Abstract
Objective: To relate fractional anisotropy (FA) changes associated with the semantic and logopenic variants of primary progressive aphasia (PPA) to measures of lexical retrieval.Methods: We collected neuropsychological testing, volumetric magnetic resonance imaging, and diffusion-weighted imaging on semantic variant PPA (svPPA) (n = 11) and logopenic variant PPA (lvPPA) (n = 13) patients diagnosed using published criteria. We also acquired neuroimaging data on a group of demographically comparable healthy seniors (n = 34). FA was calculated and analyzed using a white matter (WM) tract-specific analysis approach. This approach utilizes anatomically guided data reduction to increase sensitivity and localizes results within canonically defined tracts. We used non-parametric, cluster-based statistical analysis to relate language performance to FA and determine regions of reduced FA in patients.Results: We found widespread FA reductions in WM for both variants of PPA. FA was related to both confrontation naming and category naming fluency performance in left uncinate fasciculus and corpus callosum in svPPA and left superior and inferior longitudinal fasciculi in lvPPA.Conclusion: SvPPA and lvPPA are associated with distinct disruptions of a large-scale network implicated in lexical retrieval, and the WM disease in each phenotype may contribute to language impairments including lexical retrieval.
Highlights
fractional anisotropy (FA) was related to both confrontation naming and category naming fluency performance in left uncinate fasciculus and corpus callosum in Semantic variant PPA (svPPA) and left superior and inferior longitudinal fasciculi in Logopenic variant PPA (lvPPA)
SvPPA and lvPPA are associated with distinct disruptions of a large-scale network implicated in lexical retrieval, and the white matter (WM) disease in each phenotype may contribute to language impairments including lexical retrieval
Primary progressive aphasia (PPA) is a clinical syndrome characterized by progressive loss of language most commonly due to Alzheimer’s disease (AD) or frontotemporal lobar degeneration (FTLD)
Summary
Primary progressive aphasia (PPA) is a clinical syndrome characterized by progressive loss of language most commonly due to Alzheimer’s disease (AD) or frontotemporal lobar degeneration (FTLD). Lexical retrieval difficulty is a feature of two variants of PPA [1]. Semantic variant PPA (svPPA) is characterized by deficits in single-word and object comprehension as well as poor confrontation naming [2]. Logopenic variant PPA (lvPPA) is characterized by impaired single-word retrieval and impaired repetition of phrases and sentences [1]. This study sought to determine whether impaired lexical retrieval in these two variants of PPA is due to common or distinct patterns of white matter (WM) disease. Neuropathological and neuroimaging studies have identified patterns of gray matter (GM) atrophy in these PPA variants: svPPA is associated with left-lateralized GM atrophy of the anterior and ventral temporal lobe, while lvPPA is associated with atrophy of left posterior peri-Sylvian and inferior parietal regions [3,4,5]. The relationship between WM disease and clinical features such as lexical retrieval remains unclear
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
