"Phonological" dysphasia: a cross-modal phonological impairment affecting repetition, production, and comprehension

In this paper we describe an aphasic patient, MS, who is impaired across a wide range of auditory input processing and spoken word production tasks. MS's performance on all these tasks shows phonological features: (1) his performance is poorest on auditory tasks with a strong phonological component, such as phoneme discrimination, auditory lexical decision, and word-picture matching featuring phono-logically related distractors; and (2) in spoken word production tasks, his errors are mainly phonemic and formal paraphasias. MS's single word repetition is particularly poor and exhibits some of the features of deep dysphasia, including lexicality effects (MS is unable to repeat nonwords) and image-ability effects. However, unlike in deep dysphasia, there are no semantic errors. We show that MS's condition, although apparently heterogeneous when viewed from a functional architecture perspective, can be described quite elegantly within an interactive-activation framework by proposing a single abnormality-a pathologically fast rate of decay within phonological representations.