Characterizing cognitive performance in a large longitudinal study of aging with computerized semantic indices of verbal fluency. (August 2016)

• Record Type: Journal Article
• Authors: Pakhomov, Serguei V.S.; Eberly, Lynn; Knopman, David
• Is Part Of: Neuropsychologia. Volume 89(2016)
• Page Start: 42
• Page End: 56
• Publication Date: 2016-08
• Subjects: Semantic verbal fluency -- Clustering -- Memory -- Attention -- Dementia -- Semantic relatedness -- Word frequency; Neuropsychology -- Periodicals; Neurology -- Periodicals; Psychophysiology -- Periodicals; Neuropsychologie -- Périodiques; Neuropsychology; Periodicals; Electronic journals; 616.8
• DOI: 10.1016/j.neuropsychologia.2016.05.031
• Languages: English
• ISSNs: 0028-3932

Abstract

Abstract: A computational approach for estimating several indices of performance on the animal category verbal fluency task was validated, and examined in a large longitudinal study of aging. The performance indices included the traditional verbal fluency score, size of semantic clusters, density of repeated words, as well as measures of semantic and lexical diversity. Change over time in these measures was modeled using mixed effects regression in several groups of participants, including those that remained cognitively normal throughout the study (CN) and those that were diagnosed with mild cognitive impairment (MCI) or Alzheimer's disease (AD) dementia at some point subsequent to the baseline visit. The results of the study show that, with the exception of mean cluster size, the indices showed significantly greater declines in the MCI and AD dementia groups as compared to CN participants. Examination of associations between the indices and cognitive domains of memory, attention and visuospatial functioning showed that the traditional verbal fluency scores were associated with declines in all three domains, whereas semantic and lexical diversity measures were associated with declines only in the visuospatial domain. Baseline repetition density was associated with declines in memory and visuospatial domains. Examination of lexical and semantic diversity measures in subgroups with high vs. low attention scores (but normal functioning in other domains) showed that the performance of individuals with low attention was influenced more by word frequency rather than strength of semantic relatedness between words. These findings suggest that various automatically semantic indices may be used to examine various aspects of cognitive performance affected by dementia. Highlights: A novel computerized approach to characterize semantic verbal fluency performance. Trajectories of decline in some but not all computerized semantic indices differ across diagnostic groups computerized. Longitudinal change in word frequency information is sensitive to decreased executive function. Lexical access mechanism(s) are driven word frequency and less so by semantic relatedness under executive function load.