title: Regularity and beyond: Impaired production and comprehension of inflectional morphology in semantic dementia.
abstract: Studies on inflectional morphology in semantic dementia (SD) have focused on the contrast between the regular and the irregular English past-tense. These studies aimed to contrast the claims of single- and dual-mechanism theories. However, both theories can account for impaired production of irregular verbs observed in SD. According to the dual-mechanism theory, this impairment is related to word-retrieval difficulties, while according to single-mechanism theory it is the consequence of semantic impairment. However, authors suggest that it is time to envision a broader role for semantic memory in the production of semantically encoded aspects of inflectional morphology. This study reports the performance of 10 French-speaking patients with SD in three tasks of inflectional morphology. Their performances were compared to those of a group of 20 age-, gender- and education-matched adults without cognitive impairment. Results show that SD patients had difficulties producing tense and person inflection in verbs and pseudo-verbs, whether regular or pseudo-regular. In a second task in which participants were directly exposed to regularity manipulations, SD patients tended to choose a more typical or predictable alternative over a correctly inflected verb. Results of the third task show that their difficulties in producing semantically encoded aspects of inflection, such as tense, are related to difficulties to understand the semantic content conveyed by inflectional morphemes. Overall, these results support the claim that semantic impairment can cause morphological deficits that do not only affect irregular verbs, but that also have impacts on the production and comprehension of semantic information conveyed by inflectional morphemes.
authors.affiliation: Faculté de médecine, Université Laval, 1050, avenue de la Médecine, Québec, Québec G1V 0A6, Canada; Centre de recherche de l'Institut universitaire en santé mentale de Québec, Axe des Neurosciences cliniques et cognitives, 2601, de la Canardière, Québec, Québec G1J 2G3, Canada; Institut des sciences du langage et de la communication, Faculté des Lettres et Sciences humaines, Université de Neuchâtel, Rue de la Pierre à Mazel, 7, CH-2000 Neuchâtel, Switzerland. Electronic address: noemie.auclair-ouellet.1@ulaval.ca.
authors.forename: Noémie
authors.initials: N
authors.lastname: Auclair-Ouellet
authors.affiliation: Faculté de médecine, Université Laval, 1050, avenue de la Médecine, Québec, Québec G1V 0A6, Canada; Centre de recherche de l'Institut universitaire en santé mentale de Québec, Axe des Neurosciences cliniques et cognitives, 2601, de la Canardière, Québec, Québec G1J 2G3, Canada. Electronic address: joel.macoir@rea.ulaval.ca.
authors.forename: Joël
authors.initials: J
authors.lastname: Macoir
authors.affiliation: Clinique interdisciplinaire de mémoire, Centre hospitalier universitaire de Québec, 1401, 18(e) Rue, Québec, Québec G1J 1Z4, Canada. Electronic address: robert.laforce@fmed.ulaval.ca.
authors.forename: Robert
authors.initials: R
authors.lastname: Laforce
authors.affiliation: Centre de recherche de l'Institut universitaire de gériatrie, 4565, Chemin Queen-Mary, Montréal, Québec H3W 1W5, Canada. Electronic address: nathalie.bier@umontreal.ca.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bier
authors.affiliation: Institut des sciences du langage et de la communication, Faculté des Lettres et Sciences humaines, Université de Neuchâtel, Rue de la Pierre à Mazel, 7, CH-2000 Neuchâtel, Switzerland. Electronic address: marion.fossard@unine.ch.
authors.forename: Marion
authors.initials: M
authors.lastname: Fossard
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D032882:Comprehension; D005260:Female; D057180:Frontotemporal Dementia / Q000503:physiopathology*; D006801:Humans; D008297:Male; D012660:Semantics
keywords: Comprehension; Inflectional morphology; Production; Semantic dementia