Discourse measurement in aphasia research: have we reached the tipping point?

ABSTRACT Background: Over the past few decades, clinical aphasiologists have increasingly included various measures of discourse, across a variety of genres, to assess treatment effects and to understand spoken language in people with aphasia. The paradigm shift from assessing language at the word and sentence level to assessing at the discourse level shows an increased awareness of capturing meaningful outcomes; however, this has led to a proliferation of new discourse metrics. These new metrics often lack reliability, validity, and stability data to support their use. In fact, we propose that a tipping point has been reached. Aims: To review the recent move toward establishing a basic core outcome set (COS) for aphasia. In support of this effort, we make a strong argument for the need to dovetail these efforts with the development of a core outcome set for discourse (D-COS). Main contribution: We make a case that the current state of the art in aphasia-related discourse research leaves researchers unsure of the most representative outcomes to include in future investigations and clinicians with little guidance on best practice. We applaud and support the recent efforts toward the development of a general COS for aphasia; however, we propose that the need for a D-COS is urgent because the increasing numbers of discourse measures make it difficult to replicate and compare outcomes across studies. Moreover, these issues likely interfere with adaptation of the use of discourse measurement in clinical practice. Conclusions: Many health-related fields have adopted a COS to guide their research and ensure that the field’s data can be compiled, compared, and contrasted for a better overall understanding of how treatments address targeted illnesses. We argue that, in addition to the recent progress toward a COS for aphasia, a D-COS is also required to improve our understanding of how our treatments improve the discourse of people with aphasia, which in turn will aid in evoking a paradigm shift in clinical practice. To be successful, it is essential that the development of a D-COS includes a process by which all stakeholders are included: people with aphasia, caregivers, clinicians, and clinical researchers.