Treadmill Exercise Retrains Brain and Body of Stroke Victims, Even Years After Stroke

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Title: Treadmill Exercise Retrains Brain and Body of Stroke Victims, Even Years After Stroke
URL: http://www.pslgroup.com/dg/22A24A.htm
Doctor's Guide
August 29, 2008

BETHESDA, Md -- August 29, 2008 -- People who walk on a treadmill even years after stroke damage can significantly improve their health and mobility years after conventional physical therapy has ended -- suggesting that patients' brains may retain the capacity to rewire, according to a study published in Stroke.

"This is great news for stroke survivors because results clearly demonstrate that long-term stroke damage is not immutable and that with exercise it's never too late for the brain and body to recover," said Daniel Hanley, MD, Johns Hopkins University School of Medicine, Bethesda, Maryland.

Investigators from Johns Hopkins, and 2 other institutions combined efforts to recruit 71 patients who had a stroke at least 6 months earlier, with an average time lapse of nearly 4 years. At the study's onset, half of the subjects could walk without assistance, while the rest used a cane, a walker, or a wheelchair.

All of the subjects, separated into 2 random groups regardless of disability, were tested for mobility and VO₂ peak. Thirty-two patients drawn equally from both groups underwent functional magnetic resonance imaging (fMRI) to assess brain activity linked to moving their legs in a walking motion.

One group then participated in an exercise program that principally involved walking on a treadmill 3 times a week for up to 40 minutes, assisted by a supporting sling and tether if needed.

Physical therapists assigned to each subject increased the intensity of the workouts over time by increasing the treadmills' speed and incline, though the workouts never taxed the patients beyond a moderate level of 60 percent VO₂ peak.

With the second group of patients, therapists assisted the patients in performing stretching exercises for the same period of time.

After 6 months, patients were again tested for walking speed and VO₂ peak, and the same group who had undergone fMRI was rescanned. Walking speed for the treadmill group increased 51% compared with about 11% for those in the stretching group.

Ground walking speed among the treadmill exercisers increased 19%, compared with about 8% for the stretchers. The treadmill exercisers also were significantly more fit at study completion, with VO₂ peak increasing by about 18%. VO₂ peak decreased slightly in the stretching group.

Hoping to find evidence that improved brain activity was responsible for the results, the investigators analysed the brain scans and found markedly increased metabolic activity in brainstem areas associated with walking among all the treadmill exercisers. Brain scans of patients in the stretching group showed no such changes.

"This suggests that the brain is responsible for the improvement we saw in patients' walking ability. It seems to be recruiting other regions to take on the job of areas damaged by stroke," says guest researcher Andreas Luft, MD, University of Zurich, Zurich, Switzerland.

Those patients with the most improvement in walking showed the strongest change in brain activity, though the researchers don't yet know whether these brain changes were caused by more walking or whether participants walked better because brain activity in these key areas increased. This question will be the focus of a future study.

Dr. Hanley said that unlike heart attack patients who are often prescribed lifestyle changes and exercise programs to help recover function, most stroke rehabilitation programs focus on short-term improvement, ending just a few months after a patient has had a stroke.

"Many stroke survivors believe there's nothing to be gained from further rehabilitation, but our results suggest that health and functional benefits from walking on a treadmill can occur even decades out from stroke," said lead researcher Richard F. Macko, MD, University of Maryland School of Medicine, College Park, Maryland.

He also noted that 1 of the patients in the study had significant improvement 20 years after a stroke. "We believe exercise gives individuals a way to fight back against stroke disabilities."

SOURCE: Johns Hopkins Medical Institutions

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