Table 1. Diagnostic features for primary progressive aphasia and its variants.

(adapted from Mesulam and Weintraub 2008; Mesulam 2009):

Descriptive clinical profile: An aphasic dementia where the language impairment (aphasia) emerges in relative isolation and is the major determinant in the limitation of daily living activities. Perception, memory, personality are relatively preserved initially (usually 2 years or more).

Core diagnostic features: These features are integral to the clinical syndrome. Both must be present for making the diagnosis. Insidious onset and gradual progression Early onset of aphasic disturbance (including any combination of the following): Word-finding pauses, word comprehension deficits, naming impairments, circumlocutions speech lacking specific nouns and verbs, speech and/or writing that has impaired grammar and syntax, syntactic comprehension deficits, dysgraphia

Exclusionary features: Abrupt onset Brain imaging showing lesions other than focal atrophy that can account for the aphasia

PPA Variants

Agrammatic (PPA-G): The central feature is an abnormality in syntax (word order) or some other aspect of grammar in spoken or written language in the presence of relatively preserved single-word comprehension. Fluency is usually impaired, and speech is usually effortful and hesitant.

Semantic (PPA-S): The central feature is an abnormality in single-word comprehension in the presence of relatively preserved grammar and fluency. Output is circumlocutory, occasionally uninformative, and frequently paraphasic. Naming is severely impaired.

Logopenic (PPA-L): The central features are intermittent word-finding hesitations and phonemic paraphasias. Naming is impaired but not as severely as in PPA-S and improves on phonemic cueing. Repetition may be impaired. Fluent output in casual conversation can alternate with dysfluent speech, which emerges when the patient needs to convey precise information and cannot use circumlocution. Spelling can be impaired.

Mixed (PPA-M): Combination of agrammatism with comprehension deficit, usually accompanied by poor fluency and frequent paraphasias or whose language output was too limited for specific characterization.