Agatha Christie’s whodunits have entertained the masses for close to a century. Now, in an unexpected plot twist, the British author’s life work itself is shedding light on one of medicine’s great mysteries—Alzheimer’s.
The sleuth-work in this case was revealed last month at the Rotman Research Institute Conference held at Toronto’s Baycrest, a leading research centre on aging. There, Ian Lancashire, an English professor at the University of Toronto, and his colleague Graeme Hirst, from the computer sciences faculty, presented an abstract of their ongoing investigation of linguistic patterns in Christie’s novels. They conclude the later novels reveal signs of encroaching Alzheimer’s. More significantly, their study confirmed British neurologist Peter Garrard’s 2004 analysis of three novels by Iris Murdoch, who was afflicted with Alzheimer’s, which argued dementia’s onset could be detected in written text “before anyone has the remotest suspicion of any untoward intellectual decline.”
Lancashire initiated the project with Hirst last fall with literary, not medical, motives: he needed data on linguistic patterns of older writers for a book about how authorship is revealed in texts. He believed Christie’s oeuvre, comprised of 85 meticulously plotted novels and plays written over 53 years, offered great scope for investigation. Though the author was never diagnosed with dementia, it’s speculated it could have been responsible for her decline in her late 70s and the muddled, meandering plots of her later novels. Also, the fact editors were reluctant to interfere, with the exception of her last book, meant the texts contained her imprint only.
Sixteen novels—including Christie’s first, written at age 28, and her last, composed at 82, three years before her death in 1976—were put through a “computational-linguistic” screen to analyze vocabulary and phrase repetition. Use of indefinite nouns and the indefinite article “thing” increased significantly over time, they found, as did phrase repetition, while vocabulary declined by 15 to 30 per cent. The most precipitous change occurs in Christie’s penultimate novel, Elephants Can Remember, written when she was 81; it contained a 30 per cent drop in vocabulary compared to her writing at age 63, 18 per cent more repeated phrases, and a nearly threefold increase in indefinite nouns.
Turning to indefinite nouns is common as one ages, says Lancashire, as specific words become harder to reach. Severe vocabulary decline, however, indicates cognitive degeneration: “It suggests there’s a problem in retrieval from long-term memory.” More will be gleaned when the results from more complex analysis of Christie’s work are available in the late summer.
To contextualize the findings, they’ll also need a baseline study of an author who didn’t suffer from dementia to deduce how language changes with normal aging, says Lancashire. He believes a similar screen of the work of H.G. Wells, who had a long, prolific career without any indication of cognitive impairment, could provide that.
Whether textual analysis will ever become a routine diagnostic tool is a question mark. A decline in written skills can be a significant early marker of Alzheimer’s, says Morris Freedman, the head of neurology at Baycrest. “Because writing is a learned, not a natural skill, it breaks down early,” he says. But he’s skeptical such ambitious analysis is practical: “You’d have to have large samples over time,” he says.
Hirst believes the Internet might one day make that possible: “In time, everyone will have 30 years of emails and blogs on their hard disk; we’ll be able to do this kind of textual analysis for everyone.” Freeman remains doubtful. “The linguistic quality of emails is often lacking,” he says.
For Lancashire, the study provided proof that authors do reveal themselves in their texts. He cites Elephants Can Remember as a poignant example of an author clearly grappling with the mysteries of her own mind. The tweaking of the proverb “elephants never forget” suggests defensiveness about her tangled mental acuity, he says. It’s also telling that the protagonist, crime writer Ariadne Oliver, a recurring Christie character, is unable to puzzle out the mystery herself and must summon Christie’s first fictional detective, Hercule Poirot, to figure it out. “It reveals an author responding to something she feels is happening but cannot do anything about,” he says. “It’s almost as if the crime is not the double-murder-suicide, the crime is dementia.” How wonderfully fitting then that Agatha Christie might still be able to help solve it.