Verbal fluency in right brain damage: dissociations among production criteria and duration

This study aimed to verify dissociations in the performance of verbal fluency tasks with different production criteria and duration following vascular right-hemisphere damage. We tested the hypothesis that longer fluency tasks would be more sensitive in identifying deficits in the sample. The relationship between verbal fluency performance and sustained attention was also investigated. Forty adults with vascular right-hemisphere damage were assessed using verbal fluency tasks with three different production criteria (unconstrained, phonemic, and semantic fluencies from the Montreal Communication Evaluation Battery). Performance deficits in 1-min and 2-min fluency tasks were calculated (Z score) and compared (chi-square). Results did not suggest a difference in sensitivity between the task lengths in detecting cognitive impairment. However, double dissociations were found, highlighting the contribution of extended verbal fluency tasks to neuropsychological assessment. Analyses also showed that participants exhibited greater levels of impairment in the semantic fluency task. No relationship was identified between performance in sustained attention tasks and verbal fluency tasks, regardless of the latter's duration. The combined use of longer and shorter fluency tasks in the assessment of patients with right brain damage may contribute to the identification of different executive function impairments in this sample.