester Medical Center, attempts to help stroke patients recover vision in their blind field.
“People have to fixate on single spot, and while they're fixating we present a stimulus to their (peripheral) blind field at places we map,” she said. “Then we force them to tell us something precise about the stimulus. Is it moving right? Is it moving left? Is it oriented vertically? Is it oriented horizontally?”
The training to develop visual awareness in each portion of the blind field takes months, “and when they improve in one area we move to another and start all over,” Dr. Huxlin said.
Among other stimuli, she uses the same Gabor patches that Dr. Seitz and his colleagues use, but her patients must keep their eyes focused on a single spot, while the baseball players were free to explore the entire screen for targets. So she hopes to collaborate with Dr. Seitz on a project to adapt the training regimen he used with the baseball players to stroke patients, which might result in more rapid improvement.
“We know these stroke patients, even though their primary visual cortex has been damaged permanently, still have higher-level visual cortical areas that are not damaged and are still capable of receiving information from subcortical visual centers, but the visual information is degraded and usually unconscious, so patients tend to ignore it,” Dr. Huxlin said. “It's as though the visual system suddenly devotes all of its attention to that intact portion of the visual field and ignores this degraded information that's coming from the blind field.”
Through visual training, however, these patients learn to pay more attention to the degraded visual input and make use of it.
“When we train our patients in this rigorous regime, they try to register what's going on in the blind field,” Dr. Huxlin said. “They know what reality is because they get feedback on whether they were right or wrong, which is important for them to get better.”
The training regimen used by Dr. Seitz and his colleagues trains subjects to pay closer attention to a large portion of their visual field and extract information from it.
“I don't think anyone has done this before in the context of perceptual learning,” Dr. Huxlin said. “Either people have trained subjects visually and forced them to extract precise information from a single location, or they've done eye movement training. The unique thing that Aaron has done is combine the two, and we've very keen to see if there's a way to adapt that.”
Other potential applications of the type of visual training used in the Current Biology paper, according to Dr. Huxlin, might include improving attention among the elderly. “In aging, the functional size of the visual field tends to shrink, largely as a result of the attentional field shrinking,” she said. “This training paradigm could help people enlarge their attentional field, which could have serious implications for driving, when you need to react to things coming at you from the side. Anyone who does visual exercises will get better. There's nothing to lose with this. It's non-invasive.”
While visual training may help stroke patients recover some lost vision, the nature of the impairment must be identified, according to Ronald M. Lazar, PhD, a professor of neuropsychology at the Columbia University Medical Center, and director of the Levine Cerebral Localization Laboratory at the Columbia University College of Physicians & Surgeons.
“I think before patients go through a technique like this, they need thorough evaluation to make sure that critical prerequisites are intact,” he said. “For example, has there been impairment in reaction time, in scanning, in memory or attention and concentration? The techniques they used with these baseball players seemed to work, so perhaps they could be adapted to those who have various types of visually-related disorders from stroke or other brain impairments.”
Dr. Lazar also admired the training paradigm for the way it used continuous reinforcement to promote motivation and to maximize performance. “They make changes that are competency-based so you don't go to a more complex step until you have demonstrated mastery of a prior step, and if you don't demonstrate mastery, they make it simpler before you move up again,” he said. “That kind of titration is a definite strength of this kind of technique.”
Michael A. Dimyan, MD, an assistant professor of neurology at the University of Maryland School of Medicine and the VA Maryland Health Care System, found the results of the study compelling because of the strength of the effect produced, but he wondered if such results would generalize to other skills.
“In general, cognitive training seems to work, but it seems to be specific to whatever you train for,” he said. “If you practice a particular computer game, you get better at that computer game, but you generally don't feel a lot of effects transferring to more global skill domains. Here, at least the transfer from improvement in the app to improvement of visual acuity was probably the most exciting effect.”
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