Brain stimulation may benefit people with blinding eye disease

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In a study from the University of Waterloo, scientists found brain stimulation improves reading in patients with macular degeneration.

Drug treatments only slow down the progression of the disease, but Waterloo scientists discovered they could train the brain to use the information it receives more efficiently.

Transcranial direct current stimulation (tDCS) is a non-invasive, painless brain stimulation treatment that uses direct electrical currents to stimulate specific parts of the brain.

In the study, researchers stimulated the visual cortex to help the brain to use the information it receives from the eye as efficiently as possible.

Patients with macular degeneration can develop blurred or no central vision, which is the part that allows a person to see fine details and high resolution.

As a result, they rely on low-resolution vision from their periphery, which makes tasks like reading very difficult.

Participants in the study were presented with 30 sentences, one word at a time. Then the 20-minute stimulation began while participants read 30 additional sentences word by word.

Reading accuracy was evaluated immediately, five and 30 minutes later. Participants reading accuracy improved at all time intervals after stimulation.

Another recent study used the same methodology, except participants read one Chinese word instead of one English word.

Surprisingly, the reading skill of participants did not improve with the stimulation like those in the current study.

The researchers suspect the differences between the studies highlight the intrinsic differences between the writing systems.

For example, in English, words are comprised of multiple letters, but in Chinese, one word can be represented by a single character.

The letters within the English word crowd each other, making it difficult to correctly identify the word with peripheral vision. Brain stimulation is known to release this crowding effect.

However, since that recent study presented one character at a time, there was no between-character crowding to release.

Next, the team is assessing the impact of long-term tDCS stimulation on English reading skills, with an eye toward long-term reading improvements.

If you care about eye health, please read studies about eye problem that may signal higher risk of dementia and early death, and how vitamin B may help fight vision loss and COVID-19.

For more information about eye health, please see recent studies about 5 dangerous signs you have diabetes-related eye disease, and results showing how to protect your eyes from glaucoma.

The study was conducted by Andrew Silva et al and published in Brain Stimulation.

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