Discourse relations analysis as a resource for Alzheimers disease monitoring

Abstract

This paper explores the results of a measurement proposal for discourse coherence of elderly patients who have been diagnosed with dementia of the Alzheimer's type (DAT), in contrast with cognitively-healthy elderly. By means of the Rhetorical Structure Theory, the rhetorical relations underlying conversations of seven elderly patients in different stages of dementia and six cognitively healthy elderly were analyzed. The procedure involved segmentation of semantic discourse units (SDUs), labeling of relations and making of discourse trees. Additionally, relations of caregivers were counted for analyzing their contributions and conversational strategies in semi-structured interviews. We found that elderly patients produce more relations and use more variety of them. Involuntary Cause, Solution, Concession, Elaboration and Involuntary Result are related to cognitively healthy subjects' discourse. On the other hand, some rhetorical relations are used by caregivers for pragmatic purposes. Due to our results, we believe that it is plausible to add the discourse coherence into the catalog of linguistic affectations considered for the clinic profile of a patient with DTA.