The Christie family has always been private about the famed author’s health, but an analysis of her later books suggests that she may have been suffering from Alzheimer’s disease. 

Ian Lancashire, an English professor at the University of Toronto, analyzed 16 of Christie’s novels, written over a span of 50 years by feeding the text into a computer program. The computer then analyzed frequency of different words and phrases. He found that there was a discrete change in Christie’s language beginning in her 70s. For example, in Elephants Can Remember, Christie used 20 percent fewer words than in her earlier works. In other words, the vocabulary she employed had shrunk by one-fifth! At the same time, she used more “indefinite” words, such as thing, anything, nothing, and something.  

When Elephants Can Remember (1972) came out, it was panned by the critics for being poorly plotted and full of errors. My own review of the book will be years away, if I stick to my Agatha Christie challenge. (And if I still have enough vocabulary to write a blog posting!)

Interestingly, the central character of the book is a female novelist struggling with memory loss as she tries to help Hercule Poiroit solve a crime. In an interview, Lancashier notes that Christie may have sensed her declining mental ability and made it an essential element of the book.