Strokes are exceedingly common; they are the fifth leading cause of death in the United States. A stroke occurs when the brain is deprived of blood flow. Blood supplies essential oxygen to the brain, so any loss of blood flow marks a critical period. When brain cells are deprived of oxygen, they begin to die. When brain cells die, their corresponding regions of motor movement and processing fail.
The severity of a stroke can differ according to the brain region affected and the duration of oxygen loss. Small strokes might only temporarily impede movement or muscle control, but serious strokes can permanently paralyze body parts or inhibit speech. More than two-thirds of patients who suffer strokes become permanently disabled.
Elderly are the most affected demographic, but strokes can also affect infants. The birthing process is strenuous on a baby’s delicate head, and this can lead to trauma on their circulatory system. However, an infant who suffers a stroke in the speech areas of the brain is still able to process, understand and speak language, unlike their adults counterparts. Researchers at the American Association for the Advancement of Science collected data from teenagers who had undergone strokes as babies, and their results showed that the subjects were able to process speech and communicate just as effectively as their stroke-free siblings.
To further test how the subjects compensated for their brain damage, researchers conducted an experiment where they read sentences forward and backward to the subjects while imaging their brain function. They found that the area of the brain that processes speech had shifted from the left hemisphere to the right hemisphere, in what appeared to be a near-perfect mirror image. Normally, this area that the stroke survivors used to process speech is never used in such a manner by healthy individuals. Furthermore, this area is not used by individuals who have suffered strokes as adults.
Researchers believe that there is a specific period of time in which the infant’s brain has enough elasticity to make the changes necessary for speech processing. The precise mechanism by which these infants were able to make the accommodations has not yet been uncovered. The researchers hope that this eventual discovery will help to develop treatments for adult stroke patients who have lost the ability to speak.
