Background: The aphasiological literature has provided an extensive body of research on verb impairments but many fewer verb therapy studies. Verbs display particular complexity at various levels of linguistic analysis: phonological, morphological, semantic, and syntactic. Verb impairments can arise at any of these processing levels as well as from cognitive sources. Verb-naming therapies may therefore be relatively more vulnerable to errors, which could reduce their effectiveness. Errorless learning has been used with positive results for noun therapies.

Aims: Given the high linguistic and cognitive demands of verb processing, this study investigated whether errorless therapy would be more effective for verb naming than more traditional hierarchical cueing (relatively errorful) therapy.

Methods & Procedures: Nine participants with word-finding difficulties as a part of their chronic aphasia took part in the study.

Outcomes & Results: For the dependent variable of naming accuracy, as in previous studies, we found that errorless therapy was as effective as errorful therapy for both verb and noun naming. Three participants with most severe aphasia showed significantly greater gains in noun as opposed to verb naming. The remaining participants exhibited comparable gains in both nouns and verb naming. There was no lasting generalisation from treated to untreated therapy items. The prediction that errorless therapy would be more effective for verb naming was not upheld; errorless and errorful approaches were as effective as one another.

Conclusions: An errorless-learning approach to verb and noun naming was a time-efficient therapy, and one that was as effective as an errorful/hierarchical cueing method in improving naming accuracy, for a range of participants with varying naming skills and types of aphasia.