FILE - A 2012 file photo of an image taken from video and provided by Sen. Mark Kirk's office shows Sen. Mark Kirk, R-Ill. going through a walking exercise at the Rehabilitation Instit

 

              FILE - A  2012 file photo of an image taken from video and provided by Sen. Mark Kirk
FILE - A 2012 file photo of an image taken from video and provided by Sen. Mark Kirk's office shows Sen. Mark Kirk, R-Ill. going through a walking exercise at the Rehabilitation Institute of Chicago following a stroke. Nearly a year after a stroke left him barely able to move the left side of his body, U.S. Sen. Mark Kirk is expected to climb the 45 steps to the Senate's front door this week _ a walk that is significant not just for Illinois' junior senator, but also for medical researchers and hundreds of thousands of stroke patients. (AP Photo/Courtesy of Sen. Mark Kirk's office)