Progressive nonfluent aphasia (PNFA) is one of three clinical syndromes associated withfrontotemporal lobar degeneration. PNFA has an insidious onset of language deficits over time as opposed to other stroke-based aphasias, which occur acutely following trauma to the brain. The specific degeneration of thefrontal andtemporal lobes in PNFA creates hallmark language deficits differentiating this disorder from otherAlzheimer-type disorders by the initial absence of other cognitive and memory deficits. This disorder commonly has a primary effect on theleft hemisphere, causing the symptomatic display of expressive language deficits (production difficulties) and sometimes may disrupt receptive abilities in comprehending grammatically complex language.[1]
The main clinical features are signature language progressive difficulties with speech production. There can be problems in different parts of the speech production system, hence patients can present witharticulatory breakdown, phonemic breakdown (difficulties with sounds) and other problems. However, it is rare for patients to have just one of these problems and most people will present with more than one problem. Features include:[2]
As the disease develops, speech quantity decreases and many patients becomemute.
Cognitive domains other than language are rarely affected early on. However, as the disease progresses, other domains can be affected. Problems with writing, reading, and speech comprehension can occur, as can behavioural features similar tofrontotemporal dementia.[citation needed]
Imaging studies have shown differing results which probably represents the heterogeneity of language problems than can occur in PNFA. However, classically atrophy ofleft perisylvian areas is seen.Comprehensive meta-analyses on MRI and FDG-PET studies identified alterations in the whole left frontotemporal network for phonological and syntactical processing as the most consistent finding.[3] Based on these imaging methods, progressive nonfluent aphasia can be regionally dissociated from the other subtypes offrontotemporal lobar degeneration, frontotemporal dementia and semantic dementia.[citation needed]
Mesulam MM (October 2003). "Primary progressive aphasia--a language-based dementia".The New England Journal of Medicine.349 (16):1535–1542.doi:10.1056/NEJMra022435.PMID14561797.
