The Aktionsart of Alzheimer’s Disease: A Corpus-Based Analysis

Abstract

This presentation offers a study on the distribution and frequency of lexical aspect or Aktionsart in the verb predicates uttered by American English patients with Alzheimer’s disease, by means of transcriptions showed in the Pitt corpus (Becker, Boller, Lopez, Saxton and McGonigle, 1994). Thus, the aims of this research are, on the one hand, to test what type of lexical aspect is more frequent in these patients and how the Aktionsarten are distributed. On the other hand, to compare this frequency and distribution in the different stages and to verify if lexical aspect can help to identify the stage on which patients are. The method we have followed can be divided in two phases. First, we must determine the type of Aktionsart according to Role and Reference Grammar (GPR; Van Valin y LaPolla, 1997; Van Valin, 2005), a functionalist approach that attempts to explain the relationship between syntax, semantics and pragmatics. The semantic representation in RRG stems from the verb predicate and, to classify these verbs, it adapts the study of lexical aspect by Vendler (1976). To determine what Aktionsarten we should assign to verbs, RRG offers eight tests (Van Valin, 2005; Cortés Rodríguez, González Vergara y Jiménez Briones, 2012; Van Valin, 2018) that, although not perfect, when applied sequentially, allow to identify the type of lexical aspect of each verb predicate. In the second phase, we apply these tests to the verbs in the Pitt corpus of Alzheimer’s disease patients. This neurodegenerative disease is divided into three stages (early, intermediate and last) depending on the cognitive impairment, where language has its place. Pitt corpus shows the transcriptions of 181 English-speaking patients in the three stages, although most people belong to the first stage. All patients received at least one of the four tests: cookie, fluency, recall and sentence. After considering restrictions to the corpus, we analyze 135 patients that uttered 5660 verb predicates in cookie, recall and sentence tests; fluency test has very few predicates that are mainly isolated words due to its entity-naming type of test. We will analyze a sample of 1744 predicates, which is the sum of samples taken from the three tests with a 95% confidence interval (Altman & Gardner, 2000: 26). To know the distribution and frequency of the different Aktionsarten, we use basic statistical methods: mean, median, mode, standard deviation and variance. The analysis of this sample shows that active accomplishments (cookie and sentence tests) and states (recall test) are the most frequent types of Aktionsart. In the cookie and sentence tests, states become the most used in the last stage, so the more the disease progresses, the less active accomplishments the patients utter. In the recall test, states are the most used predicates in the three stages with more than 50% of predicates. Although more research is needed to reach robust conclusions, we show that lexical aspect seems to help in identifying the three stages of Alzheimer’s disease.