Measuring Change at the Discourse-Level Following Conversation Treatment: Examples From Mild and Severe Aphasia.

Purpose: This article reviews four discourse measures and examines whether they are sensitive to impairments in people with both mild and severe aphasia. We also ask whether these measures were sensitive to effects of conversation treatment in two case examples. Method: Two people with aphasia, one mild and fluent and the other severe and nonfluent, served as case studies. Both case studies had participated in conversation treatment, in which individualized goals were targeted in the context of naturalistic conversation-based interactions. Picture descriptions were analyzed using three discourse measures: core lexicon, words per minute, and correct information units. In addition, words per minute and conversation turns were examined in personal narratives produced by the individual with severe nonfluent aphasia in a conversational context. Results: For the individual with mild aphasia, both words per minute and core lexicon were sensitive to the presence of aphasia and treatment changes. For the individual with severe aphasia, all measures were sensitive to the presence of aphasia, but only words per minute and number/type of conversation turns were sensitive to effects of treatment. Discussion/Conclusions: Discourse measures capture relevant aspects of communication that may not be seen on standardized measures of discrete language skills. Given different aphasia profiles and individual communication goals, clinicians need to choose the most relevant, reliable, and informative measures.