Argument Structure and Time Reference in Agrammatic Aphasia

Abstract

It has repeatedly been shown that agrammatic speakers have problems with verbs: in narrative speech, they provide less information by verbs than healthy speakers and the verbs that they produce are often not inflected for tense and agreement. Several explanations have been given for this phenomenon, for example, that argument structure complexity plays an important role (Thompson, J Neurolinguistics 16:151–167, 2003) and that time reference, especially reference to the past, is hard for agrammatic speakers (Bastiaanse, J Neurolinguistics 21:104–119, 2008; Bastiaanse, Clin Linguist Phon 27:244–263, 2013). The current study tested the combined influence of argument structure and time reference through tense and aspect using the aspect assignment model and shows that agrammatic speakers use is influenced by a combination of factors, including telicity, transitivity, tense, and aspect rather than by arguments structure or past time reference alone.

Discussion

Contrary to the DOP-H’s and the ASCH’s predictions and to all other theories that focus on only one aspect of agrammatic speech, no dissociation between unaccusative and unergative verbs was found. An explanation for this is that Lee and Thompson’s (2004) and Bastiaanse and Van Zonneveld’s (2005) studies did not take preferences for tense and aspect into account. When this is done, as in the present study, then the Aspect Assignment Model offers a better description of the agrammatic performance. Of course, the present study only tested a small part of the Aspect Assignment Model and in only one language. “Aspect” is a very complex notion that is not expressed similarly in every language. For example, the difference between perfect and imperfect is not the same in Dutch and English. Actually, roughly speaking, it is reversed: where English uses perfect aspect, Dutch uses imperfect and vice versa. Another difference between Russian (the language used in the study) on the one hand and Dutch and English on the other is that perfect aspect is expressed through the finite verb in Russian but with a periphrastic form in Dutch and English (“has written”). It is, therefore, probable that the Aspect Assignment Model should be adjusted per language.

As mentioned in the Introduction, different theories on the nature of the grammatical impairment resulting in agrammatic speech refer to difference characteristics: the word order problem, the problem with complex verb–argument structures, and the problem with inflected verbs, more specifically with time reference through verbs. The question was whether these problems are related. The Aspect Assignment Model demonstrated that the difficulties with argument structure and time reference are related. However, the model makes many more predictions that still need to be tested.

It is not exactly clear how the model can be related to the obvious word order problems that agrammatic speakers have (as shown for Dutch matrix clauses and object scrambling in several languages; see Introduction), that are now captured under the DOP-H. For now, however, the Aspect Assignment Model seems to be new approach to the argument structure and time reference problems in agrammatic aphasia.

Acknowledgment

The authors wish to thank Prof. Shklovsky V.M., Director of the Federal Center of Speech Pathology and Neurorehabilitation in Moscow, Russia, and Dr. Malukova N.G., Head of the Department of Psychology and the therapist working in the center for their willingness to select the patients and their help with patients’ diagnostics. We are also very grateful to Allison Smith for her comments on an earlier version.