Right Brain Can Compensate for Speech Loss from Stroke After All

Researchers at Georgetown University Medical Center have found that loss of speech from a stroke in the left hemisphere can be recovered on the back right side of the brain, contradicting the 130-year-old belief that the right hemisphere interferes with recovery.

The findings, published online in the November 3 issue of Brain, may suggest a new direction in treatment.

The team looked at brain structure and measured grey matter volume in 32 survivors of a left-hemisphere stroke, as well as 30 healthy volunteers. The stroke survivors also underwent language assessment and other cognitive function tests.

They found that patients who regained speech had increased grey matter volume in the back of their right hemisphere, mirroring the location of one of the two left hemisphere speech areas. This group also had more grey matter than those in the control group. The researchers also measured grey matter volume in stroke survivors who had no aphasia and found that the volume of the right hemisphere was smaller in that population. These observations indicate that the right back hemisphere did increase in volume.

Nearly one-third of patients who suffer a stroke lose speech and language abilities, and most never fully regain it. Loss of speech almost always occurs in people who had a stroke in the left hemisphere. In fact, 70% of people whose stroke occurred in the left hemisphere have some language problems.

“Over the past decade, researchers have increasingly suggested that the right hemisphere interferes with good recovery of language after left hemisphere stroke,” Peter Turkeltaub, MD PhD, senior author and assistant professor of neurology at Georgetown University Medical Center and director of the aphasia clinic at Medstar National Rehabilitation Network, said in a news release. “Our results suggest the opposite — that right hemisphere compensation improves recovery.”

The team is now looking for other areas of the brain that compensate for deficits in language, such as impairment in comprehension.