Early signs of dementia are rarely dramatic. They don’t forget names or misplace keys, but they are changes so subtle that they are almost impossible to notice. This means a slightly narrower vocabulary, less variation in descriptions, and a mild flattening of the language.
New research by my colleagues and I suggests that these changes may be detectable years before a formal diagnosis is made. And one of the clearest examples may be hidden in Sir Terry Pratchett’s novels.
Pratchett is remembered as one of Britain’s most imaginative writers, the creator of the Discworld series, and a master of satire whose works combined humor with sharp moral insight. After being diagnosed with posterior cortical atrophy, a rare form of Alzheimer’s disease, he became a strong advocate for dementia research and dementia. Although it is less well known, the early effects of the disease may have already been visible in his writings long before he knew he was ill.
Dementia is often described as a condition of memory loss, but this is only part of the story. Dementia can affect attention, perception, and language in its early stages, before memory impairment becomes apparent. These early changes are gradual and difficult to detect because they can easily be mistaken for stress, aging, or changes in normal behavior.
However, language provides a unique window into cognitive change. The words we choose, the variety of our vocabulary, and the way we construct explanations are closely related to how our brains function. Even small changes in language use can reflect underlying neurological changes.
Our recent research analyzed the language used across Terry Pratchett’s Discworld novels and examined how his writing evolved over time. We focused on “lexical diversity” (a measure of how diverse an author’s word choices are), paying particular attention to adjectives that lend texture, color, and emotional depth to prose.
Across Pratchett’s subsequent novels, there was a clear and statistically significant decrease in the variety of adjectives he used. The richness of explanatory language gradually narrowed. This was not something readers would necessarily notice, nor did it reflect a sudden drop in quality. Rather, it was a subtle, gradual change that could only be detected through detailed linguistic analysis.
Significantly, the first significant decline appeared in The Last Continent, published nearly a decade before Pratchett received his formal diagnosis. This suggests that the “preclinical phase” of dementia, the period during which disease-related changes are already occurring in the brain, may begin years ago without any obvious outward symptoms.
This discovery has implications far beyond literary analysis. Dementia is known to have a long preclinical stage, and this stage offers the greatest opportunity for early intervention. However, identifying people during this period remains one of the biggest challenges in dementia care.
Linguistic analysis is not a diagnostic tool in itself, so it won’t work equally well for everyone. Factors such as education, occupation, writing habits, and linguistic background all influence the way people use language. However, alongside cognitive tests, brain imaging and biological markers, as part of a broader approach, linguistic analysis could help detect risk early in a non-invasive and cost-effective manner.
The important thing is that the linguistic data already exists. People create vast amounts of documentation through emails, reports, messages, and online communications. With appropriate privacy and consent safeguards, subtle changes in writing style may one day help alert people to the early stages of cognitive decline, long before daily functioning is affected.
Why is early detection important?
Early detection is more important than ever. In recent years, new drugs for Alzheimer’s disease have emerged that aim to slow the progression of the disease rather than simply managing symptoms. Drugs such as lecanemab and donanemab target amyloid proteins that accumulate in the brain and are thought to play an important role in the disease. Clinical trials suggest that these treatments are most effective when given early, before significant nerve damage occurs.
Identifying patients at the preclinical stage allows patients and their families more time to plan, receive support, and consider interventions that may slow progression. These may include lifestyle changes, cognitive stimulation, and increasingly new drugs to slow the progression of the disease.
More than a decade after his death, Terry Pratchett continues to contribute to our understanding of dementia. His novels are still deeply loved, but there is another legacy hidden within them. It’s evidence that dementia can leave its mark long before it develops. Paying more attention to language, even those we think we know well, could help change the way we detect, understand, and ultimately treat this devastating condition.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
