Anatomical correlates of early mutism in progressive nonfluent aphasia

Primary progressive aphasia (PPA) is characterized by speech and language deficits that remain isolated for at least 2 years.(1) Once thought a unitary syndrome, PPA is now typically divided into variants.(2,3). Progressive nonfluent aphasia (PNFA) is characterized by effortful speech, agrammatism in production and comprehension, with preserved single word comprehension. It has been shown that apraxia of speech (AOS) is the most common motor speech deficit in PNFA.(2) "Mutism," resulting from AOS or dysarthria, is the absence of speech or articulatory movement and can occur with neurologic disturbances, including Parkinson disease, ALS, progressive supranuclear palsy (PSP), and frontotemporal dementia.(4) Whereas mutism typically occurs at the end stage of dementia of any cause, in PNFA, patients can become functionally mute early in the disease course, while other cognitive functions are spared.