Is "nonpropositional" speech preserved in aphasia?

Twenty-eight aphasic patients were tested on six tasks designed to assess "nonpropositional" speech and six matched tasks designed to assess propositional speech. The most reliable differentiation between nonpropositional and propositional speech type behaviors within a group of aphasics was found for the Numbers and Picture naming tasks. A smaller effect was observed on the Days of the week and Phrase repetition tasks. Only 6 of the 28 patients consistently showed a nonpropositional advantage across the range of task comparisons. However, a principal components analysis extracted two factors which differentiated propositional from nonpropositional tasks reasonably well. We conclude that nonpropositional speech, to the extent that it is measured by these tasks, is not preserved in aphasics as a group, though some patients may show a fairly consistent nonpropositional advantage. The distinction between propositional and nonpropositional speech does appear to have some application to aphasia, however. An error analysis supports the conjecture that propositional tasks involve semantic processing while nonpropositional tasks may place a greater load on phonological processing.