http://www.sciencedaily.com/releases/2010/09/100928154259.htm

ScienceDaily (Sep. 28, 2010) — The world's largest study using
neuroimaging of stroke patients struggling to regain ability to
communicate finds that brain cells outside the damaged area can take
on new roles.

Julius Fridriksson, a researcher at the University of South Carolina's
Arnold School of Public Health, said the findings offer hope to
patients of "chronic stroke," characterized by the death of cells in a
specific area of the brain. The damage results in long-term or
permanent disability.

"For years, we heard little about stroke recovery because it was
believed that very little could be done," Fridriksson said. "But this
study shows that the adult brain is quite capable of changing, and we
are able to see those images now. This will substantially change the
treatment for chronic-stroke patients."

The study, reported in the Sept. 15 issue of the Journal of
Neuroscience, involved 26 patients with aphasia, a communication
disorder caused by damage to the language regions in the brain's left
hemisphere. Aphasia impairs a person's ability to process language and
formulate speech.

About 35 percent of stroke patients have speech and/or communication
problems. While many patients with aphasia regain some language
function in the days and weeks after a stroke, scientists have long
believed that recovery is limited after this initial phase. "Stroke is
the leading cause of disability among adults, more than accidents or
complications from Parkinson's or Alzheimer's diseases," said
Fridriksson, director of the university's Aphasia Laboratory and an
associate professor in the department of communication sciences and
disorders.

"When someone has brain damage as a result of a stroke, the recovery
is expected to be limited," he said.

But Fridriksson's study shows that the brain can recover and that a
patient's ability to communicate can improve.

Stroke patients underwent a functional magnetic resonance imaging
test, also called fMRI, which measures brain activity. Patients
received multiple MRI sessions before and after undergoing 30 hours of
traditional speech therapy used to improve communication function in
patients with aphasia.

By using fMRI -- an imaging technique more improved and widely used in
the past decade -- Fridriksson was able to see the healthy areas of
the brain that "take over" the functions of the areas damaged as a
result of a stroke.

"The areas that are immediately around the section of the brain that
was damaged become more 'plastic,' " Fridriksson said. "This
'plasticity,' so to speak, increases around the brain lesions and
supports recovery. In patients who responded well with the treatment
for anomia [difficulty in recalling words and names], their fMRI
showed evidence that areas of the brain took over the function of the
damaged cells."

The study found that patients who did not experience these changes did
not have as improved a recovery, he said.

This research lays the foundation for future studies of aphasia,
including research on the use of low-current, electrical stimulation
for the brain.

"Knowing where the brain has been damaged -- and the section that is
taking over that function -- will enable us to better use electrical
stimulation to promote recovery," said Fridriksson, the lead author of
another paper published last month in the Journal of Neuroscience that
examined the mapping of brain lesions that cause speech/communication
impairment.

"It is believed that electrical currents to the brain will promote
secretions of neurotransmitters that support brain plasticity," he
said. "This could dramatically improve the quality of life for stroke
patients."