title: Verbal fluency in Alzheimer's disease, Parkinson's disease, and major depression.
abstract: OBJECTIVE
  To compare verbal fluency among Alzheimer's disease, Parkinson's disease, and major depression and to assess the sociodemographic and clinical factors associated with the disease severity.
  
  
  METHODS
  Patients from an outpatient university center with a clinical diagnosis of Alzheimer's disease, Parkinson's disease or major depression were studied. Severity was staged using the Hoehn & Yahr scale, the Hamilton Depression scale and the Clinical Dementia Rating for Parkinson's disease, major depression, and Alzheimer's disease, respectively. All subjects were tested with the Mini-Mental State Examination, the digit span test, and the verbal fluency test (animals). We fit four types of regression models for the count variable: Poisson model, negative binomial model, zero-inflated Poisson model, and zero-inflated negative binomial model.
  
  
  RESULTS
  The mean digit span and verbal fluency scores were lower in patients with Alzheimer's disease (n = 34) than in patients with major depression (n = 52) or Parkinson's disease (n = 17) (p<0.001). The average number of words listed was much lower for Alzheimer's disease patients (7.2 words) compared to the patients presenting with major depression (14.6 words) or Parkinson's disease (15.7 words) (KW test = 32.4; p<0.01). Major depression and Parkinson's disease groups listed 44% (ROM = 1.44) and 48% (ROM = 1.48) more words, respectively, compared to those patients with Alzheimer's disease; these results were independent of age, education, disease severity and attention. Independently of diagnosis, age, and education, severe disease showed a 26% (ROM = 0.74) reduction in the number of words listed when compared to mild cases.
  
  
  CONCLUSIONS
  Verbal fluency provides a better characterization of Alzheimer's disease, major depression, and Parkinson's disease, even at later stages.
authors.affiliation: Laboratory of Exercise, EEFD-related Neuroscience, Federal University of Rio de Janeiro, RJ, Brazil. narahyanaaraujo@yahoo.com.br
authors.forename: Narahyana Bom de
authors.initials: NB
authors.lastname: Araujo
authors.forename: Maria Lage
authors.initials: ML
authors.lastname: Barca
authors.forename: Knut
authors.initials: K
authors.lastname: Engedal
authors.forename: Evandro Silva Freire
authors.initials: ES
authors.lastname: Coutinho
authors.forename: Andrea Camaz
authors.initials: AC
authors.lastname: Deslandes
authors.forename: Jerson
authors.initials: J
authors.lastname: Laks
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology* / Q000523:psychology; D003865:Major Depressive Disorder / Q000503:physiopathology* / Q000523:psychology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology; D014705:Verbal Behavior / Q000502:physiology*