Deaf people use the hearing parts of their brain to sense touch
It’s often said that when you lose one sense you heighten the others — and now we have scientific evidence to back it up. New research published in the Journal of Neuroscience has shown that people who are born deaf process the sense of touch differently than people who are born with normal hearing.
The study shows how the loss of a sense results in the rewiring of the brain — an indication that, in the absence of sensory stimuli, the brain will adapt and take on additional sensory processing tasks.
The research was conducted by Christina Karns at the University of Oregon, Eugene, who, along with her colleagues, showed that deaf people use their auditory cortex to process touch and vision much more than hearing people do. Their finding shows just how malleable the brain can be, and how it goes about “multisensory processing.”
According to an article in LiveScience, past research has shown that deaf people use their brains differently than those born with hearing:
For instance, researchers found when deaf individuals are signing, they rely on the same brain areas that interpret spoken language, suggesting that something about language is universal.
Another study has shown that those born deaf are better at processing peripheral vision and motion, the researchers noted. Perhaps, the researchers said, deaf individuals use several brain regions, particularly auditory ones, to process vision. But would deafness also affect how the brain processes touch and vision together? This has been a tough one to answer, say the researchers, because in the lab, it’s tricky to produce precise tactile stimuli.
In the new study, researchers used MRI scanners to make the discovery. The scientists observed that blood flow levels increased to active areas of the brain following touch stimuli (puffs of air on the skin). Specifically, they noted increased activity in Heschl’s gyrus, a region in the primary auditory cortex where sound first reaches the brain.
Looking ahead, the researchers predict a number of different applications for their findings. In particular, they’d like to see teachers use touch and vision to help the deaf learn math or reading. The finding could also inspire clinicians to develop better quality cochlear implants.