Athletes have long known the benefits of visualizing specific physical actions to improve sports performance. Now, scientists have been asking whether motor imagery training can be used to improve movement abilities and to stimulate brain development when active movement training is not an option—as is often the case after a stroke.
According to the authors of a research review on the subject, published in the journal Stroke (2006; 37, 1941–52), motor imagery is a “dynamic state during which the representation of a specific motor action is internally reactivated within working memory without any overt motor output, and that is governed by the principles of central motor control.” In other words, a person envisions an entire sequence of actions without doing any actual movement.
Motor imagery parallels actual physical performance in a number of interesting ways. For example, imagined movement typically takes the same amount of time as actual movement; and in imagined movement, as in actual movement, accuracy lessens when the speed of movement increases. Imagined movement can also impact the autonomic nervous system and lead to higher heart and breathing rates, just as actual movement does.
In healthy individuals such as athletes, research suggests, practicing motor imagery improves neuromuscular function, independent of actual muscle activation. As a result, motor performance is improved and changes occur in the brain even when the body does not move. The researchers’ question was, Could this still be true after a stroke, when the motor imagery network may be disrupted?
The research review found insufficient evidence to confirm the value of motor imagery training on motor recovery in stroke survivors. Nevertheless, the study authors were encouraged by their findings and suggested that, in time, motor imagery may prove useful across the full range of stroke recovery. More research is needed to determine how this tool may help to access damaged motor networks and to improve functioning after a stroke.