A customized retro-style video game helped chronic stroke survivors regain arm function by directly retraining impaired muscles rather than teaching ways to compensate for lost function, according to a study by Northwestern University researchers.

Participants wore a small wearable device on their impaired arm and used a laptop to play a game. They used the electrical activity of each of the coupled muscles (called electromyograms, or EMGs) to move a cursor in perpendicular directions in a customized video game. For example, their biceps might move the cursor to the right and their deltoids move the cursor up. When the muscles are coupled, the cursor thus moves on a diagonal (up and right, like turning both dials on an Etch-a-Sketch).

The training, called MINT (myoelectric interface for neurorehabilitation) conditioning, targets "abnormal co-activation," a common post-stroke phenomenon in which muscles fire in an uncoordinated way, making it difficult to extend an arm with a straight elbow.

The randomized, sham-controlled trial divided 59 stroke survivors with a mean age of about 60 into three experimental groups and one sham control group. All groups trained for six weeks, playing the game 90 minutes a day, five days a week at home and one day in the lab, allowing for far more repetitions than typical clinic-based therapy.

All groups, including the sham group, improved from baseline. Experimental groups improved 4.5 times as much as the sham group overall, and the group that trained on three muscles improved 7.8 times as much as the sham group by the end of training. Participants continued improving even after stopping the therapy, and researchers found a positive correlation between reduced muscle co-activation and improved movement.

Participants also reported that the game made rehab more engaging. One wrote in a survey response that the experience was enjoyable and helpful.

The research team is currently developing a fully wireless version of the wearable device and plans to test the approach on stroke survivors' legs.

To download the full study, published in Neurorehabilitation and Neural Repair, click here