Nav: Home

Retraining the brain to see after stroke

April 12, 2017

Patients who went partially blind after suffering a stroke regained large swaths of rudimentary sight after undergoing visual training designed by researchers at the University of Rochester Medical Center's Flaum Eye Institute.

A new study out today in Neurology®, the medical journal of the American Academy of Neurology, provides the first evidence that rigorous visual training recovers basic vision in cortically blind patients who suffered stroke damage in the primary visual cortex. Damage to this area of the brain prevents visual information from getting to other brain regions that help make sense of it, causing loss of sight in one-quarter to one-half of an individual's normal field of view. Somewhere between 250,000 and 500,000 people suffer vision loss due to damage to the visual cortex each year.

"We are the only people in the U.S. currently using this type of training to recover vision lost after damage to the primary visual cortex," said study senior author Krystel Huxlin, Ph.D., director of Research and James V. Aquavella, M.D. Professor of Ophthalmology at URMC's Flaum Eye Institute. "If you talk to the majority of clinicians, they still believe nothing can be done."

It was long believed that patients' visual deficits stabilize six months after their stroke - no longer getting any worse and unable to get any better. Patients with visual cortex strokes are offered no hope of recovery and are advised to adapt to their vision loss, which is in stark contrast with other types of strokes. For instance, patients with stroke damage in areas of the brain that control movement are sent to physical therapy as soon as possible and usually recover significant mobility.

Huxlin, who is also a professor in the departments of Neuroscience, Brain & Cognitive Sciences and the Center for Visual Science at UR, developed a sort of physical therapy for the visual system - a way of rerouting visual information around the dead areas of the primary visual cortex.

Her team created personalized software programs for 17 cortically blind patients that flashed small circles of striped patterns or moving dots in the patient's blind field - the area of their field of view where they could no longer see. Patients reported the orientation of the stripes or the direction in which the dots were moving as they were flashed on the screen.

At first, patients only guessed correctly half of the time, but over time they began to sense, and then actually see enough of the patterns and dots to answer correctly 80 percent of the time, which is on par with participants who have normal vision. Clinical tests also showed that the patients' blind fields shrank, but the gains in vision were hard for them to put into words.

One patient said she no longer has mishaps like she did right after her stroke - like the time she missed the "W-o-" on the women's room sign and wondered why two men's bathrooms would be side by side. Faces and objects that looked squat and distorted after her stroke have also returned to normal. Several other patients have been able to get back in the driver's seat after undergoing Huxlin's visual training and completing a driver rehabilitation program.

"Patients go from nothing to a sensation of motion, to vision, albeit not quite normal vision," said study coauthor Matthew Cavanaugh, a student in the Neuroscience Graduate Program at URMC. "The hope is that we can refine our training methods to train the recovered vision to be better, clearer and more useful."

Huxlin's study also challenged conventional wisdom that cortically blind patients' visual deficits stabilize six months after stroke. In the study, the visual deficits of five cortically blind patients who did not do any visual training continued to get progressively worse. Huxlin's team is verifying this finding in a larger group of cortically blind patients by studying how their blind field maps change over time after stroke, without visual training. The results could provide greater justification for prescribing visual training to all patients who are capable as early as possible.

"It might actually be wrong not to train these patients," said Huxlin. "Our training may be critical both for preventing and reversing a gradual, very slow, but persistent loss of vision after stroke."

Huxlin estimates that any patient - regardless of age, blind field size, or how long ago they had a stroke - could have meaningful improvements in sight in about three months if they train twice day, for 30 minutes each time, but recommends patients continue to train as long as they continue to improve.

Huxlin's visual training technology has been licensed by EnVision LLC, which will sponsor a clinical trial to be conducted at several sites including the URMC Flaum Eye Institute. Huxlin and the University of Rochester may benefit from royalties should the technology be commercially successful.
-end-
For a copy of the full study, please contact rtessman@aan.com.

For media inquiries, please contact Susanne_Pallo@urmc.rochester.edu.

If you would like to learn more about participating in visual training studies, contact Christine_Callan@URMC.Rochester.edu.

University of Rochester Medical Center

Related Stroke Articles:

Retraining the brain to see after stroke
A new study out today in Neurology, provides the first evidence that rigorous visual training restores rudimentary sight in patients who went partially blind after suffering a stroke, while patients who did not train continued to get progressively worse.
Catheter ablations reduce risks of stroke in heart patients with stroke history, study finds
Atrial fibrillation patients with a prior history of stroke who undergo catheter ablation to treat the abnormal heart rhythm lower their long-term risk of a recurrent stroke by 50 percent, according to new research from the Intermountain Medical Center Heart Institute.
Imaging stroke risk in 4-D
A new MRI technique developed at Northwestern University detects blood flow velocity to identify who is most at risk for stroke, so they can be treated accordingly.
Biomarkers may help better predict who will have a stroke
People with high levels of four biomarkers in the blood may be more likely to develop a stroke than people with low levels of the biomarkers, according to a study published in the Aug.
Pre-stroke risk factors influence long-term future stroke, dementia risk
If you had heart disease risk factors, such as high blood pressure, before your first stoke, your risk of suffering subsequent strokes and dementia long after your initial stroke may be higher.
Intervention methods of stroke need to focus on prevention for blacks to reduce stroke mortality
Blacks are four times more likely than their white counterparts to die from stroke at age 45.
Study shows area undamaged by stroke remains so, regardless of time stroke is left untreated
A study led by Achala Vagal, M.D., associate professor at the University of Cincinnati College of Medicine and a UC Health radiologist, looked at a group of untreated acute stroke patients and found that there was no evidence of time dependence on damage outcomes for the penumbra, or tissue that is at risk of progressing to dead tissue but is still salvageable if blood flow is returned in a stroke, but rather an association with collateral flow -- or rerouting of blood through clear vessels.
Immediate aspirin after mini-stroke substantially reduces risk of major stroke
Using aspirin urgently could substantially reduce the risk of major strokes in patients who have minor 'warning' events.
SAGE launches the European Stroke Journal with the European Stroke Organisation
SAGE, a world leading independent and academic publisher, is delighted to announce the launch of the European Stroke Journal, the flagship journal of the European Stroke Organisation.
The S-stroke or I-stroke?
The year 2016 is an Olympic year. Developments in high-performance swimwear for swimming continue to advance, along with other areas of scientific research.

Related Stroke Reading:

My Stroke of Insight: A Brain Scientist's Personal Journey
by Jill Bolte Taylor (Author)

Stronger After Stroke, Third Edition: Your Roadmap to Recovery
by Peter G Levine (Author)

Stroke: Pathophysiology, Diagnosis, and Management
by A David Mendelow MB BCh FRCS PhD (Author), Eng H. Lo PhD (Author), Ralph L Sacco MD MS FAHA FAAN (Author), Lawrence KS Wong MD FRCP (Author), Eng H. Lo PhD (Editor), Ralph L Sacco MD MS FAHA FAAN (Editor), Lawrence KS Wong MD FRCP (Editor), James C. Grotta MD (Editor), Gregory W Albers MD (Editor), Joseph P Broderick MD (Editor), Scott E Kasner MD MSCE FRCP (Editor)

Caplan's Stroke: A Clinical Approach
by Louis R. Caplan (Editor)

Puzzles for Stroke Patients: Rebuild Language, Math & Logic Skills to Live a More Fulfilling Life Post-Stroke
by Kalman Toth (Author)

Healing the Broken Brain: Leading Experts Answer 100 Questions about Stroke Recovery
by Dr. Mike Dow (Author), David Dow (Author), Megan Sutton CCC-SLP (Contributor)

Living With Stroke: A Guide for Patients and Their Families
by Richard C. Senelick MD (Author)

Stronger After Stroke: Your Roadmap to Recovery, 2nd Edition
by Peter G. Levine (Author)

Stroke Rehabilitation: A Function-Based Approach
by Glen Gillen (Author)

Stroke For Dummies
by John R. Marler (Author)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Unintended Consequences
Human innovation has transformed the way we live, often for the better. But as our technologies grow more powerful, so do their consequences. This hour, TED speakers explore technology's dark side. Guests include writer and artist James Bridle, historians Yuval Noah Harari and Edward Tenner, internet security strategist Yasmin Green, and journalist Kashmir Hill.
Now Playing: Science for the People

#499 Technology, Work and The Future (Rebroadcast)
This week, we're thinking about how rapidly advancing technology will change our future, our work, and our well-being. We speak to Richard and Daniel Susskind about their book "The Future of Professions: How Technology Will Transform the Work of Human Experts" about the impacts technology may have on professional work. And Nicholas Agar comes on to talk about his book "The Sceptical Optimist" and the ways new technologies will affect our perceptions and well-being.