Abstract
Phonemic and semantic verbal fluency performance was investigated in a group of young adult participants with and without traumatic brain injury (TBI). Twenty-five participants with moderate to severe TBI and 25 participants with no brain damage (NBD) were given phonemic and semantic verbal fluency tasks. Responses were analyzed quantitatively.
Results indicate that young participants with moderate to severe TBI generated significantly fewer total correct words for both fluency conditions when compared to controls. An analysis of errors suggested that the TBI group produced a significantly greater number of set-loss and repetition errors, when compared to the NBD group, on the phonemic verbal fluency task only. No significant differences were observed between the groups on the total number of set-loss errors and repetitions on the semantic verbal fluency task only.
While young participants with moderate to severe TBI produced fewer total correct words on both verbal fluency conditions in comparison to controls, these differences were greater on the phonemic condition. These results are in contrast with previous investigations that have observed greater age-related declines on semantic tasks when compared to phonemic tasks.
Introduction
Verbal fluency is a cognitive-linguistic function that appears to be particularly vulnerable to the effects of traumatic brain injury (TBI) (Capitani, Rosci, Saetti, & Laiacona, 2009; Levin, Benton, & Grossman, 1982; Raskin & Rearick, 1996; Ruff, Evans, & Marshall, 1986.) Two common types of verbal fluency tasks are phonemic fluency and semantic fluency. Phonemic verbal fluency is defined as the generation of words that begin with a specific letter of the alphabet, such as F, A, or S (Benton, 1968; Borkowski, Benton, & Spreen, 1967). Semantic verbal fluency demands the generation of words that belong to a common semantic category, such as animals (Newcombe, 1969). Typically, for each condition, individuals are given 60 seconds to generate as many words as possible (Marshall, 1986; Spreen & Strauss, 1991). The most common means by which verbal fluency performance is evaluated is through a quantitative analysis, defined simply as the total number of correct words generated on each type of fluency task (Benton, 1968; Borkowski et al., 1968).