Among the blind people tested in the study, those who perceived most quickly were the swiftest braille readers. (David Mdzinarishvili/Reuters)

People who are blind from birth are able to perceive information relayed by their sense of touch faster than people who are sighted, a new study finds.

People blind at birth typically are better at reading braille — which represents the alphabet through arrangements of raised dots — than those who go blind in adulthood.

Scientists knew that the brains of people who are blind since birth show changes, such as how the vision part of the brain tends to be taken over by touch and hearing.

Daniel Goldreich, an associate professor of psychology, neuroscience and behaviour at McMaster University in Hamilton, was interested in if those changes have perceptual consequences, such as faster processing of the sense of touch.

To find out, the neuroscientists designed an experiment involving precise microscopic vibrations to time how long the brain takes to detect tactile information. The findings were published in Wednesday's issue of The Journal of Neuroscience.

"We discovered that congenitally blind people are indeed faster to perceive a tap on the fingertip than are sighted people," said Goldreich, who came to McMaster from Pittsburgh in 2005.

"What's more, among the blind people we tested, we discovered that those who perceived most quickly were the swiftest braille readers."

The experiment focused on 89 sighted and 57 people with various levels of vision loss from the Greater Toronto Area. Their ability to perceive the movement of a small probe against the tip of their index finger was assessed in the lab.

In the experiment, participants felt a small tap followed a very short time later by a longer vibration that cuts off the brain's ability to process the tap.

Accelerated processing

On simple tasks like distinguishing small taps versus stronger taps, the two groups performed equally. But for complex tasks that required the brain to quickly discern the tap before the interference, the 22 congenitally blind participants outperformed the sighted participants.

The researchers think that the longer the time between the tap and the vibration, the better formed the perception of the tap will be, and the less interference the vibration will cause.

The researchers don't know why touch perception is faster in people who are blind.

In Wednesday's issue of The Journal of Neuroscience, the researchers concluded that "perceptual processing is accelerated in congenitally blind braille readers."

It is not known whether the advantage is due to the brain adapting to the absence of vision — a change called plasticity — or to a lifetime of practicing braille.

"The heightened skill of tactile integration seems to account for the remarkable speed of braille-reading demonstrated by some congenitally blind individuals," Richard Held, an expert in the brain and visual development at the Massachusetts Institute of Technology, who was not part of the research, said in a release.

Next, Goldreich's team is creating computer programs to mimic the sense of touch, and they hope to track blind people as they learn braille to track their perceptual ability.

The research was funded by the U.S. National Eye Institute and the Natural Sciences and Engineering Research Council in Canada.