On Mirror Neurons and Aphasia Rehabilitation

Aphasiologists, neurologists, and others interested in the improvement of post-stroke neurorehabilitation are learning that observation and imitation may hold yet-untapped potential for improving rehabilitative outcomes. The research focuses on understanding operations of the mirror neuron system and on exploring ways to exploit those operations for therapeutic purposes. It is a relatively new area of investigation, since mirror neurons were discovered only about a decade ago. But some benefits have already been documentedfor example, it has been conclusively shown that patients' observation of the actions of others positively affects rehabilitation of motor deficits after stroke.

Mirror neurons are cerebral motor neurons that fire both during one's own execution of actions with hand, foot, or mouth, and during one's observation of those same actions performed by another individual. They are so named because the observer's neurons "mirror" the neurons that are firing in the actor. Mirror neurons may also fire when an action is referenced but not actually observed. For instance, the mirror neurons aroused by the "act of kicking" fire when one person observes another person kicking a ball. But they fire as well when a person hears the sound of a ball being kicked, hears another person saying the word "kick," or observes another person pantomiming the action of kicking a ball.

Some researchers are actively seeking to improve aphasia therapy using computer programs that offer ways to stimulate the mirror neuron system. These may support observation of actions using videos, listening to spoken words, listening to the sounds of actions, viewing pantomime, and reading written words. Computers helpfully allow the user to customize presentation of stimulifor instance, by controlling timing, display size, volume, playback speed, and so on.

The workings of mirror neurons may well help explain benefits being documented for some of these computer-based programs. For instance, one project underway at the Rehabilitation Institute of Chicago displays a computer-generated face that reads text aloud, accompanying the synthesized speech with appropriate, synchronized motions of the lips and tongue. Preliminary studies have shown that selected patients with aphasia improve with the use of this program.

A related approach is to display close-up videos of individual sounds or words being spoken. This draws on the standard therapeutic practice of having patients imitate a clinician's mouth, while giving the patient a greater degree of control in timing, volume, and display magnification. Such computer displays of mouth motions cause mirror neurons to fire, which in turn will support improved imitation and comprehension of the observed actions by patients.

For Further Reading and Information

Buccino, G., Solodkin, A., & Small, S. (2006). Functions of the mirror neuron system: Implications for neurorehabilitation. Cognitive and Behavioral Neurology, 19(1), 55-63.

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