Table 1.
Characteristics of primary progressive aphasia (PPA) subtypes
| Nonfluent/agrammatic PPA | Logopenic PPA | Semantic PPA | |
|---|---|---|---|
| Seminal article | Mesulam 1982 | Gorno-Tempini et al. 2004 | Snowden et al. 1989 |
| Speech output | dysfluent, efortful, often agrammatic, telegraphic, with frequent pauses and word-finding difficulties | slowed, logopenic, halting, difficult to initiate, with frequent word-finding difficulties but no agrammatism | fluent, grammatically correct but circumlocutory, garrulous, with frequent thematic perseverations and semantic jargon |
| Paraphasias | phonemic | mostly phonemic | semantic |
| Apraxia of speech | yes | no | no |
| Single-word comprehension | preserved | preserved | impaired |
| Sentence comprehension | may be impaired if a sentence is syntactically complex | impaired for longer sentences | impaired |
| Single-word repetition | impaired | typically spared | preserved |
| Sentence repetition | impaired | impaired for longer sentences | typically preserved |
| Naming | markedly impaired | moderately impaired | severely impaired |
| Syntax | impaired | initially preserved | preserved |
| Language pragmatics | anomia | anomia | severely impaired |
| Dyslexia/dysgraphia | for meaningless words | for meaningless words | for irregular words |
| Episodic memory | relatively preserved | often impaired at the later stages of the disease | preserved, especially for recent events |
| Executive function | typically preserved | typically preserved | may be mildly impared |
| Perceptual and visuo-spatial function | typically preserved | often impaired at the later stages of the disease | well-preserved |
| Behavior | relatively normal or apathetic/depressive | relatively normal or apathetic/depressive | frequently impaired, disinhibited |
| Neuroimaging findings | left posterior fronto-insular atrophy, i.e. inferior frontal gyrus | atrophy in left posterior superior temporal and middle temporal gyri as well as the inferior parietal lobule | atrophy predominantly in anterior, but also ventral, and lateral temporal lobes, greater on the left |
| Pathology (most typical) | Pick’s disease or corticobasal degeneration with neurons containing a microtubule-associated protein tau | Alzheimer’s disease | ubiquitinated frontotemporal lobar degeneration |