title: Noun-verb dissociation in aphasia: the role of imageability and functional locus of the lesion.
abstract: Aphasic patients occasionally manifest a dissociated naming ability between objects and actions: this phenomenon has been interpreted as evidence of a separate organization for nouns and verbs in the mental lexicon. Nevertheless Bird et al. [Bird, H., Howard, D., Franklin, S. (2000). Why is a verb like an inanimate object? Grammatical category and semantic category deficits. BrainandLanguage, 72, 246-309], suggested that the damage underlying noun-verb dissociation affects the corresponding semantic concepts and not the lexical representation of words; moreover, they claimed that many dissociations reported in literature are caused merely by a strong imageability effect. In fact, most authors used a picture-naming task to assess patients' naming ability, and due to the fact that this test involves the use of pictures to represent actions and objects, nouns were frequently more imageable than verbs [Luzzatti, C., & Chierchia, G. (2002). On the nature of selective deficit involving nouns and verbs. RivistadiLinguistica, 14, 43-71]. In order to overcome this drawback, we devised a new task - nouns and verbs retrieval in a sentence context (NVR-SC) - in which nouns and verbs have the same imageability rate. Patients' performance on this task is compared with that obtained by the same patients on a standard picture-naming task. Of the 16 aphasic patients with a selective verb deficit, as revealed by the picture-naming task, two continued to show dissociation in the NVR-SC task, while 14 did not. The data indicate that at least some patients have an imageability-independent lexical deficit for verbs. The functional locus/i of the damage is also considered, with particular reference to the lemma/lexeme dichotomy suggested by Levelt et al. [Levelt, W. J. M., Roelofs, A., & Meyer, A. S. (1999). A theory of lexical access in speech production. BehavioralandBrainSciences, 22, 1-75].
authors.affiliation: Department of Psychology, University of Milano Bicocca, Piazza dell'Ateneo Nuovo 1, 20126 Milano, Italy. davide.crepaldi@unimib.it
authors.forename: Davide
authors.initials: D
authors.lastname: Crepaldi
authors.forename: Silvia
authors.initials: S
authors.lastname: Aggujaro
authors.forename: Lisa Saskia
authors.initials: LS
authors.lastname: Arduino
authors.forename: Giusy
authors.initials: G
authors.lastname: Zonca
authors.forename: Graziella
authors.initials: G
authors.lastname: Ghirardi
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Inzaghi
authors.forename: Mariarosa
authors.initials: M
authors.lastname: Colombo
authors.forename: Gennaro
authors.initials: G
authors.lastname: Chierchia
authors.forename: Claudio
authors.initials: C
authors.lastname: Luzzatti
mesh_terms: D000704:Analysis of Variance; D001037:Aphasia / Q000503:physiopathology*; D004213:Dissociative Disorders / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D007802:Language; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D012044:Regression Analysis; D015203:Reproducibility of Results; D014705:Verbal Behavior / Q000502:physiology*; D014936:Word Association Tests / Q000706:statistics & numerical data