title: The cumulative semantic interference effect in normal and pathological ageing.
abstract: People affected by mild cognitive impairment (MCI), a precursor of Alzheimer's Disease, present with impairments in picture naming, a lexical/semantic task which rests on the activation of perceptual, semantic, and phonological representations. The poor performance of MCI individuals in picture naming has been accounted for in terms of deficits of either the perceptual, semantic, or phonological stages. To disentangle the source of this deficit we compared the cumulative semantic interference effect (Howard et al., 2006. Cognition. 100, 464-482.) and the repetition priming effect of a group of people with MCI to that of a group of healthy elderly participants and with a group of healthy young participants. The cumulative semantic interference effect defines a linear increase in the picture naming reaction times which is function of the already named pictures belonging to the same semantic category to which the named picture belongs. The repetition priming effect refers to an increase in performance for repeated items compared to unrepeated items. Results showed that whereas the cumulative semantic interference effect was present in the healthy elderly and young samples, it was absent in the MCI sample; instead, all groups showed comparable repetition priming effects. This pattern of results suggests that the impairment in picture naming exhibited by MCI individuals is due to an inefficient semantic access.
authors.affiliation: Università degli Studi di Padova, Padova, Italy. Electronic address: claudio.mulatti@unipd.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Mulatti
authors.affiliation: Queen Margaret University, Musselburgh, UK.
authors.forename: Clara
authors.initials: C
authors.lastname: Calia
authors.affiliation: Università degli Studi di Bari, Bari, Italy.
authors.forename: Maria Fara
authors.initials: MF
authors.lastname: De Caro
authors.affiliation: Human Cognitive Neuroscience and Centre for Cognitive Ageing and Cognitive Epidemiology, Psychology, University of Edinburgh, Edinburgh, UK.
authors.forename: Sergio
authors.initials: S
authors.lastname: Della Sala
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D060865:Repetition Priming / Q000502:physiology*; D012660:Semantics; D055815:Young Adult
keywords: Ageing; Cumulative semantic effect; Mild cognitive impairment; Picture naming; Semantic deficit