Grammatical encoding in aphasia: Evidence from a "processing prosthesis"

Agrammatic aphasia is characterized by severely reduced grammatical structu re in spoken and written language, often accompanied by apparent insensitiv ity to grammatical structure in comprehension. Does agrammatism represent l oss of linguistic competence or rather performance factors such as memory o r resource limitations'! A considerable body of evidence supports the latte r hypothesis in the domain of comprehension. Here we present the first stro ng evidence for the performance hypothesis in the domain of production: an augmentative communication system that markedly increases the grammatical s tructure of agrammatic speech while providing no linguistic information, fu nctioning merely to reduce on-line processing demands, (C) 2000 Academic Pr ess and Unisys Corporation.