Strategy and impairment in sentence understanding by Broca's and Wernicke's aphasics.

15 Broca's aphasics and 14 Wernicke's aphasics, both German and Dutch speaking patients, were presented with a sentence-picture matching task. Both syntactic and semantic distractor pictures were used. Sentences were either reversible or non-reversible, had a topicalized or a non-topicalized word order and contained either of three types of prepositions that were labelled 'syntactic' (case-marking), 'obligatory' (subcategorized) and 'lexical' (locative). Results indicated (a) a significant difference between reversible and non reversible sentences for both Broca's and Wernicke's; (b) no significant differences between these two groups in the differences scores reversible minus non-reversible; (c) an above-chance performance on reversible sentences for both groups. To explain the pattern of differences between the various types of sentences, two schemes of interpretation are presented. The first scheme assumes that both Broca's and Wernicke's have lost basic (but different) syntactic abilities and that they can understand reversible sentences by non-syntactic strategies only. The second scheme assumes that there is no such loss, but that the impairment in Broca's and Wernicke's aphasia is such that the more syntactic analysis is required, the more errors are made. Patients are assumed to approach this task by trying to limit their syntactic analysis to the beginning of the sentence.