Analysis of Verbal Fluency Ability in Amnestic and Non-Amnestic Mild Cognitive Impairment

Abstract

The purpose of this study was to investigate the pattern of performance on letter and category fluency tests of individuals with mild cognitive impairment (MCI). Previous research has suggested that organization strategies, including "clustering" (i.e., groups of related words) and "switching" (i.e., shift from one cluster to another), are important for efficient verbal fluency performance. Participants were 25 individuals with single-domain amnestic MCI (aMCI), 49 with multidomain aMCI, 16 with non-amnestic MCI (naMCI), and 90 cognitively healthy older adults. Fluency performances were analyzed across two 30-s intervals for total words produced, cluster size, and switching. Analyses of variance (ANOVAs) with follow-up tests revealed that the single-domain aMCI group performed comparably with healthy controls on each dependent measure across both fluency tasks. In contrast, the multidomain aMCI group showed performance decrements in total words and switching production compared with healthy controls on both fluency tasks, whereas the naMCI group produced fewer words and switches on letter fluency. Each group generated more words and switches during the first 30-s on both fluency tasks, with the exception of the naMCI group, whose switching on letter fluency did not decrease as the task progressed. As indicated by the single-domain aMCI group's unimpaired performance, our findings demonstrate that verbal fluency performance decreases as domains beyond memory become impaired in MCI. Reduced switching ability, which has been linked to prefrontal executive functioning, contributed the most to the poorer performance of individuals with multidomain MCI and naMCI.

Semantic and Phonemic Verbal Fluency Discrepancy in Mild Cognitive Impairment: Potential Predictor of Progression to Alzheimer's Disease

“…Individuals with single‐domain MCI performed better than controls in phonemic fluency while underperforming in animal fluency. We reproduced the impairments seen by other studies in individuals with amnestic multidomain MCI compared to controls, but did not show deficits in phonemic fluency in any MCI subtype relative to controls (and indeed better performance on phonemic fluency in participants with single‐domain MCI). One important point in reconciling these conflicting results is the question of diagnosis of MCI.…”

Visuoconstructional Impairment in Subtypes of Mild Cognitive Impairment

“…Other research examining performance on verbally mediated executive tests has clearly linked better performance on executive tests with relatively good performance on the BNT and the “animal” fluency tests, the language-related measures used in the current research (Bondi et al, 2002). Lou (1999) has also suggested that the alterations in response set can occur when verbally mediated executive tests require language-related abilities (Ahmed et al, 2013; Weakley, Schmitter-Edgecombe, & Anderson, 2013). …”

Detailed analysis of the supermarket task included on the Japanese version of the Rapid Dementia Screening Test

“…Weakley et al . investigated cluster size and switches on phonemic fluency (F, A, S) and animal fluency tasks between subjects with mild cognitive impairment (MCI) and healthy controls, but the supermarket task was not included in their study. Finally, a larger cluster size strategy may use superordinate concepts and fewer subordinate concepts, leading to fewer switches.…”