Time reference in agrammatic aphasia: A cross-linguistic study

Abstract

It has been shown across several languages that verb inflection is difficult for agrammatic aphasic speakers. In particular, Tense inflection is vulnerable. Several theoretical accounts for this have been posed, for example, a pure syntactic one suggesting that the Tense node is unavailable due to its position in the syntactic tree (Friedmann & Grodzinsky, 1997); one suggesting that the interpretable features of the Tense node are underspecified (Burchert, Swoboda-Moll, & De Bleser, 2005; Wenzlaff & Clahsen, 2004, 2005); and a morphosemantic one, arguing that the diacritic Tense features are affected in agrammatism (Faroqi–Shah & Dickey, 2009; Lee, Milman, & Thompson, 2008). However recent findings (Bastiaanse, 2008) and a reanalysis of some oral production studies (e.g. Lee et al., 2008; Nanousi, Masterson, Druks, & Atkinson, 2006) suggest that both Tense and Aspect are impaired and, most importantly, reference to the past is selectively impaired, both through simple verb forms (such as simple past in English) and through periphrastic verb forms (such as the present perfect, ‘has V-ed’, in English). It will be argued that reference to the past is discourse linked and reference to the present and future is not (Zagona, 2003, in press). In-line with Avrutin’s (2000) theory that suggests discourse linking is impaired in Broca’s aphasia, the PAst DIscourse LInking Hypothesis (PADILIH) has been formulated. Three predictions were tested: (1) patients with agrammatic aphasia are selectively impaired in use of grammatical morphology associated with reference to the past, whereas, inflected forms which refer to the present and future are relatively spared; (2) this impairment is language-independent; and (3) this impairment will occur in both production and comprehension. Agrammatic Chinese, English and Turkish speakers were tested with the Test for Assessing Reference of Time (TART; Bastiaanse, Jonkers, & Thompson, unpublished). Results showed that both the English and Turkish agrammatic speakers performed as hypothesized, showing a selective deficit for production of inflected forms referring to the past, despite the typological difference between the languages. The Chinese agrammatic speakers were poor in reference to the past as well, but reference to the present and future also was severely impaired. For comprehension, the results were strikingly similar for the three languages: reference to the past was impaired for all. These results confirmed our hypothesis that reference to the past is discourse linked and, therefore, grammatical morphology used for reference to the past is impaired in agrammatic aphasia, whether this is done through Tense and/or Aspect markers.

A characterization of verb use in Turkish agrammatic narrative speech

“…Abuom and Bastiaanse (2012) showed that Swahili-English agrammatic speakers failed in producing correct verb forms that refer to the past in both English and Swahili, whereas verb forms referring to present and future were virtually unaffected. The data from those studies are consistent with the past discourse linking hypothesis (PADILIH; Bastiaanse, 2013;Bastiaanse, Bamyacı, Hsu, Lee, Yarbay-Duman, & Thompson, 2011). The PADILIH assumes that reference to the past through verb inflection and reference to any time frame by aspectual adverbs require 'discourse linking', and thus, are impaired in agrammatic aphasia.…”

“…Consistently, Avrutin (2000Avrutin ( , 2006 showed that discourse-linked structures, such as which-NP questions, are more impaired in agrammatic aphasia than non-discourse-linked ones. Integrating Zagona's and Avrutin's perspectives, Bastiaanse et al (2011) showed that reference to the past, not only through tense, but also through grammatical morphology (including aspectual adverbs), is difficult for agrammatic speakers.…”

“…We believe that the common denominator here is that the verb forms for which discourse linking is required are difficult. This is because referring to past needs to be parsed by discourse syntax, which is hard for agrammatic speakers (Avrutin, 2000(Avrutin, , 2006Bastiaanse et al, 2011;Bos & Bastiaanse, 2014).…”

Why reference to the past is difficult for agrammatic speakers

“…It is not entirely clear, however, why Zagona (2003) assumes that discourse linking is needed for past tense only and not for all verb forms that refer to the past. Bastiaanse et al (2011) adapted Zagona's theory and extended the discourse linking requirement to all verb forms that refer to the past, including perfect aspect, even when the finite auxiliary is in present tense. In order to interpret the Dutch sentence de man heeft een brief geschreven: lit.…”

“…If this is true and if it is true, as suggested by Zagona (2003) and Bastiaanse et al (2011), that reference to the past is discourse-linked and reference to the present is not, then the following can be hypothesized: Reference to the past through verb inflection is impaired in agrammatic aphasia because discourse linking is required; for reference to the present through verb inflection, less discourse linking is needed, and, hence, it will be relatively spared. Following Zagona (in press), reference to the future pairs with reference to the present, because they are both "non-past".…”