Billy Connolly, who is being treated for the "initial symptoms" of Parkinson's Disease, admitted earlier this year that he had started to forget lines during performances.
Speaking about it, he said: "This is f*****g terrifying. I feel like I'm going out of my mind."
There is no cure for the disease but symptoms can be controlled using a combination of drugs, therapies and occasionally surgery.
Actor Bob Hoskins announced his retirement last year after being diagnosed with the disease.
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The decision represents something of a victory for the president who will now be able to enforce most of his controversial 90-day ban.
Cool in the north, warmer air to the south
Police have warned the drug, known locally as "pink champagne", could be deadly.