Thanh An
Stroke is a leading cause of disability in the US, with loss of speech being one of its many devastating effects. For years, some scientists have claimed the right hemisphere of the brain interferes with speech recovery following stroke in the left hemisphere; but according to a new study, the opposite is true.
Publishing in the journal Brain, researchers from Georgetown University Medical Center (GUMC) in Washington, DC, found that the right side of the brain increases growth of gray matter to compensate for loss of gray matter in speech-related areas in the left side due to stroke, which can aid speech recovery.
Study coauthor Dr. Peter Turkeltaub, assistant professor of neurology at GUMC, and colleagues say their findings may offer new treatment options for stroke.
Each year, more than 795,000 people in the US have a stroke. Of these, around 185,000 are first-time strokes.
The effects of stroke depend on how much brain tissue is affected and in what part of the brain it occurs. For example, if stroke occurs in the right side of the brain, this may lead to problems such as vision loss and paralysis on the left side of the body.
If stroke occurs in the left side of the brain, this may lead to paralysis on the right side of the body and speech and language problems. Around a third of people who survive a stroke experience loss of speech, known as aphasia, and this almost always occurs in those who have experienced left-hemisphere strokes; around 70% of left-hemisphere stroke survivors have language problems.
Some individuals who experience speech loss after stroke may recover gradually in subsequent months, although most never fully recover. Over the past decade, studies have suggested the right side of the brain impairs the speech recovery process; the GUMC team set out to investigate this theory further.
'Right hemisphere compensation improves speech recovery'The researchers enrolled 32 individuals with aphasia who had experienced stroke in the left hemisphere of the brain, alongside 30 people who had not had a stroke.
The stroke survivors underwent language assessments to determine severity of their speech problems, and all participants underwent high-resoluti