title: Preservation of the Semantic Verbal Fluency Advantage in a Large Population-Based Sample: Normative Data from the TILDA Study.
abstract: OBJECTIVE
  It is widely believed that phonemic fluency is more difficult than naming exemplars from a semantic category. Normative data in this regard are scarce, and there is considerable disagreement in the literature regarding the pattern in normal ageing and neurodegenerative conditions. Our objective was to provide normative data for semantic phonemic discrepancy scores from a large sample of older adults.
  
  
  METHODS
  A total of 5780 community-dwelling older adults were included in this prospective, longitudinal study. Discrepancy scores were calculated by subtracting phonemic fluency score from semantic fluency score for each participant. Quantile regression was used to estimate normative values stratified for age.
  
  
  RESULTS
  Subjects did better on testing of semantic fluency. The average discrepancy score was 9.18±6.89 words, (range, -20 to 37; n=5780). At the fiftieth percentile, those in their fifth decade produced 10 more "animals" than "letter F" words. Subjects scored one word less per decade, with an average of seven more "animal" words produced by those in their eighth decade.
  
  
  CONCLUSIONS
  Our study is the first to provide normative data and confirms that, for animal versus letter F fluency, the semantic advantage persists into later life in a population-based sample of community-dwelling older adults. Given that a majority of clinical samples have confirmed a reverse of this pattern in Alzheimer's dementia (i.e., loss of semantic advantage in Alzheimer's disease, yielding a phonemic advantage), our findings support the clinical utility of brief fluency tests and encourage further research into their use in diagnosis and prediction of progression to dementia.
authors.affiliation: 1St. Ita's Hospital,Portrane,Co. Dublin,Ireland.
authors.forename: Roisin M
authors.identifier: http://orcid.org/0000-0002-9602-0780
authors.initials: RM
authors.lastname: Vaughan
authors.affiliation: 2Mercer's Institute of Research on Ageing,St. James's Hospital,Dublin 8,Ireland.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Coen
authors.affiliation: 3The Irish Longitudinal Study on Ageing (TILDA),Trinity College,Dublin,Ireland.
authors.forename: RoseAnne
authors.initials: R
authors.lastname: Kenny
authors.affiliation: 2Mercer's Institute of Research on Ageing,St. James's Hospital,Dublin 8,Ireland.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Lawlor
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D018672:Community Health Planning; D005260:Female; D006801:Humans; D057187:Independent Living; D007494:Ireland; D008137:Longitudinal Studies; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009483:Neuropsychological Tests; D010700:Phonetics; D012016:Reference Values; D012660:Semantics; D014705:Verbal Behavior / Q000502:physiology*
keywords: Assessment; Cognition; Language; Neuropsychological; Normative; Phonemic fluency; Semantics