Obamacare premium costs vary from state to state, city to city Amputee controls bionic leg with brainwaves Zac Vawter lost his lower leg in a motorcycle accident four years ago, and after years in a regular prosthetic leg, he's testing the first one controlled by brainwaves. The Army-funded research could improve the lives of the more than 1,200 soldiers and approximately one million Americans who have lower leg amputations. Dr. Jon LaPook reports.