Imagining Limb Movement Aids Stroke Recovery

A study has found that asking stroke patients to imagine the movement of a weakened or paralyzed arm or leg can help to improve functional recovery of the limb. The results were reported in the September 2003 issue of Archives of Physical Medicine and Rehabilitation.

Researchers used a motor imagery training program for patients with hemiparesis, which is weakness or paralysis on the opposite side of the body from the hemisphere of the brain that was affected by stroke. The program consisted of imagined wrist movements and mental simulations of reaching and object manipulation, making use of a mirror-box apparatus. The first task was computer-facilitated motor imagery training, in which the patient was instructed to explicitly imagine his/her own hand completing a movement just observed on a computer screen.

For the second task, designed for example to stimulate left-arm moving, the researchers had the patient move the right arm around in the mirror-box workspace, resulting in a reflection of the affected left limb moving about successfully in space. Patients were told to imagine that the reflected limb "actually is your limb moving about.” The program consisted of three one-hour sessions for four consecutive weeks. Results showed that performance of the affected limb improved after the imagery intervention, indicated by increases in assessment scores and functionality and decreases in movement times. The researchers believe that applying motor simulation therapy less than six months after the stroke may increase these effects.

"Actions generated using motor imagery adhere to the same movement rules and constraints that physical movements follow, and the neural network involved in motor imagery and motor execution overlap in areas of the brain concerned with movement,” said Jennifer A. Stevens, a researcher at the Feinberg School of Medicine at Northwestern University (Chicago, IL, USA; www.nums.nwu.edu).




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