title: Typicality of words produced on a semantic fluency task in amnesic mild cognitive impairment: linguistic analysis and risk of conversion to dementia.
abstract: Semantic and, to a lesser extent, phonological verbal fluency tasks are impaired in Alzheimer's disease (AD) and in amnesic mild cognitive impairment (aMCI). Furthermore, both fluency tasks have been considered as possible markers of conversion from aMCI to AD. Up to recent years, the use of fluency tasks has been limited to word count, but, more recently, linguistic variables, such as word frequency, age of acquisition, familiarity, and typicality, have also been considered. In particular, attention has been focused on typicality of words produced on semantic verbal fluency tasks, because the tendency to produce only the more typical members of various categories points to an impoverishment of semantic memory. The aim of our study was to compare in aMCI, AD, and control subjects a lexical (word frequency) and a lexical-semantic variable (item typicality) in a semantic verbal fluency task, and to evaluate the possible value of these variables in predicting conversion from aMCI to AD during a 2 years follow-up period. We found no difference in mean typicality of words produced by aMCI and AD subjects whereas both groups produced words of higher mean typicality than control subjects. Furthermore, to assess the relationship between typicality values and risk of conversion to AD, the aMCI group was split in two subgroups, including subjects who obtained a mean typicality value lower or higher than the median value of the whole aMCI group. Consistent with our hypothesis, conversion to AD was significantly more frequent in high typicality than in low typicality subjects.
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Maria Gabriella
authors.initials: MG
authors.lastname: Vita
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy Research Center for Neuropsychology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Camillo
authors.initials: C
authors.lastname: Marra
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Spinelli
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Caprara
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Scaricamazza
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: Castelli
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Canulli
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy Research Center for Neuropsychology, Catholic University of the Sacred Heart, Rome, Italy IRCCS Santa Lucia, Rome, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Gainotti
authors.affiliation: Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy Research Center for Neuropsychology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Quaranta
mesh_terms: D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000523:psychology*; D060825:Cognitive Dysfunction / Q000175:diagnosis / Q000523:psychology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007807:Language Tests; D008297:Male; D009483:Neuropsychological Tests; D011379:Prognosis; D012306:Risk; D012660:Semantics; D014825:Vocabulary
keywords: Alzheimer's disease; frequency of use; mild cognitive impairment; semantic disturbance; semantic fluency; typicality