A Morphological Approach to the Longitudinal Detection of Dementia

Abstract

The impact of cognitive impairment on linguistic abilities has been a topic of continuous interest in dementia studies. However, there is a lack of systematic agreement on the longitudinal association between dementia progression and the patients' morphological capacity, and the role of morphological phenomena other than inflection has been relatively underreported. We present a longitudinal study of writings by Iris Murdoch (diagnosed of Alzheimer's Disease after her death) and Arthur Conan Doyle (no known record of dementia diagnosis), using two novel measures to account for the usage of complex morphology and lexical innovation. The results imply an association between lexical innovation and cognitive decline caused by dementia, as observed in Murdoch's works beginning from her mid-fifties, in contrast to a milder tendency in Doyle's works. Our findings contribute to a potential for facilitating early diagnosis of dementia through automated language processing approaches.