Letter and category fluency in community-dwelling Canadian seniors: a comparison of normal participants to those with dementia of the Alzheimer or vascular type.

Measures of letter (FAS) and category (Animal Naming) fluency were completed by community-dwelling, cognitively normal seniors (n = 635), and by individuals diagnosed with dementia of the Alzheimer type (DAT) (n = 155), or with vascular dementia (n = 39). Among normal seniors, category, but not letter fluency, declined with age, females performed better than males on letter but not on category fluency, and performance increased with education on both tasks. Among participants with DAT, letter fluency was influenced by level of education, whereas category fluency was education-, age-, and gender-invariant. Both measures differentiated normal seniors from those with dementia. Category fluency was more impaired than letter fluency at both mild and moderate stages of dementia, but neither task differentiated DAT from vascular dementia.