Disparate letter and semantic category fluency deficits in autopsy-confirmed frontotemporal dementia and Alzheimer's disease

Neuropsychology. 2007 Jan;21(1):20-30. doi: 10.1037/0894-4105.21.1.20.


Patients with autopsy-confirmed frontotemporal dementia (FTD; n = 16) and Alzheimer's disease (AD; n = 32) were compared on first-letter and semantic category fluency tasks. Despite being matched on age, education, and dementia severity, FTD patients performed worse overall and showed similar impairment in letter and semantic category fluency, whereas AD patients showed greater impairment in semantic category than letter fluency. A measure of the disparity between letter and semantic category fluency (the semantic index) was effective in differentiating FTD from AD patients, and this disparity increased with increasing severity of dementia. These unique patterns of letter and semantic category fluency deficits may be indicative of differences in the relative contribution of frontal-lobe-mediated retrieval deficits and temporal-lobe-mediated semantic deficits in FTD and AD.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Alzheimer Disease / complications*
  • Alzheimer Disease / pathology
  • Analysis of Variance
  • Autopsy / methods
  • Dementia / complications*
  • Dementia / pathology
  • Female
  • Humans
  • Language Disorders / etiology*
  • Male
  • Mental Status Schedule / statistics & numerical data
  • Middle Aged
  • Neuropsychological Tests / statistics & numerical data
  • Semantics*
  • Verbal Behavior / physiology*