title: Semantic interference during object naming in agrammatic and logopenic primary progressive aphasia (PPA).
abstract: This study examined the time course of object naming in 21 individuals with primary progressive aphasia (PPA) (8 agrammatic (PPA-G); 13 logopenic (PPA-L)) and healthy age-matched speakers (n=17) using a semantic interference paradigm with related and unrelated interfering stimuli presented at stimulus onset asynchronies (SOAs) of -1000, -500, -100 and 0 ms. Results showed semantic interference (SI) (i.e. significantly slower RTs in related compared to unrelated conditions) for all groups at -500, -100 and 0 ms, indicating timely spreading activation to semantic competitors. However, both PPA groups showed a greater magnitude of SI than normal across SOAs. The PPA-L group and six PPA-G participants also evinced SI at -1000 ms, suggesting an abnormal time course of semantic interference resolution, and concomitant left hemisphere cortical atrophy in brain regions associated with semantic processing. These subtle semantic mapping impairments in non-semantic variants of PPA may contribute to the anomia of these patients.
authors.affiliation: Department of Communication Sciences and Disorders, Northwestern University, United States. ckthom@northwestern.edu
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Thompson
authors.forename: Soojin
authors.initials: S
authors.lastname: Cho
authors.forename: Charis
authors.initials: C
authors.lastname: Price
authors.forename: Christina
authors.initials: C
authors.lastname: Wieneke
authors.forename: Borna
authors.initials: B
authors.lastname: Bonakdarpour
authors.forename: Emily
authors.initials: E
authors.lastname: Rogalski
authors.forename: Sandra
authors.initials: S
authors.lastname: Weintraub
authors.forename: M-Marsel
authors.initials: MM
authors.lastname: Mesulam
mesh_terms: D000368:Aged; D000849:Anomia / Q000473:pathology / Q000503:physiopathology*; D001039:Aphasia, Broca / Q000473:pathology / Q000503:physiopathology*; D018888:Aphasia, Primary Progressive / Q000473:pathology / Q000503:physiopathology*; D001184:Articulation Disorders / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D005556:Form Perception / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012660:Semantics