Children outperform adults in recovering language abilities following brain damage. A landmark U.S. study reveals that young brains leverage both hemispheres for sentence comprehension, unlike adults who rely solely on the left.
In neurologically typical adults, language processing—especially sentence comprehension—predominantly occurs in the left hemisphere. Young children, however, engage both hemispheres. This finding, published in PNAS on September 8, 2020, by researchers at Georgetown University Medical Center, sheds light on why infants with left-hemisphere lesions at birth can still develop language skills. The team used functional MRI to scan 39 children and 14 adults aged 4 to 29.
While language-related functions are lateralized to the left in adults, prosody and discourse processing often involve the right. Infants and toddlers also favor the left for core syntax, yet right-hemisphere damage in children can impair language—a puzzle this research addresses.
Functional MRI tracks blood oxygenation to map brain activity. Participants listened to sentences inside the scanner and pressed a button for grammatically correct ones—a proven measure of comprehension. Analyzing whole-brain data, the researchers pinpointed regions where activation correlated with age.
Children showed language processing skewed leftward but with notable right-hemisphere involvement in key areas. This bilateral activation wanes with age, fully lateralizing to the left by adulthood, as confirmed by the study leads.
These insights offer optimism for children with early brain injuries. Bilateral engagement provides a natural compensation mechanism: a perinatal stroke victim might rely on the right hemisphere to acquire language, while a child with cerebral palsy develops essential cognitive skills there too.
The right hemisphere thus serves as a vital backup during development, explaining superior language recovery in children after left-hemisphere damage. The Georgetown team plans follow-up studies on adults and adolescents who had perinatal strokes to validate and expand these findings.
