US researchers found that patients who had experienced strokes as long as six months earlier were able to regain brain function through the help of a novel robotic device that they squeezed with their hand. The researchers believe this is the first time that fMRI (function magnetic resonance imaging) has been used to map patients’ brains to track progress of rehabilitation.
The study was the work of Dr A. Aria Tzika and colleagues and was presented on 4 December at the 94th scientific meeting of the Radiological Society of North America (RSNA) in Chicago. Tzika is director of the NMR Surgical Laboratory at Massachusetts General Hospital (MGH) and Shriners Burn Institute and assistant professor in the Department of Surgery at Harvard Medical School in Boston.
Tzika said they had found that after a stroke the brain is able to regain function through rehabilitative exercise, even as long as six months later, longer than most experts would think possible, showing how malleable it is.
Stroke is the third leading cause of death among Americans, according to figures from the US Centers for Disease Control and Prevention (CDC). It’s a principal cause of long term disability and about 700,000 of them occur every year in the US, where 80 to 90 per cent of stroke survivors are left with motor weaknesses.
Before this study many people believed that rehabilitation following a stroke was only possible up to a period of three to six months; after that there was unlikely to be any improvement. As Tzika explained:
“Our research is important because 65 percent of people who have a stroke affecting hand use are still unable to incorporate the affected hand into their daily activities after six months.”
For the study, Tzika and colleagues recruited five right-handed patients who had suffered strokes at least six months earlier. In all cases the stroke had affected the left side of the brain and the use of the right hand. For one hour a day on three days a week for four weeks, the patients squeezed a special robotic device with their affected hand.
Before, during and after the hand exercising, including for a while later to assess the permanence of rehabilitation, the researchers took fMRI scans of the patients’ brains. (The robotic device was MR-compatible, which meant it would not significantly affect the quality of the fMRI readings obtained from the brain scans.) The fMRI scans enabled the researchers to measure very small changes in blood oxygen levels in the part of the brain that is active for those particular motor movements.
The results showed there was significant increase in activity of the cortex of the left brain, the part that lights up when the right hand is used. They also found that this part of the brain remained active for several months after patients stopped doing the hand exercises.
“These findings should give hope to people who have had strokes, their families and the rehabilitative specialists who treat them,” said Tzika.
“Functional MRI of Rehabilitation in Chronic Stroke Using a Novel MR-Compatible, Hand-induced, Robotic Device.”
A Aria Tzika, Dionyssios Mintzopoulos, Azadeh Khanicheh, Bruce Rosen, Loukas Astrakas, and Michael Moskowitz.
Scientific paper SSQ15-07, presented at 94th scientific meeting of the Radiological Society of North America (RSNA) in Chicago, 4 December 2008.
Sources: RSNA.
Written by: Catharine Paddock, PhD