Abstract
Objective
Studies that have used semantic fluency tasks to guide differential diagnosis of Alzheimer’s disease (ad) and vascular dementia (VaD) typically only examine the total number of words produced, which has yielded conflicting results. The present study examined whether other indices of semantic fluency (i.e., clustering and switching), which are thought to better isolate the components of semantic memory and executive functioning abilities, would discriminate among ad, VaD, and mild cognitive impairment (MCI).
Method
A retrospective sample of 156 patients (mean age = 78.64; 76.3% female, 23.7% male; 26.9% White, 71.2% Black, 1.9% Other) who completed a comprehensive neuropsychological evaluation as part of a workup related to memory concerns and were diagnosed with ad, VaD, or MCI was utilized. Separate univariate analyses of variance were used to examine group differences on three indices of semantic fluency (animals): total words, mean cluster size, and number of switches.
Results
There was a significant main effect of group for total words [F(2,153) = 7.09, p = 0.001], mean cluster size [F(2, 153) = 3.44, p = 0.035] and number of switches [F(2,153) = 3.36, p = 0.037]. Bonferroni post-hoc tests revealed that the ad and VaD groups produced significantly fewer total words than the MCI group, the ad group produced significantly smaller clusters than the VaD group, and the VaD group produced significantly fewer switches than the MCI group.
Conclusion
Observed group differences suggest that clustering and switching may aid in discriminating between dementia etiologies. Future studies may benefit from examining the association between these fluency indices and performance on executive functioning and semantic knowledge tasks to better understand these findings.
Cognitive Correlates of Functional Abilities in Individuals with Mild Cognitive Impairment: Comparison of Questionnaire, Direct Observation, and Performance-Based Measures
