Structural Correlates of Language Processing in Primary Progressive Aphasia

EasyChair Preprint 6419

Abstract

Studies exploring the relation between brain structure and language function in primary progressive aphasia (PPA) provide key information about pathomechanisms of PPA and healthy brain function. However, existing studies mostly rely on small samples, include only one PPA variant or probe only one aspect of language processing, limiting their power to find brain-behavior relationships and identify commonly damaged areas across PPA groups involved in task performance. Our study addresses these issues. We analyzed data from 61 controls and 118 PPA patients—including semantic (svPPA), logopenic, and nonfluent-agrammatic variants—using multiple regression to analyze the relationship between either cortical density (VBM) or thickness measures and several language tests and examining PPA subtype atrophy overlap in task-associated regions. Tasks included picture naming, auditory word-picture matching and repetition, category and phonemic fluency, and reading and writing. Tasks sharing semantic demands showed degrees of overlapping atrophy in bilateral temporal and left frontal cortex. Shared temporal atrophy within clusters of these areas suggested a common contribution to naming problems. Unique damage in svPPA supported ventral and medial temporal cortex as the source of severe semantic deficits. Phonemic fluency, repetition, and reading and writing were associated with atrophy to left medial frontal or a left fronto-parietal network, suggesting roles of phonological, working memory and attention deficits. Unatrophied, task-associated areas suggested the path of future PPA atrophy. Our results illustrate, consistent with previous research, how gray matter atrophy in the language network contributes to deficits of PPA patients. Furthermore, we show that overlapping damage across PPA variants is likely to create similarities in group performance in many single-word language tasks and that non-atrophied cortex plays an informative role in PPA task performance.

Keyphrases: Dementia, Neuropsychology, language, primary progressive aphasia

@booklet{EasyChair:6419,
  author    = {Curtiss Chapman and Maryna Polyakova and Karsten Mueller and Janine Diehl-Schmid and Markus Otto and Adrian Danek and Gesa Hartwigsen and Matthias L. Schroeter},
  title     = {Structural Correlates of Language Processing in Primary Progressive Aphasia},
  howpublished = {EasyChair Preprint 6419},
  year      = {EasyChair, 2021}}