When Terry Pratchett died in March this year at the age of 66, he was celebrated globally not only for his colossally popular Discworld novels but also his fight against the stigma of dementia, of which he had a rare form.

Speaking at the Cheltenham Literature Festival, Tim Parry from British charity Alzheimer's Research UK said that the late author had transformed attitudes towards the disease.

"Terry Pratchett has played a huge role in just bringing it to people's attention and beginning to change the language towards the idea that we actually may be able to fight these diseases," he said. "He was the first person to say he wanted to kick it in the arse.”

Parry, who is head of communications for the organisation, also spoke about how crucial it was to remove the stigma and shame around the disease, and that Pratchett's frank and very public discussion of his condition had helped.

He was joined on stage by author Lisa Genova, whose 2007 novel Still Alice was made into a film (released in the UK earlier this year) which won Julianne Moore an Oscar for her portrayal of a Columbia University linguistics professor diagnosed with the rare, early-onset strain of Alzheimer’s.

Genova, who is an American neuroscientist as well as a writer, said she was "thrilled" by Hollywood's interpretation of her novel. "It could have been a total train wreck of a film and I could have been cringing throughout it and telling everyone I knew not to see it, but it was the opposite of that.

"It required a lot of trust. Julianne spent four months doing research prior to the role and spent time with people living with Alzheimer's. She went through neuro-psychology testing too. She really did her homework."

But while the portrayal of Alzheimer's was true to the book, Moore's busy schedule meant that there were some key differences between the novel and film.

"Julianne was in the middle of filming Hunger Games when she agreed to do this little four-week film," said Genova. "She had been away from her teenagers for almost a year filming that movie and said she’d do it only if she could do it in New York instead of Boston [where the novel is set]. So Alice had to become a Columbia University professor instead and other scenes had to change too.

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"The constraints that go along with filmmaking were fascinating to observe and I think they did a phenomenal job."