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. Researchers stimulated the visual cortex to help the brain to use the information it receives from the eye as efficiently as possible.
“This finding is exciting because this is the first study to demonstrate brain stimulation in patients with macular degeneration had a positive impact on an important real-world skill like reading,” said Andrew Silva, a postdoctoral fellow in Waterloo’s School of Optometry and Vision Science.
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 the 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.
A parallel study conducted at Hong Kong Polytechnic University Waterloo's Centre for Eye and Vision Research used the same methodology, except participants read one Chinese word instead of one English word. Surprisingly, the reading skill of participants in the Hong Kong study did not improve with the stimulation like those in the Canadian study.