The Food and Drug Administration has approved a strap-on robotic arm brace that can help stroke patients regain the use of their paralyzed limbs. The e-100 NeuroRobotic System has sensors on the upper arm that detect muscle movements, which in turn trigger a motor in a backpack that is worn by the user to control arm motion. The brace is manufactured by the Boston-based devices firm, Myomo Inc., and will be available commercially within the next few months. Clinics and specialists will be able to order the new device by sending an email to clinicalservices@myomo.com or calling 877-736-9666.