Primary Progressive Aphasia and Semantic Dementia Primary progressive aphasia (PPA) is a progressive, isolated impairment of language that may have fluent or nonfluent characteristics. Progressive aphasia can result from impairment to phonological, syntactic, or semantic components of language processing and accordingly, a variety of subtypes of the disorder have been described in the literature. The selective ... Article
Article  |   April 01, 2006
Primary Progressive Aphasia and Semantic Dementia
Author Affiliations & Notes
  • Maya L. Henry
    University of Arizona, Tucson, AZ
  • Pélagie Beeson
    University of Arizona, Tucson, AZ
Article Information
Special Populations / Older Adults & Aging / Language Disorders / Aphasia / Articles
Article   |   April 01, 2006
Primary Progressive Aphasia and Semantic Dementia
SIG 2 Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders, April 2006, Vol. 16, 21-27. doi:10.1044/nnsld16.1.21
SIG 2 Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders, April 2006, Vol. 16, 21-27. doi:10.1044/nnsld16.1.21
Primary progressive aphasia (PPA) is a progressive, isolated impairment of language that may have fluent or nonfluent characteristics. Progressive aphasia can result from impairment to phonological, syntactic, or semantic components of language processing and accordingly, a variety of subtypes of the disorder have been described in the literature. The selective impairment of semantic knowledge is referred to by a distinct diagnostic label, namely, semantic dementia (Snowden, Goulding, & Neary, 1989). Semantic dementia is considered by some to be a subtype of fluent PPA and by others to be a clinical entity distinct from PPA. The syndrome is characterized by impaired word production and comprehension in the context of a relative sparing of other components of language and is often accompanied by face- and object-recognition deficits (Hodges, Patterson, & Tyler, 1994). Nonfluent PPA and semantic dementia are two of the three clinical variants of frontotemporal lobar degeneration (FTLD), a progressive degeneration of the frontotemporal lobes whose etiology is not known. The third subtype of FTLD is a frontal variant that primarily affects personality and social behavior, rather than language (Neary et al., 1998). Although this disorder may overlap clinically with language impairment in FTLD, it will not be dealt with in detail here. While FTLD dementias are not well-recognized by the lay public, they are thought to be the third most common type of cortical dementia after Alzheimer’s disease (AD) and Lewy body disease (Neary et al.). As such, they are certainly worthy of the attention of clinical speech-language pathologists working in the area of neurogenic communication disorders.
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