The professors digitized 14 Christie novels (and included two more available in the Gutenberg online text archive), and then, with the aid of textual-analysis software, analyzed them for "vocabulary size and richness," an increase in repeated phrases (like "all sorts of") and an uptick in indefinite words ("anything," "something") — linguistic indicators of the cognitive deficits typical of Alzheimer's disease. The results were statistically significant; Christie's lexicon decreased with age, while both the number of vague words she employed and phrases she repeated increased.
Further studies are planned for the works of P.D. James and Ross Macdonald.
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