Breakdown at the morphological level in agrammatism

Samenvatting

In this study, we intend to take a closer look at the morphological deficit observed in agrammatism from the two perspectives of language production and language comprehension. In order to be able to assess the influence of the syntactic context on the patients’ ability to correctly produce and comprehend morphological material, we administered several tests to a group of Germanspeaking agrammatic patients. Some of these tests aimed at assessing the agrammatic subjects’ morphological abilities in production and comprehension in morpholexical tasks (such as structural analysis of compounds and nominal plural formation), whereas others were intended to provide information on the patients’ capacity to make use of morphology in syntactic contexts of differing degrees of complexity (case assignment in prepositional phrases, noun phrases, canonical and non-canonical sentences; interpretation of ambiguously and unambiguously case-marked constituents in canonical and non-canonical position). The results show that the agrammatic patients were generally able to exploit morphology in both production and comprehension in the morpholexical tasks and in local or canonical syntactic structures. Performance deteriorated, however, when the production or interpretation of morphological markers depended on more complex syntactic configurations. We argue that the breakdown of morphology in agrammatism must thus be considered as the consequence of an underlying syntactic deficit and that the results further provide neurolinguistic evidence for theories of Lexical Morphology.