Primary Progressive Aphasia and Apraxia of Speech

Primary progressive aphasia (PPA) is a clinical syndrome characterized by progressive language dysfunction. There are three variants:

• Logopenic variant is most often associated with Alzheimer’s disease pathology.

• Semantic variant (also called semantic dementia or temporal variant frontotemporal dementia) is most often associated with TDP-43 pathology.

• Nonfluent/agrammatic variant (also called progressive nonfluent aphasia) is most often associated with tau pathology.

Primary progressive apraxia of speech (PPAOS) is an impairment in the production of speech sounds in the absence of language impairment (also called progressive apraxia of speech [PAOS]). It is most often associated with tau pathology.

Impairments of speech and language are common in neurodegenerative diseases.

The number of patients who meet criteria for primary progressive aphasia or primary progressive apraxia of speech is relatively small.

Genetic risk will depend upon underlying etiology; most individuals with primary progressive aphasia or apraxia of speech have no family history.

In the logopenic variant of primary progressive aphasia there is hesitant speech, difficulty naming and finding words, and phonologic and/or repetition errors, with no loss of comprehension and preserved grammar.

In the semantic variant of primary progressive aphasia there is a loss of memory for words, starting with anomia, continuing with impaired comprehension of single words, and ultimately leading to impaired comprehension of objects as well. Speech is fluent with normal rate and minimal syntactic errors.

In the nonfluent/agrammatic variant of primary progressive aphasia there is a reduction in the ability to produce speech characterized by slow, effortful, apraxic speech; grammatical errors; short sentences; reduced phrase length; omission of articles (a, an, the); and difficulty pronouncing words, somewhat similar to that of a patient with Broca’s aphasia.

Characteristics of primary progressive apraxia of speech include slow rate, articulatory distortions, distorted sound substitutions, and segmentation of syllables.

Primary progressive aphasia core criteria

• Inclusion: (1) Most prominent clinical feature is difficulty with language; (2) these deficits are the principal cause of impaired function; (3) aphasia is the most prominent deficit at onset and for the initial phases of the disease. (For exclusion criteria see Box 9.1 .)

  Box 9.1

  Primary Progressive Aphasia Core Criteria

  Modified from Gorno-Tempini, M. L., Hillis, A. E., Weintraub, S., et al. (2011). Classification of primary progressive aphasia and its variants. Neurology, 76, 1006–1014.

  • Inclusion: Criteria 1–3 must be answered positively.

    • 1.

      Most prominent clinical feature is difficulty with language

    • 2.

      These deficits are the principal cause of impaired daily living activities

    • 3.

      Aphasia should be the most prominent deficit at symptom onset and for the initial phases of the disease

  • Exclusion: Criteria 1–4 must be answered negatively.

    • 1.

      Pattern of deficits is better accounted for by other nondegenerative nervous system or medical disorders

    • 2.

      Cognitive disturbance is better accounted for by a psychiatric diagnosis

    • 3.

      Prominent initial episodic memory and visuoperceptual impairments are present

    • 4.

      Prominent, initial behavioral disturbance is present

For specific criteria for the logopenic, semantic, and nonfluent/agrammatic variants, see Boxes 9.2–9.4 .