Progressive non-fluent aphasia

AgrammaticProgressive nonfluent aphasia (PNFA), also known as agrammatic variant primary progressive aphasia, also known as progressive nonfluent aphasia (PNFA) is generally considered to be one of three subtypes of primary progressive aphasia, along with semantic dementia and logopaenic dementia.

Terminology

It is important to note that the clinical literature surrounding primary progressive aphasias, and neurodegenerative diseases associated with fronto-temporal lobar degeneration (FTLD) and generally, is a subtypelarge, rapidly evolving and heterogeneous, more so than many other fields ^2,3. The result is that there is great variation in terminology and classification of language variant front-temporal lobar degeneration (lvFTLD)various conditions making it perilous for student and clinicians alike.

PNFA is typically characterised by "effortful, dysfluent and agrammatical speech". Atrophy is most marked in a perisylvian distribution on the left involving the inferior frontal gyrus (including Broca's area) and superior temporal gyrus [needs reference]. There is often unilateral widening of the Sylvian fissure [needs reference].

Diagnostic Criteria

Diagnostic criteria have been proposed as follows ^1:

Clinical

• clinical diagnosis of nonfluent/agrammatic variant PPA:

  At

  PNFA
  • at least one of:
    1. agrammatism in language production
    2. effortful, halting speech with inconsistent speech sound error (apraxia of speech)

    And

  • and at least 2 of:
    1. impaired comprehension of syntactically complex sentences
    2. spared single word comprehension
    3. spared object knowledge
• Imaging-supported nonfluent/agrammatic variant PPA diagnosis:

  Both

  diagnosis of PNFA
  • both of the following:
    1. clinical diagnosis of nonfluentnon-fluent/agrammatic variant PPA
    2. imaging showing predominant left posterior front-insular atrophy on MRI and/or predominant left posterior front-insular hypoperfusion on SPECT or PET

    Nonfluent/agrammatic variant PPA

• PNFA with definite pathology:

  Both

  • both of the following:
    1. clinical diagnosis of nonfluentnon-fluent/agrammatic variant PPA
    2. histopathologic evidence of a specific neurodegenerative pathology (eg. FTLD-tau, FTLD-TDP, AD, other) or presence of a known pathogenic mutation

Radiographic features

CT and MRI

Atrophy is variable, but generally most marked in the posterior frontal, insular cortex and temporal lobe, including the hippocampus ^1,2. Generally, the left hemisphere is thought as being most involved, although this is neither universally the case ^1,2.

Nuclear medicine

SPECT or FDG-PET demonstrate hypoperfusion in a similar distribution to morphological changes (see above).