Joyce Powell, 80, attends an exercise class at UT-Arlington with her husband, Thomas (right). Powell says she feels more confident in getting around and traveling since taking the classes. Dane Walters/KERA hide caption

itoggle caption Dane Walters/KERA

In sighted people, the part of the brain that recognizes faces is linked to the brain's visual system. But in blind people it seems wired to circuits that process sound. Tina Zellmer/Ikon Images/Corbis hide caption

itoggle caption Tina Zellmer/Ikon Images/Corbis

The Johns Hopkins Applied Physics Lab created an electronic prosthetic hand and arm that has the same dexterity as a human arm. Electronic prosthetics are the biggest area of growth in this industry. Johns Hopkins Applied Physics Lab hide caption

itoggle caption Johns Hopkins Applied Physics Lab

Patients with certain kinds of brain damage can wind up with locked-in syndrome: they may be able to think just fine, but are unable to communicate their thoughts to others. A recently published case study shows that a non-invasive brain-computer interface can help. iStockphoto hide caption

itoggle caption iStockphoto

Sofia Jarvis, seen here with her family at a press conference in February, is one of several dozen children in California who have been diagnosed with a rare paralytic syndrome. It has left her left arm paralyzed. Martha Mendoza/AP hide caption

itoggle caption Martha Mendoza/AP

Tom Murphy, 56, in his home in Gainesville, Va., was diagnosed with ALS four years ago. An experimental drug seems to have slowed the progression of his disease, he says, though most ALS patients aren't as lucky. T.J. Kirkpatrick for NPR hide caption

itoggle caption T.J. Kirkpatrick for NPR

Surgeons at Methodist University Hospital in Memphis prepare to transplant a liver in 2010. Karen Pulfer Focht/The Commercial Appeal/Landov hide caption

itoggle caption Karen Pulfer Focht/The Commercial Appeal/Landov

One of the scariest parts of advanced macular degeneration can be losing the ability to read facial expressions. Maria Pavlova /iStockphoto hide caption

itoggle caption Maria Pavlova /iStockphoto