Characteristics of word fluency in healthy aging and Alzheimer’s disease

Abstract

Purpose: In general, aging factor or neurological disease degrades a function of working memory, leading poor word fluency. The purpose of this study was to investigate the characteristics of word fluency in healthy aging and Alzheimer’s disease (AD). Methods: Nineteen healthy older adults, sixteen mild AD and twelve moderate AD subjects performed semantic and phonemic word fluency tasks. A series of cognitive-linguistic assessments were also administered to index working memory capacity, confrontation naming, attention, processing speed, and executive function as correlates of word fluency performance. Results: Findings indicated that the performances of word fluency differed significantly among three groups. In particular, all groups had better performances in semantic word fluency task. Mild and moderate AD groups had significant differences in performances of semantic and phonemic word fluency. Word fluency were also significantly correlated with most cognitive-linguistic abilities in all groups. Executive function and working memory capacity were found to be the best predictors of word fluency. Conclusion: These results demonstrate that the performances of word fluency differed according to neurological aspects and severity of AD. In addition, the primary role of executive function and working memory capacity suggests the clinical usefulness of word fluency tasks in healthy aging and AD.