Speech and language in primary progressive anarthria.

We describe a patient with a progressive loss of speech up to muteness due to frontal atrophy. The clinical and neuropsychological examination documented a severe progressive articulatory disorder associated with a mild language deficit consisting of agrammatic production and spelling errors. Investigation of the patient's auditory-verbal short-term memory system revealed a selective impairment of the articulatory rehearsal system (covert re-circulation of verbal information), suggesting that not only overt but also covert articulation is impaired in this pathology. The conclusion is drawn that pure anarthria is a disorder of executive aspects of language. The hypothesis is advanced that language deficits such as spelling errors and agrammatic features might be due to ineffective covert articulation.