Researchers at the University of Toronto have been analyzing the works of prolific authors (PD James, Agatha Chrisite and Iris Murdoch ) over their years of writing.
Neuro-cognitive literary theory, a part of computational linguistics seeks to discover and analyize the changing language of these authors over their life time body of work. Scanning in the first 50,000 words of each book and graphing the amount of vocabulary decline, the increase of repetition and the increased occurance of vague terms.
Murdock had been diagnosed with Alzheimers at 74. With Chrisite the professors found that Elephants Can Remember "represents a staggering 31 per cent drop in vocabulary compared to Destination Unknown, written 18 years earlier, when Christie was 63. Repetitions also increased, and the use of "thing" words was four times as frequent in her final book as in her first". She was never diagnosed.
P.D. James, is still writing at the age of 89. "James's linguistic prowess turns out to be undiminished, providing a sort of one-woman control group of the healthy aged. Her vocabulary also turns out to be much more extensive than either of the two other writers'."
Writing samples kept over 10 years or more may offer a glimpse into our mental processes. So keep those memos, e-mails, blogs and letters.