Written Language Impairments in Primary Progressive Aphasia: A Reflection of Damage to Central Semantic and Phonological Processes

摘要

Connectionist theories of language propose that written languagendeficits arise as a result of damage to semantic and phonologicalnsystems that also support spoken language productionnand comprehension, a view referred to as the “primary systems”nhypothesis. The objective of the current study was to evaluatenthe primary systems account in a mixed group of individuals withnprimary progressive aphasia (PPA) by investigating the relationnbetween measures of nonorthographic semantic and phonologicalnprocessing and written language performance and by examiningnwhether common patterns of cortical atrophy underlienimpairments in spoken versus written language domains. Individualsnwith PPA and healthy controls were administered a languagenbattery, including assessments of semantics, phonology, reading,nand spelling. Voxel-based morphometry was used to examine thenrelation between gray matter volumes and language measuresnwithin brain regions previously implicated in semantic and phonologicalnprocessing. In accordance with the primary systemsnaccount, our findings indicate that spoken language performancenis strongly predictive of reading/spelling profile in individualsnwith PPA and suggest that common networks of critical left hemispherenregions support central semantic and phonological processesnrecruited for spoken and written language.