After a stroke, survivors often experience uncontrollable spasms that can twist their arms and hands into perpetual fists. The only treatments are expensive, frequently painful injections of botulinum toxin or oral medications so strong they may put patients to sleep. Both offer only temporary relief.

Engineers at Stanford University and the Georgia Institute of Technology now say they have developed a glove-like wearable medical device that achieves as good or better results as the injections or drugs by applying simple, high-frequency mechanical vibrations to the hands and fingers.