The Aphasia Communication Outcome Measure: Motivation, Development, Validity Evidence, and Interpretation of Change Scores.

The Aphasia Communication Outcome Measure (ACOM) is a patient-reported measure of communicative functioning developed for persons with stroke-induced aphasia. It was motivated by the desire to include the perspective of persons with aphasia in the measurement of treatment outcomes and to apply newly accessible psychometric tools to improve the quality and usefulness of available outcome measures for aphasia. The ACOM was developed within an item response theory framework, and the validity of the score estimates it provides is supported by evidence based on its content, internal structure, relationships with other variables, stability over time, and responsiveness to treatment. This article summarizes the background and motivation for the ACOM, the steps in its initial development, evidence supporting its validity as a measure of patient-reported communication functioning, and current recommendations for interpreting change scores.