Scientists at EPFL in Switzerland have developed a new, non-invasive brain therapy that could help stroke patients regain their vision faster and more effectively.
This method combines gentle brain stimulation with visual training, offering new hope for people living with hemianopia—a condition that causes them to lose half of their field of vision after a stroke.
Each year, many stroke survivors are left with hemianopia. This condition affects their ability to see everything on one side of their visual field, often split down the middle. It makes everyday activities like reading, walking in crowded areas, or driving extremely difficult.
Currently, there is no reliable treatment to restore vision lost due to hemianopia. Most existing therapies help people learn how to cope with the vision loss rather than actually recover it. And even the best recovery methods today require months of hard training with only limited results.
The EPFL research team, led by Professor Friedhelm Hummel, focused on how different parts of the brain responsible for vision work together.
Normally, the primary visual cortex and the medio-temporal area (which helps detect movement) communicate smoothly through specific brain rhythms or electrical signals called oscillations. But after a stroke, this communication can break down.
In earlier studies, scientists suggested that restoring these disrupted brain rhythms with external stimulation might help bring back visual function. The EPFL team took this idea further by testing a new type of brain therapy that stimulates two brain areas at the same time while the patient trains on a vision task.
The clinical trial included 16 stroke patients with hemianopia. During the study, each patient practiced detecting motion in the part of their visual field that had gone blind.
At the same time, they received a gentle brain stimulation called cross-frequency transcranial alternating current stimulation (cf-tACS). This method sends low-level electrical currents through the scalp to help re-align brain waves.
In this therapy, alpha waves (low frequency) were sent to the primary visual cortex and gamma waves (high frequency) to the medio-temporal area. This mimics the brain’s normal pattern of visual information flow and helps these two brain regions “talk” to each other again.
The results were very promising. Patients who received this “forward-pattern” brain stimulation improved more in motion detection compared to those who received the reverse-pattern control.
Some patients even noticed changes in their daily life. For example, one person was able to see their spouse’s arm on the side that was previously blind—something that was impossible before the treatment.
Brain scans and EEG tests confirmed that the brain areas involved in vision were working together more effectively after treatment. The biggest improvements were seen in patients whose visual brain pathways were still partly intact, showing that even partial preservation of these areas can support recovery.
This study shows that targeting specific brain pathways with synchronized stimulation can make visual training much more effective. If confirmed in larger trials, this therapy could become a faster, easier, and more accessible way to help stroke survivors regain lost vision.
If you care about stroke, please read studies about how to eat to prevent stroke, and diets high in flavonoids could help reduce stroke risk.
For more health information, please see recent studies about how Mediterranean diet could protect your brain health, and wild blueberries can benefit your heart and brain.
The study is published in Brain.
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