Intact higher-level constraints on the pronunciation of new written words by nonfluent dysphasics

Nonfluent, Broca-type dysphasics are characterized by impaired syntactic processing. However, grammaticality judgements and certain on-line tasks have shown some preservation of this processing in such subjects. We report an experiment with nonfluent dysphasics in which they read aloud th-initial nonwords (e.g., thuz) in sentential contexts that predicted a function word or a content word. This paradigm was first used by Campbell and Besner (1981) to demonstrate syntactic effects on pronunciation: normal subjects pronounce word-initial th- as voiced in function word contexts and unvoiced in content word contexts, reflecting a regularity in the English lexicon. Poorer performance by the dysphasic subjects on this task is the default prediction of most "syntactic" accounts of agrammatism, including an account based on the impairment of functional projections, which we discuss. We replicate Campbell and Besner's effect in our normal control group and in the dysphasic group, with no significant difference between the two groups. We conclude that syntactic influences on pronunciation may be unimpaired in nonfluent dysphasia, and that the task used resembles the class of online tasks, in its capacity to elicit unimpaired processing. We argue that this result is compatible with the account of agrammatism discussed if the latter is grounded in a distributed, constraint-based processing device allowing graceful degradation of functioning.