In adults, the processing of language and sentence structure is only made possible in the left hemisphere of the brain. This is according to MRI brain scanning and clinical findings from adult stroke patients with loss of language due to left hemisphere damage.
But from a study done at Georgetown University Medical Center and published in September of 2020 in PNAS, finds that young children are able to process and understand spoken language in both hemispheres.
This information puts to bed what has puzzled clinicians and neuroscientists for many years.
As adults, we process certain information that is assigned to specific brain regions in each hemisphere. Each neural task activates these centers. In children, it appears they can process the same information using different set of neural networks from either side of the brain. This is good news for children who suffer from prenatal strokes. This information seems to provide answers to why children recover so much faster than adults from neural injury.
Georgetown neurology professor, Elissa L. Newport, PhD, a former postdoctoral fellow Olumide Olulade, MD, PhD, and neurology assistant professor Anna Greenwald, PhD. said, ”This is very good news for young children who experience a neural injury. Use of both hemispheres provides a mechanism to compensate after a neural injury. For example, if the left hemisphere is damaged from a perinatal stroke-one that occurs right after birth- a child will learn language using the right hemisphere. 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.”
By looking at fMRI scans researchers can now see that both hemispheres participate early on in the development of language skills.
Neural networks in early childhood localize to one hemisphere or the other but are not complete until the ages of 10 or 11. Through these findings they now have a clearer understanding of how this process works when dealing with recovery from brain injury. What they still don’t know is whether the left hemisphere dominance in language skills exists at birth or gradually develops.
The basis of the study enrolled 39 children ages 4-13 years of age and 14 young adults ages18-29. They were all given a sentence comprehension task. Then the research team looked at fMRI scans from each participant and made evaluations of language activation maps from 4 age groups; 4-6,7-9,10-13,and 18-29. After performing whole brain scans they analyzed the percentage of activation of the language centers used as it correlated with each age group.
It was found that in young children left hemisphere language activation was easily seen. But, also within the youngest group levels, there was a significant portion of right corresponding hemisphere language activity as well.
In adults, the right side of the brain will participate in processing the emotional content in language comprehension. Here, they see that in the youngest age group, they were capable of utilizing both hemispheres to comprehend sentence meaning and emotional content.
The consensus was that they now believe that if they were to test even younger children they would likely find even greater right hemisphere involvement for language development.
This study is now leading to further examination of language activity brain regions in teenagers and young adults with critical left hemisphere damage from stroke at birth.
With so many things in life, timing is everything. This study indicates how our human pattern for brain development is dynamic and takes a necessary amount of time to ensure our survival. Having the flexibility to understand language from either hemisphere in early childhood is a great example of this.
-A Balanced Brain is a Better Brain for a Happier Life-