Children use both brain hemispheres to learn languages and also recover from head injuries
Brain injury or stroke can rob people of their ability to communicate, but language skills appear to bounce back in infants and young children, unlike adults. Why is that? A new study that investigated the question suggests that children may have hidden "superpowers" in the brain.
Brain imaging reveals that children can use the right and left hemispheres of the brain for language skills, researchers from Georgetown University Medical Center said. It suggests that damage to one half allows the young to use the other. Adults, on the other hand, can engage only certain regions in the left hemisphere for communicating. The finding suggests a possible reason why children appear to recover from brain injury a lot easier than adults, according to the team.
"I have long been interested in why young children are better at language learning," Dr Elissa L Newport, a neurologist at Georgetown University Medical Center, told MEA WorldWide (MEAWW). One part of that question includes looking at their brains and understanding how they recover from an injury.
The brain is divided into two halves. The left hemisphere is responsible for language, studies suggest. Damage to the left half of the brain is linked with a communication problem known as aphasia, which strikes suddenly after a stroke or a head injury. Some of the signs of the condition include speaking in short, incomplete or incomprehensible sentences and writing sentences that don't make sense.
Using both hemispheres could help children compensate for damage following an injury. "For example, if the left hemisphere is damaged from a perinatal stroke — one that occurs right after birth — a child will learn a language using the right hemisphere," Newport explained. "A child born with cerebral palsy that damages only one hemisphere can develop needed cognitive abilities in the other hemisphere. Our study demonstrates how that is possible."
Young children who suffer damage to either half of the brain are unlikely to suffer from language impairments. These facts suggest that language is distributed to both hemispheres early in life, Newport says. However, previous studies have not dug deeper to investigate the matter.
In their study, Dr Newport and her colleagues enrolled 39 children aged between 4 and 13 years. They scanned their brains using a sophisticated imaging technique that helps experts map the functions of the brain called functional Magnetic Resonance technique (fMRI). As children performed a sentence comprehension task, the researchers looked at which part of the brain was getting activated.
Their analysis allowed the team to note that children, in the early stages of development, can use both hemispheres of the brain for language. This ability was strong in those aged 4-6 years and it weakened with age. "This is very good news for young children who experience a neural injury," Newport, director of the Center for Brain Plasticity and Recovery, a joint enterprise of Georgetown University and MedStar National Rehabilitation Network, said.
Experts do not understand why children lose the ability to engage both halves of the brain with time. But they speculate that this could be due to adult brains having specific regions for processing speech. "This has not yet fully developed in children. The adult division of skills, each with their own space in the brain, seems to mean that we can no longer reorganize things after injury," she added.
The study is published in PNAS.