Rob's miracle: Paralyzed man's first steps

Electrical stimulators of the sort that enables Summers to walk cost up to $20,000 and are typically used to relieve pain. Doctors were surprised that it was able to help Summers voluntarily move his legs. It "opens up a whole new avenue for us to address paralysis," Dr. Harkema, the study's lead author, told the AP.

Credit: University of Louisville