CHICAGO (CBS) – Senator Mark Kirk’s surgeon released Wednesday a letter to the media in regards to Sen. Kirk’s recovery since his 2012 stroke.

Senator Mark Kirk has no use of his left arm or hand and limited use of his left leg, but he has made a full cognitive recovery from his ischemic stroke in 2012, said Dr. Richard Fessler, Kirk’s surgeon, in a letter.

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Dr. Fessler said Sen. Kirk, “has made rapid improvements in his physical recovery,” as demonstrated by climbing the capitol steps in 2012 and climbing up 41 stories of the Willis Tower twice, CBS 2’s Derrick Blakley reports.

The stoke did not affect the left side of his brain, which controls cognitive and verbal functions, said Dr. Fessler.

Health is becoming a campaign issue, with two candidates living with disabilities. Sen. Kirk is still recovering from his stroke, while Dem. Tammy Duckworth is living with the loss of both her legs following a crash of her army helicopter in Iraq.

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Duckworth’s new ad campaign states that Duckworth waitressed her way through college with the same perseverance that fueled her recovery, after her Blackhawk was shot down in Iraq.

Kirk’s ad reaches out to Hispanic voters, saying in Spanish, when Donald Trump says bad things about immigrants, I have spoken out against him. I do not support Donald Trump.

Duckworth has already indirectly made Kirk’s health an issue, calling him ‘unhinged,’ after Kirk said President Obama was acting like a drug dealer-in-chief, following cash payments to Iran.

That is only one of many eccentric statements the senator has made since his stroke. The Kirk campaign challenged Duckworth to release more of her medical records.

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Minutes ago, Duckworth staffers said she is about to do that, in short order.