Differential impacts of age of acquisition on letter and semantic fluency in Alzheimer's disease patients and healthy older adults.

Department of Psychology, Lehman College, City University of New York, Bronx, NY 10468-1589, USA.
Quarterly journal of experimental psychology (2006) (Impact Factor: 1.73). 08/2011; 64(12):2383-91. DOI: 10.1080/17470218.2011.596660
Source: PubMed

ABSTRACT The degree to which the typical age of acquisition (AoA) of words and word frequency have separable influences on verbal production tasks has been strongly debated. To examine the overlap between these factors in verbal fluency tasks, the performance of Alzheimer's disease (AD) patients (N = 34) and normal elderly controls (N = 36) was compared on semantic (e.g., vegetables) and letter (e.g., words that begin with F) fluency tasks. These comparisons revealed that words generated for the semantic fluency task had an earlier AoA while words generated for the letter fluency task had a higher word frequency. Differences in AoA between AD patients and controls were larger for semantic than letter fluency. These results suggest that AoA has an effect on verbal production that is independent of word frequency and that AoA has a semantic locus.

1 Bookmark
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present age-of-acquisition (AoA) ratings for 30,121 English content words (nouns, verbs, and adjectives). For data collection, this megastudy used the Web-based crowdsourcing technology offered by the Amazon Mechanical Turk. Our data indicate that the ratings collected in this way are as valid and reliable as those collected in laboratory conditions (the correlation between our ratings and those collected in the lab from U.S. students reached .93 for a subsample of 2,500 monosyllabic words). We also show that our AoA ratings explain a substantial percentage of the variance in the lexical-decision data of the English Lexicon Project, over and above the effects of log frequency, word length, and similarity to other words. This is true not only for the lemmas used in our rating study, but also for their inflected forms. We further discuss the relationships of AoA with other predictors of word recognition and illustrate the utility of AoA ratings for research on vocabulary growth.
    Behavior Research Methods 05/2012; · 2.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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.
    Journal of Alzheimer's disease: JAD 07/2014; · 3.61 Impact Factor


1 Download
Available from