Primary progressive aphasia

Last revised by Dr Francis Deng on 30 Apr 2021

Primary progressive aphasia is a group of neurodegenerative disorders mainly characterized by increasing language impairment. The group is clinically and pathologically heterogeneous and includes two clinical variants usually associated with frontotemporal lobar degeneration pathology and one clinical variant usually associated with Alzheimer disease pathology.

This article presents an overview and details can be found in the separate articles: nonfluent (agrammatic) variantsemantic variant, and logopenic variant.

Primary progressive aphasia is characterized by gradual impairment of language that predates, usually by many years, the onset of more global cognitive deficits.

Inclusion criteria 2:

  • most prominent clinical feature is difficulty with language
  • these deficits are the principal cause of impaired daily living activities
  • aphasia should be the most prominent deficit at symptom onset and for the initial phases of the disease

Exclusion criteria 2:

  • pattern of deficit is better accounted for by other nondegenerative nervous system or other disorders
  • cognitive disturbance is better accounted for by a  psychiatric diagnosis
  • prominent initial episodic memory, visual memory, and visuoperceptual impairments
  • prominent, initial behavioral disturbance

There are three clinical variants 2:

  • nonfluent (agrammatic) variant: characterized by motor speech deficit with difficulty articulating phonemes and also agrammatism
  • semantic variant (semantic dementia): characterized by deficits in single-word object naming and comprehension
  • logopenic variant (logopenic dementia): characterized by deficits in repetition and single-word retrieval, resulting in frequent word-finding pauses

The nonfluent and semantic variants are considered clinical syndromes of frontotemporal dementia, while the logopenic variant is not.

The nonfluent and semantic variants are usually associated with frontotemporal lobar degeneration pathology, while the logopenic variant is usually associated with Alzheimer pathology 1,2,4. It is, therefore, important to note that this group is not only clinically heterogeneous but also is the result of a number of pathological processes1,4.  

Primary progressive aphasia was first described in 1982.

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Cases and figures

  • Figure 1: Broca and Wernicke areas
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