I search for a mainstream source on this and I find none.
What I do find is in late July, the White House hosted a Special Olympics celebration and Stevie Wonder was at that event.
http://www.kxnet.com/story/26168939/at-white-house-gala-obama-honors-special-olympics
“Wonder and tennis star Andy Roddick mingled with Maria Shriver and AOL co-founder Steve Case as they munched on Maryland crab with corn ravioli and spiced pecans in the East Room. After dessert and coffee, former NBA star Dikembe Mutombo squeezed his 7-foot 2 frame into one of the gold seats in the State Dining Room as pop icon Perry treated guests to a rendition of her hit “Roar,” her sequined blue dress shimmering under the stage lights installed for the occasion.”
Obama was not actually in Cleveland, although this story makes it sounds as such, it was a recorded message for the games that was played.
It was reported here on local news late last night.