An Analysis of Perplexity to Reveal the Effects of Alzheimer’s Disease on Language

Abstract:
The effects of Alzheimer’s disease on language have been examined in the past years. However, most of the methods described so far rely on language specific tools like part-of-speech taggers or parsers. We describe a novel approach based on N-gram models which has the benefit of being able to be used for any language which has a writing system. We evaluated our approach on the works of novelist Iris Murdoch whose last novel was written in the stage of early Alzheimer’s disease. We show that our approach reveals the influence of Alzheimer’s disease similarly well to the approaches that have previously been described in literature.