Do people with agrammatic aphasia understand verb movement?

Abstract

Background: Many studies report that the comprehension of sentences derived by movement of phrases is impaired in agrammatism. However, only few studies have explored the comprehension of sentences that involve a movement of the verb. In several languages, the verb can or should move to the second position of a sentence, creating VSO sentences like “Yesterday ate the girl a watermelon” from an SVO sentence. Previous studies of comprehension of verb movement either allowed the patients to use a strategy, or used grammaticality judgement tasks, which probably tap different abilities from interpretation tasks. The research was supported by a research grant from the National Institute for Psychobiology in Israel (Friedmann 2004‐5‐2b), and by the Joint German–Israeli Research Program grant (Friedmann GR‐01791). Many thanks to Ronit Szterman for her participation in the development of this experiment and to Esther Ruigendijk for her helpful comments. Aims: The present study tested the comprehension of sentences with verb movement to second position in agrammatism using a novel sentence type that prevented participants from employing strategy‐based comprehension. Comprehension was tested using sentences with verb–noun homophones and homographs. In general, the choice between the noun and the verb meaning of homophones and homographs relies on the construction of the syntactic structure of the sentence, and the syntactic role of the ambiguous word. In the current study, we used sentences in which the ambiguous word was placed at the object position, such as “Yesterday caught the bat flies in the garden” (literally transcribed into English). In order to understand whether it is a verb or a noun (whether the bat in this sentence flies, or whether it catches flies), comprehension of the relation between the moved verb and its object is required. Thus, these sentences might shed light on whether individuals with agrammatism can understand verb movement. Methods & Procedures: participants were six Hebrew‐speaking individuals with agrammatic aphasia. In Experiment 1 they paraphrased auditorily presented sentences with homophones; in Experiment 2 they read aloud and then paraphrased written sentences with heterophonic homographs. Both experiments also included, in addition to the target sentences with verb movement, matched sentences with the same homographs and homophones that did not include verb movement. Experiment 1 included 51 sentences, Experiment 2 included 48 sentences per participant. Outcomes & Results: The individuals with agrammatic aphasia failed to read and paraphrase the sentences with verb movement. They either took the object to be the verb, read the moved verb incorrectly, said they did not understand the sentence, or said that there were two parts of the sentence that did not connect. Matched sentences with the same homophones and homographs without verb movement were comprehended significantly better. Normal subjects performed correctly in all conditions. Conclusions: Not only is the comprehension of movement of phrases impaired in agrammatism, but also the comprehension of sentences derived by verb movement.