Phonological buffer and selective deficits of grammar, with distinct time onsets, in a patient with a focal degenerative disorder.

We report a patient with a focal degenerative disorder and very circumscribed neuropsychological deficits, the evolution of which we were able to study over a lengthy period. For years, he presented with only a speech production impediment that clinical observations and experimental studies enabled us to identify as a phonological buffer disorder. Subsequently, he developed agrammatism that appeared to be largely due to his inability to produce pronouns and auxiliary verbs. Remarkably, throughout our studies, even when he was virtually rendered mute, his ability to name objects on demand in writing remained intact. We discuss his case from clinical and theoretical perspectives.