The late author Terry Pratchett was diagnosed with Alzheimer's in 2007. But researchers poring over his old works suggest telltale clues emerged in his writing roughly a decade before that, reports IFL Science. A team led by Loughborough University's Dr. Thom Wilcockson analyzed 33 books from the British author's fantasy Discworld series to track "lexical diversity"—essentially the range of nouns and adjectives Pratchett used, according to a university release.
They found a marked drop in linguistic complexity in The Last Continent, published nearly a decade before Pratchett was diagnosed with posterior cortical atrophy, a rare form of early-onset Alzheimer's. "This suggests that the 'preclinical phase' of dementia—the period during which disease-related changes are already occurring in the brain—may have begun many years earlier, without obvious outward symptoms," they write in the peer-reviewed journal Brain Sciences.
Pratchett, who campaigned publicly for better dementia awareness after his diagnosis, died in 2015 at 66. Researchers say the method used on his work could eventually help doctors detect dementia earlier in other patients. That's crucial because "it may enable us to use interventions sooner before the brain is damaged beyond repair," says Wilcockson. Co-author Melody Pattison of Cardiff University noted that even after adjusting for book length, the decline in lexical variety remained "significant," though not something a casual reader would spot.