The shift was documented by researchers led by Jerzy Szaflarski, MD, PhD, assistant professor in the Department of Neurology at the University of Cincinnati (UC) Academic Health Center, and Scott Holland, PhD, professor in the UC departments of biomedical engineering, pediatrics and radiology. Dr. Holland also heads the Pediatric Brain Imaging Research Program at Cincinnati Children's Hospital Medical Center.
Their results will be published in the February 2006 edition of the journal Human Brain Mapping.
While the site of language activity in right-handed people is originally the left side of the brain, the researchers report, starting as early as age 5 language gradually becomes a function shared by both sides. Between the ages of about 25 to 67, the site becomes more evenly distributed, until language activity can be measured in both hemispheres simultaneously.
This, the researchers say, may explain why young children who have had a large portion of one side of the brain surgically removed often recover completely.
"This knowledge may give new hope for rehabilitation of brain function in adults after stroke or traumatic brain injuries," said Dr. Szaflarski. "The fact that language adaptability is seen even in the older people supports the notion that these patients can be rehabilitated and returned to productive life, possibly even after a devastating stroke."
Scientists have long thought that the hemisphere or side of the brain that controls language and speech is determined before birth. Most people are right-handed and demonstrate more activity during language or speech in the left hemisphere of the brain. In left-handed people language centers are located more symmetrically.
Contact: Sheryl Hilton
University of Cincinnati