When Thorsten Siess was in graduate school, he came up with the idea for a heart device that's now been used in hundreds of thousands of patients around the world.

Two stroke patients regained control of a disabled arm and hand after researchers delivered electrical stimulation to their spines, paving the way toward a medical device that could aid movement.

Philips is trying to fix or replace 5 million of the devices because foam in them can deteriorate into harmful particles. But the process is taking years, forcing some patients to risk their health.

A stroke left a man paralyzed and speechless. Now a device that decodes brain signals is letting him generate words and sentences.

A man who is paralyzed can quickly perform tasks like pouring a glass of water, thanks to a mind-controlled robotic arm that conveys a sense of touch.