Effects of semantic weight on verb retrieval in individuals with aphasia: A different perspective.

The majority of people with aphasia have word retrieval difficulty and effective treatment remains elusive. There have been a few studies that have explored the effects of semantic complexity on verb retrieval in individuals with aphasia; each used a variation of Breedin et al.'s (1998) delayed repetition/story completion task. Although each subsequent investigator worked to address potential confounds in order to achieve more valid results that would give rise to a clearer understanding of these deficits, findings and their interpretations have varied. In our replication, groups of individuals with aphasia (9 agrammatic and 9 anomic) plus 12 age-matched controls participated in a story completion task that included novel distracter stories to prevent rehearsal. Additionally, stimuli were developed in strict adherence to novel semantic and syntactic templates to control for relevant factors, and stimuli were prerecorded to ensure uniform delivery. We calculated the number of target verbs produced and overall production of light and heavy verbs, and error analysis was performed with special attention to semantically appropriate substitutions. In contrast to previous studies, we found no significant performance differences on these measures within or between groups. Exploratory analyses were performed. Results are discussed in terms of relevant factors of verb retrieval and implications for future experimental design. Application to much-needed verb retrieval treatment is also considered.