Improved vocabulary production after naming therapy in aphasia: can gains in picture naming generalise to connected speech?
Background: Naming accuracy for nouns and verbs in aphasia can vary across different elicitation contexts, for example, simple picture naming, composite picture description, narratives, and conversation. For some people with aphasia, naming may be more accurate to simple pictures as opposed to naming in spontaneous, connected speech; for others, the opposite pattern may be evident. These differences have, in some instances, been related to word class (for example, noun or verb) as well as aphasia subtype. Given that the aim of picture-naming therapies is to improve word-finding in general, these differences in naming accuracy across contexts may have important implications for the potential functional benefits of picture-naming therapies. Aims: This study aimed to explore single-word therapy for both nouns and verbs, and to answer the following questions. (1) To what extent does an increase in naming accuracy after picture-naming therapy (for both nouns and verbs) predict accurate naming of the same items in less constrained spontaneous connected speech tasks such as composite picture description and retelling of a narrative? (2) Does the word class targeted in therapy (verb or noun) dictate whether there is ‘carry-over’ of the therapy item to connected speech tasks? (3) Does the speed at which the picture is named after therapy predict whether it will also be used appropriately in connected speech tasks? Methods & Procedures: Seven participants with aphasia of varying degrees of severity and subtype took part in ten therapy sessions over five weeks. A set of potentially useful items was collected from control participant accounts of the Cookie Theft Picture Description and the Cinderella Story from the Quantitative Production Analysis. Twenty-four of these words (twelve verbs and twelve nouns) were collated for each participant, on the basis that they had failed to name them in either simple picture naming or connected speech tasks (picture-supported narrative and unsupported retelling of a narrative). These were placed in a larger cohort of verb and noun sets for therapy. Post-therapy assessments examined naming accuracy and speed of target items in single-word picture-naming and naming accuracy in connected speech contexts. Outcomes & Results: There was a step-wise decrement in naming accuracy over the three naming contexts following targeted therapy. Simple pictures elicited the most correct names, followed by picture-supported narratives and lastly unsupported narratives. Picture-naming accuracy significantly predicted naming in the connected speech contexts for the group as a whole. The speed of picture naming after therapy did not predict the extent to which items were named in composite picture description and narrative tasks. Conclusions & Implications: The findings suggest that gains in naming accuracy obtained through picture-naming therapy may generalize to naming of the same items in more linguistically and cognitively demanding connected speech tasks. Demonstrating this generalization is methodologically challenging and the method utilized in this study may serve as one starting point for gathering a larger database in order to answer the question posed by this paper more robustly.