Analyzing the books a person reads tells a lot about the person. In this case, reviewing what they write for patterns and trends tells even more.
The pair digitized 14 of her novels and used textual analysis software to determine the richness and size of the vocabulary used, as well as phrases often repeated and an increase in the use of indefinite words, an indicator of the disease.
This has interesting applications for those that want to understand more about cognitive studies and how writing displays the symptoms of physical issues.
The paper is here.
Some of the software used is here.