Narrative Discourse Predictors of Response to Naming Intervention in Aphasia

While aphasia treatment studies commonly use picture-naming performance as an outcome measure, narrative discourse better reflects functional language use. Discourse variables may also hold prognostic value for naming treatment response, but their predictive role remains underexplored.

We analyzed baseline and posttreatment narrative discourse samples from 95 chronic stroke survivors with aphasia enrolled in a lexical retrieval intervention study. Participants received 3 weeks each of phonological and semantic naming therapy in a crossover design. The Cinderella story retells were analyzed for a range of discourse features: mean length of utterance, words per minute, verbs per utterance, propositional density, type-token ratio, core lexicon, main concepts analysis, and error ratios. We used univariate (generalized) binomial and linear mixed-effects modeling with multiple predictors to assess whether baseline discourse variables predicted naming gains on the Philadelphia Naming Test and whether discourse variables themselves changed following treatment.

Higher aphasia severity and lower baseline propositional density predicted greater naming gains across time points and treatment types. Gains after phonological therapy were also predicted by higher baseline core lexicon production. Posttreatment discourse showed gains in mean length of utterance, words per minute, and core lexicon, which were maintained at 6 months, while phonological errors declined only at follow-up. Phonological treatment led to increases in words per minute.

Discourse variables reflecting propositional efficiency and lexical appropriateness uniquely predict treatment response beyond general aphasia severity. Lexical retrieval therapy generalizes to improvements in narrative discourse, underscoring the clinical value of incorporating discourse-level measures in aphasia assessment and treatment outcome evaluation.

https://doi.org/10.23641/asha.32568822.