Per Chicago Tribune:
About an hour into a rapidly-deteriorating concert at the Congress Theatre Saturday night, Chuck Berry slumped over an accompanist's keyboard before being helped offstage.
The 84-year-old rock and roll legend and a backing band of three Chicago musicians attempted to resume the show for a packed house about 15 minutes later, but Berry almost immediately was taken off again to be checked by paramedics who had been called to the scene.
After being examined, Berry returned one last time to thank the fans who had waited in hopes for the show to continue, but he left the stage -- using a bit of his signature "duck walk" -- without playing again. Shortly afterward, he walked out of the theatre's stage door on his own into an awaiting limousine. Berry signed a release saying he was OK, and he was not taken to a hospital, according to Fire Department spokesman Joe Roccasalva.
"All I know is he felt faint, he felt weak, and I was told to call 911," said Michael Petryshyn, the concert's promoter, backstage after Berry's departure.
Berry had been active in recent days: He had performed two shows in New York City the night before. Although Berry performs regularly in his hometown of St. Louis, he infrequently gives concerts elsewhere.A message left with Berry's management Sunday was not returned.
The show had started promisingly. Taking the stage in a red sequined shirt, black slacks and a white sailor hat, Berry began with "Roll Over Beethoven," one of his many 1950s hits, which formed the foundation for guitar-based rock and roll.
Although Berry played this and following songs -- "Sweet Little Sixteen" and "School Days" -- at slower tempos than the original recordings, he filled them with his classic guitar riffs and sang them with weathered authority. Drummer Steve Gillis and bassist Bill Stephens kept the songs swinging steadily, and Vijay Tellis-Nayak added jubilant boogie piano.
Things then quickly began going off the rails. Berry played snippets of blues songs and an unsteady version of " Memphis Tennessee," before taking an extended pause to try to retune his guitar, complaining that it was out of key with the piano. He made several unsuccessful attempts at "Let It Rock," in part seated at the piano, and performed disjointed bits of "Carol" and "Johnny B. Goode."
Berry revived to lead the crowd in a sing-along of "My Ding-a-Ling" and acknowledged things weren't going well, telling the crowd he'd try to do better at entertaining them. It was not to be. After a version of "Reelin' and Rockin'" they found the band gamely following his inconsistent tempo, Berry made his way to the piano, where the show came to an end completely at odds with the joy in his music.
"Obviously, something was off," said Petryshyn, the promoter. "Fifteen minutes into the set it went from fine to something wasn't right. He was starting songs mid-song, playing 15 seconds of a song."
"I'm sorry to see his health be in that shape," Tellis-Nayak said. "He obviously loves performing. The music is still there. It's hard to see his health deteriorating. He may be working harder than he should."