Longitudinal gray matter contraction in three variants of primary progressive aphasia: A tenser-based morphometry study

Abstract

The present study investigated the pattern of longitudinal changes in cognition and anatomy in three variants of primary progressive aphasia (PPA). Eight patients with the non-fluent variant of PPA (nfvPPA), 13 patients with the semantic variant (svPPA), seven patients with the logopenic variant (lvPPA), and 29 age-matched, neurologically healthy controls were included in the study. All participants underwent longitudinal MRI, neuropsychological and language testing at baseline and at a 1-year follow-up. Tenser-based morphometry (TBM) was applied to T1-weighted MRI images in order to map the progression of gray and white matter atrophy over a 1-year period. Results showed that each patient group was characterized by a specific pattern of cognitive and anatomical changes. Specifically, nfvPPA patients showed gray matter atrophy progression in the left frontal and subcortical areas as well as a decline in motor speech and executive functions; svPPA patients presented atrophy progression in the medial and lateral temporal lobe and decline in semantic memory abilities; and lvPPA patients showed atrophy progression in lateral/posterior temporal and medial parietal regions with a decline in memory, sentence repetition and calculations. In addition, in all three variants, the white matter fibers underlying the abovementioned cortical areas underwent significant volume contraction over a 1-year period.Overall, these results indicate that the three PPA variants present distinct patterns of neuroanatomical contraction, which reflect their clinical and cognitive progression.

Neuropsychological differentiation of progressive aphasic disorders

“…The finding by Foxe et al (2013) and Meyer et al (2015) of poorer phonological short-term memory in lvPPA were compared with AD, despite patients being matched for visual short-term memory performance might represent a transient distinction. It is of interest in this regard that longitudinal studies of lvPPA have indicated a convergence over time with the clinical symptoms of AD (Leyton, Hsieh, Mioshi, & Hodges, 2013) and a spread of atrophy consistent with AD (Brambati et al, 2015) (Rohrer et al, 2013). It is possible that at an earlier stage of disease greater differences might have been elicited between the two groups.…”

Divergent Longitudinal Propagation of White Matter Degradation in Logopenic and Semantic Variants of Primary Progressive Aphasia

“…Cognitively, lvPPA, svPPA, and nfvPPA variants are characterized by core language deficits involving repetition, comprehension, and agrammatism, respectively [1]. Structural neuroimaging studies also highlight distinct, primarily left hemispheric, patterns of atrophy in temporal and frontal lobe structures, across PPA variants [1][2][3][4][5][6].…”

Jargonaphasia: A Systematic Overview and Characterization in Primary Progressive Aphasia

“…Damage of these 2 rather distant regions would require large vascular lesions which usually lead to global aphasia in vascular conditions. Regarding agrammatic PPA, it mainly affects Broca's region [23], but lesion extension towards temporal cortices subtending language monitoring has not been reported in imaging studies, including longitudinal investigations on this PPA variant [44].…”