Analyzing Language in the Picnic Scene Picture and in Conversation: The Type of Discourse Sample We Choose Influences Findings in People With Aphasia

People with aphasia express that improved conversational discourse is a primary rehabilitation goal. Discourse is usually assessed using monologue, such as a picture description task, but research shows that language in monologue varies from language in everyday conversation. Consequently, we investigated the relationship of language in unstructured conversation and in the picnic scene picture because it is a part of the most often used aphasia battery (Western Aphasia Battery-Revised) and thus is frequently used to inform therapy. Second, because previous research suggests people with severe aphasia may not demonstrate language production variability between types of monologue-level discourse, we evaluated the relationship of severity and the difference in scores between conversation and the picnic scene task. Thirty-four people with mild-to-severe aphasia described the picnic scene and provided a conversation sample. We measured language production and communicative success using seven measures with established psychometrics in conversation/monologue. We conducted correlations to answer the research questions. Correlations were moderate and weaker for the measures in the two conditions. A strong negative relationship was demonstrated between aphasia severity and global coherence. All other relationships were moderate and weaker for the remaining measures when correlated with aphasia severity (also negative). Results are consistent with other studies indicating that language varies in different types of discourse. We conclude that for accurate, meaningful assessment, discourse sampling needs to include the specific type of discourse the individual wishes to address in therapy, because discourse samples and their findings are not interchangeable.