Verbal Fluency: Language or Executive Function Measure?

Abstract

Measures of phonemic and semantic verbal fluency, such as FAS and Animal Fluency (Benton, Hamsher, & Sivan, 1989), are often thought to be measures of executive functioning (EF). However, some studies (Henry & Crawford, 2004a , 2004b , 2004c ) have noted there is also a language component to these tasks. The current exploratory factor-analytic study examined the underlying cognitive structure of verbal fluency. Participants were administered language and EF measures, including the Controlled Oral Word Association Test (FAS version), Animal Fluency, Boston Naming Test (BNT), Vocabulary (Wechsler Adult Intelligence Scale-III), Wisconsin Card-Sorting Test (WCST, perseverative responses), and Trail-Making Test-Part B (TMT-B). A 2-factor solution was found with the 1st factor, language, having significant loadings for BNT and Vocabulary, while the second factor was labeled EF because of significant loading from the WCST and TMT-B. Surprisingly, FAS and Animal Fluency loaded exclusively on to the language factor and not EF. The current results do not exclude EF as a determinant of verbal fluency, but they do suggest that language processing is the critical component for this task, even without significant aphasic symptoms. Thus, the results indicated that both letter (phonemic) and category (semantic) fluency are related to language, but the relationship to EF is not supported by the results.

Verbal Fluency Fruits as a Predictor of Alzheimer’s Disease Progression in Brazilian Portuguese Speakers

“…Several studies have tried to separate these two components. These studies did not exclude EF as a determinant of verbal fluency, but they did suggest that language processing is the critical component for this task [22,23].…”

New ways to analyze word generation performance in brain injury: A systematic review and meta-analysis of additional performance measures

“…Benassi, Richter, & Gödde, 2012;Paulsen et al, 1996;Sumiyoshi et al, 2001), since these two domains are considered to be essential prerequisites for good word generation performance. On the one hand, word generation performance is assumed to reflect multi-factorial demands based on efficient language skills, such as the integrity of lexical and semantic stores, and on the other hand on different executive function processes, such as the initiation of word retrieval and adequate provision of attention resources, lexical search and word retrieval, triggering responses, ongoing and systematic monitoring of retrieval process and verbal output, inhibition of previously named words, strategy application with respect to given rules, and appropriate speed of performance (Bittner & Crowe, 2006;Drechsler, 2007;Lezak et al, 2012;Ruff et al, 1997;Tröster et al, 1995;Unsworth, Spillers, & Brewer, 2010;Whiteside et al, 2016). Hence, to identify the underlying deficit and facilitate diagnostic procedures, word generation analyses require quantifiable and specific performance measures (Troyer, Moscovitch, & Winocur, 1997;Wong et al, 2010).…”

Assessing Cognition Post-Stroke using Virtual Reality Technology

“…Our animal fluency results are supported by Whiteside et al (2016) where factor analysis was used to verify that animal fluency loaded exclusively to language, rather than executive functioning. Although executive skills may be impaired in aphasia (Fridriksson, Nettles, Davis, Morrow, & Montgomery, 2006) using the animal fluency task to determine executive skills in people with aphasia may mislead diagnoses.…”

“…While fluency tasks (such as animal fluency) undoubtedly include facets of executive function in planning search and retrieval, they are predominantly a reflection of language skills (Whiteside et al, 2016).…”

“…For example, verbal fluency is a task often used in standard language assessments (Swinburn, Porter, & Howard, 2005), but it is also used to measure executive skills in stroke (Hachinski et al, 2006). This highly language-dependent task (Whiteside et al, 2016) Cognitive tests vary in the cognitive domain being tested, the task complexity, the delivery of instructions and the responses needed for completion. There has been no systematic analysis of the relationship between language performance in post-stroke aphasia (naming and comprehension) and performance on a broad range of widely used neuropsychological tasks.…”