Category fluency (animals, professions) in normal cognitive ageing and dementia

Abstract Regression-based normative data for commonly used semantic verbal fluency test (VFT) scores were derived from data of the Maastricht Aging Study (N=1,825; age range 24-81). Animal naming, profession naming, and the summed score (animal + profession naming) were shown to be profoundly affected by demographical variables, especially age and educational level. The clinical utility of the newly established regression-based VFT norms was evaluated in a large sample of psychogeriatric patients (N=1,063, of which n=890 met the criteria for Alzheimer's or vascular dementia). Results showed that the animal naming VFT score was the most sensitive measure to distinguish normal aging from dementia (when the specificities of the various VFT measures were equated). Fifty patients were found to commit stuck-in-set perseverations, i.e. they generated animal names during test administration of the profession naming VFT. The prevalence of stuck-in-set perseveration was 11.3% in Parkinson dementia and frontal variant frontotemporal dementia, versus 4.6% and 5.3% in dementia of the Alzheimer type and vascular dementia, respectively. Bivariate analyses revealed that people who committed stuck-in-set perseverations were more deficient on a measure of free recall and on several tests of executive control, such as the Expanded Mental Control Test, the Behavioral Dyscontrol Scale and the Alternating Graphical Sequences Test as a measure of response inhibition. Using multivariate logistic regression analysis, only the Alternating Graphical Sequences Test retained an independent effect in the association with stuck-in-set perseveration.