CHICAGO (CBS) – U.S. Sen. Mark Kirk, who suffered a stroke last month, has been transferred to a rehabilitation center, doctors announced Friday.

Kirk, 52, was moved from Northwestern Memorial Hospital to the Rehabilitation Institute of Chicago, where doctors will assess his condition and tailor a treatment program for him, RIC said.

“The Senator has several pre-stroke factors in his favor that our research and experience demonstrate will foster a better recovery, including his relative youth, good general health and fitness, strong personal motivation, and high intelligence,” Dr. Richard L. Harvey, RIC medical director for stroke rehabilitation, said in a news release.

Kirk had the stroke the weekend of Jan. 21 and has undergone a series of surgeries, most recently this week to reattach part of his skull that had been removed to alleviate brain swelling. Doctors initially said the senator lost some physical abilities on the left side of his body.

Physicians have said Kirk suffered an ischemic stroke, the most common type. According to the American Stroke Association’s website, ischemic strokes are the most common form of stroke, accounting for about 87 percent of all cases. They are the result of an obstruction within a blood vessel that supplies blood to the brain, caused by fatty deposits in the blood vessels.

Kirk, a North Shore Republican, was elected to the U.S. Senate in 2010, winning the seat once held by President Barack Obama. Before that, he spent 10 years in the U.S. House.

“As Mark begins the next phase in his recovery, we want to thank the thousands of people around the state, the nation and the world who have called, written notes, sent flowers and offered their thoughts and prayers,” Kirk’s family said in a written statement Friday.

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