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Differences in word learning ability and subsequent memory performance between Primary Progressive Aphasia variants
Poster D21 in Poster Session D, Wednesday, October 25, 4:45 - 6:30 pm CEST, Espace Vieux-Port
Guillem Olivé Cadena1,2,3, Maria F Porto1,2,3, Gemma Cardona1,2,3, Anna Gerloff1,3, Sonia Marques-Kiderle4,5, Lucía Vaquero6, Claudia Penaloza1,2,3, Ignacio Illan-Gala4,5, Alberto Lleó4,5, Miguel Ángel Santos-SAntos4,5, Antoni Rodríguez-Fornells1,2,3,7; 1University of Barcelona, Spain, 2Bellvitge Biomedical Research Institute-IDIBELL, Spain, 3Institute of Neurosciences, Spain, 4Hospital de la Santa Creu I Sant Pau, Spain, 5Centre of Biomedical Investigation Network for Neurodegenerative Diseases, Spain, 6Complutense University of Madrid, Spain, 7Institució Catalana de Recerca i Estudis Avançats-ICREA, Spain
Background: Previous studies have proposed that processing and learning words from different grammatical categories (i.e., nouns and verbs) is subserved by distinct neural regions/networks (Shapiro et al., 2005; Mestres-Missé et al., 2010), although the evidence appears to be inconclusive regarding the origin of this distinction. Here, we addressed this issue by comparing Primary Progressive Aphasic (PPA) patients and healthy controls in their ability to learn novel nouns and verbs in a contextual word learning task that requires the acquisition of word meanings via inference from a verbal context. Aims: The primary aim of this study is to test the ability to learn the meaning of new words in PPA patients compared to age-matching controls. We further wanted to examine whether differences in learning and memory performance arose for different word classes between groups. Finally, we aimed to compare if patients with different PPA variants showed distinct word learning or memory performance. Methods: We adapted the contextual new-word learning task from Mestres-Missé et al. (2010). Participants were required to discover the meaning of 24 novel nouns or verbs across several sentences. Learning was assessed using (i) a free-response test that required participants to write the hidden meaning of the trained pseudowords, and (ii) a 4-alternative forced choice (4AFC) test that required them to choose the right meaning for the trained words among 4 alternatives. Subsequent memory for learnt items was tested on a 4AFC test at a short and long term, as well as a recognition test of previously presented new-words. Our preliminary sample consisted of 22 healthy older control participants, 9 non-fluent variant PPA (nfvPPA) patients, and 9 logopenic variant PPA (lvPPA) patients. The experimental task was validated with 30 younger control participants and compared to the older controls to evaluate age-related differences in noun- and verb-learning in healthy individuals. Generalized Linear Mixed Models were used to assess performance differences between patients and controls in learning and memory tests for nouns and verbs. Also, paired t-tests were used to assess differences between noun and verb learning and memory scores within group separately. Results: Preliminary results revealed a clear effect of group in learning measures for both nouns and verbs, with a significant higher performance of controls compared to both PPA groups, and nfvPPA patients showing significantly better learning accuracy than lvPPA. However, these group differences were not present for memory measures, as controls performed better than patients but no differences were found between PPA variants. When taking each group separately, no differences were found between noun and verb learning or memory scores. Discussion: Given that temporo-parietal left regions are the site of maximal neural damage in lvPPA patients, as opposed to the posterior frontal-insular left damage in nfvPPA patients (Gorno-Tempini et al., 2011), these initial results suggest potential differences in the neural correlates underlying the acquisition of meaning (both for nouns and verbs) and support the involvement of temporo-parietal left regions in contextual word-learning.
Topic Areas: Meaning: Lexical Semantics, Control, Selection, and Executive Processes