13 Investigating the Influence of Educational Attainment and Crystalized Verbal Skills on Verbal Fluency Performance Among Patients from a Community-Based Outpatient Neurology Clinic

Abstract

Objective:

Neuropsychological measures of verbal fluency help detect cognitive decline and neuropathology. The discrepancy between semantic verbal fluency and phonemic verbal fluency is commonly utilized to differentiate between cortical and subcortical processes. Understanding how other factors influence a patient’s verbal fluency scores is vital in informing clinical interpretation of neuropsychological test data. This study aimed to investigate how educational attainment and crystalized verbal skills (i.e., word reading and vocabulary) influence verbal fluency performance among a clinical sample of patients seen for neuropsychological evaluation services at a community-based outpatient neurology clinic.

Participants and Methods:

We utilized data from N=26 patients [mean age = 50.5 (SD = 22.0), 31% female, mean education = 13.5 (SD = 2.3)] who completed neuropsychological evaluations as part of their clinical care at an outpatient neurology clinic. Participants were included in this study if they had complete data for all variables of interest. We used Pearson correlation analyses to investigate associations between each predictor variable of interest (years of education, WRAT-5 Reading, WASI-2 Vocabulary) and age-norm corrected D-KEFS Verbal Fluency scores. Prior to analysis, all variables were converted to z-scores.

Results:

We found that years of education (r = 0.49, p = 0.01) and vocabulary (r = 0.41, p = 0.04) were significantly positively correlated with category fluency performance. Reading was also positively correlated with category fluency at trend level, but this association was not statistically significant (r = 0.36, p = 0.07). We found that vocabulary (r = 0.47, p = 0.02) and reading (r = 0.51, p = 0.007) were significantly positively correlated with phonemic fluency performance, while the association between education and phonemic verbal fluency performance was not significant (r = 0.27, p = 0.18).

Conclusions:

Our results suggest that educational attainment and crystalized verbal skills are positively associated with verbal fluency performance, though the degree of influence of these individual factors may differ for category fluency vs phonemic fluency performance. Our results have implications for the clinical practice of neuropsychology. Namely, appreciating a patient’s educational attainment and crystalized verbal skills can help guide clinical interpretation of whether or not a patient’s verbal fluency test scores reflect a decline from their baseline. This may be particularly important to consider among patients with high educational attainment or high premorbid verbal skills, as a subtle decline in their verbal fluency abilities may not be appreciated if relying only on age-based norms for interpretation. This is clinically relevant including when assessing for the early stages of neurodegenerative disorders (e.g., Alzheimer’s disease, Primary Progressive Aphasia) or for subtle changes associated with stroke or brain injury.