Executive functions predict verbal fluency scores in healthy participants

Abstract

While there is a clear link between impairments of executive functions (EFs), i.e. cognitive control mechanisms that facilitate goal-directed behavior, and speech problems, it is so far unclear exactly which of the complex subdomains of EFs most strongly contribute to speech performance, as measured by verbal fluency (VF) tasks. Furthermore, the impact of intra-individual variability is largely unknown. This study on healthy participants (n = 235) shows that the use of a relevance vector machine approach allows for the prediction of VF performance from EF scores. Based on a comprehensive set of EF scores, results identified cognitive flexibility and inhibition as well as processing speed as strongest predictors for VF performance, but also highlighted a modulatory influence of fluctuating hormone levels. These findings demonstrate that speech production performance is strongly linked to specific EF subdomains, but they also suggest that inter-individual differences should be taken into account.

Figure 1

Plots of significant correlations of executive function tests and total verbal fluency sum score. The performance in verbal fluency task is represented by the total number of correct words produced across all three semantic VF tasks (t₁ + t₂ + t₃).The negative correlation in plot b-f are due to the divergent direction of the scores since these variables describe different types of errors, reaction or process times (the higher the worse the performance) while the performance in the verbal fluency is represented by the total amount of correct items (the higher the better).

Figure 2

Correlation of true and predicted verbal fluency sum scores applying Relevance Vector Machine algorithm.

Figure 3

Features displaying strongest impact on prediction analysis.