Systematic administration and analysis of verbal fluency tasks: Preliminary evidence for reliable exploration of processes underlying task performance

Abstract

Verbal fluency (VF) tasks are typically scored by the number of acceptable words generated within an allotted time (i.e., total score). However, total scores do not provide insight into verbal and executive processes underlying VF task performance. Further analyses have been implemented to increase the analytical power of VF tasks, but systematic scoring guidelines are needed. We generated instructions for administration, scoring, and analyses of total scores, errors, temporal parameters, clustering, and switching with strong inter-rater reliability. To investigate the reliability of the proposed analysis, we modeled the performance of Finnish-speaking older adults (N ¼ 50) in phonemic (/k/, /a/, and /p/) and semantic (animals) categories. Our results are in line with previous studies: We observed a higher performance on semantic than phonemic fluency (p 0.001, d ¼ 0.91) and significant effects for education (p 0.001, d ¼ 1.11) and gender (p 0.001, d ¼ À1.11), but not for age (p ¼ 0.10, d ¼ 0.48). Most errors were repetitions. Performance declined over the allotted time frame as measured in 15-s segments (all ps < 0.001 with medium to large effect sizes). Task congruent clustering and switching were productive strategies (all ps < 0.001 with large effect sizes), and participants generated task discrepant clusters in both phonemic (p ¼ 0.004, d ¼ 0.69) and semantic tasks (p ¼ 0.66, d ¼ 0.18). The results substantiate the proposed method, providing evidence that these guidelines are a reliable starting point for VF task performance analyses in various clinical populations investigating VF task performance in depth.

Objective and Subjective Clustering Methods for Verb Fluency Responses From Individuals With Alzheimer's Dementia and Cognitively Healthy Older Adults

“…For example, Tröger et al (2019) reported a significant difference between groups on an animal fluency task where IwDs switched significantly less than MCI and CHOA groups (IwDs < MCI = CHOA), highlighting the different cognitive characteristics of CHOAs and IwDs. Switching is considered to be a more cognitively demanding skill than clustering, as it involves “higher cognitive functions, such as cognitive flexibility and strategic search processes” ( Lehtinen et al, 2021 , p. 3). Troyer et al (1998) reported that participants with frontal lobe lesions demonstrated less switching than healthy controls, indicating that executive functioning difficulties could be a factor in the decreased performance on verbal fluency tasks.…”

“…Both methods used a task congruent method to cluster responses. A task congruent method of clustering includes clustering either semantically related words for a category fluency task (i.e., verb fluency or animal fluency) or phoneme-relatedness criteria for letter fluency tasks ( Lehtinen et al, 2021 ). The objective clustering method utilized the Lancaster Norms database ( Lynott et al, 2020 ) to analyze clusters and switches.…”

“…Although task congruent clustering can provide insight into the categorization and organization during generative naming, it is possible that other clustering methods (i.e., task discrepant clusters) could be used as a strategy during analyses of verbal fluency responses. An example of a task-discrepant cluster for a category fluency task would be using a phonemic relatedness criterion for clustering methods (e.g., words that start with the same letter and then switching to another letter) or using a semantically relatedness criterion for a letter fluency task (e.g., words that belong to the same subcategory), which was reported as part of Faroqi-Shah and Milman (2017) 's criteria ( Lehtinen et al, 2021 ). By choosing to use a task-congruent method, the results of this study can be reported in the context of the clustering method used but cannot be generalized to all clustering methods as they were not analyzed.…”

Factor structure and clinical applicability of new semantic tasks in Alzheimer’s disease and aphasia

“…The number of correct items were counted. Intrusions, repetitions, proper names, paraphasias (the meaning of the word is unclear) and grammatical variations were not accepted (See Lehtinen et al, 2021).…”

Early recognition of neurocognitive disorders: Dementia screening in primary care and the detection of mild cognitive impairment via verbal fluency tests

“…PVF tests usually include 3 trials (with 3 different starting letters) (Lehtinen et al, 2021). The starting letters in PVF have a significant effect, as they determine the number and frequency of the eligible words (Strauss et al, 2006).…”