The logopenic/phonological variant of primary progressive aphasia
Article [Version of Record]
Is part of
Neurology ; vol. 71, pp. 1227-1234.Publisher(s)
American Academy of NeurologyAuthor(s)
Abstract(s)
Objective: Primary progressive aphasia (PPA) is characterized by isolated decline in language
functions. Semantic dementia and progressive nonfluent aphasia are accepted PPA variants. A
“logopenic” variant (LPA) has also been proposed, but its cognitive and anatomic profile is less
defined. The aim of this study was to establish the cognitive and anatomic features of LPA.
Methods: Six previously unreported LPA cases underwent extensive neuropsychological evaluation and an experimental study of phonological loop functions, including auditory and visual span
tasks with digits, letters, and words. For each patient, a voxel-wise, automated analysis of MRI or
SPECT data were conducted using SPM2.
Results: In LPA, speech rate was slow, with long word-finding pauses. Grammar and articulation
were preserved, although phonological paraphasias could be present. Repetition and comprehension were impaired for sentences but preserved for single words, and naming was moderately
affected. Investigation of phonological loop functions showed that patients were severely impaired in digit, letter, and word span tasks. Performance did not improve with pointing, was influenced by word length, and did not show the normal phonological similarity effect. Atrophy or
decreased blood flow was consistently found in the posterior portion of the left superior and
middle temporal gyri and inferior parietal lobule.
Conclusions: Logopenic progressive aphasia (LPA) is a distinctive variant of primary progressive
aphasia. Cognitive and neuroimaging data indicate that a deficit in phonological loop functions
may be the core mechanism underlying the LPA clinical syndrome. Recent studies suggest that
Alzheimer disease may be the most common pathology underlying the LPA clinical syndrome.
Other location(s)
This document disseminated on Papyrus is the exclusive property of the copyright holders and is protected by the Copyright Act (R.S.C. 1985, c. C-42). It may be used for fair dealing and non-commercial purposes, for private study or research, criticism and review as provided by law. For any other use, written authorization from the copyright holders is required.