"I know this will come as a shock to many of you," the 51-year-old wrote in a statement on his website. "It wasn’t for me. I’ve had my fears and suspicions, but I was remaining hopeful that there was some other cause for the problems I was experiencing."
Alzheimer’s is a degenerative brain disorder characterized by memory loss, behavioural changes and difficulty performing tasks. It is a terminal condition with no cure.
A statement on the band's website confessed his band mates had known about Mann's condition for "some time," but they had been unable, until now, to "reach the acceptance necessary to be able to speak of it publicly."
Mann, who is also in remission from colorectal cancer, explains he now needs to read the lyrics to his band's iconic songs (like the frosh week drinking standard Home for a Rest) off an iPad on stage.
He also need accompaniment on guitar for his solo shows, but Mann insists he's not giving up performing:
"I don’t want to feel embarrassed. I want to accept what has happened and live."
The band says it is committed to standing behind Mann "foresquare" as they have for more than 30 years.
Spirit of the West is scheduled to take the stage Thursday in Revelstoke, B.C.