An experimental therapy improves arm function in chronically impaired stroke survivors long after the possibility of spontaneous recovery has been exhausted, researchers reported today at the 5th World Stroke Congress.
The report, the first on brain changes linked to a bilateral repetitive rhythmic training intervention (BATRAC), also found changes in brain regions that govern movement.
Interestingly, researchers found the changes only in patients who responded to the therapy, said lead author Andreas R. Luft, M.D., of the Department of General Neurology in the Hertie Institute for Clinical Brain Research at the University of Tübingen, Germany. BATRAC is an experimental treatment studied since 1998.
“Reorganization of the central motor networks in the brain occurs during the spontaneous recovery and rehabilitative therapy in the weeks following a stroke,” Luft said. He said reorganization would include lasting changes in the strength of nerve synapses (connections), formation of new dendrites and axons — two components of neurons (nerve cells) — and maybe even the formation of new neurons, resulting in the recovery of movements.
“Our hypothesis was that brain reorganization is the mechanism by which BATRAC improves function in chronic stroke patients,” Luft said.
The study compared eight impaired stroke survivors who received hour-long, thrice-weekly BATRAC therapy sessions for six weeks with 12 others who had standard physical therapy for the same amount of time. The survivors had experienced stroke from 10 months to 39 years earlier, nine years earlier on average.
Each BATRAC session consisted of four 5-minute movement periods in which subjects pushed or pulled on a T-bar handle with both arms either simultaneously or in an alternating pattern. A metronome provided auditory feedback on whether they were keeping up with the beat of the exercise plan, said co-author Jill Whitall, Ph.D., a professor in the Department of Physical Therapy and Rehabilitation Science at the University of Maryland in Baltimore.
The 12 control patients received dose-matched physical therapy (PT) for the same amount of time. Although active movement was encouraged where possible, the PT emphasized therapists passively moving a subject’s trunk, shoulder, shoulder blade, wrist and fingers and encouraging leaning (weight shifting) on the weak arm, she said.
The researchers used functional magnetic resonance imaging (fMRI) to non-invasively map brain function related to the movement of the paralyzed limb before and after both kinds of therapy.
The BATRAC group had significant improvements in motor function and fMRI found new and larger areas of activity in the primary motor cortex on the uninjured side of the brain as well as changes in the injured side. However, the brain changes were found only in six of the eight patients who responded to BATRAC therapy with improvement of arm function, Luft said.
Physical therapy produced no functional improvement and no detectable change in brain activation patterns for either arm, they said.
“Physical therapy is absolutely necessary for successful recovery once the stroke has occurred and brain tissue has died,” Luft said. “This study is the first to indicate that BATRAC therapy also has a neuroscience basis. Being able to observe changes in brain biology that account for treatment effects brings BATRAC therapy out of the shade of non-scientific treatments.”
The World Stroke Congress is held every four years to provide a forum for stroke research. The International Stroke Society sponsors the event, which is hosted this year by the Canadian Stroke Consortium, the National Stroke Association and the Canadian Stroke Network. The American Stroke Association provided support for the meeting. The abstracts are published in the June issue of Stroke: Journal of the American Heart Association.