He was an hour or so into his first set when he slumped face first into his keyboard. He was rushed off stage, only to return a few minutes later to tune up and resume the show. An unidentified man approached him, lifted his guitar off him and escorted Chuck off stage. He again returned  and told the crowd "someone stole my guitar"

His confusion got worse throughout the concert. "I want to play my favorite song" he told the audience, but had to ask the band what it was.

He took requests from the audience, someone shouted "Maybellene". He sang part of it, but then slipped into another song after forgetting the words.

It's sad to see someone of Chuck Berry's stature perform like that. I assume  his age (84) has alot to do with it, and I hope this was not the onset of something more severe. I  remember Chuck Berry and Keith Richards going at it. "The song is played like this, and if you can't do it...get off the stage"  he told Keith.  That's the Chuck Berry I love.